Novel polymethine dyes and UV absorbers and imaging materials for their use
FIELD OF THE INVENTION 
     This invention relates to polymethine dyes and ultraviolet absorbers and to imaging compositions and photographic elements containing these dyes and ultraviolet absorbers. 
     BACKGROUND OF THE INVENTION 
     Polymethine dyes and ultraviolet (UV) absorbers containing a chromophore formed by an acidic electron accepting terminal nucleus and a basic electron donating terminal nucleus joined through a methine chain are well known. Such polymethines are commonly further categorized as merocyanines, hemioxonols, or merostyryls. 
     In merocyanines the basic terminal nucleus is a heterocyclic nucleus comprised of a five or six membered heterocyclic ring containing at least one nitrogen heteroatom. To achieve significant light absorption in the visible spectrum, thereby qualifying as a dye, the heterocyclic nucleus must exhibit aromaticity. In so-called zero methine merocyanines there are two methine groups linking the nuclei, but one linking methine group lies in the basic nucleus while the second linking methine group lies in the acidic nucleus. Thus, there are no methine groups separating the nuclei. Homologues of the zero methine merocyanines are those which contain two, four, or a higher even number of methine groups joining the terminal acidic and basic nuclei. 
     Hemioxonols can be viewed as differing from merocyanines in that their basic terminal nuclei take the form of aminomethine nuclei. 
     The acidic electron accepting terminal nucleus of each of these polymethines can be either heterocyclic or acyclic. When the acidic terminal nucleus is acyclic, it takes the form of a methylene group which is disubstituted with two strong electron withdrawing groups. The most commonly employed strong electron withdrawing groups are cyano, sulfo, and carbonyl groups, where the latter includes carboxylic acid and ester as well as acyl groups. Acylic acidic electron accepting terminal nuclei of polymethines are illustrated by 
     (R-1) Collins et al U.S. Pat. No. 2,411,507, 
     (R-2) Kendall et al U.S. Pat. No. 2,511,210, 
     (R-3) Kendall et al U.S. Pat. No. 2,693,472, 
     (R-4) Edwards et al U.S. Pat. No. 2,721,799, 
     (R-5) Kofron et al U.S. Pat. No. 4,439,520, and 
     (R-6) Gunther et al U.S. Pat. No. 4,576,905. 
     Polymethines with a basic electron donating terminal nucleus and an acidic terminal nucleus are known to serve a variety of uses. Such polymethines are known to be useful both as UV absorbers and dyes. These dyes and UV absorbers have been incorporated into photographic elements to serve a variety of purposes. In one application of particular interest these polymethines are incorporated in ultraviolet responsive imaging systems. Since ultraviolet light is both more energetic and capable of absorption with simpler molecular resonance structures than visible light, it is not surprising that there are a variety of known imaging materials which respond to ultraviolet, but not visible light. The sensitivity of these imaging systems can be extended to longer wavelength UV radiation and into the visible portion of the spectrum by incorporating a photosensitizer. Merocyanines have been extensively employed as photosensitizers and to a lesser extent (largely due to shorter wavelength absorption peaks) hemioxonols have been similarly employed. 
     Photographic silver halide emulsions are illustrative of imaging systems known to employ dyes from these polymethine classes as photosensitizers. The radiation sensitive silver halide grains present in photographic emulsions exhibit very limited absorption of radiation of wavelengths extending into the visible spectrum. However, with a dye adsorbed to the grain surfaces, the emulsions are highly responsive to visible light. The dye absorbs exposing photons and transfers either energy or an electron to the grain. The patents cited above disclose this photographic utility for merocyanine and hemioxonol dyes. 
     A variety of photographic imaging systems are known wherein a hardenable organic component containing ethylenic unsaturation sites is relied upon for image formation. The organic component undergoes photoinduced addition reactions, typically either polymerization or crosslinking, at the ethylenic unsaturation sites which produce hardening and allow image discrimination to be achieved. 
     It is common practice in preparing these compositions to employ coinitiators. One of the coinitiators is a photosensitizer. Photosensitizers are relied upon to capture photons of exposing radiation. The remaining coinitiator is referred to as an activator. The activator is not relied upon to respond directly to exposing radiation, but rather adjacent activator and photosensitizer molecules react, following excitation of the latter by photon capture, causing release by the activator of a free radical which in turn induces immobilizing addition reactions at sites of ethylenic unsaturation. The use of merocyanine dyes and UV absorbers as photosensitizers in such imaging systems is illustrated by 
     (R-7) Specht et al U.K. Pat. No. 3,083,832A, 
     (R-8) Research Disclosure, Vol. 200, Dec. 1980, Item 20036, 
     while the use of a variety of polymethine dyes as photosensitizers in such imaging systems are disclosed by the following four commonly assigned copending patent applications: 
     (A) Farid et al U.S. Ser. No. 933,712, filed Nov. 21, 1986, titled DYE SENSITIZED PHOTOGRAPHIC IMAGING SYSTEM, now U.S. Pat. No. 4,743,531; 
     (B) Farid et al U.S. Ser. No. 933,658, filed Nov. 21, 1986, titled NEGATIVE WORKING PHOTORESISTS RESPONSIVE TO SHORTER VISIBLE WAVELENGTHS AND NOVEL COATED ARTICLES, now U.S. Pat. No. 4,743,529; 
     (C) Farid et al U.S. Ser. No. 933,660, filed Nov. 21, 1986, titled NEGATIVE WORKING PHOTORESISTS RESPONSIVE TO LONGER VISIBLE WAVELENGTHS AND NOVEL COATED ARTICLES, now U.S. Pat. No. 4,743,530; 
     (D) Farid et al U.S. Ser. No. 933,657, filed Nov. 21, 1986, titled ENHANCED IMAGING COMPOSITION CONTAINING AN AZINIUM ACTIVATOR, now U.S. Pat. No. 4,743,528. 
     The polymethines of this invention are produced by first synthesizing corresponding polymethines containing an isocyano group as a part of the acidic terminal nucleus. The synthesis of dyes containing such an isocyano group is the subject of commonly assigned, concurrently filed patent application Ser. No. 067,843, titled NOVEL MEROCYANINE DYES AND IMAGING COMPOSITIONS, now abandoned in favor of continuation-in-part U.S. Ser. No. 183,876, filed Apr. 20, 1988. 
     The following illustrate known compounds containing isocyano groups: 
     (R-9) U. Schollkopf, &#34;Recent Applications of α-Metalated Isocyanides in Organic Synthesis&#34;, Angew. Chemie, Int. Ed., 1977, 16, 339-422. Note particularly compounds 9, 16, 17a, 17b, 18, 19, 32, and 34. 
     (R-10) R. H. Hall et al, &#34;Synthesis of C-Glycosyl Compounds. Part 1. Reaction of Ethylisocyanoacetate with 2,3,5,6-Di-O-isopropylidene-D-mannono-1,4-lactone&#34;, J. Chem. Soc., Perkin Trans. 1, 1977, 743-753. Note particularly compounds 6, 7, 11, and 12. 
     (R-11) C. Herdeis et al, &#34;Heterocyclic Substituted Amino Acids via α,β-Dehydroamino Acid Derivatives. Studies on Amino Acids&#34;, Heterocycles, 1983, 20, 2163-2167. Note particularly compounds 3a and 3b. 
     (R-12) Schollkopf et al, &#34;Syntheses with α-Metalated Isocyanides, XLIV. Note on β-Dimethylamino-αisocyanoacrylates and Their Use in Heterocyclic Chemistry&#34;, Justus Liebigs Ann. Chem., 1979, 1444-6. Note particularly compound 3. 
     A second step in preparing polymethines according to the present invention is to convert the acidic nucleus isocyano group of the corresponding polymethine to a triarylborylisocyano group. Polymethines containing a triarylborylisocyano group in the acidic terminal nucleus are the subject of commonly assigned, concurrently filed patent application Ser. No. 067,841, titled NOVEL POLYMETHINE DYES AND UV ABSORBERS AND IMAGING MATERIALS FOR THEIR USE. 
     the following illustrated known compounds containing boron atoms, particularly those containing boron atoms along with oxygen and/or nitrogen atoms in a ring structure: 
     (R-13) Ugi Isonitrile Chemistry, Chapter 6, &#34;The Reaction of Isonitriles with Boranes&#34;, Academic Press, 1971, New York and London. 
     (R-14) Daniel et al U.S. Pat. No. 3,745,160, which discloses polymethine dyes containing 1,3,2-dioxaborinium, 1,3,2,-oxazoborinium, or 1,3,2-diazaborinium salt moieties. 
     (R-15) Halm U.S. Pat. No. 4,123,268, which discloses 1,3,2-dioxaborinium salts as sensitizers in electrophotography. 
     (R-16) Van Allen et al U.S. Pat. No. 4,394,428, which discloses polymethine dyes having a nucleus selected from the group consisting of 1,3,2-dioxaborin, 1,3,2-oxazoborin, and 1,3,2-diazoborin rings. 
     SUMMARY OF THE INVENTION 
     In one aspect this invention is directed to a polymethine dye or ultraviolet absorber containing a basic electron donating terminal nucleus joined through a methine linkage to an acidic electron accepting terminal nucleus satisfying the formula: ##STR2## where 
     Ar is independently in each occurrence an aromatic group and 
     D is an oxy or amino group. 
     In another aspect this invention is directed to an imaging composition comprised of an imaging material and the above identified polymethine dye or ultraviolet absorber. 
     In still another aspect this invention is directed to a photographic element comprised of a support and, coated on the support, one or more layers including at least one radiation sensitive imaging layer, at least one of the layers being conprised of the above identified polymethine dye or ultraviolet absorber. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention is directed to and employs polymethine dyes and ultraviolet (UV) absorbers differing from conventional polymethines containing a basic electron donating terminal nucleus joined through a methine linkage to an acidic electron accepting terminal nucleus satisfying the formula: ##STR3## where 
     Ar is independently in each occurence an aromatic group and 
     D is an oxy or amino group. 
     Since the acidic nuclei of polymethines are usually depicted by formula and discussed in terms of the resonance from in which electron displacement to the acidic terminal nucleus has not occurred (the first of the two formulae above), this established practice is followed in the subsequent discussion. Therefore, the acidic terminal nucleus can be named as a 6-oxy or amino-2,2,3-triaryl-1,4,2-oxazoborin-5-ylidene and it is expected that this is the name which will be adopted once these ring structures become known in the art. In view of the novelty of the ring structure and the availability of more familiar alternative nomenclature, specific compounds of the invention are named below as α substituted amide and carboxylic acid derivatives. The prefix (O-B) designates the presence of the bond between the oxygen of the carbonyl group and the boron atom. the legitimacy of both approaches to naming is supported by IUPAC Nomenclature of Organic Chemistry, Sections A,B,C,D,E,F and H, 1979 Ed., Pergamon Press, New York, Section D-7.74, p. 456. 
     When D is an oxy group it can take the form of --OR group, where R can take the form of hydrogen, a salt forming cation (e.g., ammonium or alkali metal), or any convenient aliphatic or aromatic group. For example, R can be chosen from among alkyl, cycloalkyl, alkenyl, alkynyl, aryl, alkaryl, and aralkyl hydrocarbons. These hydrocarbon groups can be further substituted, if desired. Typical substituents of the hydrocarbon include oxy groups (e.g., alkoxy or aryloxy), thio groups (e.g., alkylthio or arylthio), sulfonyl groups (e.g., alkysulfonyl or arylsulfonyl), sulfo or sulfato (including a counterion, such as hydrogen or an alkali metal ion), amine, amino, amide, amido, carbamoyl, thioamido, thiocarbamoyl, ureido, thioureido, carbonyl (e.g., carboxyl, acyl, or carboxylic ester), and halogen. The alkyl moieties can be varied widely in the number of carbon atoms contained. Alkyl, alkenyl, and alkynyl moieties of from 1 to 15 carbon atoms are specifically contemplated, with 1 to 10 carbon atoms being preferred, and 1 to 6 carbon atoms being generally optimum for use in polar solvents or hydrophilic media. Alkyl moieties of from 1 to 6 carbon atoms, hereinafter referred to as lower alkyl moieties, are most commonly employed. The aryl moieties are commonly limited to from 6 to 10 ring carbon atoms to minimize molecular bulk. Phenyl and naphthyl area the most commonly employed aryl moieties; however, there is no reason in principle that other aromatic fused ring systems cannot be employed. 
     when D is an amino group it can take the form of a secondary amino group and can satisfy the formula: ##STR4## where 
     G and G 1  can independently take any of the forms of R described above or can together complete a ring system derived from a cyclic secondary amine, such as pyrrolidine, 3- pyrroline, piperidine, piperazine (e.g., 4-methylpiperazine and 4-phenylpiperazine), morpholine, 1,2,3,4-tetrahydroquinoline, decahydroquinoline, 3-azabicyclo[3,2,2]nonane, indoline, azetidine, and hexahydroazepine. 
     The aromatic groups Ar can independently take the form of any convenient aromatic ring structure. The aromatic ring structure is preferably an aromatic group containing from 6 to 10 carbon atoms. Specifically preferred are carbocyclic aromatic ring structures containing from 6 to 10 carbon atoms--e.g, phenyl, α-naphthyl, or β-naphthyl. Other carbocyclic aromatic ring structures are contemplated, such as anthracyl, phenathracyl, and analogues having even larger numbers of fused rings, but such structures are generally less preferred, since they increase molecular bulk without correspondingly increasing radiation absorption. It is also possible to form the aromatic group from any one of a variety of aromatic heterocyclic ring structures, including those containing fused benzo ring structures. Useful heterocyclic aromatic ring structures include all those more specifically described below in connection with the basic terminal nuclei of the polymethines. Whether carbocyclic or heterocyclic the aromatic ring structures can be substituted, if desired, with any of a variety of groups. For example, aromatic ring substituents can readily take any of the various substituents of aryl groups described above in connection with R. However, it should be borne in mind that the synthetic route for preparing the compounds of the invention described below call for all of the three Ar groups to be one stage of preparation appended to the boron atom. In order to append three separate aromatic substituents from a single boron atom steric compatibility must be considered in selecting substituents of the aryl groups. When the aryl groups are phenyl, α-naphthyl, or β-naphthyl groups, no more than four ortho position substituents are permissible during this stage of synthesis, and these should be limited in molecular bulk-e.g. alkyl of from 1 to 3 carbon atoms or less bulky substituents. When the aryl groups are α-naphthyl and larger ring structures, substituents ortho to the ring bonding position should be avoided during this stage of synthesis. Once the 1,4,2-oxazoborinylidene ring has been formed with the accompanying shift of one aryl group to the 3 position ring carbon atom, the range of substituents is again broadened. For example, bulkier substituents can replace those originally present or further substitution of the aryl groups can be undertaken. 
     In addition to the acidic electron accepting terminal nucleus the polymethines additionally include a basic electron donating terminal nucleus linked to the acidic nucleus through a carbon to carbon double bond or intervening methine groups. The basic terminal nucleus and, when present, the methine groups linking the basic and acidic terminal nuclei can take any convenient form found in conventional polymethine dyes and UV absorbers. 
     In one preferred form the basic nucleus takes the form a heterocyclic nucleus comprised of a five or six membered heterocyclic ring containing at least one heteroatom chosen from the class consisting of nitrogen and chalcogen (i.e. oxygen, sulfur selenium, or tellurium). When the basic nucleus contains a nitrogen atom the polymethine is a merocyanine. In another preferred form the basic nucleus is an aminomethine group, and the resulting polymethine is a hemioxonol. 
     Thus, the preferred polymethine dyes and UV absorbers according to the present invention comprise those satisfying the fomulae: ##STR5## where 
     Ar is independently in each occurrence an aromatic nucleus containing from 6 10 ring carbon atoms; 
     D is an axy or amino group; 
     E is chosen from the class consisting of 
     (i) a heterocyclic nucleus comprised of a five or six membered heterocyclic ring containing at least one heteroatom chosen from the class consisting of nitrogen and chalcogen and 
     (ii) an aminomethine group; 
     L 1  and L 2  are methine groups; and 
     n is the integer 0, 1, or 2. 
     In one preferred form the heterocyclic nucleus E completes an azolinylidene or azinylidene ring. In the neutral and charged resonance forms of the merocyanine dye the basic nucleus containing the azolinylidene or azinylidene ring can be represented by the formulae: ##STR6## wherein 
     p is the integer 0 or 1; 
     L 3  and L 4  independently represent methine groups; 
     R 1  is a quaternizing substituent; and 
     Q represents the atoms completing a basic azolinylidene or azinylidene nucleus. 
     In specifically preferred forms Q is chosen to complete an azolinylidene or azinylidene nucleus chosen from the group consisting of 2-piperidylidene, 2-pyrrolidinylidene, 2-or 4pyridylidene, imidazopyridylidene, 2- or 4-quinolinylidene, 1-or 3-isoquinolinylidene, benzoquinolinylidene, thiazoloquinolylidene, imidazoquinolinylidene, 3H-indolylidene, 1H or 3H-benzindolylidene, oxazolinylidene, oxazolidinylidene, benzoxazolinylidene, napthoxazolinylidene, oxadiazolinylidene, thiazolidinylidene, phenanthrothiazolinylidene, acenaphthothiazolinylidene, thiazolinylidene, benzothiazolinylidene, naphthothiazolinylidene, tetrahydrobenzothiazolinylidene, dihydronapthothiazolinylidene, thiadioxazolinylidene, selenazolidinylidene, selenazolinylidene, benzoselenazolinylidene, naphthoselenazolinylidene, selenadiazolinylidene, benzotellurazolinylidene, naphthotelluroazolinylidene, pyrazolylidene, imidazolinylidene, imidazolidinylidene, benzimidazolinylidene, naphthimdazolinylidene, diazolinylidene, tetrazolinylidene, and imidazoquinoxalinylidene nuclei. 
     The quaternizing substituent (R 1 ) is an optionally substituted hydrocarbon substituent, such as an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, aralkyl, or alkaryl group. The number of carbon atoms in the hydrocarbon moieties as well as the various optional subtituents can be chosen similarly as described above in connection with R. 
     In addition to azolinylidene and azinylidene nuclei, heterocyclic aromatic basic electron donating terminal nuclei satisfying the requirements of E in formulae III can be chosen from a variety of nuclei known to form dyes which contain only chalcogen heteroatoms. Such nuclei include pyranylidene, benzopyranylidene, dibenzopyranylidene, thiapyranylidene, benzothiapyranylidene, naphthothiapyranlidene, selenapyranylidene, tellurapyranylidene, benzotellurapyranylidene, naphthotellurapyranylidene, dithiolylidnen (a.k.a. disulfolylidene), benzodithiolylidene, and naphthodithiolyidene nuclei. These nuclei are similar to the azolinylidene and azinylidene nuclei described above in that they resonate between a form in which a ring heteroatom is charged or uncharged, except that in these rings, no nitrogen atom being present, it is a chalcogen atom which assumes a positive charge. In the resonance form in which the chalcogen atom is charged each pyranylidene nucleus is usually named as the corresponding pyrylium nucleus. Dyes containing exemplary useful pyranylidene (i.e., pyrylium) nuclei containing an oxygen, sulfur, selenium, or tellurium atom are disclosed in Detty el al U.S. Pat. Nos. 4,365,017 and 4,584,258. 
     When the polymethines of the invention are hemioxonols, E takes the form an aminomethine nucleus, which can be represented by the following formulae: ##STR7## where 
     L 5  is a methine group and 
     G 2  and G 3  can independently take any of the forms of G and G 1  described above. 
     The methine groups in formulae III, IV, and v--i.e., L 1 , L 2 , L 3 , L 4 , and L 5  can be independently in each occurrence unsubstituted methine groups (i.e., --CH═ groups) or substituted methine groups represented by the formula --C(R 2 )═, where R 2  can represent any convenient monovalent substituent. Alkyl substituents of from 1 to 4 carbon atoms (e.g., methyl or ethyl) and phenyl substituents (e.g., phenyl, tolyl, or xylyl) are most commonly encountered and are preferred. It is common to incorporate a substituted methine in the methine linkage joining the terminal neclei to promote dye aggregation. In a variant form R 2  in two different methine groups can together take the form of an alkylene group of from 1 to 6 carbon atoms. Such alkylene groups are referred to as bridging groups and are commonly employed to rigidize the dye molecule. 
     In one specifically contemplated form the methine groups, particularly L 5 , can take the form ##STR8## where R 2  can take the form of the secondary amino group shown in formula (II) above. 
     When E takes the form of an aminomethine nucleus as represented by formula IV and L 5  takes the form --C(R 2 )═, where R 2  is a secondary amino group, a preferred polymethine results satisfying the following formula: ##STR9## where 
     G 2  G 3  independently or together can take any of the various forms of G and G 1 , G 4  and G 5  independently or together can taken any of the various forms of G and G 1 , or G 2  and G 4  can together complete a 5 or 6 membered ring (e.g., an alkylene group providing 2 or 3 ring carbon atoms joining the amino nitrogen atoms) and 
     Ar, D, L 1 , L 2 , and n can take any of the forms identified above. 
     Procedures for synthesizing representative polymethines according to the invention are included in the examples below. From these examples the synthesis of variant forms of the polymethines will be readily apparent. 
     Specific polymethines according to the invention are listed in Table I. 
     
                       TABLE I                                                     
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D-1     (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(3-ethyl-2-benzothiazolinlli-                        
        dene)-2-butenoate                                                 
D-2     (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(3-ethyl-2-                        
        benzothiazolinylidene)-2-butenoate                                
D-3     (O--B)-{[(Diphenylboryl)phenylmethylene]-                         
        amino}-4-(3-ethyl-2-benzothiazolinylidene)-                       
        N,N--tetramethylene-2-butenamide                                  
D-4     (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(3-ethyl-2-benzothiazolinyli-                        
        dene)acetate                                                      
D-5     (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(3-ethyl-2-                        
        benzothiazolinylidene)acetate                                     
D-6     (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(3-ethyl-2-benzothiazolinyli-                        
        dene)-2,4-hexadienoate                                            
D-7     (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(3-ethyl-2-                        
        benzothiazolinylidene)-2,4-hexadienoate                           
D-8     (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(3-ethyl-2-benzoxazolinyli-                          
        dene)-2-butenoate                                                 
D-9     (O--B)-Ethyl 2-{[di-( -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(3-ethyl-2-                        
        benzoxazolinylidene)-2-butenoate                                  
D-10    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(3-ethyl-2-benzoxazolinyli-                          
        dene)-2,4-hexadienoate                                            
D-11    (O--B)-Ethyl 2-{[(di- -p-fluorophenyl)- -p-                       
        fluorophenylmethylene]amino}-4-(3-ethyl-2-                        
        benzoxazolinylidene)-2,4-hexadienoate                             
D-12    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(3-ethyl-2-selenazolinylidine)-2-                    
        butenoate                                                         
D-13    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(3-ethyl-2-                        
        benzoselenazolinylidene)-2-butenoate                              
D-14    (O--B)-Methyl 2-{[(diphenylboryl)phenylmethyl-                    
        ene]amino}-2-(3-ethyl-2-benzotellurazolinyli-                     
        dene)acetate                                                      
D-15    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(1-ethyl-2-quinolinylidene)-2-                       
        butenoate                                                         
D-16    (O--B)-Ethyl 2{[(di- -p-fluorophenylboryl)- -p-                   
        fluorophenylmethylene]amino}-4-(3-ethyl-2-                        
        quinolinylidene)-2-butenoate                                      
D-17    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(1,3-diethyl-5,6-diphenyl-2-                         
        imidazquinoxalinylidene)-2-butenoate                              
D-18    (O--B)-Ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-                    
        dithiol-2-ylidene)-2-{[diphenylboryl)phenyl-                      
        methylene]amino}acetate                                           
D-19    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        flourophenylmethylene]amino}-2-(4,5-dihydro-                      
        naphtho[1,2-d]-1,3-dithiol-2-ylidene)acetate                      
D-20    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene[amino}-4-(4,6-diphenyl-2-pyranylidene)-                       
        2-butenoate                                                       
D-21    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(4,6-diphenyl-                     
        2-pyranylidene)-2-butenoate                                       
D-22    (O--B)-Ethyl 2-}[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(4,6-di-t-butyl-                   
        2-selenapyranylidene)-2-butenoate                                 
D-23    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-2-(4,6-diphenyl-2-tellurapyranyli-                     
        dene)acetate                                                      
D-24    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(4-phenyl-2-                       
        benzothiapyranylidene)-2-butenoate                                
D-25    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino}-4-(2,6-diphenyl-4-pyranylidene)-2-                     
        butenoate                                                         
D-26    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(2,6-diphenyl-                     
        4-pyranylidene-2-butenoate                                        
D-27    (O--B)-Ethyl 2-{[(diphenylboryl)phenylmethyl-                     
        ene]amino} -4-(1-ethyl-4-quinolinylidene)-2-                      
        butenoate                                                         
D-28    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-4-(1-ethyl-4-                        
        quinolinylidene)-2-butenoate                                      
D-29    (O--B)-Ethyl 3-dimethylamino-2-{[(diphenyl-                       
        boryl)phenylmethylene]amino}-2-propenoate                         
D-30    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-3-dimethylamino-                     
        2-propenoate                                                      
D-31    (O--B)-Ethyl 3,3-bis(dimethylamino)-2-{[(di-                      
        phenylboryl)phenylmethylene]amino}-2-propenoate                   
D-32    (O--B)-Ethyl 3,3-bis(dimethylamino)-2-{[(di- -p-                  
        fluorophenyl)- -p-fluorophenylmethylene]amino}-2-                 
        propenoate                                                        
D-33    (O--B)-Ethyl 5-dimethylamino-2-{[(diphenyl-                       
        boryl)phenylmethylene]amino}-2,4-pentadienoate                    
D-34    (O--B)-Ethyl 2-(1,3-dimethyl-2-imidazolidinyli-                   
        dene)-2-{[(diphenylboryl)phenylmethylene[-                        
        amino}acetate                                                     
D-35    (O--B)-Ethyl 2-{[(di- -p-fluorophenylboryl)- -p-                  
        fluorophenylmethylene]amino}-2-(1,3-dimethyl-                     
        2-imidazolidinylidene)acetate                                     
D-36    (O--B)-2-{[(Diphenylboryl)phenylmethylene]-                       
        amino}-3-pyrrolidino-N,N--tetramethylene-2-                       
        propenamide                                                       
D-37    (O--B)-2-{[(Di- -p-fluorophenylboryl)- -p-fluoro-                 
        phenylmethylene]amino}-3-pyrrolidino-N,N--                        
        tetramethylene-2-propenamide                                      
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     The polymethine dyes and UV absorbers of this invention can serve any of the known uses for corresponding conventional polymethine dyes and UV absorbers. Polymethine dyes have found extensive use in photography. The polymethines of this invention are specifically contemplated to be used as photosensitizers in photographic imaging systems. 
     In one specific form a photographic imaging system according to the present invention containing a polymethine satisfying formulae III above can take the form of a silver halide photographic element. In its most widely employed form silver halide photography employs for imaging radiation sensitive silver halide grains. The grains are suspended in a dispersing medium, typically including a hydrophilic colloid, such as gelatin, so that the grains and dispersing medium together form a radiation sensitive silver halide emulsion. The silver halide emulsions are typically coated on a photographic film or paper support to form a photographic element. A simple photographic element can consist of a support and an emulsion layer; however, typically additional hydrophilic colloid layers, such as multiple emulsion layers, subbing layers, interlayers, and overcoats are also present. The silver halide emulsions can be usefully, though incompletely, categorized as those which form predominantly surface or predominantly internal latent images upon exposure. Photographic elements can be conveniently classified as being direct positive photographic elements or negative working photographic elements. Whether a positive or negative viewable image is produced is a function of both the emulsion chosen and the photographic processing undertaken. Although light processing is known and employed for specialized applications, in most instances photographic processing to produce a viewable image is accomplished by development of an imagewise exposed photographic element in an aqueous alkaline processing solution. Usually internal latent image forming emulsions are employed in combination with uniform light exposure or, preferably a nucleating agent, to produce direct positive images. Direct positive images can be produced also be employing initially surface fogged silver halide grains which rely on selective development of unexposed grains to produce direct positive images. In ternal latent image emulsions can be used to produce negative images by internal development --that is, developing in the presence of iodide ion or a silver halide solvent capable of rendering the internal latent image site accessible to the developing agent. Aside from solarization effects, surface latent image emulsions cannot produce direct postivie images, but are extensively used to produce positive color images by reversal processing. Of extreme importance to obtaining commercially attractive photographic images are a large variety of emulsion, photographic element, and processing solution addenda. A succinct summary of radiation sensitive silver halide emulsions, photographic elements, processing solutions, their basic and modifying components, and significant patents and publications describing their features is contained in Research Disclosure, Vol. 176, December 1978, Item 17643. Research Disclosure is published by Kenneth Mason Publications, Ltd., 8 North Street, Emsworth, Hampshire P010 7DD, England. The polymethines of this invention are in a preferred application incorporated into one or more hydrophilic colloid layers of silver halide photographic elements. The location and concentration the polymethine is dictated by the photographically useful function sought to be realized. The polymethine dyes of the invention can be located behind one or more silver halide emulsion layers as imagewise exposed to absorb actinic radiation penetrating the silver halide emulsion layer or layers, thereby reducing scattered radiation. In other words, the dyes can be employed as antihalation dyes. The polymethines can be incorporated in interlayers or in overcoats to function as filter dyes and UV absorbers. When used as UV absorbers in overcoat layers the polymethines can protect dye images in the photographic elements from fading. In a preferred application the polymethines can be incorporated directly in the silver halide emulsion. They can increase photographic sharpness by intercepting and absorbing actinic radiation that would otherwise be reflected between grains. In other words, the dyes can take the form of inter-grain absorbers. 
     When the merocyanine dyes are employed as a photosensitizer in a photographic silver halide emulsion, they are adsorbed to the surfaces of the radiation-sensitive silver halide grains. As is generally well understood in the art, optimum photosensitization is achieved when the dye concentration is chosen to provide a monomolecular coverage of from 25 to 100 percent of the silver halide grain surface, as disclosed, for example, in West et al, &#34;The Adsorption of Sensitizing Dyes in Photographic Emulsions&#34;, Journal of Phys. Chem., Vol. 56, 1952, p. 1065; Spence el al, &#34;Desensitization of Sensitizing Dyes&#34;, Journal of Physical and Colloid Chemistry, Vol. 56, No. 6, June 1948, pp. 1090-1103; and Gilman et al U.S. Pat. No. 3,979,213. Optimum dye concentration levels of photosensitization can be chosen by procedures taught be Mees, Theory of the Photographic Process, First Edition, pp. 1067-1069. 
     A variety of imaging systems are known which contain a composition capable of being hardened imagewise by ultraviolet exposure. By incorporating a polymethine dye according to the present invention these imaging systems can be made to respond to imagewise exposures within the near ultraviolet and/or visible spectrum. Such systems embrace negative working photoresists, which are used primarily to define image patterns of protective layers. Such systems additionally embrace dye imaging systems in which hardening controls the mobility of an image dye or dye precursor. 
     A typical hardenable imaging system which can be rendered responsive to radiation in the near UV or visible spectrum by incorporation of a polymethine according to this invention includes in addition to the polymethine an organic component which undergoes photoinduced addition reactions, typically either polymerization or crosslinking, at the ethylenic unsaturation sites which produce hardening and an activator. 
     The photosensitizer and activator together form coinitiators for hardening. The photosensitizer is relied upon for photon capture in the visible spectrum. Adjacent activator and photosensitizer molecules react, following excitation of the latter by photon capture, causing release by the activator of a free radical which in turn induces immobilizing addition reactions at sites of ethylenic unsaturation. 
     Since interaction of the activator and photosensitizer are required for successful visible imaging, it is apparent that the choice of the specific dye according to the invention chosen for use as a photosensitizer is related to the specific choice of the activator. 
     In one specifically contemplated form of the invention the activator can take the form of an azinium salt. The azinium salt activators employed in the imaging compositions of this invention can take any convenient form and can be chasen from among known azinium salt activators. The azinium activators disclosed by Heseltine et al and Jenkins et al U.S. Pat. Nos. Re. 27,922 and Re. 27,925, Specht and Farid U.K. Pat No. 3,083,832A, and Research Disclosure, Vol. 200, Dec. 1980, Item 20036, cited above, provide a variety of examples of useful azinium activators. 
     In addition to being a polymethine as previously defined, to be useful as a photosensitizer in the present invention the polymethine must exhibit a reduction potential which is at most 0.1 volt more positive than the reduction potential of the azinium salt activator with which it is employed. Electron transfer from the photosensitizer to the activator is efficiently achieved when the reduction potential of the longer wavelength dye is more negative than that of the photoactivator. In addition, when the reduction potentials of the photosensitizer and activator are equal, energy transfer can still occur. Further, effective performance has been observed when the reduction potential of the photosensitizer is more positive than that of the activator to a limited degree. 
     In the overwhelming majority of instances precise determinations of reduction potentials are not required to ascertain that the proper relationship of reduction potentials of the azinium activator and the polymethine exists. In those few instances in which the reduction potential of the dye is sufficiently positive with respect to that of the activator that a precise determination of reduction potentials is desired, it must be taken into account that reduction potentials can vary as a function of the manner in which they are measured. To provide a specific standard for reduction potential determinations, the procedure is employed described by J. Lenhard, &#34;Measurement of Reversible Electrode Potentials for Cyanine Dyes by the Use of Phase-Selective Second Harmonic AC Voltammetry&#34;, Journal of Imaging Science, Vol. 30, No. 1, Jan./Feb. 1986. 
     The remaining essential ingredient of the coinitiator containing imaging composition is an organic component containing ethylenic unsaturation sites and capable of selective hardening by addition at the sites of ethylenic unsaturation. A broad variety of vinyl monomers, vinyl oligomers, and polymers containing ethylenic unsaturation are known and useful in imaging systems according to the invention. Specific choices of hardenable organic components are illustrated by reference to certain preferred imaging systems. 
     In one preferred form of the invention the imaging composition can take the form of a negative working photoresist. The organic component of the negative-working photoresist to be acted upon by the coinitiators can take the form of any conventional negative-working photoresist organic film forming component containing ethylenic unsaturation and capable of selective immobilization by undergoing a hardening addition reaction at the site of the ethylenic unsaturation. Immobilization can be imparted by initiating polymerization of monomers containing ethylenic unsaturation or by initiating corsslinking of linear polymers or oligomers containing ethylenic unsaturation. For example, any of the monomeric or crosslinkable polymeric film forming components disclosed in Jenkins et al and Heseltine et al U.S. Pat. Nos. Re. 27,925 or Re. 27,922, respectively, are suitable for use in the imaging compositions of this invention and are here incorporated by reference. Tan et al U.S. Pat. No. 4,289,842, here incorporated by reference, discloses negative working hardenable imaging compositions containing light sensitive acrylate copolymers containing pendant groups, such as alkenyl group with ethylenic unsaturation. Lindley U.S. Pat. No. 4,590,147, here incorporated by reference, discloses vinyl oligomers which can be employed as film forming components in the hardenable imaging compositions of this invention. Useful film forming components containing vinyl monomers are disclosed in Fuerniss U.S. Pat. No. 4,497,889 and Anderson et al U.S. Pat. No. 4,535,052, both here incorporated by reference. Kosar Light-Sensitive Systems, John Wiley &amp; Sons, 1965, further describes a variety of useful film forming components for use in the practice of this invention, including ethylenically unsaturated monomers and polymers. 
     Preferred film forming components are comprised of at least one addition polymerizable ethylenically unsaturated compound having a boiling point above 100° C. at normal pressure which is preferably employed in combination with a polymeric binder. The ethylenically unsaturated compound (typically a monomer) and the polymeric binder can be employed together in widely varying proportions, including ethylenically unsaturated compound ranging from 3 to 97 percent by weight of the film forming component and polymeric binder ranging from 97 to 3 percent by weight of the film forming component. A separate polymeric binder, though preferred, is not an essential part of the film forming component and is most commonly omitted when the ethylenically unsaturated compound is itself a polymer. 
     Chang U.S. Pat. No. 3,756,827, here incorporated by reference, discloses in column 2, line 36 to column 3, line 30, a variety of suitable organic monomers for use in the hardenable imaging compositions of this invention. Specifically illustrated in the examples below are ester monomers containing ethylenic unsaturation. Similar monomers include ethylenically unsaturated diester polyhydroxy polyethers, described in Chambers U.S. Pat. No. 4,245,031, here incorporated by reference. 
     Organic polymeric binders which can form a part of the film forming component of the photoresist include: (1) polyesters, including those based on terephthalic, isophthalic, sebacic, adipic, and hexahydroterephthalic acids; (2) nylons or polyamides; (3) cellulose ethers and esters; (4) polyaldehydes; (5) high molecular weight ethylene oxide polymers--e.g., poly (ethylene glycols), having weight average molecular weights from 4000 to 4,000,000; (6) polyurethanes; (7) polycarbonates; (8) synthetic rubbers--e.g., homopolymers and copolymers of butadienes; and (9) homopolymers and copolymers formed from monomers containing ethylenic unsaturation, such as polymerized forms of any of the various the ethylenically unsaturated monomers, such as polyalkylenes--e.g. polyethylene and polypropylene; poly(vinyl alcohol); poly(vinyl esters)--e.g., poly(vinyl acetate); polystyrene; poly(acrylic and methacrylic acids and esters)--e.g., poly(methyl methacrylate) and poly(ethyl acrylate), as well as copolymer variants. 
     The foregoing is, of course, only an illustrative listing of the most commonly encountered hardenable components. Other specific illustrative hardenable components are included in the examples. 
     In addition to the hardenable component and the coinitiators the imaging compositions can contain any one or combination of known addenda, such as thermal inhibitors, colorants (including dyes and pigments), plasticizers, fillers, etc. To facilitate coating on a substrate the film forming component, coinitiators, and addenda, if any, are usually dispersed in a solvent to create a solution or slurry, the liquid being evaporatively removed after coating. Any solvent can be employed for this purpose which is inert toward the film forming components and addenda of the photoresist. Solvents can be chosen from among a wide variety of organic liquids, including N,N-dimethylformamide; N,N-dimethylacetamide; alcohols, such as methanol, ethanol, butanol, etc.; ketones, such as acetone, cyclohexanone, and butanone; esters, such as ethyl acetate and ethyl benzoate; ethers, such as tetrahydrofuran and dioxane; chlorinated aliphatic hydrocarbons, such as methylene chloride and 1,2-dichloroethane; aromatic hydrocarbons, such as benzene and toluene; and other common solvents, such as dimethyl sulfoxide, chlorobenzene, and various mixtures of solvents. 
     The substrate onto which the photoresist is coated can take any convenient conventional form. For example, the photoresist can be used to define a pattern during fabrication of an electronic component. In this instance the substrate can take the form of a printed circuit board or semiconductor chip, typically one which has been only partially fabricated to a completed form. In other instances hardenable imaging compositions can be coated on simple unitary substrates, such as glass, ceramic, metal, cellulose paper, fiberboard, or polymer substrates. Specific substrates include alumina-blasted aluminum, anodized aluminum, alumina-blasted poly(ethylene terephthalate) film, poly(ethylene terephthalate) film, flame or electrostatic discharge treated poly(ethylene terephthalate) film, poly(vinyl alcohol)-coated paper, crosslinked polyester-coated paper, nylon, glass, cellulose acetate film, heavy paper, such as lithographic paper, and the like. 
     In perhaps their most commonly used form hardenable imaging compositions are coated in a fluid form on a substrate and evaporatively dried, usually with heating, to produce a uniform coating. Often, particularly in the manufacture of semiconductor devices, the substrate is spun, thereby employing centrifugal forces to assure the uniformity of the photoresist coating before drying. After exposure to actinic radiation causes addition to occur at the ethylenic unsaturation sites of the film forming component, a liquid developer is brought into contact with the coated substrate to remove selectively the photoresist in areas which were not exposed to actinic radiation. 
     The liquid developer can be any convenient liquid which is capable of selectively removing the photoresist in unexposed areas. The coated photoresist can be sprayed, flushed, swabbed, soaked, or otherwise treated with the developer to achieve selective removal. In its simplest form the liquid developer can be the same liquid employed as a solvent in coating the photoresist. Methoxyethyl acetate and ethoxyethyl acetate are common developers. Also aqueous developers are commonly employed, such as miscible combinations of water and alcohols, with proportions in the range of from 20 to 80 percent water and 80 to 20 percent alcohol being common. Exemplary water miscible alcohols include glycerol, benzyl alcohol, 1,2-propanediol, sec-butyl alcohol, and ethers derived from glycols, such as dihydroxy poly(alkylene oxides). Lactone developers, such as those disclosed by Martinson et al U.S. Pat. No. 3,707,373, can be employed. Optimum developer choices for specific hardenable imaging compositions are disclosed in the various patents cited above illustrating the specific film forming components. 
     In another manner of use, a photoresist layer is coated on a support and overcoated with a strippable cover sheet. The end user typically purchases the photoresist as an article rather than a liquid composition. After removing the cover sheet, the photoresist layer together with its support is laminated to the substrate on which the image pattern is desired. Following patterned exposure to actinic radiation through the support, the support is stripped from the substrate leaving photoresist on the substrate in an imagewise pattern. 
     In still another manner of use the photoresist is coated on a support surface modified to facilitate electroless metal deposition. Again, a strippable cover sheet is located on the photoresist coating. In this use imagewise exposure to actinic radiation occurs through the cover sheet followed by stripping. Upon stripping of the cover sheet there is selective removal of the photoresist so that remaining photoresist defines the desired pattern. Electroless metal plating can then be undertaken to convert the support into an article having a metal pattern thereon. A common application is in the formation of electrical circuits. 
     Any conventional ratio of activator to film forming component can be present in the hardenable imaging compositions of this invention. Activator concentrations are as a pratical matter most conveniently specified in terms of moles of activator per gram of dry solids, the latter consisting of the film forming component and the minor amounts of various addenda, but excluding any liquid component introduced to facilitate coating. Typically from about 2×10 -5  to 25≦10 -5 , most preferably from about 5×10 -5  to 20×10 -5  mole of activator is present per gram of dry solids. 
     The photosensitizer can be present in any concentration capable of increasing the response of the photoresist to ultraviolet or visible light. While the photosensitizer concentration can vary widely, it is generally contemplated to employ photosensitizer in concentrations ranging from about 5×10 -7  to 1×10 -4  mole per gram of dry solids. Preferred photosensitizer concentrations are in the range of from 10 -6  to 5×10 -5  mole per gram by solids, with optimum concentrations generally being in the range of from about 2×10 -6  to 2×10 -5  mole per gram of dry solids. 
     It is possible to employ the various photoresists described above to form either monochromic or multicolor dye images merely by incorporating an imaging dye or dye precursor in the photoresist composition. Following development of the photoresist a retained dye image is presented by the photoresist coating remaining on the substrate. The colored areas correspond to the areas of exposure. Multicolor images, such as images employed for color proofing, can be produced by superimposing three elements each comprised of a transparent support and a photoresist image, where each image is formed by a different additive or subtractive primary dye. 
     In the foregoing imaging systems only a single coated layer is required for imaging. However, it is recognized that the imaging systems of the invention can employ multiple layers. For exmple, instead of blending the imaging dye with the film forming component as described above, a separate imaging dye layer can be coated between the substrate and the photoresist layer. Upon imagewise exposure and development the photoresist is removed in exposed areas. Where the photoresist remains the underlying image dye remains in its initial immobilized condition, while in other areas the dye can be removed or decolorized by washing or any other convenient technique. 
     In the foregoing description of photoresists the hardenable organic component containing ethylenic unsaturation sites is a film forming component. However, in certain preferred imaging systems of the invention the hardenable organic component can be present as a discontinuous or internal phase forming microcapsules which can be in contact with a surrounding continuous phase or separated therefrom by intervening rupturable encapsulating walls. While it is possible to coat microcapsules each containing the hardenable organic component, cointiators, and imaging dye or dye precursor to form a single color image, the present invention makes possible the formation of multicolor images employing a single layer of microcapsules coated on a support. Since the microcapsules form discrete packets of materials, it is possible to mix in the same layer microcapsules containing dye photosensitizers which absorb at differing locations in the visible spectrum and imaging dyes (or their precursors) of differing imaging hues. For example, it is contemplated to coat as a single layer on a substrate (a) microcapsules containing a yellow dye photosensitizer and a yellow or blue imaging dye or its precursor, (b) microcapsules containing a magenta dye photosensitizer and a magenta or green imaging dye or its precursor, and (c) microcapsules containing a cyan dye photosensitizer and a cyan or red imaging dye or its precursor. Except for the choice of dye photosensitizer and imaging dye the microcapsules can be otherwise identical. Thus, merely by blending three different populations of microcapsules it is possible to obtain multicolor images with the same ease and facility as monochromic dye images are obtained. Except for hue selection of components and blending of microcapsule populations prior to coating, monochromic and multicolor imaging according to this invention are identical. Therefore, for simplicity the description which follows is in terms of monochromic imaging, but the description is applicable to both monochromic and multicolor imaging, except as specifically noted. 
     The microcapsules can be employed to produce either a retained or a transferred dye image. Further, either a preformed dye or, preferably, a dye precursor can be contained in the microcapsules. 
     In the retained imaging system a receiver layer is coated on a substrate and is overcoated by a layer of microcapsules. Within each coated microcapsule exposure to light which is absorbed by the dye photosensitizer results in release of a free radical by the azinium activator which in turn results in hardening of the organic component containing ethylenic unsaturation. Subsequent uniform rupture of all the coated microcapsules, as by passing the exposed element between pressure rollers, results in migration of imaging dye or its precursor from the microcapsules which were not exposed and hence were not internally hardened. 
     The released dye or dye precursor diffuses into the receiver layer. Where an imaging dye is contained in the microcapsules, the receiver layer can be formed of any convenient transparent dye penetrable material. For example, the dye can enter a hydrophilic colloid layer or film forming polymer layer. Preferably a mordant is present in the receiver layer to immobilize the image dye on receipt. 
     When the microcapsules contain a dye precursor, the dye image forming layer contains a second component capable of interacting with the dye precursor to form the image dye. One of the two components is hereinafter referred to as a chromogenic material and the other is referred to as a developer. Either or both can be viewed as a dye precursor and either can be located within the microcapsules with the other located in the dye image forming layer in monochromic imaging. However, for multicolor imaging the chromogenic materials, which differ based on the hue of the dye to be produced, are located within the microcapsules. For simplicity subsequent discussion is directed to chromogenic materials contained in the microcapsules with developer being located in the reciever layer, but the converse arrangement is possible, except as specifically noted. The receiver layer can be similar to the receiver for a preformed imaging dye, differing only by the additonal inclusion of a developer. 
     Transferred dye image systems can be similar to the retained dye image systems described above, but differ in the location of the receiver layer. Instead of coating the receiver layer on the same support as the microcapsules, the receiver layer is coated on a separate support. In integral format arrangements the receiver layer and its support can be associated with the microcapsule layer and its support at the time of exposure as well as at the time transfer to the receiver from the microcapsules occurs. Alternatively, the receiver layer and its support need not be associated with the microcapsule layer until rupture of the microcapsules occurs. In either arrangement the receiver layer and its support can be employed alone as the image bearing element or can be retained with the microcapsule layer and it support. In the latter instance the photobleachability of the photosensitizer and the initially colorless form of the chromogenic material are particularly advantageous. 
     In general similar materials can be employed in forming the microcapsule systems described above as have been previously described in connection with negative-working photoresists, the principal difference being in the physical continuity of the imaging layer. However, certain materials described below have been found to be particularly well suited to use in microcapsules imaging systems and constitutes preferred materials. 
     Preferred hardenable organic components containing ethylenic unsaturation include compounds containing at least one terminal ethylenic group per molecule and preferably two or more terminal ethylenic groups per molecule. Typically they are liquid and can also double as a carrier oil for the chromogenic material in the internal phase. Representative examples of these compounds include ethylenically unsaturated acid esters of polyhydric alcohols such as trimethylol propane triacrylate. Another preferred hardenable component can include an acrylate prepolymer derived from the partial reaction of pentaerythritrol with acrylic acid or acrylic acis esters. Such materials are available from Richardson Company, Melrose Park, Ill.--e.g., Rl-1482 and Rl-1483. Also useful are isocyanate modified acrylate, methacrylate, and itaconic acid esters of polyhydric alcohols, such as disclosed by Carlick et al U.S. Pat. Nos. 3,825,479; 3,759,809; and 3,783,151. 
     The chromogenic materials used in the present invention are preferably oil soluble color formers which produce a dye upon reaction with a developer in the presence of a carrier oil. Representative examples of such chromogenic materials include substantially colorless compounds including a lactone, lactam, sultone, spiropyran, ester, or amido structure. Specifically preferred chromogenic materials are triarylmethane, bisphenylmethane, xanthene, thiazine, spiropyran, and similar compounds. Also useful as chromogenic materials are organic compounds capable of complexing with heavy metals to form dyes--e.g., copper phthalocyanine. Specific additive and substractive dye forming chromogenic materials are disclosed in U.S. Pat. Nos. 3,920,510; 4,399,209; and 4,440,846, here incorporated by reference. 
     In addition to the hardenable organic component, the coinitiators, and the chromogenic material, the discrete phase or microcapsules can also contain a carrier oil. Preferred carrier oils are weakly polar solvents having boiling points above 170° C. and preferably in the range of from 180° C. to 300° C. Exemplary carrier oils include alkylated biphenyls (e.g., monoisopropylbiphenyl), polychorinated biphenyls, caster oil, mineral oil, deodorized kersene, naphthenic mineral oils, dibutyl phthalate, dibutyl fumerate, brominated paraffin, and mixtures thereof. Alkylated biphenyls are preferred on the basis of low toxicity while brominated paraffins employed in combination with trimethylol propane triacrylate are particularly preferred for halftone imaging. 
     Carrier oils are not required. As previously noted the hardenable organic component can in many instances perform the mobility providing function of a carrier oil, particularly where the hardenable organic component is a monomer. The choice of carrier oil will depend to some extent on the chromogenic material to be transported on rupture of the microcapsule. Carrier oils are chosen on the basis of their ability to impart mobility to the chromogenic material in the absence of hardening of the organic component containing ethylenic unsaturation as well as being nonreactive with the various components of the microcapsules. 
     The internal phase forming the microcapsules is then comprised of the hardenable organic component, an optional carrier oil, a chromogenic material, coinitiators, and any of a variety of optional components intended to offer improvement in imaging properties, such as light scattering materials, stabilizers, and the like. 
     The materials forming the internal phase of the microcapsules can be present in generally similar concentration ranges as previously described in connection with photoresists. In general the hardenable organic component constitutes at least about 40 percent by weight of the internal phase and typically constitutes from about 50 to 99 percent by weight of the internal phase. The chromogenic material can be present in any concentration compatible with providing a visible dye image. In general useful concentrations range from about 0.5 to 20.0 percent by weight, based on the weight of the internal phase. A preferred range of chromogenic material for monochromic imaging is from about 2 to 7 percent by weight of the internal phase. In multicolor imaging a somewhat higher concentration of chromogenic material is preferred, since only a third of the microcapsules are available to provide a maximum image dye density of any primary hue. For example, a maximum density magenta image must be formed using only the one third of the microcapsules containing the chromogenic material which fomrs a magenta dye. A preferred range of chromogenic material for multicolor imaging is from about 5 to 15 percent by weight of the internal phase. Carrier oils are not required, but can be present in concentrations of up to about 50 percent by weight of the internal phase, preferably in concentrations of from about 10 to 40 percent of the internal phase. The coinitiators can be present in the same concentrations set out above for the photoresists, where the dry solids percentage bases correspond to internal phase percentage bases for the microcapsule utility. 
     In preferred forms the microcapsules each include in addition to the internal phase a rupturable surrounding encapsulating wall. Encapsulation can be undertaken in any convenient conventional manner. Oil soluble chromogenic materials have been encapsulated in hydrophilic wall forming materials, such as gelatin and gelatin derivatives (e.g., phthalated gelatin), gum arabic, polyvinyl alcohol, and carboxymethylcellulose wall forming materials, as illustrated by Green et al U.S. Pat. Nos. 2,730,456 and 2,800,457; resorcinol-formaldehyde wall formers, as illustrated by Vassiliades U.S. Pat. No. 3,914,511; isocyanate-polyol wall formers, as illustrated by Kiritani et al U.S. Pat. No. 3,796,669; urea-formaldehyde wall formers, particulary urea-resorcinol-formaldehyde wall formers, as illustrated by Foris et al U.S. Pat. Nos. 4,001,140, 4,087,376, and 4,089,802; melamine-formaldehyde resin wall formers; and the hydroxypropyl cellulose wall formers, as illustrated by Shackle U.S. Pat. No. 4,025,455; all of the foregoing patents being here incorporated by reference. The wall formers must, of course, be capable of transmitting exposing radiation. Preferred wall formers are gelatin and gelatin derivatives as well as urea-resorcinol-formaldehyde wall formers. Microencapsulation can be accomplished by any convenient conventional technique, including coacervation, interfacial polymerization, polymerization of one or more monomers in oil, as well as various melting dispersing, and cooling methods. 
     The microcapsules normally are chosen to be of a size too small to be individually discerned by the unaided eye. The microcapsules preferably range from about 1 to 25 micrometers (μm) in diameter, more typically from about 3 to 15 μm in diameter, depending upon the sharpness of the image desired, the smoothness of the support surface, and the technique used for rupturing the microcapsules. Generally the sharpness of the dye image increases as the size of microcapsules decreases. However, smaller microcapsules are less easily coated on rough surface supports and less easily ruptured uniformly by mechanical techniques. 
     The microcapsules are normally coated at a density sufficient to at least cover the surface of the support. That is, based on the average diameter of the microcapsules the coating coverage is chosen to provide at least a monolayer coverage of microcapsules on the support. 
     Instead of forming the microcapsules with discrete walls, it is appreciated that microcapsule containing compositions suitable for coating on a substrate can be produced by forming an emulsion in which the microcapsules constitute the discontinuous or internal phase and a binder analogous to the wall formers above constitutes the continuous phase. For example, such microcapsules coatings can be formed employing hydrophilic binders, such as hardened gelatin and gelatin derivatives. 
     Reacting with the chromogenic material (or first dye precursor) is a developer (or second dye precursor). The developer can take the form of any material capable of reacting with the chromogenic material to produce a dye. For the preferred classes of chromogenic materials identified above illustrative developers include clay minerals, such as acid clay, and active clay attapulgite; organic acids such as tannic acid, gallic acid, and propyl gallate; acid polymers, such as phenol-formaldehyde resins; condensates of carboxylic acids containing at least one hydroxy group and formaldehyde; metal salts of aromatic carboxylic acids, such as zinc salicylate, tin salicylate, zinc 2-hydroxynaphthenoate, zinc 3,5-di-tert-butylsalicylate; oil soluble metal salts of phenol-formaldehyde novolak resins (more specifically illustrated by U.S. Pat. Nos. 3,672,935; 3,732,120; and 3,737,410), zinc carbonate, and mixtures of the above. 
     When the developer is coated on a substrate, as is preferred, the developer is typically dispersed in a binder. The binder is chosen to be a relatively dye permeable inert material, such as poly(vinyl alchol), gelatin or a gelatin derivative, maleic anhydride-styrene copolymer, starch, gum arabic, or a cellulose ester. In general well known film forming binders are useful. As mentioned above, a mordant can be incorporated in the binder for the developer to assist in immobilizing the dye once it is formed. A variety of mordants particularly compatible with gelatin and gelatin derivatives are disclosed by Hartman U.S. Pat. No. 4,315,978. 
     While the microcapsule containing imaging system has been described above in terms of employing a chromogenic material and a developer, it is appreciated that mobile imaging dyes can be substituted for the the chromogenic material, if desired. The advantage of employing chromogenic materials is that the chromogenic material need contain no chromophore to compete with the photosensitizer for photon dye capture. Further, the chromogenic material minimizes coloration of the imaging system in areas where no image dye is formed. 
     While the preferred microcapsule imaging systems above have been described in terms of forming a discontinuous oleophilic phase in a continuous hydrophilic phase, it is appreciated that the reserve relationship is also possible. It is specifically contemplated to form microcapsules containing dyes or chromogenic materials which are more hydrophilic and to rely on the relative hydrophobicity if not impermeability of the microcapsule walls to initially confine the dyes. Where microcapsule wall formers are present, the same relatively hydrophilic binders described above can still be employed. The important point to note is that an extremely broad range of imaging dyes and chromogenic materials are available for use. Hartman U.S. Pat. No. 4,315,978 illustrates a variety of yellow magenta, and cyan dyes containing polar substituents to impart mobility in more hydrophilic media. 
     While a few diverse imaging systems which constitute preferred embodiments of the invention have been specifically described, it is apparent that still other image systems employing an organic component which is hardenable by addition at sites of ethylenic unsaturation can be also be improved by the incorporation of coinitiators as previously described. 
    
    
     EXAMPLES 
     The invention can be better appreciated by reference to the following specific examples. 
     EXAMPLE 1 
     Preparation of (O-B)-Ethyl 2-{[(di-phenylboryl)phenylmethylene]amino}-4-(3-ethyl-2-benzthiazolinylidene)-2-butenoate 
     (a) Preparation of ethyl 4-(3-ethyl-2-benzothia-zolinylidene-2-isocyano-2-butenoate (D-1a) 
     To a solution of potassium t-butoxide (3.05 g, 27.2 mmol) in dry, distilled tetrahydrofuran (70 ml) at -78° C. under argon was added dropwise from an addition funnel a solution of ethyl isocyanoacetate (3.08 g, 27.2 mmol) in dry distilled tetrahydrofuran (30 mL). The resulting thin, brown slurry was stirred 30 min at -78° C. Solid 2-(2-acetanilidovinyl)-3-ethylbenzothiazolium iodide (12.3 g, 27.2 mmol) was added in one portion, and the reaction was allowed to warm to ambient temperature and stir 16 hours. The reaction was poured onto 150 mL water and 50 mL saturated aqueous ammonium chloride, and extracted three times with ethyl acetate. The combined extracts were washed with water and saturated sodium chloride, dried over sodium sulfate, and filtered. The solvent was removed under reduced pressure. The residue was triturated with absolute ethanol, and the resulting solid was filtered, then recrystallized from absolute ethanol to give 4.05 g (50%) D-1a as orange needles (mp 134-135° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.62 (1H, d, J=12.4), 7.47 (1H, d, J=7.7), 7.36 (1H, t, J=7.8), 7.16 (1H, t, J=7.6), 7.06 (1H, d, J=8.2), 5.69 (1H, d, J=12.4), 4.30 (2H, q, J=7.1), 4.06 (2H, g J=7.1), 1.42 (3H, t, J=7.1), 1.37 (3H, t, J=7.1). IR(KBr) 2105, 1690, 1595, 1565, 1535 cm -1 . FDMS (m/e) 300 (M + ). 
     λ max  CH 2  Cl 2  (ε): 443 (62,000). Anal. calc&#39;d for C 16  H 16  N 2  O 2  S: C, 64.0; H, 5.4; N, 9.3. Found: C, 63.9; H, 5.4; N, 9.3. 
     (b) Preparation of Ethyl 4-(3-ethyl-2-benzothiazolinylidene-2-triphenylborylisocyano-2-butenoate (D-1b) 
     Triphenylborane (1.56 g, 6.45 mmol) was transferred to a 100 ml 2-neck flask in a glove bag under argon. Dry, distilled tetrahydrofuran (10 ml) was added, and the slurry was cooled to 0° C. under argon. A solution of ethyl 4-(3-ethyl-2-benzothizolinylidene)-2-isocyano-2-butenoate (1.94 g, 6.45 mmol) in dry, distilled tetrahydrofuran (10 ml) was transferred to the triphenylborane slurry through a cannula. The resulting thick orange slurry was allowed to warm to ambient temperature, and was stirred 30 min. Diethyl ether (70 ml) was added, then the orange solid was collected by filtration, washed with additional ether, and dried to give 2.79 g (80%) D-1b. The filtrate was evaporated to dryness and triturated with 1:1 ether:absolute ethanol. Filtration gave an additional 0.40 g (11%) of D-1b (total crude yield: 91%). The crude material was homogeneous by thin layer chromatography and 300 MHz  1  H NMR, and was used without purification for most purposes. A portion was recrystallized from dichloromethane/ethanol to give D-1b as an orange, flaky solid (mp 160°-161° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) ⊕7.81 (1H, d, J=13.0), 7.51 (1H, d, J=7.7), 7.42-7.34 (7H, m), 7.30-7.20 9H, M), 7.16 (1H, t, J=7.2), 7.10 (1H, d, J=8.2), 5.48 (1H, d, J=13.0), 4.29 (2H, q, J=7.1), 3.63 (2H, q, J=7.1), 1.37 (3H, t, J=7.1), 1.10 (3H, t, J=7.1). IR (KBr) 1710, 1600, 1565, 1530 cm -1 . FDMS (m/e) 542 (M+), 300. 
     λ max  CH 2  Cl 2  (ε): 462 (87,000). Anal. calc&#39;d. for C 34  H 31  BN 2  O 2  S: C 75.3; H, 5.8; N, 5.2. Found: C, 75.7; H, 5.9; N, 5.2. 
     (c) Preparation of Product (D-1) 
     Ethyl 4-(3-ethyl-2-benzothiazolinylidene)-2-triphenylborylisocyano-2-butenoate (D1b) (1.63 g, 3.0 mmol) was placed in a 25 ml flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 180° C., held at 180° C. for 10 minutes, then removed from the oil bath and allowed to cool to room temperature. The resulting red solid was dissolved in hot dichloromethane (75 mL). After filtration, absolute ethanol (75 mL) was added to induce crystallization. The resulting red crystalline solid was filtered and dried to give 1.37 g (84%) D-1, mp 198-200 (dec). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.80 (2H, m), 7.63 (1H, d, J=12.2), 7.46 (1H, d, J=7.9), 7.42 4H, d, J=6.7), 7.35 (1H, t, J=7.5), 7.24-7.13 (10H, m), 7.06 (1H, d, J=8.2), 6.80 (1H, d, J=12.2), 4.42 (2H, q J=7.1), 4.14 (2H, q, J=7.1), 1.47 (3H, t, J=7.1), 1.36 (3H, t, J=7.1). IR (KBr) 1565, 1520, 1480, 1415 cm -1 . FDMS (m/e) 542 (M + ). 
     λ max  CH 2  Cl 2  (ε): 514 (80,000). Anal. calc&#39;d. for C 34  H 31  BN 2  O 2  S: C, 75.3; H, 5.8; N, 5.2. Found: C, 75.5; H, 5.9; N, 5.2. 
     EXAMPLE 2 
     Preparation of (O-B)-Ethyl {[(di-p-fluorophenylboryl)-p-fluorophenylmethyl-ene]amino}-4-(3-ethyl-2-benzothiazolinylidene)-2-butenoate (D-2) 
     (a) Preparation of Ethyl 4-(3-ethyl-2-benzothiazolinylidene)-2-tri(p-fluorophenyl)borylisocyano-2-butenoate (D-2b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: 1) tris(p-fluorophenyl)borane (1.91 g, 6.47 mmol) in tetrahydrofuran (20 mL); and 2) ethyl 4-(3-ethyl-2-benzothiazolinylidene)-2-isocyano-2-butenoate (D-1a) (1.94 g, 6.47 mmol) in tetrahydrofuran (20 mL). After the reaction had stirred 30 min at 0° C., the solvent was removed under reduced pressure and the residue was triturated with ethanol (20 mL) with slight warming. After cooling, the resulting orange-yellow solid was collected by filtration and dried (crude yield: 2.59 g). The material was recrystallized from dichloromethane/ethanol, with filtration to remove insolubles, and the product D-2b was isolated as red-orange needles (2.30 g, 60%). 
     In a separate experiment a small portion was recrystallized from ethanol to give an orange flaky solid (mp 164°-166° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.87 (1H, d, J=13.0), 7.56 (1H, d, J=7.6), 7.44 (1H, t, J=7.7), 7.27 (7H, m), 7.17 (1H, d, J=8.2), 6.97 (6H, app t, J=8.9), 5.40 1H, d, J=13.0), 4.33 (2H, q, J=7.1), 3.72 (2H, q, J=7.1), 1.39 (3H, t, J=7.1) 1.16 (3H, t, J=7.1). IR (KBr) 1710, 1595, 1560, 1525, 1475 cm -1 . FDMS (m/e) 596 (M+), 300, 296. 
     λ max  CH 2  Cl 2  (ε): 483 (86,000), 441 (52,000) (sh), 248 (11,000), 266 (17,000). Anal. calc&#39;d. for C 34  H 28  BF 3  N 2  O 2  S: C, 68.5; H, 4.7: N, 4.7. Found: C, 68.3; H, 4.9; N, 4.6. 
     (b) Preparation of Product (D-2) 
     Ethyl 4-(3-ethyl-2-benzothiazolinylidene)-2-tri(p-flurorophenyl)boryisocyano-2-butenoate (D-2b) (1.0 g, 1.67 mmol) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated to 150° C. in an oil bath and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The resulting red solid was recrystallized from dichloromethane/ethanol to give the pure product (0.86 g, 86%) as a red crystalline solid. 
     In a separate experiment, recrystallization from absolute ethanol gave a red-orange crystalline solid for analysis and melting point (mp 165°-170° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.76 (2H, dd, J=5.9, 8.7), 7.70 (1H, d, J=12.4), 7.51 1H, d, J=7.8), 7.40 (1H, t, J=7.8), 7.34 (4H, dd, J=6.5, 8.2), 7.21 (1H, t, J=7.7), 7.13 (1H, d, J=8.2), 6.94 (4H, app t, J=8.9), 6.88 2H, app t, J=8.7), 6.80 (1H, d, J=12.3), 4.42 (2H, 2, J=7.1), 4.19 (2H, q, J=7.1), 1.51 (3H, t, J=7.1), 1.38 (3H, t, J=7.1), IR (KBr) 1600, 1560, 1505, 1475 cm -1 . FDMS (m/e) 596 (M + ). 
     λ max  CH 2  Cl 2  (ε): 515 (84,000), 492 (67,000) (sh). Anal. calc&#39;d. for C 34  H 28  BF 3  N 2  O 2  S: C, 68.5; H, 4.7; N, 4.7. Found: C, 68.5; H, 5.0; N, 4.7. 
     EXAMPLE 3 
     Preparation of (O-B)-Ethyl 2-{[(diphenylboryl)phenylmethylene]amino}-(4-3-ethyl-2-benzothiazolinylidene)acetate (D-4) 
     (a) Preparation of Ethyl 2-(3-ethyl-2-benzothiazolinylidene)-2-isocyanoacetate (D-4a) 
     The same procedure was employed as for Example 1 (D-1a), but using 3-ethyl-2-thiophenylbenzothiazolium iodide (10.9 g, 27.2 mmol) as the alkylating agent. The reaction was worked up as the Example 1, and trituration of the crude product obtained after solvent evaporation gave 3.91 g (52%) D-4a as a light solid that was pure by NMR and TLC (20/80 ethyl acetate/cyclohexane). 
     A small portion was recrystallized from ethyl acetate/ethanol for analysis and melting point (168.5°-171° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.54 (1H, d, J=7.8), 7.38 (1H, t, J=7.8), 7.26-7.19 (2H, m), 4.59 (2H, q, J=7.1), 4.33 (2H, q, J=7.1), 1.58 (3H, t, J=7.1), 1.37 (3H, t, J=7.1). IR (KBr) 2090, 1665, 1510 cm -1 . FDMS (m/e) 274 (M+). 
     λ max  CH 2  Cl 2  (ε): 347 (⃡,000), 337 (32,000) (sh). Anal. calc&#39;d. for C 14  H 14  N 2  O 2  S: C, 61.3; 5.1; N, 10.2. Found: C, 61.7; H, 5.2; N, 10.2. 
     (b) Preparation of Ethyl 2-(3-ethyl-2-benzothiazolinylidene)-2-triphenylborylisocyanoacetate (D-4b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylboron (1.51 g, 6.23 mmol) in tetrahydrofuran (10 mL); and (2) ethyl 2-(3-ethyl-2-benzothiazolinylidene)-2-isocyano-2-acetate (D-4a) (1.7 g, 6.23 mmol) in tetrahydrofuran (10 mL). The resulting thick slurry was stirred briefly at 0° C., then allowed to warm to ambient temperature and stir for 30 min. The solvent was removed under reduced pressure and the residue was triturated with ether (70 mL). The solid was collected by filtration to give the product as an off-white flaky solid (2.79 g). The material was homogenous by TLC and NMR. 
     A portion was recrystallized from dichloromethane/ethanol with a hot filtration for analysis and mp (140°-142° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.62 (1H, d, J=7.8), 7.44-7.38 (7H, m), 7.33-7.15 (11H, m), 4.40 (2H, q, J=7.1), 4.01 (2H, q, J=7.1), 1.40 (3H, t, J=7.1), 0.92 (3H, t, J=7.1). IR (KBr) 1680, 1510, 1470 cm -1 . FDMS (m/e) 516 (M+), 274, 242. 
     λ max  CH 2  Cl 2  (ε): 349 (46,000). Anal. calc&#39;d. for C 32  H 29  BN 2  O 2  S: C, 74.4; H, 5.7; N, 5.4. Found: C, 74.7; H, 5.8; N, 5.4. 
     (c) Preparation of Product (D-4) 
     Ethyl 2-(3-ethyl-2-benzothiazolinylidene)-2-triphenylborylisocyanoacetate (D-4b) (1.55 g, 3.0 mmol) was placed in a 25 ml flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 140° C. and held at that temperature for 10 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (1.33 g, 86%) as a yellow crystalline solid. 
     A small portion was recrystallized a second time for analysis and melting point (mp 228°-231° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.64 (2H, m), 7.59 (1H, d, J=7.8), 7.44 (5H, m), 7.35-7.12 (11H, m), 5.11 (2H, q, J=7.1), 4.57 (2H, q, J=7.1), 1.54 (3H, t, J=7.1), 1.49 (3H, t, J=7.1). IR (KBr) 1475, 1420 cm -1 . FDMS (m/e) 516 (M + ). 
     λ max  CH 2  Cl 2  (ε): 403 (40,000), 334 (9,400). Anal. calc&#39;d. for C 32  H 29  BN 2  O 2  S: C, 74.4; H, 5.7; N, 5.4. Found: C, 74.3; H, 5.7; N, 5.3. 
     EXAMPLE 4 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethyl-ene]amino}-4-(3-ethyl-2-benzothiazolinylidene)acetate (D-5) 
     (a) Preparation of Ethyl 2-(3-ethyl-2-benzothiazolinylidene-2-tri(p-fluorophenyl)borylisocyanoacetate (D-5b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: 1) tris(p-fluorophenyl)borane (1.78 g, 6.01 mmol) in tetrahydrofuran (10 mL); and 2) ethyl 2-(3-ethyl-2-benzothiazolinylidene)-2-isocyanoacetate (D-4a) (1.65 g, 6.01 mmol) in tetrahydrofuran (10 mL). The resulting dark solution was stirred at 0° C. for 30 minutes, and the solvent was removed under reduced pressure. The residue was triturated with ethanol and the resulting off-white solid was isolated by filtration (3.05 g, 89%). Recrystallization from a 1:1 mixture of ethyl acetate and ethanol gave the pure product as light yellow needles (1.68 g, 49%). A second crop (0.93 g) consisted of a mixture of the desired product and a rearrangement product. 
     In a separate experiment, recrystallization of the crude material from ethanol gave the pure product as a tan crystalline solid (mp 158°-160° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.66 (1H, d, J=7.5), 7.47 (1H, t, J=7.6), 7.38-7.22 (8H, m), 6.98 (6H, t, J=8.9), 4.41 (2H, q, J=7.1), 4.08 (2H, q, J=7.1), 1.39 (3H, t, J=7.1), 1.00 (3H, t, J=7.1). IR (KBr) 1690, 1595, 1510, 1480 cm -1 . FDMS (m/e) 570 (M+), 296, 274. 
     λ max  CH 2  Cl 2  (ε): 349 (46,000). Anal. calc&#39;d. for C 32  H 26  BF 3  N 2  O 2  S: C, 67.4; H, 4.6; N, 4.9. Found: C, 67.0; H, 4.8; N, 4.8. 
     (b) Preparation of Product D-5) 
     Ethyl 2-(3-ethyl-2-benzothiazolinylidene)-2-tri(p-fluorophenyl)borylisocyanoacetate (D-5b) (0.10 g, 0.175 mmol) was placed in a 10 ml flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 150° C. and held at that temperature for 15 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from ethanol to give the pure product (0.059 g, 59%) as a yellow crystalline solid (mp 183°-184° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.62 (1H, d, J=7.6), 7.58 (2H, dd, J=5.8, 8.6), 7.49 (1H, t, J=7.5), 7.41-7.30 (6H, m) 6.93 (4H, t, J=9.1), 6.86 (2H, t, J=8.7), 5.10 (2H, q, J=7.1), 4.57 (2H, q, J=7.1), 1.55 (3H, t, J=7.1), 150 (3H, t, J=7.1). IR (KBr) 1595, 1510, 1490, 1425 cm -1 . FDMS (m/e) 570 (M + ). 
     λ max  CH 2  Cl 2  (ε): 402 (35,000). Anal. calc&#39;d. for C 32  H 26  BF 3  N 2  O 2  S: C, 67.4; H, 4.6; N, 4.9. Found: C, 67.3; H, 4.8; N, 4.9. 
     EXAMPLE 5 
     Preparation of (O-B)-Ethyl 2-{[(di-phenylboryl)phenylmethylene]amino}-6-(3ethyl-2-benzothiazolinylidene)-2, 4-hexadienoate (D-6) 
     (a) Preparation of Ethyl 6-(3-ethyl-2-benzothiazolinylidene)-2-isocyano-2, 4-hexadienoate (D-6a) 
     The same procedure was employed for the reaction as for Example 1 (D-1a), but using the following materials: (1) potassium t-butoxide (5.6 g, 50 mmol) in tetrahydrofuran (120 mL); (2) ethyl isocyanoacetate (5.65 g, 50 mmol) in tetrahydrofuran (40 mL); (3) 2-(4-acetanilido-1-butadienyl)-3-ethyl-benzothiazolium iodide (23.8 g, 50 mmol). After the reaction was stirred at ambient temperature overnight, it was quenched with 1:3 saturated ammonium chloride/water and ethyl acetate (200 mL), then was filtered to remove insolubles. The organic layer was separated and the aqueous layer was extracted twice more with ethyl acetate. The combined extracts were washed with saturated sodium chloride and dried over sodium sulfate, then filtered. The solvent was removed under reduced pressure. The residue was triturated with 1:1 ethyl acetate/ether to give 2.49 g (15%) D-6a as a blue crystalline solid that was homogeneous by TLC (2:8 ethyl acetate/cyclohexane). 
     In a different experiment, a small portion of crude material was recrystallized from ethanol to give D-6a (black needles) for analysis and melting point (163°-165° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.40 (1H, d, J=8.8), 7.39 (1H, d, J,=11,2), 7.28 (1H, t, J=7.9), 7.07 (1H, t, J=7.5), 6.97 (1H, dd, J=13.5, 12.2), 6.94 (1H, d, J=7.9), 6.28 (1H, dd, J=13.5, 12.2), 5.67 (1H, d, J=11.8), 4.27 (2H, q, J=7.1), 3.92 (2H, q, J=7.1), 1.35 (6H, 2 overlapping t). IR (KBr): 2100, 1705, 1570, 1500 cm -1 . FDMS (m/e) 326 (M+). 
     λ max  CH 2  Cl 2  (ε): 508 (60,000), 318 (3,400), 281 (6,800). Anal. calc&#39;d. for C 18  H 18  N 2  O 2  S: C, 66.2; H, 5.6; N, 8.6. Found: C, 66.1; H, 5.6; N, 8.5. 
     (b) Preparation of Ethyl 6-(3-ethyl-2-benzothiazolinylidene)-2-triphenylborylisocyano-2,4-hexadienoate (D-6b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylboron (0.737 g, 3.05 mmol) in tetrahydrofuran (10 mL); and (2) ethyl 6-(3-ethyl-2-benzothiazolinylidene)-2-isocyano-2,4-hexadienoate (D-6a) (0.993 g, 3.05 mmol) in tetrahydrofuran (10 mL). The resulting magenta slurry was stirred 30 min at 0° C., then ethanol (40 mL) was added. The product was isolated by filtration, washed with ethanol, and dried. The resulting green solid (1.30 g 75% was pure by NMR. 
     In a separate experiment, a portion was recrystallized from dichloromethane/ethanol to give a green solid for analysis and melting point (mp 147°-149° C.) 
       1  H NMR (300 MHz, CDCl 3 ) δ7.56 (1H, d, J=12.5), 7.46 (1H, d, J=7.7), 7.39-7.06 (19H, m), 5.91 (1H, t, J=12.9), 5.57 (1H, d, J=12.2), 4.28 (2H, q, J=7.1), 4.01 (2H, q, J=7.2), 1.41 (3H, t, J=7.2), 1.34 (3H, t, J=7.1) IR (KBr) 1700, 1565, 1485, 1465 cm -1 . FDMS (m/e) 568 (M+), 326. 
     λ max  CH 2  Cl 2  (ε): 555 (112,000), 525 (69,000) (sh), 276 (17,000). Anal. calc&#39;d. for C 36  H 33  BN 2  O 2  S: C, 76.1; H, 5.9; N, 4.9. Found: C, 75.8; H, 5.8; N, 5.2. 
     (c) Preparation of Product (D-6) 
     Ethyl 6-(3-ethyl-2-benzothiazolinylidene) -2-triphenylborylisocyano-2,4-hexadienoate (D-6b) (0.800 g, 1.41 mmol) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 150° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recystallized from dichloromethane/ethanol to give the pure product (0.608 g, 71%) in two crops as a blue crystalline solid (mp 187°-193° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.84 (2H, dd, J=5.6, 7.7), 7.56-6.95 (14H, m), 7.42 (4H, d, J=6.9), 7.09 (1H, t, J=7.4) 6.96 (1H, d, J=8.1), 5.86 (1H, d, J=11.7), 4.44 (2H, q, J=7.1), 3.98 (2H, q, J=7.1), 1.42-1.36 (6H, 2 overlapping t, J=7.1). IR (KBr) 1575, 1535, 1500, 1470, 1415 cm -1 . FDMS (m/e) 568 (M + ). 
     λ max  CH 2  Cl 2  (ε): 592 (71,000), 567 (76,000). Anal. calc&#39;d. for C 36  H 33  BN 2  O 2  S: C, 76.1; H, 5.9; N, 4.9. Found: C, 75.7; H, 6.0; N, 5.1. 
     EXAMPLE 6 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethyl-ene]amino}-6-(3-ethyl-2-benzothiazolinylidene)-2,4-hexadienoate (D-7) 
     (a) Preparation of Ethyl 6-(3-ethyl-2-benzothiazolinylidene)-2-tri(p-fluorophenyl)borylisocyano-2,4-hexadiehnoate (D-7b) 
     The same procedure was employed for the reaction as for Example 1 D-1b), but using the following materials: (1) tris(p-fluorophenyl)boron (1.03 g, 3.48 mmol) in tetrahydrofuran (10 mL); and (2) ethyl 6-(3-ethyl-2-benzothiazolinylidene)-2-isocyano-2,4-hexadienoate (D-6a) (1.13 g, 3.48 mmol) in tetrahydrofuran (10 mL). The resulting magenta solution was stirred 30 min at 0° C., then the solvent was removed under reduced pressure. The residue was triturated with ethanol, and the resulting magenta solid was isolated by filtration and dried (1.65 g, 76%). The material was pure by NMR, and was used without further purification. 
     In a separate experiment, a portion was recrystallized from dichloromethane/ethanol to give a magent solid (mp 146.5°-147° C.) 
       1  H NMR (300 MHz, CDCl 3 ) δ7.56 (1H, d, J=12.6), 7.48 (1H, d, J=7.8), 7.38 (1H, t, J=7.7), 7.28 (6H, t, J=6.5), 7.22-7.10 (3H, m) 6.96 (6H, t, J=8.9), 5.70 (1H, br t, J=12.6), 5.52 (1H, d, J=12.2), 4.29 (2H, q, J=7.1), 4.04 (2H, q, J=7.1), 1.42 (3H, t, J=7.1), 1.34 (3H, t, J=7.1). IR (KBr) 1705, 1590, 1570, 1485, 1464 cm -1 . FDMS (m/e) 622 (M+), 326. 
     λ max  CH 2  Cl 2  (ε): 556 (118,000), 527 (66,000) (sh). Anal. calc&#39;d. for C 36  H 30  BF 3  N 2  O 2  S: C, 69.5; H, 4.9; N, 4.5. Found: C, 69.2; H, 5.1; N, 4,5. 
     (b) Preparation of Product (D-7) 
     Ethyl 6-(3-ethyl-2-benzothiazolinylidene)-2-tri(p-fluorophenyl)borylisocyano-2,4-hexadienoate (D-7b) (0.650 g, 1.04 mmol) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 150° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (0.430 g, 66%) as a green powder that was pure by NMR. 
     In another experiment, recrystallization from dichloromethane/ethanol gave green needles for analysis and melting point (mp 194°-197° C., dec.) 
       1  H NMR (300 MHz, CDCl 3 ) δ7.77 (2H, dd, J=5.9, 8.6), 7.43 (1H, d, J=12.0), 7.42 (1H, d, J=7.3), 7.33-7.22 (6H: 4H, dd, J=6.5, 8.2; 2H, m), 7.09 (1H, t J=7.7), 7.03 (1H, t J=13.4), 6.96 (1H, d, J=8.3), 6.90 (4H, t, J=8.9), 6.85 (2H, t, J=8.6), 5.85 (1H, d, J=7.7 ), 4.40 (2H, q, J=7.1), 3.97 (2H, q, J=7.2), 1.37 (6H, 2 overlapping t, J=7.1, 7.2). IR (KBr) 1590, 1570, 1530, 1490, 1470, 1415 cm -1 . FDMS (m/e) 622 (M 30 ). 
     λ max  CH 2  Cl 2  (ε): 601 (81,000), 569 (81,000). Anal. calc&#39;d. for C 36  H 30  BF 3  N 2  O 2  S: C, 69.5; H, 4.9; N, 4.5. Found: C, 69.1; H, 5.1; N, 4.7. 
     EXAMPLE 7 
     Preparation of (O-B)-Ethyl 2-{[(di-phenylboryl)phenylmethylene]amino}-4-(3-ethyl-2-benzoxazolinylidene)-2-butenoate (D-8) 
     (a) Preparation of Ethyl 4-(3-ethyl-2-benzoxazolinylidene)-2-isocyano-2-butenoate (D-8a) 
     The same procedure was employed for the reaction and work-up as for Example 1 (D-1a), but using the following materials: (1) potassium t-butoxide (2.8 g, 25 mmol); (2) ethyl isocyanoacetate (2.83 g, 25 mmol); and (3) 2-(2-acetanilidovinyl)-3-ethylbenzoxazolium iodide (10.9 g, 25 mmol). Trituration of the residue obtained after solvent evaporation with 2:1 ethanol/ether gave 3.33 g (47%) D-8a as a powdery yellow solid that was homogeneous by TLC (3:7 ethyl acetate/cyclohexane). 
     A portion of the material was recrystallized from ethanol to give yellow needles that were used for analysis and melting point (135°-136.5° C.). 
       1  NMR (300 MHz, CDCl 3 ) δ7.98 (1H, d, J=12.4), 7.29-7.20 (2H, overlapping d, t), 7.13 (1H, t, J=7.7), 7.00 (1H, d, J=7.6), 5.05 (1H, d, J=12.5), 4.27 (2H, q, J=7.1), 3.90 (2H, q, J=7.2), 1.40 (3H, t, J=7.2), 1.34 (3H, t, J=7.1). IR (KBr) 2125, 1685, 1640, 1610, 1570, 1480 cm -1 . FDMS (m/e) 284 (M+). 
     λ max  CH 2  Cl 2  (ε): 408 (72,000). Anal. calc&#39;d. for C 16  H 16  N 2  O 3  : C, 67.6; H, 5.7; N, 9.9. Found: C, 67.6; H, 5.8; N, 9.8. 
     (b) Preparation of Ethyl 4-(3-ethyl-2-benzoxazolinylidene)-2-triphenylborylisocyano-2-butenoate (D-8b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylborane (1.15 g, 4.75 mmol) in tetrahydrofuran (15 mL); and (2) ethyl 4-(3-ethyl-2-benzoxazolinylidene)-2-isocyano-2-butenoate (D-8a) (1.35 g, 4.75 mmol) in tetrahydrofuran (15 mL). After the reaction had stirred 30 min at 0° C., the solvent was removed under reduced pressure and the residue was triturated with ethanol. The resulting yelow solid was isolated by filtration and dried (crude yield 2.01 g, 80%). Recrystallization from dichloromethane/ethanol (hot filtration) gave pure (D-8b) (1.64 g, 66%) as a yellow flaky solid (mp 151°-151.5° C.) 
       1  H NMR (300 MHz, CDCl 3 ) δ8.19 (1H, d, J=13.0), 7.39-7.34 (7H: 6H, d, J=7.2; 1H, m), 7.31-7.23 (8H: 6H, t, J=7.2; 2H, m), 7.16 (3H, t, J=7.0), 7.05 (1H, d, J=7.6), 4.86 (1H, d, J=13.0), 4.31 (2H, q, J=7.1), 3.55 (2H, q, J=7.2), 1.38 (3H, t, J=7.1), 1.19 (3H, t, J=7.2). IR (KBr) 2230(W), 1700, 1633, 1587, 1555, 1480 cm -1 . FDMS (m/e) 526 (M+), 284. 
     λ max  CH 2  Cl 2  (ε): 424 (87,000), 410 (63,000) (sh). Anal. calc&#39;d. for C 34  H 31  BN 2  O 3  : C, 77.6; H, 5.9; N, 5.3. Found: C, 77.5; H, 5.9; N, 5.3. 
     (c) Preparation of product (D-8) 
     Ethyl 4-(3-ethyl-2-benzoxazolinylidene)-2-triphenylborylisocyano-2-butenoate (D-8b) (1.0 g, 1.90 mmol) was placed in a 50 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 170° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (0.84 g, 84%) as an orange flaky solid (mp 173°-178° C., dec.) 
       1  H NMR (300 MHz, CDCl 3 ) δ8.05 (1H, d, J=12.4), 7.80 (2H, m), 7.44 (4H, d, J=6.9), 7.33 (1H, d, J=7.8), 7.27-7.13 (11H, m) 7.01 (1H, d, J=7.7), 6.20 (1H, d, J=12.5), 4.43 (2H, q, J=7.1), 4.01 (2H, q, J=7.2), 1.47 (3H, t, J=7.2), 1.37 (3H, t, J=7.1). IR (KBr) 1637, 1603, 1547, 1517 cm -1 . FDMS (m/e) 526 (M + ). 
     λ max  CH 2  Cl 2  (ε): 476 (84,000), 458 (72,000). Anal. calc&#39;d. for C 34  H 31  BN 2  O 3  : C, 77.6; H, 5.9; N, 5.3. Found: C, 77.4; H, 6.0; N, 5.2. 
     EXAMPLE 8 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-4-(3-ethyl-2-benzoxazolidinylidene)-2-butenoate (D-9) 
     (a) Preparation of Ethyl 4-(3-ethyl-2-benzoxazolinylidene)-2-tri-p-fluorophenylborylisocyano-2-butenoate (D-9a) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) tris(p-fluorophenyl)borane (0.919 g, 3.10 mmol) in tetrahydrofuran (10 mL); and (2) ethyl 4-(3-ethyl-2-benzoxazolinylidene-2-isocyano-2-butenoate (D-8a) (0.882 g, 3.10 mmol) in thetrahydrofuran (10 mL). After the reation had stirred 30 min at 0° C., the solvent was removed under reduced pressure and the residue was triturated with ethanol. The resulting yellow solid was filtered and dried (crude yield: 1.35 g, 75%). Recrystallization from dichloromethane/ethanol (hot filtration) gave pure D9b (1.18 g, 66%) as yellow plates (mp 156.5-158° C.). 
     A second crop (0.13 g, 7%) that was pure by NMR was also isolated (total yield: 1.31 g, 73%). 
       1  H NMR (300 MHz, CDCl 3 ) δ8.18 (1H, d, J=13.0), 7.36 (1H, d, J=8.0), 7.33-7.21 (8H: 6H, dd, J=6.3, 8.1; 2H, m), 7.08 (1H, d, J=7.7), 6.94 (6H, t, J=8.8), 4.73 (1H, d, J=13.0), 4.31 (2H, q, J=7.1), 3.59 (2H, q, J=7.2), 1.37 (3H, t, J=7.1), 1.21 (3H, t, J=7.2). IR (KBr) 2230(w), 1700, 1635, 1587, 1560, 1495, 1480 cm -1 . FDMS (m/e) 580 (M+). 
     λ max  CH 2  Cl 2  (ε): 425 (91,000 ), 413 (70,000) (sh). Anal. calc&#39;d. for C 34  H 28  BF 3  N 2  O 3  : C, 70.4; H, 4.9; N, 4.8. Found: C, 70.1; H, 4.8; N, 4.7. 
     (b) Preparation of Product (D-9) 
     Ethyl 4-(3-ethyl-2-benzoxazolinylidene)-2-tri-p-fluorophenylborylisocyano-2-butenoate (D-9b) (0.75 g, 1.29 mmol) was placed in a 50 mL flask. The flask was evacuated and refilled wtih argon four times. The flask was heated in an oil bath to 170° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The materials was recrystallized from dichloromethane/ethanol to give the pure product (0.652 g, 87%) as orange chunky crystals (mp 140°-181° C. dec.).  1  H NMR (300 MHz, CDCl 3 ) δ8.09 (1H, d, J=12.5), 7.73 (2H, dd, J=6.0, 8.6), 7.33 (5H: 4H, dd, J=6.6, 8.1; 1H, m), 7.26 (1H, d, J=7.4), 7.19 (1H, t, J=7.6), 7.06 (1H, d, J=7.7), 6.91 (4H, t, J=8.8), 6.86 (2H, t, J=8.6), 6.18 (1H, d, J=12.5), 4.41 (2H, q, J=7.1), 4.04 (2H, q, J=7.2), 1.49 (3H, t, J=7.2), 1.37 (3H, t, J=7.1). IR (KBr) 1635, 1597, 1565, 1560, 1513, 1500 cm -1 . FDMS (m/e) 580 (M + ). 
     λ max  CH 2  Cl 2  (ε): 476 (83,000 ), 460, (70,000). Anal. calc&#39;d. for C 34  H 28  BF 3  N 2  O 3  : C, 70.4; H, 4.9; N, 4.8. Found: C, 70.2; H, 4.9; N, 4.7. 
     EXAMPLE 9 
     Preparation of (O-B)-Ethyl 2-{[(diphenylboryl)phenylmethylene]amino}-6-(3-ethyl-2-benzoxazolinylidene)-2, 4-hexadienoate (D-10) 
     (a) Preparation of Ethyl 6-(3-ethyl-2-benzoxazolinylidene-2-isocyano-2,4-hexadienoate (D-10a) 
     The same procedure was employed for the reaction as for Example 1 (D-1a), but using the following materials: (1) potassium t-butoxide (5.6 g, 50 mmol) in tetrahydrofuran (120 mL); (2) ethyl isocyanoacetate (5.65 g, 50 mmol) in tetrahydrofuran (40 mL); 3) 2-(4-acetanilido-1-butadienyl)-3-ethyl-benzoxazolium iodide (23.0 g, 50 mmol). Trituration of the residue obtained after solvent evaporation with ethanol gave 2.02 g (13%) D-10a as a blue crystalline solid that was homogeneous by TLC (3:7 ethyl acetate/cyclohexane). 
     In a different experiment, a small portion of the crude material was recrystallized from ethanol for analysis and melting point (154.5-155.5° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ7.45-7.37 (2H, overlapping d, t), 7.22-7.15 (2H, ovelapping d, t), 7.06 (1H, t, J=7.7), 6.91 (1H, t, J=7.7), 6.91 (1H, t, J=7.7), 6.26 (1H, dd, J=12.5, 13.6), 5.02 (1H, d, J=11.9), 4.26 (2H, q, J=7.1), 3.81 (2H, q, J=7.2), 1.37 (3H, t, J=7.2), 1.33 (3H, t, J=7.1). IR (KBr) 2125, 1685, 1640, 1610, 1570, 1480. FDMS (m/e) 310 (M+). 
     λ max  CH 2  Cl 2  (ε): 490 (71,000). Anal. calc&#39;d. for C 18  H 18  N 2  O 3  : C, 69.7; H, 5.8; N, 9.0. Found: C, 69.5; H, 5.6; N, 8.9. 
     (b) Preparation of Ethyl 6-(3-ethyl-2-benzoxazolinylidene)-2-triphenylborylisocyano-2,4-hexadienoate (D-10b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylboron (0.919 g, 3.80 mmol) in tetrahydrofuran (15 mL); and (2) ethyl 6-(3-ethyl-2-benzoxazolinylidene)-2-isocyano-2,4-hexadienoate (D-10a) (1.18 g, 3.80 mmol) in tetrahydrofuran (10 mL). After the resulting red slurry had stirred 30 min at 0° C., the solvent was removed under reduced pressure and the residue was triturated with ethanol. The resulting red solid was filtered and dried (crude yield: 1.67 g, 80%). Recrystallization from dichloromethand/ethanol (hot filtration) gave pure D-10b (1.29 g, 61%) as a red solid. 
     A second crop was obtained (0.18 g, 9%) that was also pure by NMR (total yield: 1.47 g, 70%). A small portion was recrystallized from acetonitrile to give tiny red needles (mp 145°-148° C., dec). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.60 (2H, m), 7.40 (6H, d, J=7.4), 7.27 (8H: 6H, t, J=7.2; 2H, m), 7.18 (4H, m), 7.04 (1H, d, J=7.7), 5.91 (1H, t, J=12.1), 4.90 (1H, d, J=12.3), 4.29 (2H, q, J=7.1), 3.91 (2H, q, J=7.2), 1.46 (3H, t, J=7.2), 1.35 (3H, t, J=7.1). IR (KBr) 2220(w), 1700, 1640, 1620, 1570, 1565, 1500 cm -1 . FDMS (m/e) 552 (m+) 310. 
     λ max  CH 2  Cl 2  (ε): 520 (120,000), 499 (68,000) (sh). Anal. calc&#39;d. for C 36  H 33  BN 2  O 3  : C, 78.3: H, 6.0; N, 5.1. Found C, 78.1; H, 6.1; N, 5.0. 
     (c) Preparation of Procudt (D-10) 
     Ethyl 6-(3-ethyl-2-benzoxazolinylidene)-2-triphenylborylisocyano-2,4-hexadienoate (D-10b) (0.800 g, 1.45 mmol) was placed in a 50 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 165° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (0.686 g, 86%) as a blue solid (mp 135°-140° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.84 (2H, m), 7.48-7.41 (6H, m), 7.33-7.07 (13H, m), 6.90 (1H, d, J=7.6), 5.18 (1H, d, J=11.9), 4.41 (2H, q, J=7.1), 3.83 (2H, q, J=7.2), 1.39 (3H, t, J=7.2), 1.35 (3H, t, J=7.2). IR (KBr) 1640, 1617, 1520 cm -1 . FDMS (m/e) 552 (M + ). 
     λ max  CH 2  Cl 2  (ε): 564 (83,000), 541 (80,000). Anal. calc&#39;d. for C 36  H 33  BN 2  O 3  : C, 78.3; H, 6.0; N, 5.1. Found C, 78.4; H, 6.1; N, 5.0. 
     EXAMPLE 10 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-6-(3-ethyl-2-benzoxazolinylidene)-2,4-hexadienoate 
     (a) Preparaton of Ethyl 6-(3-ethyl-2-benzoxazolinylidene)-2-tri(p-fluorophenyl)borylisocyano-2,4-hexadienoate (D-11b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials:(1) tris(p-fluorophenyl)boron (1.16 g, 3.92 mmol) in tetrahydrofuran (15 mL); and (2) ethyl 6-(3-ethyl-2-benzoaxzolinylidene)-2-isocyano-2,4-hexadienoate (D-10a) (1.21 g, 3.92 mmol) in tetrahydrofuran (10 mL). The reaction was stirred 30 min at 0° C., then the solvent was removed under reduced pressure. The residue was triturated with ethanol, and the resulting red solid was isolated by filtration and dried. 
     The crude material (1.75 g, slightly impure by NMR) was recrystallized from dichloromethane/ethanol (hot filtration) to give pure D-11b (1.55 g, 65%) as a red-brown crystalline solid (mp 167.5°-169° C., dec). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.58 (2H, m), 7.41-7.13 (9H: 6H, dd, J=6.4, 8.1; 3H, m), 7.07 (1H, d, J=7.8), 6.97 (6H, t, J=8.9), 5.64 (1H, t, J=12.1), 4.93 (1H, d, J=12.3), 4.30 (2H, q, J=7.1), 3.94 (2H, q, J=7.2), 1.45 (3H, t, J=7.2), 1.35 (3H, t, J=7.1). IR (KBr) 2230 (w), 1700, 1640, 1620, 1585, 1570, 1495 cm -1 . FDMS (m/e) 606 (M+), 310. 
     λ max  CH 2  Cl 2  (ε): 521 (101,000), 497 (61,000) (sh). Anal. calc&#39;d. for C 36  H 30  BF 3  N 2  O 3  : C, 71.3; H, 5.0; N, 4.6. Found: C, 70.9; H, 5.1; N, 4.5. 
     (b) Preparation of Product D-11 
     Ethyl 6-(3-ethyl-2-benzoxazolinylidene)-2-tri(p-fluorophenyl)borylisocyano-2,4-hexadienoate (D-11b) (0.900 g. 1.49 mmol) was placed in a 50 ml flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 175° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (0.63 g, 70%) as a blue crystalline solid (mp 185°-195° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.77 (2H, dd, J=5.9, 8.6), 7.51 (2H, m), 7.31 (5H: 4H, dd, J=6.6, 8.2; 1H, m), 7.26-7.17 (2H, m), 7.09 (1H, t, J=7.7), 6.90 (5H: 4H, t, J=8.8; 1H, m), 6.85 (2H, t, J=8.8), 5.21 (1H, d, J=12.0), 4.39 (2H, q, J=7.1), 3.86 (2H, q, J=7.2), 1.40 (3H, t, J=7.2), 1.35 (3H, t, J=7.2). IR (KBr) 1640, 1620, 1590, 1520, 1500 cm -1 . FDMS (m/e) 606 (M + ), 605. 
     λ max  CH 2  Cl 2  (ε): 568 (93,000), 547 (86,000). Anal. calc&#39;d. for C 36  H 30  BF 3  N 2  O 3  : C, 71.3; H, 5.0; N, 4.6. Found: C, 70.9; H, 4.8; N, 4.4. 
     EXAMPLE 11 
     Preparation of (O-B)-Ethyl 2-{[(diphenylboryl)phenylmethylene]amino}-4-(1-ethyl-2-quinolinylidene)-2-butenoate (D-15) 
     (a) Preparation of Ethyl 4-(1-ethyl-2-quinolinylidene)-2-isocyano-2-butenoate (D-15a) 
     The same procedure was employed for the reaction as for Example 1 (D-1a), but using the following materials: (1) potassium t-butoxide (3.36 g, 30 mmol) in tetrahydrofuran (90 mL); (2) ethyl isocyanoacetate (3.39 g, 30 mmol) in tetrahydrofuran (30 mL); (3) 2-(2-acetanilidovinyl)-1-ethylquinolinium iodide (13.3 g, 30 mmol). Trituration of the residue obtained after solvent evaporation with ethanol gave 5.18 g (59%) D-15a as an orange solid. 
     Recrystallization from ethanol (hot filtration) gave 4.42 g (50%) pure D-15a as an orange crystalline solid (mp 137.5°-139° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.93 (1H, d, J=12.7), 7.54 (1H, dt, J=1.1, 8.0), 7.45 (1H, dd, J=1.0, 7.7), 7.39-7.28 (3H, m), 7.21 (1H, t, J=7.4), 5.63 (1H, d, J=12.8), 4.31 (2H, q, J=7.1), 4.19 (2H, q, J=7.1), 1.50 (3H, t, J=7.2), 1.38 (3H, t, J=7.1). IR (KBr) 2100, 1685, 1630, 1555 cm -1 . FDMS (m/e) 294 (M+). 
     λ max  CH 2  CL 2  (ε): 506 (25,000) (sh), 480 (42,500), 455 (39,000) (sh), 387 (19,000). Anal. calc&#39;d. for C 18  H 18  N 2  O 2  : C, 73.4; H, 6.2; N, 9.5. Found: C, 73.7; H, 6.3; N, 9.5. 
     (b) Preparation of Ethyl 4-(1-ethyl-2-quinolinylidene)-2-triphenylborylisocyano-2-butenoate (D-15b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylborane (1.51 g, 6.24 mmol) in tetrahydrofuran (20 mL); and (2) ethyl 4-(1-ethyl-2-quinolinylidene-2-isocyano-2-butenoate (D-15a) (1.83 g, 6.24 mmol) in tetrahydrofuran (20 mL). After the reaction slurry has stirred 30 min at 0° C., ethanol (40 mL) was added and the precipitated product was isolated by filtration, washed with ethanol, and dried to give an orange solid (2.79 g, 84%). It was pure by TLC and NMR, and was used without further purification. 
     A portion was recrystallized from dichloromethane/ethanol (hot filtration) to give an orange flaky solid (mp 174°-175° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.12 (1H, t, J=8.4), 7.60 (1H, t, J=8.4), 7.55 (1H, d, J=7.8), 7.49 (2H, app s), 7.38 (7H: 6H, d, J=7.3; 1H, obscured), 7.34-7.24 (8H, 6H, t, J=6.9; 2H, obscured), 7.18 (3H, t, J=7.0), 5.53 (1H, d, J=13.3), 4.31 (2H, q, J=7.1), 3.82 (2H, br s), 1.41 (3H, t, J=7.1), 1.02 (3H, t, J=7.1). IR (KBr) 2220, 1690, 1622, 1540, 1490 cm -1 . FDMS (m/e) 536 (M+), 294, 242. 
     λ max  CH 2  Cl 2  (ε): 509 (47,000), 480 (57,000), 456 (39,000) (sh), 432 (33,000) (sh). Anal. calc&#39;d. for C 36  H 33  BN 2  O 2  : C, 80.6; H, 6.2; N, 5.2. Found: C, 80.2; H, 6.2; N, 5.2. 
     (c) Preparation of Product (D-15) 
     Ethyl 4-(1-ethyl-2-quinolinylidene)-2-triphenylborylisocyano-2-butenoate (D-15b) (1.62 g, 3.0 mmol) was placed in a 50 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 170° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (1.39 g, 86%) as a magenta crystalline solid (mp 204.5°-206° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.92 (1H, d, J=12.5), 7.85 (2H, m) 7.54-7.43 (7H, m), 7.33-7.13 (12H, m), 6.96 (1H, d, J=12.6), 4.41 (2H, q, J=7.1), 4.28 (2H, q, J=7.1), 1.58 (3H, t, J=7.1), 1.35 (3H, t, J=7.1). IR (KBr) 1622, 1560, 1535, 1520 cm -1 . FDMS (m/e) 536 (M + ). 
     λ max  CH 2  CL 2  (ε): 575 (40,000) (sh), 543 (58,000), 519 (47,000) (sh). Anal. calc&#39;d. for C 36  H 33  BN 2  O 2  : C, 80.6; H, 6.2; N, 5.2. Found: C, 80.4; H, 6.3; N, 5.1. 
     EXAMPLE 12 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-4-(1-ethyl-2-quinolinylidene)-2-butenoate (D-16) 
     (a) Preparation of Ethyl 4-(1-ethyl-2-quinolinylidene)-2-tri-p-fluorophenylborylisocyano-2-butenoate (D-16b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) tris(p-fluorophenyl)borane (1.83 g, 6.18 mmol) in tetrahydrofuran (20 mL); and (2) ethyl 4-(1-ethyl-2-quinolinylidene)-2-isocyano-2-butenoate (D-15a) (1.82 g, 6.18 mmol) in tetrahydrofuran (20 mL). After the reaction slurry had stirred 30 min at 0° C., the solvent was removed under reduced pressure. The residue was triturated with ethanol and the resulting product was isolated by filtration, washed with ethanol, and dried to give an orange solid (D-16b) (3.01 g, 82%). It was pure by TLC and NMR, and was used without further purification. 
     A portion was recrystallized from dichloromethane/ethanol (hot filtration) to give an orange flaky solid (mp 175°-176° C., dec). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.13 (1H, d, J=13.4), 7.64 (1H, t, J=7.9), 7.58 (1H, d, J=7.2), 7.52 (2H, m), 7.42 (1H, d, J=8.4), 7.35 (1H, t, J=7.5), 7.28 (6H, dd, J=6.4, 8.0), 6.96 (6H, d, J=8.8), 5.46 (1H, d, J=13.4), 4.32 (2H, q, J=7.1), 3.90 (2H, br s), 1.40 (3H, t, J=7.1), 1.07 (3H, t, J=7.1). IR (KBr) 2220, 1695, 1623, 1587, 1540, 1495 cm -1 . FDMS (m/e) 590 (M+) 296, 294. 
     λ max  CH 2  Cl 2  (ε): 507 (48,000), 479 (55,000), 458 (34,000) (sh). Anal. calc&#39;d. for C 36  H 30  BF 3  N 2  O 2  : C, 73.2; H, 5.4; N, 4.7. Found: C, 73.2; H, 5.4; N, 4.7. 
     (b) Preparation of Product (D-16) 
     Ethyl 4-(1-ethyl-2-quinolinylidene)-2-tri-p-fluorophenylborylisocyano-2-butenoate (D-16b) (1.2 g, 2.03 mmol) was placed in a 50 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 170° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (0.870 g, 72%) as a green crystalline solid (mp 206°-210° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.89 (1H, d, 12.6), 7.70 (2H, dd, J=6.0, 8.4), 7.48 (1H, t, J=7.8), 7.42 (2H, m), 7.26 (5H, m), 7.17 (2H, m), 6.84 (5H: 4H, t, J=8.9; 1H, m), 6.78 (2H, t, J=8.5), 4.33 (2H, q, J=7.1), 4.25 (2H, q, J=7.1), 1.53 (3H, t, J=7.1), 1.28 (3H, t, J=7.1). IR (KBr) 1623, 1587, 1560, 1540, 1520, 1500 cm -1 . FDMS (m/e) 590 (M + ). 
     λ max  CH 2  Cl 2  (ε): 571 (41,000) (sh), 543 (57,000), 516 (45,000) (sh). Anal. calc&#39;d. for C 36  H 30  BF 3  N 2  O 2  : C, 73.2; H, 5.1; N, 4.7. Found: C, 72.9; H, 5.2; N, 4.6. 
     EXAMPLE 13 
     Preparation of (O-B)-Ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-2-{[(diphenylboryl)phenylmethylene]amino}acetate (D-18) 
     (a) Preparation of Ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene-2-isocyanoacetate (D-18a) 
     The same procedure was employed for the reaction as for Example 1 (D-1a), but using the following materials: (1) potassium t-butoxide (5.6 g, 50 mmol) in tetrahydrofuran (120 mL); (2) ethyl isocyanoacetate (5.65 g, 20 mmol) in tetrahydrofuran (40 mL); (3) 4,5-dihydronaphtho-2-(2-thiopropyl)-[1,2-d]-1,3-dithiolium hexafluorophosphate (21.2 g, 50 mmol). After the reaction was stirred overnight at ambient temperature, water (90 mL), saturated ammonium chloride (10 mL), and ethyl acetate (150 mL) where added. The undissolved material was filtered, then slurried in 1:1 ethanol/ether, filtered again and dried to give (1) (3.5 g). The original filtrate was transferred to a separatory funnel and extracted three times with ethyl acetate. The combined extracts were washed with saturated sodium chloride, dried over sodium sulfate, and filtered, and the solvent was removed under reduced pressure. The residue was triturated with 1:1 ethanol/ether, and the tan solid was filtered to give (2) (2.7 g). By NMR, (1) and (2) appeared to be double bond isomers of the desired product, each contaminated by a small amount of the other. (1) was recrystallized from dichloromethane/ethanol to give pure material D-18a(1) (2.25 g). (2) was flash chromatographed with 15:85 ethyl acetate/cyclohexane to give after trituration with 1:1 ethanol/ether pure D-18a(2) (0.28 g). A second group of fractions gave after evaporation and trituration as above 0.96 g D-18a(2) contaminated with a small amount of D-18a(1). The remaining fractions contained mixtures and were combined with the mother and wash liquors from the crystallization of D-18a(1) and the trituration of chromatographed material, and the solvent was removed under reduced pressure to give a tan solid (1.06 g) that was a mixture of D-18a(1) and D-18a(2) by NMR and TLC (20:80 ethyl acetate/cyclohexane). The total yield was 4.55 g (29%). D-18a(1) and D-18a(2) were fully characterized separately, although the double bond geometries could not be assigned. 
     D-18a(1) mp 184.5°-188° C., dec. (dichloromethane/ethanol). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.30-7.25 (3H, m), 7.17 (1H, m), 4.34 (2H, q, J=7.1), 3.07 (2H, t, J=7.9), 2.79 (2H, t, J=7.9), 1.39 (3H, t, J=7.1). IR (KBr): 2085, 1680, cm -1 . FDMS (m/e) 315 (M+). 
     λ max  CH 2  Cl 2  (ε): 391 (25,000) 377, (21,000). Anal. calc&#39;d. for C 16  H 13  NO 2  S 2  : C, 60.9; H, 4.2; N, 4.4. Found: C, 60.8; H, 4.3; N, 4.4. 
     D-18a(2) mp 175°-177° C., dec. (dichloromethane/ethanol). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.27 (4H, m), 4.36 (2H, q, J=7.1), 3.08 (2H, t J=7.9), 2.81 (2H, t, J=7.9), 1.41 (3H t, J=7.1). IR (KBr): 2100, 1670 cm -1 . FDMS (m/e) 315 (M+). 
     λ max  CH 2  Cl 2  (ε): 390 (25,000), 377 (21,000). Anal. calc&#39;d. for C 16  H 13  NO 2  S 2  : C, 60.9; H, 4.2; N, 4.4. Found: C, 60.6; H, 4.2; N, 4.3. 
     (b) Preparation of Ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-2-triphenylborylisocyanoacetate (D-18b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylborane (0.330 g, 1.36 mmol) in tetrahydrofuran (5 mL); and (2) ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene-2-isocyanoacetate (D-18a) (0.430 g, 1.36 mmol, mixture of olefin isomers) in tetrahydrofuran (5 mL). After the reaction slurry had stirred 30 min at 0° C., the solvent was removed under reduced pressure. The residue was dissolved in warm dichloromethane, filtered, and precipitated with ethanol to give pure D-18b (mixture of olefin isomers) (0.636 g, 84%) as a yellow solid (mp 119°-121° C., dec). 
     A small portion was recrystallized a second time for analysis. 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.45-7.19 (19H, m), 4.38 (2H, q, J=7.1), 3.09 (2H, t, J=7.9), 2.82 (2H, t, J=7.9), 1.41 (3H, q, J=7.1). IR (KBr) 2210, 1680, 1460, 1445, 1430 cm -1 . FDMS (m/e) 557 (M+) 315. 
     λ max  CH 2  Cl 2  (ε): 406 (26,000). Anal. calc&#39;d. for C 34  H 28  BNO 2  S 2  : C, 73.2; H, 5.1; N, 2.5. Found: C, 73.1; H, 5.3; N, 2.5. 
     (c) Preparation of Product (D-18) 
     Ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-2-triphenylborylisocyanoacetate (D-18b) (0.200 g, 0.36 mmol, mixture of olefin isomers) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 160° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (0.124 g. 62%, mixture of olefin misomers by NMR) as a yellow solid (mp 179°-181° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.84 (2H, m), 7.45-7.37 (5H, m), 7.33-7.16 (12H, m), 4.57 (2H, 2 overlapping q, J=7.1), 3.07 (2H, t, J=7.7), 2.82 (2H, 2 overlapping t, J=7.9), 1.47 (3H, 2 overlapping t, J=7.1). IR (KBr) 1530, 1470, 1415 cm -1 . FDMS (m/e) 557 (M + ). 
     λ max  CH 2  Cl 2  (ε): 460 (39,000), 442 (33,000) (sh). Anal. calc&#39;d. for C 34  H 28  BNO 2  S 2  : C, 73.2; H, 5.1; N, 2.5. Found: C, 72.5; H, 5.1; N, 2.5. 
     EXAMPLE 14 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)acetate (D-19) 
     (a) Preparation of Ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-2-tri(p-fluorophenyl)borylisocyanoacetate (D-19b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) tris(p-fluorophenyl)borane (1.14 g, 3.85 mmol) in tetrahydrofuran (10 mL); and (2) ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-2-isocyanoacetate (D-18a) (1.21 g, 3.85 mmol, mixture of olefin isomers) in tetrahydrofuran (10 mL). After the reaction slurry had stirred 30 min at 0° C., the colvent was removed under reduced pressure. The residue was triturated with ethanol to give D-19b (1.90 g, mixture of double bond isomers) as a yellow solid. The material was pure by NMR with the exception of a small amount of residual tetrahydrofuran. 
     A portion (0.885 g) was recrystallized from dichloromethane/thanol (hot filtration) to give pure material (0.734 g) for analysis and yield (81% crude×83% recovery=67% total yield). The pure material (a mixture of olefin isomers) was obtained as a yellow-orange solid (mp 117°-127° C., dec). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.31-7.22 (10H, m), 6.95 (6H, t, J=8.8), 4.34 (2H, q, J=7.1), 3.09-3.02 (2H, m), 2.84-2.78 (2H, m), 1.36 (3H, t, J=7.1). IR (KBr) 2220, 1685, 1585, 1470, 1445 cm -1 . FDMS (m/e) 611 (M+), 315, 296. 
     λ max  CH 2  Cl 2  (ε): 406 (28,000). Anal. calc&#39;d. for C 34  H 25  BF 3  NO 2  S 2  : C, 66.8; H, 4.1; N, 2.3. Found: C, 66.8; H, 4.2; N, 2.3. 
     (b) Preparation of Product (D-19) 
     Ethyl 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-2-tri(p-fluorophenyl)borylisocyanoacetate (D-19b) (1.0 g, 1.64 mmol, mixture of olefin isomers) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 150° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was a mixture of double bond isomers by NMR and TLC (15/85 ethyl acetate/cyclohexane). An attempt was made to separate the isomers by flash chromatography, eluting with 10/90 ethyl acetate/cyclohexane, but all fractions contained mixtures of the two isomers. The fractions were combined and the solvent was evaporated under reduced pressure. Recrystallization from dichloromethane/ethanol gave the pure product (0.604 g, 60%, mixture of olefin isomers by NMR) as a yellow-orange solid (mp 167°-170° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.84-7.77 (2H, m), 7.42-7.21 (8H, m), 6.98-6.86 (6H, m), 2.91-2.83 (2H, m), 1.53-1.45 (3H, 2 overlapping t, J=7.1). IR (KBr) 1590, 1530, 1500, 1470, 1420 cm -1 . FDMS (m/e) 611 (M + ). 
     λ max  CH 2  Cl 2  (ε): 460 (40,000), 444 (34,000) (sh). Anal. calc&#39;d. for C 34  H 25  BF 3  NO 2  S 2  : C, 66.8; H, 4.1; N, 2.3. Found: C, 66.4; H, 4.0; N, 2.3. 
     EXAMPLE 15 
     Preparation of (O-B)-Ethyl 2-{[(diphenylboryl)phenylmethylene]amino}-4-(4,6-diphenyl-2-pyranylidene)-2-butenoate (D-20) 
     (a) Preparation of Ethyl 4-(4,6-diphenyl-2-pyranylidene)-2-isocyano-2-butenoate (D-20a) 
     The same procedure was employed for the reactioin as for Example 1 (D-1a), but using the following materials: (1) potassium t-butoxide (2.8 g, 25 mmol) in tetrahydrofuran (100 mL); (2) ethyl isocyanoacetate (2.82 g, 25 mmol) in tetrahydrofuran (20 mL); (3) 2-(2-dimethylaminovinyl)-4,6-diphenylpyrilium perchlorrate (10 g, 25 mmol). Ethanol trituration of the residue obtained after solvent evaporation gave 3.58 g D-20a as a black crystalline solid. The crude material was recrystallized from ethanol with a hot filtration to give 2.12 g D-20a(1) as a black crystalline solid. The material that had crystallized in the filter funnel during the hot filtration was recrystallized from dichloromethand/ethanol to give 0.44 g D-20a(2). The mother and wash liquors from D-20a(1) and D-20a(2) were combined and the solvent was removed under reduced pressure. The residue was recrystallized form dichloromethane/ethanol to give 0.30 g D-20a(3) (mp 150.5°-152° C.). All three crops (total: 2.92 g, 32%) were homogeneous and identical by TLC (dichloromethane), but by NMR they were mixtures of double bond isomers in various proportions (D-20a(1): 4:1 isomer ratio; D-20a(2): 1:1 isomer ratio; D-20a(3): &gt;9:1 isomer ratio). This was irrelevant for subsequent chemistry, so no attempt was made to separate them. 
     For simplicity, the NMR data for D-20a(3) is given. The other analytical data was essentially the same for all three crops. 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.06 (1H, d, J=12.5), 7.86-7.83 (2H, m) 7.65-7.62 (2H, m), 7.54-7.52 (6H, m), 6.76 (1H, d, J=1.1), 6.70 1H, d, J=1.0), 5.76 (1H, d, J=12.5), 4.35 (2H, q, J=7.1), 1.42 (3H, t, J=7.1). IR (KBr): 2110, 1700, 1635, 1585, 1575, 1545, 1510, 1490 cm -1 . FDMS (m/e) 369 (M+). 
     λ max  CH 2  Cl 2  (ε): 536 (17,400), 504 (17,400), 407 (15,800), 388 (17,100), 309 (23,000). Anal. calc&#39;d. for C 24  H 19  NO 3  : C, 78.0; H, 5.2; N, 3.8. Found: C, 78.2; H, 5.3; N, 3.7. 
     (b) Preparation of Ethyl 4-(4,6-diphenyl-2-pyranylidene)-2-triphenylborylisocyano-2-butenoate (D-20b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylborane (0.607 g, 2.51 mmol) in tetrahydrofuran (5 mL); and (2) ethyl 4-(4,6-diphenyl-2-pyranylidene)-2-isocyano-2-butenoate (D-a) (0.923 g, 2.51 mmol) in tetrahydrofuran (5 mL). After the reaction slurry had stirred 30 min. at 0° C., the solvent was removed under reduced pressure. The residue was triturated with ether and filtered, giving a black solid (1.31 g). The crude product was dissolved in warm dichloromethane, filtered, and precipitated with ethanol to give pure D-20b (1.13 g, 73%, mixture of double bond isomers) as a black crystalline solid. 
     A small portion was purified by chromatography on silica gel (eluting with 20/80 dichloromethane/cyclohexane), then a second recrystallization, giving material for analysis (mp 148.5°-150° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.20 (1H, d, J=13.0), 7.83 (2H, m), 7.64 (2H, m), 7.85-7.53 (6H, m), 7.42 (6H, d, J=6.9), 7.30 (6H, t, J=6.9), 7.21 (3H, t, J=7.2), 6.88 (1H, d, J=0.9), 6.47 (1H, s), 5.34 (1H, d, J=12.8), 4.36 (2H, q, J=7.1), 1.41 (3H, t, J=7.1), as well as small peaks from the minor olefin isomer. IR (KBr) 2220, 1710, 1633, 1585, 1573, 1543, 1507, 1485 cm 31  1. FDMS (m/e) 611 (M+), 369. 
     λ max  CH 2  Cl 2  (ε): 636 (8,400) (sh), 580 (20,000) (sh), 544 (24,300), 513 (20,900) (sh), 409 (13,900), 391 (13,100), 317 (20,300). Anal. calc&#39;d. for C 42  H 34  BNO 3  : C, 82.5; H, 5.6; N, 2.3. Found: C, 82.7; H, 5.8; N, 2.4. 
     (c) Preparation of Product (D-20) 
     Ethyl 4-(4,6-diphenyl-2-pyranylidene)-2-triphenylborylisocyano-2-butenoate (D-20b) (0.200 g, 0.327 mmol, mixture of olefin isomers) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 160° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The reaction was repeated using: 0.500 g, 0.818 mmol. The crude material was combined and recrystallized from dichloromethane/ethanol to give the pure product (0.556 g, 79%) as a black crystalline solid. 
     A small portion was recrystallized a second time for analysis and melting point (mp 173°-178° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.05 (1H, d, J=12.5), 7.90-7.84 (4H, m), 7.68-7.64 (2H, m), 7.55-7.46 (9H, m), 7.30-7.19 (9H, m), 6.83 (1H, s), 6.80 (1H, d, J=12.5), 6.76 (1H, d, J=1.2), 4.50 (2H, q, J=7.1), 1.45 (3H, t, J=7.1). IR (KBr) 1630, 1570, 1520 cm 31  1. FDMS (m/e) 611 (M + ). 
     λ max  CH 2  Cl 2  (ε): 598 (26,200), 560 (24,700), 456 (19,500), 434 (18,200), 296 (24,000). Anal. calc&#39;d. for C 42  H 34  BNO 3  : C, 82.5; H, 5.6; N, 2.3. Found: C, 82.7; H, 5.8; N, 2.2. 
     EXAMPLE 16 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-4-(4,6-diphenyl-2-pyranylidene)-2-butenoate (D-21) 
     (a) Preparation of Ethyl 4-(4,6-diphenyl-2-pyranylidene)-2-tri(p-fluorophenyl)borylisocyano-2-butenoate (D-21b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) tris(p-fluorophenyl)borane (0.845 g, 2.85 mmol) in tetrahydrofuran (5 mL); and (2) ethyl 4-(4,6-diphenyl-2-pyranylidene)-2-isocyano-2-butenoate (D-20a) (1.05 g, 2.85 mmol) in tetrahydrofuran (5 mL). After the reaction slurry had stirred 30 min at 0° C., the solvent was removed under reduced pressure. The residue was triturated with ether and filtered, giving a black solid (1.13 g). The crude product was dissolved in warm dichloromethane, filtered, and precipitated with ethanol to give D-21b (0.780 g, mixture of double bond isomers) as an oily black crystalline solid. A second recrystallization gave pure D-21b as a black crystalline solid (0.560 g, 56%). 
     A small portion was purified by chromatography on silica gel (eluting with 20/80 dichloromethane/cyclohexane), then another recrystallization, giving material for analysis (mp 139°-141° C., dec). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.24 (1H, d, J=13.0), 7.88-7.84 (2H, m), 7.71-7.66 (2H, m), 7.60-7.56 (6H, m), 7.35-7.30 (6H, dd, J=6.3, 8.1), 7.05-6.99 (6H, t, J=8.8), 6.95 (1H, d, J=1.0), 5.28 (1H, d, J=13.0), 4.38 (2H, q, J=7.1), 1.42 (3H, t, J=7.1). IR (KBr) 1710, 1635, 1585, 1540, 1485 cm -1 . FDMS (m/e) 665 (M+), 369, 296. 
     λ max  CH 2  Cl 2  (ε): 629 (9,400) (sh), 574 (21,000) (sh, 544 (25,100), 513 (21,500) (sh), 409 (14,100), 391 (13,100), 317 (20,700). Anal. calc&#39;d. for C 42  H 31  BF 3  NO 3  : C, 75.8; H, 4.7; N, 2.1. Found: C, 75.4; H, 4.9; N, 2.0. 
     (b) Preparation of Product (D-21) 
     Ethyl 4-(4,6-diphenyl-2-pyranylidene)-2-tri-(p-fluorophenyl)borylisocyano-2-butenoate (D-21b) (0.500 g, 0.752 mmol, mixture of olefin isomers) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 160° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ethanol to give the pure product (0.350 g, 70%, predominantly one olefin isomer by NMR) as a black crystalline solid (mp 197°-202° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.06 (1H, d, J=12.5), 7.87-7.81 (4H, m), 7.67-7.64 (2H, m), 7.53-7.51 (6H, m), 7.34 (4H, dd, J=6.4, 8.2), 6.94 (4H, t, J=8.8), 6.89 (2H, t, J=8.4), 6.83 (1H, d, J=0.9), 6.79 (1H, d, J=1.1), 6.75 (1H, d, J=12.5), 4.47 (2H, q, J=7.1), 1.42 (3H, t, J=7.1), as well as peaks attributable to the other olefin isomer. IR (KBr) 1630, 1585, 1570, 1520, 1500 cm -1 . FDMS (m/e) 665 (M + ). 
     λ max  CH 2  Cl 2  (ε): 599 (27,000), 561 (26,000), 454 (19,700), 433 (18,100), 297 (24,300). Anal. calc&#39;d. for C 42  H 31  BF 3  NO 3  : C, 75.8; H, 4.7; N, 2.1, Found: C, 75.6; H, 4.8; N, 2.0. 
     EXAMPLE 17 
     Preparation of (O-B)-Ethyl 2-{[(diphenylboryl)phenylmethylene]amino}-4-(2,6-diphenyl-4-pyranylidene)-2-butenoate (D-25) 
     (a) Preparation of Ethyl 4-(2,6-diphenyl-4-pyranylidene)-2-isocyano-2-butenoate (D-25a) 
     The same procedure was employed for the reaction as for Example 1 (D-1a), but usine the following materials: (1) potassium t-butoxide (1.68 g, 15 mmol) in tetrahydrofuran (50 mL); (2) ethyl isocyanoacetate (1.69 g, 15 mmol) in tetrahydrofuran (15 mL); (3) 2-(2-dimethylaminovinyl)-4,6-diphenylpyrilium perchlorate (6.02 g, 15 mmol). After the reaction was stirred overnight at ambient temperature, it was poured onto water (75 mL) and saturated ammonium chloride (25 mL), and extracted twice with ethyl acetate (75 mL). There was a large amount of undissolved orange solid, and it was removed from both the aqueous and organic layers by filtration. (It was subsequently found to be unreacted starting material.) The aqueous layer was extracted once more with ethyl acetate, and the work-up completed as in Example 1 (D-1a). Ethanol trituration of the residue obtained after solvent evaporation gave 1.51 g (27%) D-25a as a flaky orange solid that was homogeneous by TLC (3:7 ethyl acetate/cyclohexane). 
     A small portion of the crude material was recrystallized from ethanol for analysis and melting point (mp 145°-145.5° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.87-7.80 (4H, m) 7.84 (1H, d, J=12.6)8 7.54-7.50 (6H, m), 6.99 (1H, s), 6.70 (1H, s), 6.00 (1H, d, J=12.9), 4.35 (2H, q, J=7.1), 1.40 (3H, t, J=7.1). IR (KBr): 2125, 1710, 1653, 1553, 1493 cm -1 . FDMS (m/e) 369 (M+). 
     λ max  CH 2  Cl 2  (ε): 470 (36,800) (sh), 446 (40,600), 314 (13,800). Anal. calc&#39;d. for C 24  H 19  NO 3  : C, 78.0; H, 5.2; N, 3.8. Found: C, 78.1, H, 5.3; N, 3.7. 
     (b) Preparation of Ethyl 4-(2,6-diphenyl-4-pyranylidene)-2-triphenylborylisocyano-2-butenoate (D-25b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylborane (0.361 g, 1.49 mmol) in tetrahydrofuran (5 mL); and (2) ethyl 4-(2,6-diphenyl-4-pyranylidene)-2-isocyano-2-butenoate (D-25a) (0.550 g, 1.49 mmol) in tetrahydrofuran (5 mL). After the orange reaction slurry had stirred 30 min at 0° C., the solvent was removed under reduced pressure. The residue was triturated with ether and filtered, giving an orange solid (0.804 g). The crude product was dissolved in warm dichloromethane, filtered, and precipitated with ethanol to give pure D-25b (0.654 g, 73%) as a red-orange flaky solid (mp 117°-120° C., dec). 
     A second crop (0.060 g, 7%) was also obtained (total yield 0.714 g, 80%). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.07 (1H, d, J=13.3), 7.92-7.85 (4H, m), 7.60-7.57 (6H, m), 7.46-7.43 (6H, m), 7.33 (6H, t, J=7.2), 7.25 (3H, t, J=7.1), 7.12 (1H, s), 6.48 (1H, d, J=0.9), 5.65 (1H, d, J=13.3), 4.39 (2H, q, J=7.1), 1.43 (3H, t, J=7.1). IR (KBr) 2225, 1710, 1650, 1565, 1545, 1493 cm -1 . FDMS (m/e) 611 (M+), 369. 
     λ max  CH 2  Cl 2  (ε): 519 (18,800), 492 (29,500), 470 (25,700), 330 (8,000). Anal. calc&#39;d. for C 42  H 34  BNO 3  : C, 82.5; H, 5.6; N, 2.3. Found C, 80.7; H, 5.9; N, 2.2. 
     (c) Preparation of Product (D-25) 
     Ethyl 4-(2,6-diphenyl-4-pyranylidene)-2-triphenylborylisocyano-2-butenoate (D-25b) (0.400 g, 0.655 mmol) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath. At a bath temperature of 110° C. the compound began to melt. Heating was continued to 145° C. and the reaction was held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. By NMR and TLC, the crude product contained a number of compounds. Approximately 100 mg of the crude was recrystallized from dichloromethane/ethanol to give D-25 as a black crystalline solid (0.021 g, 5%) that was homogeneous by NMR and TLC (mp 160°-163° C., dec.). 
     An attempt to recrystallize the remaining crude material failed, and no additional product could be isolated. 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.9 (7H, m), 7.55 (6H, m), 7.47 (4H, m), 7.4-7.1 (11H, m), 6.87 (1H, s), 4.55 (2H, q), 1.45 (3H, t). IR (KBr) 1650, 1570, 1550 cm -1 . FDMS (m/e) 611 (M + ). 
     λ max  CH 2  Cl 2  (ε): 538 (46,700), 513 (47,500). Anal. calc&#39;d. for C 42  H 34  BNO 3  : C, 82.5; H, 5.6; N, 2.3. Found C, 81.5; H, 5.7; N, 2.2. 
     EXAMPLE 18 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-4-(2,6-diphenyl-4-pyranylidene)-2-butenoate (D-26) 
     (a) Preparation of Ethyl 4-(2,6-diphenyl-4-pyranylidene)-2-tri-p-fluorophenylborylisocyano-2-butenoate (D-26b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) tris(p-fluorophenyl)borane (0.475 g, 1.60 mmol) in tetrahydrofuran (5 mL); and (2) ethyl 4-(2,6-diphenyl-4-pyranylidene)-2-isocyano-2-butenoate (D-25a) (0.592 g, 1.60 mmol) in tetrahydrofuran (5 mL). After the orange reaction slurry had stirred 30 min at 0° C., the solvent was removed under reduced pressure. The residue was triturated with ether and filtered, giving an orange solid (0.854 g). The crude product was dissolved in warm dichloromethane, filtered and precipitated with ethanol to give pure D-26b (0.709 g, 67%) as a red-orange flaky solid (mp 114°-120° C., dec). 
     A second crop (0.016 g, 2%) was also obtained (total yield 0.725 g, 69%). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.08 (1H, d, J=13.3), 7.93-7.86 (4H, m), 7.64-7.59 (6H, m), 7.32 (6H, dd, J=6.5, 8.3), 7.14 (1H, s), 7.03 (6H, t, J=8.8), 6.49 (1H, s), 5.57 (1H, d, J=13.3), 4.39 (2H, q, J=7.1), 1.42 (3H, t, J=7.1). IR (KBr) 225, 1710, 1650, 1585, 1567, 1545, 1493 cm -1 . FDMS (m/e) 665 (M+), 369. 
     λ max  CH 2  Cl 2  (ε): 525 (12,800). Anal. calc&#39;d. for C 42  H 31  BF 3  NO 3  : C, 75.8; H, 4.7; N, 2.1. Found: C, 75.4; H, 5.2; N, 2.2. 
     (b) Preparation of Product (D-26) 
     Ethyl 4-(2,6-diphenyl-4-pyranylidene)-2-tri-p-fluorophenylborylisocyano-2-butenoate (D-26b) (0.20 g, 0.30 mmol) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath. At a bath temperature of 110° C., the compound began to melt. Heating was continued to 140° C. and the reaction was held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. By NMR and TLC, the crude product contained a number of compounds. Recrystallization of the material from dichloromethane/ethanol gave the pure product (0.036 g, 18%) as a black crystalline solid (mp 189°-190° C., dec.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.93-7.81 (7H, m), 7.58-7.54 (6H, m), 7.35 (4H, dd, J=6.4, 8.2), 7.11 (1H, s), 7.09 (1H, d, J=12.9), 6.99-6.89 (7H: 4H, t centered at 6.96, J+9.1; 2H, t centered at 6.92, J=9.5; 1H, obscured), 4.53 (2H, q, J=7.1), 1.45 (3H, t, J=7.1). IR (KBr) 1650, 1590, 1540, 1500 cm -1 . FDMS (m/e) 665 (M + ). 
     λ max  CH 2  Cl 2  (ε): 544 (46,900), 516 (46,100). Anal. calc&#39;d. for C 42  H 31  BF 3  NO 3  : C, 75.8; H, 4.7; N, 2.1. Found: C, 74.7; H, 5.0; N, 2.4. 
     EXAMPLE 19 
     Preparation of (O-B)-Ethyl 2-{[(diphenylboryl)phenylmethylene]amino}-4-(1-ethyl-4-quinolinylidene)-2-butenoate (D-27) 
     (a) Preparation of Ethyl 4-(1-ethyl-4-quinolinylidene)-2-isocyano-2-butenoate (D-27a) 
     The same procedure was empolyed for the reaction as for Example 1 (D-1a) but using the following materials: (1) potassium t-butoxide (5.80 g, 51.8 mmol) in tetrahydrofuran (140 mL); (2) ethyl isocyanoacetate (5.86 g, 51.8 mmol) in tetrahydrofuran (60 ml); (3) 4-(2-acetanilidovinyl)-1-ethylquinolinium iodide (23.0 g, 51.8 mmol). After the reaction was stirred overnight at ambient temperature, it was poured onto water (300 mL) and saturated ammonium chloride (100 mL). Attempts to extract with ethyl acetate led to crystallization of the product, so the ethyl acetate/product suspension was evaporated under reduced pressure. The residue was dissolved in dichloromethane, and combined with dichloromethane extractions of the aqueous layer. The work-up was completed as in Example 1 (D-1a). 
     After filtration, the dichloromethane was concentrated to 100-150 mL, and then warmed to take the material into solution. Ethanol (150-200 mL) was added. Crystals formed upon cooling in the refrigerator, and these were collected by filtration to give 11.1 g (73%) D-27a as black flaky crystals (mp 161.5°-162.5° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.17 (1H, d, J=8.2), 7.96 (1H, D, J=12.8), 7.57 (1H, t, J=7.7), 7.31 (2H, m), 7.01 (1H, d, J=5.6), 6.67 (1H, d, J=7.7), 6.46 (1H, d, J=12.9), 4.32 (2H, q, J=7.1), 4.06 (2H, q, J=7.2)8 1.48 (3H, t, J=7.2), 1.39 (3H, t, J=7.1). IR (KBr) 2100, 1670, 1630, 1535 cm -1 . FDMS (m/e) 294 (M+). 
     λ max  CH 2  Cl 2  (ε): 544 (35,000), 510 (39,000), 483 (24,000). Anal. calc&#39;d. for C 18  H 18  N 2  O 2  : C, 73.4; H, 6.2; N, 9.5. Found: C, 73.0; H, 6.1; N, 9.4. 
     (b) Preparation of Ethyl 4-(1-ethyl-4-quinolinylidene)-2-triphenylborylisocyano-2-butenoate (D-27b) 
     The same procedure was empolyed for the reaction as for Example 1 (D-1b) but using the following materials: (1) triphenylborane (3.39 g, 14.0 mmol) in tetrahydrofuran (40 L); and (2) ethyl 4-(1-ethyl-4-quinolinylidene)-2-isocyano-2-butenoate (D-27a) (4.12 g, 14.0 mmol) in tetrahydrofuran (125 mL). After the reaction slurry had stirred 30 min, warning from 0° C. to ambient temperature, ethanol (150 mL) was added and the precipitated product was isolated by filtration, washed with ethanol, and dried. A second crop was obtained by removing some of the solvent under reduced pressure (total crude yield, 6.31 g). The red-gold solid was dissolved in warm dichloromethane (250 mL), filtered, and ethanol (200 mL) was added to induce crystallization. The precipitate was collected by filtration, washed with ethanol, and dried (4.03 g) to give small red-gold crystals (mp 168°-168.5° C.). 
     A second crop gave additional red-gold solid (1.99 g), for a total yield of 6.02 g, 80%). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.12 (1H, d, J=13.4), 7.64 (1H, t, J=7.9), 7.52-7.18 (19H, m), 6.87 (1H, d, J=7.6), 6.24 (1H, d, J=13.5), 4.32 (2H, q, J=7.1), 4.16 (2H, q, J=7.1), 1.50 (3H, t, J=7.2), 1.40 (3H, t, J=7.1). IR (KBr) 1690, 1620, 1530 cm -1 . FDMS (m/e) 536 (M+), 294. 
     λ max  CH 2  Cl 2  (ε): 555 (85,000), 519 (53,000), 489 (20,000) (sh). Anal. calc&#39;d. for C 36  H 33  BN 2  O 2  : C, 80.6; H, 6.2; N, 5.2. Found: C, 80.5; H, 6.1; N, 5.1. 
     (c) Preparation of Product (D-27) 
     Ethyl 4-(1-ethyl-4-quinolinylidene)-2-triphenylborylisocyano-2-butenoate (D-27b) (0.10 g, 0.19 mmol) was placed in a 10 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 180° C. and held at that temperature for 10 minutes, then removed from the oil bath and allowed to cool to room temperature. NMR and TLC analysis of the crude product indicated that the reaction had proceeded as expected. The reaction was repeated on a larger scale (3.44 g, 6.42 mmol) in a 100 mL flask. The crudes were combined for recrystallization from dichloromethane/ethanol to give the pure product in two crops (2.54 g, 72%) as green needles (first crop, mp 184.5°-186° C.) and a green powder (second crop). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.31 (1H, d, J=8.4), 7.96 (1H, d, J=12.7), 7.89 (2H, m), 7.62 (1H, d, J=12.9), 7.56 (1H, t, J=7.3), 7.46 (4H, d, J=6.8), 7.36 (1H, t, J=7.7), 7.30-7.14 (10H, m), 7.01 (1H, d, J=7.6), 6.78 (1H, d, J=7.7), 4.44 (2H, q, J=7.1), 4.05 (2H, q, J=7.1), 1.48 (3H, t, J=7.1), 1.38 (3H, t, J=7.1). IR (KBr) 1620, 1535, 1510 cm -1 . FDMS (m/e) 537 (M +  +1) 536 (M + ), 535, 
     λ max  CH 2  Cl 2  (ε): 623 (55,000), 580 (63,000). Anal. calc&#39;d. for C 36  H 33  BN 2  O 2  : C, 80.6; H, 6.2; N, 5.2. Found: C, 80.2; N, 5.1. 
     EXAMPLE 20 
     Preparation of (O-B)-Ethyl 2{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-4-(1-ethyl-4-quinolinylidene)-2-butenoate (D-28) 
     (a) Preparation of Ethyl 4-(1-ethyl-4-quinolinylidene-2-tri(p-fluorophenyl)borylisocyano-2-butenoate (D-28b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b) but using the following materials: (1) tris(p-fluorophenyl)borane (4.00 g, 13.5 mmol) in tetrahydrofuran (40 mL); and (2) ethyl 4-(1-ethyl-4-quinolinylidene)-2-isocyano-2-butenoate (D-27a) (3.98 g, 13.5 mmol) in tetrahydrofuran (125 mL). The reaction was stirred 30 min, warming from 0° C. to ambient temperature. The solvent was removed under reduced pressure, and the residue was triturated with ethanol (75 mL). After warming slightly then recooling, the resulting product was isolated by filtration, washed with ethanol, and dried to give a dark green solid (7.11 g). Recrystallization from dichloromethane/ethanol (hot filtration) gave pure D-28b (6.25 g, 78%) as small dark green needles (mp 164.5°-166° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.10 (1H, d, J=13.5), 7.66 (1H, t, J=7.8), J=13.5), 7.66 (1H, t, J=7.8), 7.41 (2H, m), 7.36-7.26 (8H, m), 6.96 (6H, t, J=8.8), 6.89 (1H, d, J=4.6), 6.12 (1H, d, J=13.4), 4.30 (2H, q, J=7.1), 4.17 (2H, q, J=7.1), 1.50 (3H, t, J=7.2), 1.36 (3H, t, J=7.1). IR (KBr) 1690, 1620 , 1585, 1530, 1495 cm -1 . FDMS (m/e) 590 (M+), 294. 
     λ max  CH 2  Cl 2  (ε): 555 (90,000), 519 (54,000). Ana.. calc&#39;d. for C 36  H 30  BF 3  N 2  O 2  : C, 73.2; H, 5.1; N, 4.7. Found: C, 73.3; H, 5.4; N, 4.4. 
     (b) Preparation of Product (D-28) 
     Ethyl 4-(1-ethyl-4-quinolinylidene)-2-tri-p-fluorophenylborylisocyano-2-butenoate (D-28b) (0.400 g, 0.678 mmol) was placed in a 100 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 180° C. until the starting material had completely melted, then the flask was immediately removed from the bath. By TLC (1/1 ethyl acetate/cyclohexane) the crude consisted of the desired product (less polar) and a second material (more polar). The two could be separated cleanly by vacuum chromatography on a 150 mL fritted funnel (fine silica gel). 
     THe crude material was loaded onto the silica gel with minimal volumes of dichloromethane, then a gradient elution with ethyl acetate/cyclohexane was performed. The desired product eluted with a 30/70 ratio. The fractions were evaporated under reduced pressure, and the residue was triturated with ethanol and filtered to give product (0.096 g, 24%) as a blue solid that was pure by NMR. 
     The mother liquor was evaporated under reduced pressure, and the residue was recrystallized from dichloromethane/ethanol to give additional material (0.030 g, 7%; total yield: 0.126 g, 31%) as a blue crystalline solid (mp 183°-186° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 8.31 (1H, d, J=8.3), 8.00 (1H, d, J=12.9), 7.83(2H, dd, J=2.5, 6.0), 7.59 (2H, d, J=12.0) 7.42-7.32 (6H, m), 7.08 (1H, d, J=7.5), 6.96-6.88 (6H, m), 6.83 (1H, d, J=7.7), 4.42 (2H, q, J=7.1), 4.09 (2H, q, J=7.1), 1.50 (3H, t, J=7.1), 1.37 (3H, t, J=7.1). IR (KBr) 1630, 1590, 1540, 1540, 1500, 1445 cm -1 . FDMS (m/e) 591 (M +  +1) 590 (M + ). 
     λ max  CH 2  Cl 2  (ε): 623 (45,500), 580 (65,600). Anal. calc&#39;d. for C 36  H 30  BF 3  N 2  O 2  : C, 73.2; H, 5.1; N, 4.7. Found: c, 73.0; H, 5.2; N, 4.7. 
     EXAMPLE 21 
     Preparation of (O-B)-Ethyl 3-dimethylamino-2-{[(diphenylboryl)phenylmethylene]amino}-2-propenoate (D-29) 
     (a) Preparation of Ethyl 3idimathylamino-2-triphenylborylisocyano-2-propenoate (D-29b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b) but using the following materials: (1) triphenylborane (1.99 g, 8.22 mmol) in tetrahydrofuran (10 mL); and (2) 3-dimethylamino-2-isocyano-2-propenoate (1.38 g, 8.22 mmol, prepared as described in U. Schollkopf, P. -H. Prosch, H. -H. Lau, Justus Liebigs Ann. Chem., 1444 (1979)) in tetrahydrofuran (10 mL). The reaction was allowed to warm to ambient temperature and stir overnight, the the solvent was evaporated under reduced pressure. The resulting oily solid was triturated with ether, and the product was isolated by filtration as a light yellow solid (1.87 g , 55%). 
     In another experiment, recrystallization from methylene chloride/cyclohexane (hot filtration) gave analytically pure material as a white crystalline solid (mp 114°-116.5° C.). 
       1  H NMR (270 MHz, CDCl 3 ) δ 7.35 (1H, s), 7.28 (6H, dd, J=1.5, 8). 7.22-7.05 (9H, m) 4.23 (2H, q, J=7), 3.09 (3H, br s), 2.78 (3H, br s), 1.32 (3H, q, J=7). IR (KBr) 2225, 1720, 1650 cm -1 . FDMS (m/e) 410 (M+), 242. 
     λ max  CH 2  Cl 2  (ε): 294 (20,400) Anal. calc&#39;d. for C 26  H 27  BN 2  O 2  : C, 76.1; H, 6.6; N, 6.8; B, 2.6. Found: C, ;76.3; H, 6.6; N, 6.8; B, 2.7. 
     (b) Preparation of Product (D-29) 
     Ethyl 3-dimethylamino-2-triphenylborylisocyano-2-propenoate (D-29b) (1.87 g, 4.56 mmol) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 150° C. and held at that temperature for 15 min, then removed from the oil bath and allowed to cool to room temperature. Recrystallization from dichloromethane/ether gave the pure product (1.13 g, 60%) as an off-white solid. 
     In a separate experiment, recrystallization from dichloromethane/cyclohexane gave a white solid for analysis and melting point (mp 169.5°-170.5° C.). 
       1  H NMR (270 MHz, CDCl 3 ) &#34;7.60 (2H, m), 7.38 (1H, m), 7.36 (1H, s), 7.26-7.07 (9H, m), 4.35 (2H, q, J=7), 3.87 (3H, s), 3.26 (3H, s) 1.33 (3H, t, J=7). IR (KBr) 1650, 1535 cm -1 . FDMS (m/e) 410 (M + ). 
     λ max  CH 2  Cl 2  (ε): 339 (27,300). Anal. calc&#39;d. for C 26  H 27  BN 2  O 2  : C, 76,1; H, 6.6; N, 6.8; B, 2.6. Found: C, 76.5; H, 6.7; N, 6.8; B, 2.5. 
     EXAMPLE 22 
     Preparation of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-3-dimethylamino-2-propenoate (D-30) 
     (a) Preparation of Ethyl 3-dimethylamino-2-tri(p-fluorophenyl)borylisocyano-2-propenoate (D-30b) 
     The same procedure was employed for the reaction as to Example 1 (D-1b) but using the following materials: (1) tris(p-fluorophenyl)borane (0.913 g, 3.1 mmol) in tetrahydrofuran (10 mL); and (2) 3-dimethylamino-2-isocyano-2-prpoenoate (see Example 29) (0.518 g, 3.08 mmol) in tetrahydrofuran (5 mL). The reaction was stirred 1 hour at 0° C. and 1 hour at ambient temperature, then the solvent was evaporated under reduced pressure. Trituration with ether gave D-30b (0.76 g, 53%) as a white crystalline solid. 
     A small portion was recrystallized from methylene chloride/ether for analysis (mp 124.5°-127.5° C.). 
       1  H NMR (270 MHz, CDCl 3 ) δ 7.40 (1H, s), 7.18 (6H, dd, J=6, 8.5), 6.92 (6H, m), 4.28 (2H, q, J=7), 3.18 (3H, br s), 2.88 (3H, br s), 1.36 (3H, t, J=7). IR (KBr) 2225, 1705, 1640 cm -1 . FDMS (m/e) 464 (M+), 296. 
     λ max  CH 2  Cl 2  (ε): 293 (19,500). Anal. calc&#39;d. for C 26  H 24  BF 3  N 2  O 2  : c, 67.3; H, 5.2; N, 6.0; B, 2.3. Found: C, 67.2; H, 5.3; N, 6.0; B, 2.0. 
     (c) Preparation of Product (D-30) 
     Ethyl 3-dimethylamino-2-tri(p-fluorophenyl)borylisocyano-2-propenoate (D-30b) (0.400 g, 0.862 mmol) was placed in a 10 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bathe to 150° C. and held at that temperature fro 5 minutes, then removed from the oil bath and allowed to cool to room temperature. Trituration of the reaction with ether gave product that was pure by TLC and NMR (0.342 g, 85%) as a pale yellow solid. 
     In a separate experiment, recrystallization from dichloromethane/ether gave a white solid for analysis and melting point (mp 193°-194° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.53 (2H, dd, J=6,9), 7.37 (1H, s), 7.28 (4H, dd, J=6,9), 6.88 (4H, app t, J=9) 6.82 (2H, app t, J=9), 4.33 (2H, q, J=7), 3.83 (3H, s), 3.27 (3H, s), 1.31 (3H, t, J=7). IR (KBr) 1630, 1590, 1525, 1505 cm -1 . FDMS (m/e) 465 (M +  +1), 464 (M + ), 463. 
     λ max  CH 2  Cl 2  (ε): 339 (26,900). Anal. calc&#39;d. for C 26  H 24  BF 3  N 2  O 2  : C, 67.3; H, 5.2; N, 6.0; B, 2.3. Found: C, 67.5; H, 5.3; N, 5.9; B, 1.9. 
     EXAMPLE 23 
     Preparation of (O-B)-Ethyl 3,3-bis(dimethylamino)-2-{[(diphenyllboryl)phenylmethylene]amino}-2-propenoate (D-31) 
     (a) Preparation of Ethyl 3,3-bis(dimethylamino)-2-isocyano-2-propenoate (D-31a) 
     To a slurry of potassium t-butoxide (4.48 g, 40 mmol) in dry distilled tetrahydrofuran (40 mL) in a 3-neck 250 mL flask at -18° C., under argon was added dropwise from an addition funnel a solution of ethyl isocyanoacetate (4.52 g, 40 mmol) in dry, distalled tetrahydrofuran (40 mL). The anion was allowed to form for 25 min at -78° C., then solid bis(dimethylamino)ethoxymethylium tetrafluoroborate [9.28 g, 40 mmol, prepared as described by von H. Meerwein, W. Florian, N. Schon, G. Stopp, Justus Liebigs Ann. Chem. 641, 1, (1960)] was added as quickly as possible through a powder funnel with a stream of argon. The reaction was allowed to warm to ambient temperature and stir for 4 hours. It was then poured onto water (200 mL) and saturated ammonium chloride (40 mL) and extracted three times with ethyl acetate (100 mL). The combined extracts were washed with water and saturated sodium chloride, dried over sodium sulfate, and the solvent removed under reduced pressure. The resulting brown oil (6.9 g) was flash chromatographed, eluting with ethyl acetate, to give slightly impure D-31a as a brown oil (4.78 g, 57%). It was used without further purification 
       1  H NMR (90 MHz, CDCl 3 ) δ 4.16 (2H, q, J=7), 2.87 (12H, s), 1.32 (3H, t, J=7). 
     (b) preparation of Ethyl 3,3-bis(dimethylamino)-2-triphenylborylisocyano-2-propenoate (D-31b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylborane (1.94 g, 8.02 mmol) in tetrahydrofuran (8 mL); and (2) 3,3-bis(dimethylamino)-2-isocyano-2-propenoate (D-31a) (1.69 g, 8.02 mmol) in tetrahydrofuran (8 mL). After the reaction had stirred 1.5 hour at 0° C., the solvent was evaporated under reduced pressure. 
     The residue was recrystallized from ethanol (hot filtration) to give pure D-31g (2.63 g, 72%) as an off-white crystalline solid (mp 141.5-143° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.35 (6H, d, J=6.8), 7.25 (6H, t, J=7.1), 7.17 (3H, d, J=7.1), 4.23 (2H, q, J=7.1), 2.92 (6H, br s), 2.72 (3H, br s), 2.65 (3H, br s), 1.35 (3H, t, J=7.1). IR (IBr) 1700, 1570, 1540 cm -1 . FDMS (m/e) 453 (M+), 242, 211. 
     λ max  CH 2  Cl 2  (ε): 296 (19,300). 
     Anal. calc&#39;d. for C 28  H 32  BN 3  O 2  : C, 74.2; H, 7.1; N, 9.3l. Found: C, 74.4; H, 7.1; N, 9.2. 
     (c) Preparation of Product (D-31) 
     Ethyl 3,3-bis(dimethylamino)-2-triphenylborylisocyano-2-propenoate (D-31b) (2.0 g, 4.42 mmol) was placed in a 25 ml flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 150° C. and held at that temperature for 5 minutes, then removed from the oil bath and allowed to cool to room temperature. By TLC (ethyl acetate), mostly starting material was present. The flask was put under an argon atmosphere again, and heated to 160° C. for 30 minutes, then allowed to cool to room temperature. By TLC the reaction was complete. Recrystallization from dichloromethane/ether gave the product (1.80 g) in two crops as a tan solid. Recrystallization from ethanol then gave the pure product (1.19 g, 60%) as a light tan solid (mp 180.5°-185° ≢C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.62 (2H, m), 7.45 (4H, m), 7.20 (4H, m), 7.12 (5H, m), 4.35 (2H, q, J=7.1), 2.96 (12H, br s), 1.28 (3H, t, J=7.1). IR (KBr) 1565, 1510, 1500 cm -1 . FDMS (m/e) 435 (M + ). 
     λ max  CH 2  Cl 2  (ε): 348 (21,100). Anal. calc&#39;d. for C 28  H 32  BN 3  O 2  : C, 74.2; H, 7.1; N, 9.3. Found: C, 74.2;H, 6.9; N, 9.2. 
     EXAMPLE 24 
     Preparation of (O-B)-Ethyl 3,3-bis(dimethylamino)-2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-2-propenoate (D-32) 
     (a) Preparation of Ethyl 3,3-bis(dimethylamino)-2-tri-p-fluorophenylborylisocyano-2-propenoate (D-32) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) tris(p-fluorophenyl)borane (1.96 g, 6.62 mmol) in tetrahydrofuran (6 mL); and (2) 3,3-bis(dimethylamino)-2-isocyano-2-propenoate (D-31a) (1.40 g, 6.62 mmol) in tetrahydrofuran (6 mL). After the reaction had stirred 1 hour at 0° C., the solvent was evaporated under reduced pressure. The residue was chromatographed on silica gel, eluting with ethyl acetate to give a light tan solid (2.69 g). 
     It was recrystallized from ethanol (hot filtration) to give pure D-32b (2.23 g, 66%) as a white crystalline solid (mp 150.5°-152.5° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.23 (6H, dd, J=6.4, 8.2), 6.94 (6H, t, J=8.9), 4.22 (2H, q, J=7.1), 2.94 (6H, br s), 2.76 (3H, br s), 1.31 (3H, t, J=7.1). IR (IBr) 1700, 1600, 1565, 1540, 1505 cm -1 . FDMS (m/e) 507 (M+), 296. 
     λ max  CH 2  Cl 2  (ε): 295 (19,300). 
     Anal, calc&#39;d. for C 28  H 29  BF 3  N 3  O 2  : C, 66.5; H, 5.8; N, 8.3. Found: C, 66.5; H, 5.8; N, 8.2. 
     (b) Preparation of Product (D-32) 
     Ethyl 3,3-bis(dimethylamino)-2-tri-p-fluorophenylborylisocyano-2-propenoate (D-32b) (1.80 g, 3.55 mmol) was placed in a 25 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 160° C. and held at that temperature for 30 minutes, then removed from the oil bath and allowed to cool to room temperature. By TLC (ethyl acetate) the reaction was complete. Recrystallization from dichloromethane/ether gave the pure product (1.33 g, 74%) in two crops as a light tan solid. 
     A small portion was recrystallized from ethanol for analysis and melting point (mp 178°-180.5° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.54 (2H, dd, J=5.9, 8.6), 7.33 (4H, dd, J=6.7, 8.3), 6.89 (4H, t, J=9.0), 6.81 (2H, t, J=8.8), 4.31 (2H, q, J=7.1), 2.96 (12H, s), 1.27 (3H, t, J=7.1). IR (KBr) 1590, 1560, 1525, 1500 cm -1 . FDMS (m/e) 507 (M + ). 
     λ max  CH 2  Cl 2  (ε): 345 (20,600). Anal. calc&#39;d. for C 28  H 29  BF 3  N 3  O 2  : C, 66.3; H, 5.8; N, 8.3. Found: C, 66.1; H, 6.0; N, 7.9. 
     EXAMPLE 25 
     Preparation of (O-B)-Ethyl 2-(1,3-dimethyl-2-imidazolidinylidene)-2-{[(diphenylboryl)phenylmethylene]amino}-acetate (D-34) 
     (a) Preparation of Ethyl 2-(1,3-dimethyl-2-imidazolidinylidene)-2-isocyanoacetate (D-34a) 
     A slurry of 1.3-dimethyl-2-ethoxy-4,5-dihydroimidazolium tetrafluoroborate (100 mmol as 100% of theory) was prepared as described by von H. Meerwein, W. Florian, N. Schon, G. Stopp, Liebigs Ann. Chem. 641, 1, (1960), using the following materials: (1) boron trifluoride etherate (19.0 g, 134 mmol); (2) epichlorohydrin (9.28 g, 100 mol): and (3) 1,3-dimethylimidazolidin-2-one (11.4 g, 100 mmol). 
     the anion of ethyl isocyanoacetate was made as follows: To a slurry of potassium t-butoxide (11.2 g, 100 mmol) in dry, distilled tetrahydrofuran (80 mL) in a 3-neck 500 mL flask at -78° C. under argon was added dropwise from an addition funnel a solution of ethyl isocyanoacetate (11.3 g, 100 mmol) in dry, distilled tetrahydrofuran (80 mL). The anion was allowed to form for 25 min at -78° C., then the flask was equipped with an overhead stirrer. The slurry of the tetrafluoroborate salt was added as quickly as possible through a powder funnel with a stream of argon. The reaction was stirred 15 min at -78° C., then was allowed to warm to ambient temperature and stir overnight. It was then diluted with water (100 mL) and ethyl acetate and filtered through celite. The filtrated was transferred to an addition funnel and extracted three times with ethyl acetate. The combined extracts were washed with water and saturated sodium chloride, dried over sodium sulfate, and the solvent removed under reduced pressure. The residue (15 g) was a black oil containing some solid. When the material was loaded on a silica gel column for flash chromatography with ethyl acetate, the solid would not dissolve (1.40 g, pure D-34a by TLC and NMR). The material on the column was eluted with ethyl acetate, to give a brown solid that was a mixture of the produce D-34a and the urea starting material. 
     The material was recrystallized from ethyl acetate to give the product (2.68 g) as a light tan crystalline solid (total yield 4.08 g, 20%). A small portion was recrystallized from ethyl acetate for analysis and melting point (mp 102°-103° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 4.18 (2H, q, J=7.1), 3.66 (4H, s), 3.02 (6H, s), 1.32 (3H, t, J=7.1). IR (KBr) 1660, 1545 cm -1 . FDMS (m/e) 209 (M+). 
     Anal. calc&#39;d. for C 10  H 15  N 3  O 2  : C, 57.4; H, 7.2; N, 20.1. Found: C, 57.4; H, 7.1; N, 20.0. 
     (c) Preparation of Ethyl 2-(1,3-dimethyl-2-imidazolinylidene)-2-triphenylborylisocyanoacetate (D-34b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) triphenylborane (2.20 g, 9.1 mmol) in tetrahydrofuran (20 mL); and (2) ethyl 2-(1,3-dimethyl-4,5-dihydroimidazolinylidene)-2-isocyanoacetate (D-34a) (1.90 g, 9.1 mmol) in tetrahydrofuran (20 mL). After the reaction had stirred 1 hour at 0° C., the solvent was evaporated under reduced pressure. 
     The residue was recrystallized from ethanol (hot filtration) to give (in two crops) pure D-34b (2.59 g, 63%) as a white crystalline solid (mp 167°-169° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.36 (6H, d, J=6.9), 7.24 (6H, app t, J=7.2), 7.15 (3H, t, J=7.1), 4.23 (2H, q, J=7.1), 3.61 (4H, s), 2.82 (6H, s), 1.35 (3H, t, J=7.1). IR (KBr) 1680, 1545 cm -1 . FDMS (m/e) 451 (M+), 450. 
     λ max  CH 2  Cl 2  (ε): 286 (12,600). 
     Anal. calc&#39;d. for C 28  H 30  BN 3  O 2  : C, 74.5; H, 6.7; N, 9.3. Found: C, 74.3; H, 6.7; N, 9.3. 
     (c) Preparation of Product (D-34) 
     Ethyl 2-(1,3-dimethyl-2-imidazolidinylidene)-2-triphenylborylisocyanoacetate (D-34b) (1.50 g, 3.33 mmol) was placed in a 35 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 175°-180° C. and held at that temperature for 15 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from dichloromethane/ether to give the pure product (1.17 g, 78%) as a white crystalline solid (mp 238°-239.5° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.54 (2H, m), 7.42 (4H, d, J=7.4), 7.18°-7.06 (9H, m), 4.30 (2H, q, J=7.1), 3.68 (4H, s), 2.97 (6H, s), 1.25 (3H, t, J=7.1). IR (KBr) 1560, 1505, 1480 cm -1 . FDMS (m/e) 451 (M + ). 
     λ max  CH 2  Cl 2  (ε): 332 (18,800). Anal. calc&#39;d. for C 28  H 30  BN 3  O 2  : C, 74.5; H, 6.7; N, 9.3. Found: C, 74.6; H, 6.5; N, 9.3. 
     EXAMPLE 26 
     Preparation of (O-B)-Ethyl 2-(1,3-dimethyl-2-imidazolidinylidene)-2-{[(di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino})acetate (D-35) 
     (a) Preparation of Ethyl 2-(1,3-dimethyl-2-imidazolidinylidene)-2-triphenylborylisocyanoacetate (D-35b) 
     The same procedure was employed for the reaction as for Example 1 (D-1b), but using the following materials: (1) tris(p-fluorophenyl)borane (2.63 g, 8.89 mmol) in tetrahydrofuran (20 mL); and (2) ethyl 2-(1,3-dimethyl-4,5-dihydroimidazolinylidene-2-isocyanoacetate (D-34a) (1.86 g, 8.89 mmol) in tetrahydrofuran (20 mL. After the reaction had stirred 1 hour at 0° C., the solvent was evaporated under reduced pressure. 
     The residue was recrystallized from ethanol (hot filtration) to give pure D-35b (3.36 g, 75%) as a white crystalline solid (mp 165.5°-167° C.). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.24 (6H, dd, J=6.4, 8.3), 6.93 (6H, app t, J=8.9), 4.22 (2H, q, J=7.1), 3.67 (4H, s), 2.84 (6H, s), 1.32 (3H, t, J=7.1). IR (KBr) 1680, 1595, 1550, 1500 cm -1 . FDMS (m/e) 505 (M+), 504. 
     λ max  CH 2  Cl 2  (ε): 280 (12,900). 
     Anal. calc&#39;d. for C 28  H 27  BF 3  N 3  O 2  : C, 66.5 H, 5.4; N, 8.3. Found: C, 66.2; H, 5.5; N, 8.3. 
     (b) Preparation of Product (D-35) 
     Ethyl 2-(1,3-dimethyl-2-imidazolidinylidene)-2-triphenylborylisocyanoacetate (D-35b) (1.68 g, 3.30 mmol) was placed in a 35 mL flask. The flask was evacuated and refilled with argon four times. The flask was heated in an oil bath to 175°-180° C. and held at that temperature for 15 minutes, then removed from the oil bath and allowed to cool to room temperature. The material was recrystallized from ethyl acetate/ether to give the pure produce (1.18 g, 70%) as a white powdery solid (mp 222°-222.5° C.). 
     The mother liquours were evaporated under reduced pressure, and the residue was recrystallized from dichloromethane/ether to give a second crop of D-35 as a white powder (0.26 g, 15%; total yield: 1.44 g, 86%). 
       1  H NMR (300 MHz, CDCl 3 ) δ 7.47 (2H, dd, J=5.9, 8.6), 7.31 (4H, dd, J=6.7, 8.0), 6.86 (4H, t, J=8.9), 6.78 (2H, t, J=8.8), 4.26 (2H, q, J=7.1), 3.71 (4H, s), 2.98 (6H, s), 1.24 (3H, t, J=7.1). IR (KBr) 1595, 1565, 1505, 1485 cm -1 . FDMS (m/e) 505 (M + ). 
     λ max  CH 2  Cl 2  (ε): 330 (19,700). Anal. calc&#39;d. for C 28  H 27  BF 3  N 3  O 2  : C, 66.5 H, 5.4; N, 8.3. Found: C, 66.6; H, 5.4; N, 8.3. 
     EXAMPLE 27 
     Preparation of (O-B)-2-{[(Diphenylboryl)phenylmethylene]amino}-3-pyrrolidino-N,N-tetramethylene-2-propenamide (D-36) 
     A solution of (O-B)-Ethyl 3-dimethylamino-2-{[(diphenylboryl)phenylmethylene]amino-2-propenoate (D-29) (205 mg, 0.50 mmol) in pyrrolidine (2 ml) was stirred under argon 1 hour at room temperature. Thin layer chromatography (1:1 ether/cyclohexane) indicated the disappearance of starting material and the appearance of a yellow, much more polar spot. The excess pyrrolidine was removed under reduced pressure, and the residue was recrystallized from methylene chloride/ether to give D-36 as a yellow solid (163 mg, 71%), mp 214.5°-224.5° C., dec. 
       1  H NMR (270 MHz, CDCl 3 ) δ 7.56 (2H, m), 7.30 (4H, m), 7.18-7.01 (9H, m), 6.72 (1H, s), 4.28-3.27 (4H, br s), 3.70 (4H, br t), 1.93 (8H, m). IR (KBr) 1615, 1520 cm -1 . FDMS (m/e) 461 (M + ). 
     λ max  CH 2  Cl 2  (ε): 347 (20,000). Anal. calc&#39;d. for C 30  H 32  BN 3  O: C, 78.1; H, 7.0; N, 9.1. Found: C, 77.5; H, 7.3; N, 8.8. 
     EXAMPLE 28 
     Preparation of (O-B)-2-{[(Di-p-fluorophenylboryl)-p-fluorophenylmethylene]amino}-3-pyrrolidino-N,N-tetramethylene-2propenamide (D-37) 
     A solution of (O-B)-Ethyl 2-{[(di-p-fluorophenylboryl)-p-flurorophenylmethylene]amino}-3-dimethylamino-2-propenoate (D-30) (232 mg, 0.50 mmol) in pyrrolidine (3 ml) was stirred under argon 3 hours at room temperature. The excess pyrrolidine was removed under reduced pressure, and the residue was recrystallized from methylene chloride/ether to give D-37 as a yellow solid (147 mg, 57%), mp 201.5°-212.5° C., dec. 
       1  H NMR (270 MHz, CDCl 3 ) δ 7.50 (2H, dd, J=5,9), 7.18 (4H, dd, J=6.9), 6.83 (7H, m), 4.25-3.22 (4H, br s), 3.70 (4H, br, t), 1.95 (8H, m). IR (KBr) 1623, 1597, 1523, 1510 cm -1 . FDMS (m/e) 515 (M + ). 
     λ max  CH 2  Cl 2  (ε): 350 (14,500). Anal calc&#39;d. for C 30  H 29  BF 3  N 3  O: C, 69.9; H, 5.7; N, 8.2. Found: C, 69.6; H, 5.7; N, 8.1. 
     
                                           TABLE II                                
__________________________________________________________________________
Analytical Data for Intermediates*                                        
                            Calc&#39;d. For                                   
                                    Found                                 
Dye  g .sub.max.sup.nm                                                    
        ε                                                         
              M.P. °C.                                             
                    Mol. Formula                                          
                            C  H N  C  H N                                
__________________________________________________________________________
D-1a 443                                                                  
        62,000                                                            
                134-134.5                                                 
                    C.sub.16 H.sub.16 N.sub.2 O.sub.2 S                   
                            64.0                                          
                               5.4                                        
                                 9.3                                      
                                    63.9                                  
                                       5.4                                
                                         9.3                              
D-4a 347                                                                  
        39,000                                                            
              168.5-171                                                   
                    C.sub.14 H.sub.14 N.sub.2 O.sub.2 S                   
                            61.3                                          
                               5.1                                        
                                 10.2                                     
                                    61.7                                  
                                       5.2                                
                                         10.2                             
D-6a 509                                                                  
        62,000                                                            
              163-165                                                     
                    C.sub.18 H.sub.18 N.sub.2 O.sub.2 S                   
                            66.2                                          
                               5.6                                        
                                 8.6                                      
                                    66.1                                  
                                       5.6                                
                                         8.5                              
D-8a 408                                                                  
        72,000                                                            
                135-136.5                                                 
                    C.sub.16 H.sub.16 N.sub.2 O.sub.3                     
                            67.6                                          
                               5.7                                        
                                 9.9                                      
                                    67.6                                  
                                       5.8                                
                                         9.8                              
D-10a                                                                     
     490                                                                  
        71,000                                                            
              154.5-155.5                                                 
                    C.sub.18 H.sub.18 N.sub.2 O.sub.3                     
                            69.7                                          
                               5.8                                        
                                 9.0                                      
                                    69.5                                  
                                       5.6                                
                                         8.9                              
D-15a                                                                     
     480                                                                  
        42,500                                                            
              137.5-139                                                   
                    C.sub.18 H.sub.18 N.sub.2 O.sub.2                     
                            73.4                                          
                               6.2                                        
                                 9.5                                      
                                    73.7                                  
                                       6.3                                
                                         9.5                              
     455                                                                  
        39,000                                                            
D-18a(1)                                                                  
     391                                                                  
        25,000                                                            
              184.5-188                                                   
                    C.sub.16 H.sub.13 NO.sub.2 S.sub.2                    
                            60.9                                          
                               4.2                                        
                                 4.4                                      
                                    60.8                                  
                                       4.3                                
                                         4.4                              
     377                                                                  
        21,000                                                            
D-18a(2)                                                                  
     390                                                                  
        25,000                                                            
              175-177                                                     
                    C.sub.16 H.sub.13 NO.sub.2 S.sub.2                    
                            60.9                                          
                               4.2                                        
                                 4.4                                      
                                    60.6                                  
                                       4.2                                
                                         4.3                              
     377                                                                  
        21,000                                                            
D-20a                                                                     
     536                                                                  
        17,400                                                            
              150.5-152                                                   
                    C.sub.24 H.sub.19 NO.sub.3                            
                            78.0                                          
                               5.2                                        
                                 3.8                                      
                                    78.2                                  
                                       5.3                                
                                         3.7                              
     504                                                                  
        17,400                                                            
     407                                                                  
        15,800                                                            
     388                                                                  
        17,100                                                            
     309                                                                  
        23,000                                                            
D-25a                                                                     
     470                                                                  
        36,800(sh)                                                        
                145-145.5                                                 
                    C.sub.24 H.sub.19 NO.sub.3                            
                            78.0                                          
                               5.2                                        
                                 3.8                                      
                                    78.1                                  
                                       5.3                                
                                         3.7                              
     446                                                                  
        40,600                                                            
D-27a                                                                     
     544                                                                  
        35,000                                                            
              161.5-162.5                                                 
                    C.sub.18 H.sub.18 N.sub.2 O.sub.2                     
                            73.4                                          
                               6.2                                        
                                 9.5                                      
                                    73.0                                  
                                       6.1                                
                                         9.4                              
     510                                                                  
        39,000                                                            
D-34a                                                                     
     483                                                                  
        24,000                                                            
              102-103                                                     
                    C.sub.10 H.sub.15 N.sub.3 O.sub.2                     
                            57.4                                          
                               7.2                                        
                                 20.1                                     
                                    57.4                                  
                                       7.1                                
                                         20.0                             
__________________________________________________________________________
 *All compounds were also characterized by 300MHz .sup.1 H NMR, IR, and   
 FDMS.                                                                    
 
    
     
                                           TABLE III                               
__________________________________________________________________________
Analytical and Absorption Data for the Polymethines*                      
                              Calc&#39;d. For                                 
                                     Found                                
Dye λ .sub.max.sup.nm                                              
       ε                                                          
            M.P. °C.                                               
                     Mol. Formula                                         
                              C  H N C  H N                               
__________________________________________________________________________
D-1b                                                                      
    462                                                                   
       87,000                                                             
            160-161  C.sub.34 H.sub.31 BN.sub.2 O.sub.2 S                 
                              75.3                                        
                                 5.8                                      
                                   5.2                                    
                                     75.7                                 
                                        5.9                               
                                          5.2                             
D-2b                                                                      
    463                                                                   
       86,000                                                             
            164-166  C.sub.34 H.sub.28 BF.sub.3 N.sub.2 O.sub.2 S         
                              68.5                                        
                                 4.7                                      
                                   4.7                                    
                                     68.3                                 
                                        4.9                               
                                          4.6                             
D-4b                                                                      
    349                                                                   
       46,000                                                             
            140-142  C.sub.32 H.sub.29 BN.sub.2 O.sub.2 S                 
                              74.4                                        
                                 5.7                                      
                                   5.4                                    
                                     74.7                                 
                                        5.8                               
                                          5.4                             
D-5b                                                                      
    349                                                                   
       46,000                                                             
            158-160  C.sub.32 H.sub.26 BF.sub.3 N.sub.2 O.sub.2 S         
                              67.4                                        
                                 4.6                                      
                                   4.9                                    
                                     67.3                                 
                                        4.8                               
                                          4.9                             
D-6b                                                                      
    555                                                                   
       112,000                                                            
            187-189  C.sub.36 H.sub.33 BN.sub.2 O.sub.2 S                 
                              76.1                                        
                                 5.9                                      
                                   4.9                                    
                                     75.8                                 
                                        5.8                               
                                          5.2                             
D-7b                                                                      
    556                                                                   
       118,000                                                            
            146.5-147                                                     
                     C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.2 S         
                              69.5                                        
                                 4.9                                      
                                   4.5                                    
                                     69.2                                 
                                        5.1                               
                                          4.5                             
D-8b                                                                      
    424                                                                   
       87,000                                                             
               151-151.5                                                  
                     C.sub.34 H.sub.31 BN.sub.2 O.sub.3                   
                              77.6                                        
                                 5.9                                      
                                   5.3                                    
                                     77.5                                 
                                        5.9                               
                                          5.3                             
D-9b                                                                      
    425                                                                   
       91,000                                                             
            156.5-158                                                     
                     C.sub.34 H.sub.28 BF.sub.3 N.sub.2 O.sub.3           
                              70.4                                        
                                 4.9                                      
                                   4.8                                    
                                     70.1                                 
                                        4.8                               
                                          4.7                             
D-10b                                                                     
    520                                                                   
       102,000                                                            
               145-148(dec)                                               
                     C.sub.36 H.sub.33 BN.sub.2 O.sub.3                   
                              78.3                                        
                                 6.0                                      
                                   5.1                                    
                                     78.1                                 
                                        6.1                               
                                          5.0                             
D-11b                                                                     
    521                                                                   
       101,000                                                            
              167.5-169(dec)                                              
                     C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.3           
                              71.3                                        
                                 5.0                                      
                                   4.6                                    
                                     70.9                                 
                                        5.1                               
                                          4.5                             
D-15b                                                                     
    509                                                                   
       47,000                                                             
               174-175(dec)                                               
                     C.sub.36 H.sub.33 BN.sub.2 O.sub.2                   
                              80.6                                        
                                 6.2                                      
                                   5.2                                    
                                     80.2                                 
                                        6.2                               
                                          5.2                             
    480                                                                   
       57,000                                                             
D-16b                                                                     
    507                                                                   
       48,500                                                             
               175-176(dec)                                               
                     C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.3           
                              73.2                                        
                                 5.1                                      
                                   4.7                                    
                                     73.2                                 
                                        5.4                               
                                          4.7                             
    479                                                                   
       55,000                                                             
D-18b                                                                     
    406                                                                   
       26,000                                                             
               119-121(dec)                                               
                     C.sub.34 H.sub.28 BNO.sub.2 S.sub.2                  
                              73.2                                        
                                 5.1                                      
                                   2.5                                    
                                     73.1                                 
                                        5.3                               
                                          2.5                             
D-19b                                                                     
    406                                                                   
       28,000                                                             
               117-127(dec)                                               
                     C.sub.34 H.sub.25 BF.sub.3 NO.sub.2 S.sub.2          
                              66.8                                        
                                 4.1                                      
                                   2.3                                    
                                     66.8                                 
                                        4.2                               
                                          2.3                             
D-20b                                                                     
    544                                                                   
       24,300                                                             
            148.5-150                                                     
                     C.sub.42 H.sub.34 BNO.sub.2                          
                              82.5                                        
                                 5.6                                      
                                   2.3                                    
                                     82.7                                 
                                        5.8                               
                                          2.4                             
    513                                                                   
       20,900                                                             
    391                                                                   
       13,100                                                             
    317                                                                   
       20,300                                                             
D-21b                                                                     
    544                                                                   
       25,100                                                             
               139-141(dec)                                               
                     C.sub.42 H.sub.31 BF.sub.3 NO.sub.3                  
                              75.8                                        
                                 4.7                                      
                                   2.1                                    
                                     75.9                                 
                                        5.0                               
                                          2.0                             
    409                                                                   
       14,100                                                             
    391                                                                   
       13,100                                                             
    317                                                                   
       20,700                                                             
D-25b                                                                     
    519                                                                   
       18,800                                                             
               117-120(dec)                                               
                     C.sub.42 H.sub.34 BNO.sub.3                          
                              82.5                                        
                                 5.6                                      
                                   2.3                                    
                                     80.7                                 
                                        5.9                               
                                          2.2                             
    492                                                                   
       29,500                                                             
    470                                                                   
       25,700                                                             
    330                                                                   
        8,000                                                             
D-26b                                                                     
    525                                                                   
       32,200                                                             
               114-120(dec)                                               
                     C.sub.42 H.sub.31 BF.sub.3 NO.sub.3                  
                              75.8                                        
                                 4.7                                      
                                   2.1                                    
                                     75.5                                 
                                        5.2                               
                                          2.3                             
    493                                                                   
       48,700                                                             
    330                                                                   
       12,800                                                             
D-27b                                                                     
    555                                                                   
       85,000                                                             
              168-168.5                                                   
                     C.sub.36 H.sub.33 BN.sub.2 O.sub.2                   
                              80.6                                        
                                 6.2                                      
                                   5.2                                    
                                     80.7                                 
                                        6.7                               
                                          5.1                             
    519                                                                   
       53,000                                                             
D-28b                                                                     
    555                                                                   
       90,000                                                             
            164.5-166                                                     
                     C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.2           
                              73.2                                        
                                 5.1                                      
                                   4.7                                    
                                     73.3                                 
                                        5.4                               
                                          4.4                             
    519                                                                   
       54,000                                                             
D-29b                                                                     
    294                                                                   
       20,400                                                             
              114-116.5                                                   
                     C.sub.26 H.sub.27 BN.sub.2 O.sub.2                   
                              76.1                                        
                                 6.6                                      
                                   6.8                                    
                                     76.3                                 
                                        6.6                               
                                          6.8                             
D-30b                                                                     
    293                                                                   
       19,500                                                             
            124.5-127.5                                                   
                     C.sub.26 H.sub.24 BF.sub.3 N.sub.2 O.sub.2           
                              67.3                                        
                                 5.2                                      
                                   6.0                                    
                                     67.2                                 
                                        5.3                               
                                          6.0                             
D-31b                                                                     
    296                                                                   
       19,200                                                             
            141.5-143 12                                                  
                     C.sub.28 H.sub.32 BN.sub.3 O.sub.2                   
                              74.2                                        
                                 7.1                                      
                                   9.3                                    
                                     74.4                                 
                                        7.1                               
                                          9.2                             
D-32b                                                                     
    295                                                                   
       19,300                                                             
            150.5-152.5                                                   
                     C.sub.28 H.sub.29 BF.sub.3 N.sub.3 O.sub.2           
                              66.3                                        
                                 5.8                                      
                                   8.3                                    
                                     66.5                                 
                                        5.8                               
                                          8.2                             
D-34b                                                                     
    286                                                                   
       12,600                                                             
            167-169  C.sub.28 H.sub.30 BN.sub.3 O.sub.2                   
                              74.5                                        
                                 6.7                                      
                                   9.3                                    
                                     74.3                                 
                                        6.7                               
                                          9.3                             
D-45b                                                                     
    280                                                                   
       12,900                                                             
            165.5-167                                                     
                     C.sub.28 H.sub.27 BF.sub.3 N.sub.3 O.sub.2           
                              66.5                                        
                                 5.4                                      
                                   8.3                                    
                                     66.2                                 
                                        5.5                               
                                          8.3                             
__________________________________________________________________________
 *All compounds were also characterized by 300MHz .sup.1 H NMR, IR, and   
 FDMS.                                                                    
 
    
     
                                           TABLE IV                                
__________________________________________________________________________
Analytical and Absorption Data for the Polymethines*                      
             M.P. °C.                                              
                            Calc&#39;d. For                                   
                                   Found                                  
Compound                                                                  
      λ .sub.max.sup.nm                                            
         ε                                                        
             (dec) Mol. Formula                                           
                            C  H N C  H N                                 
__________________________________________________________________________
D-1   514                                                                 
         80,000                                                           
             198-200                                                      
                   C.sub.34 H.sub.31 BN.sub.2 O.sub.2 S                   
                            75.3                                          
                               5.8                                        
                                 5.2                                      
                                   75.5                                   
                                      5.9                                 
                                        5.2                               
D-2   515                                                                 
         80,000                                                           
             165-170                                                      
                   C.sub.34 H.sub.28 BF.sub.3 N.sub.2 O.sub.2 S           
                            68.5                                          
                               4.7                                        
                                 4.7                                      
                                   68.9                                   
                                      5.0                                 
                                        4.7                               
D-4   403                                                                 
         40,000                                                           
             228-231                                                      
                   C.sub.32 H.sub.29 BN.sub.2 O.sub.2 S                   
                            74.4                                          
                               5.7                                        
                                 5.4                                      
                                   74.3                                   
                                      5.7                                 
                                        5.3                               
D-5   402                                                                 
         35,000                                                           
             183-184                                                      
                   C.sub.32 H.sub.26 BF.sub.3 N.sub.2 O.sub.2 S           
                            67.4                                          
                               4.6                                        
                                 4.9                                      
                                   67.3                                   
                                      4.8                                 
                                        4.9                               
D-6   592                                                                 
         71,000                                                           
             187-193                                                      
                   C.sub.36 H.sub.33 BN.sub.2 O.sub.2 S                   
                            76.1                                          
                               5.9                                        
                                 4.9                                      
                                   75.7                                   
                                      6.0                                 
                                        5.1                               
      567                                                                 
         76,000                                                           
D-7   601                                                                 
         81,000                                                           
             191-197                                                      
                   C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.2 S           
                            69.5                                          
                               4.9                                        
                                 4.5                                      
                                   69.1                                   
                                      5.1                                 
                                        4.7                               
      569                                                                 
         81,000                                                           
D-8   476                                                                 
         84,000                                                           
             173-178                                                      
                   C.sub.34 H.sub.31 BN.sub.2 O.sub.3                     
                            77.6                                          
                               5.9                                        
                                 5.3                                      
                                   77.4                                   
                                      6.0                                 
                                        5.2                               
      458                                                                 
         72,000                                                           
D-9   476                                                                 
         83,000                                                           
             140-181                                                      
                   C.sub.34 H.sub.28 BF.sub.3 N.sub.2 O.sub.3             
                            70.4                                          
                               4.9                                        
                                 4.8                                      
                                   70.2                                   
                                      4.9                                 
                                        4.7                               
      460                                                                 
         70,000                                                           
D-10  564                                                                 
         83,000                                                           
             135-140                                                      
                   C.sub.36 H.sub.33 BN.sub.2 O.sub.3                     
                            78.3                                          
                               6.0                                        
                                 5.1                                      
                                   78.4                                   
                                      6.1                                 
                                        5.0                               
      541                                                                 
         80,000                                                           
D-11  568                                                                 
         93,000                                                           
             185-195                                                      
                   C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.3             
                            71.3                                          
                               5.0                                        
                                 4.6                                      
                                   70.9                                   
                                      4.8                                 
                                        4.4                               
      547                                                                 
         86,000                                                           
D-15  543                                                                 
         58,000                                                           
             204.5-206                                                    
                   C.sub.36 H.sub.33 BN.sub.2 O.sub.3                     
                            80.6                                          
                               6.2                                        
                                 5.2                                      
                                   80.4                                   
                                      6.3                                 
                                        5.1                               
D-16  543                                                                 
         57,000                                                           
             206-210                                                      
                   C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.3             
                            73.2                                          
                               5.1                                        
                                 4.7                                      
                                   72.9                                   
                                      5.2                                 
                                        4.6                               
D-18  460                                                                 
         39,000                                                           
             167-170                                                      
                   C.sub.34 H.sub.28 BNO.sub.2 S.sub.2                    
                            73.2                                          
                               5.1                                        
                                 2.5                                      
                                   72.5                                   
                                      5.1                                 
                                        2.5                               
D-19  460                                                                 
         40,500                                                           
             179-181                                                      
                   C.sub.34 H.sub.25 BF.sub.3 NO.sub.2 S.sub.2            
                            66.8                                          
                               4.1                                        
                                 2.3                                      
                                   66.4                                   
                                      4.1                                 
                                        2.3                               
D-20  598                                                                 
         26,200                                                           
             173-178                                                      
                   C.sub.42 H.sub.34 BNO.sub.3                            
                            82.5                                          
                               5.6                                        
                                 2.3                                      
                                   82.7                                   
                                      5.8                                 
                                        2.2                               
      560                                                                 
         24,700                                                           
      456                                                                 
         19,500                                                           
      434                                                                 
         18,200                                                           
D-21  599                                                                 
         27,800                                                           
             197-202                                                      
                   C.sub.42 H.sub.31 BF.sub.3 NO.sub.3                    
                            75.8                                          
                               4.7                                        
                                 2.1                                      
                                   75.6                                   
                                      4.8                                 
                                        2.0                               
      561                                                                 
         26,000                                                           
      454                                                                 
         19,700                                                           
      433                                                                 
         18,100                                                           
D-25  538                                                                 
         46,700                                                           
             160-163                                                      
                   C.sub.42 H.sub.34 BNO.sub.3                            
                            82.5                                          
                               5.6                                        
                                 2.3                                      
                                   81.5                                   
                                      5.7                                 
                                        2.2                               
      513                                                                 
         47,500                                                           
D-26  544                                                                 
         46,900                                                           
             189-190                                                      
                   C.sub.42 H.sub.31 BF.sub.3 NO.sub.3                    
                            75.8                                          
                               4.7                                        
                                 2.1                                      
                                   74.7                                   
                                      5.0                                 
                                        2.4                               
      516                                                                 
         46,100                                                           
D-27  623                                                                 
         55,000                                                           
             184.5-186                                                    
                   C.sub.36 H.sub.33 BN.sub.2 O.sub.2                     
                            80.6                                          
                               6.2                                        
                                 5.2                                      
                                   80.2                                   
                                      6.2                                 
                                        5.1                               
      580                                                                 
         63,000                                                           
D-28  623                                                                 
         45,500                                                           
             183-186                                                      
                   C.sub.36 H.sub.30 BF.sub.3 N.sub.2 O.sub.2             
                            73.2                                          
                               5.1                                        
                                 4.7                                      
                                   73.0                                   
                                      5.2                                 
                                        4.7                               
      580                                                                 
         65,600                                                           
D-29  339                                                                 
         27,300                                                           
             169.5-170.5                                                  
                   C.sub.26 H.sub.27 BN.sub.2 O.sub.2                     
                            76.1                                          
                               6.6                                        
                                 6.8                                      
                                   76.5                                   
                                      6.7                                 
                                        6.8                               
D-30  339                                                                 
         26,900                                                           
             193-194                                                      
                   C.sub.26 H.sub.24 BF.sub.3 N.sub.2 O.sub.2             
                            67.3                                          
                               5.2                                        
                                 6.0                                      
                                   67.5                                   
                                      5.3                                 
                                        5.9                               
D-31  348                                                                 
         21,100                                                           
             180.5-185                                                    
                   C.sub.28 H.sub.32 BN.sub.3 O.sub.2                     
                            74.2                                          
                               7.1                                        
                                 9.3                                      
                                   74.2                                   
                                      6.9                                 
                                        9.2                               
D-32  345                                                                 
         20,600                                                           
               178-180.5                                                  
                   C.sub.28 H.sub.29 BF.sub.3 N.sub.3 O.sub.2             
                            66.3                                          
                               5.8                                        
                                 8.3                                      
                                   66.1                                   
                                      6.0                                 
                                        7.9                               
D-34  332                                                                 
         18,800                                                           
               238-239.5                                                  
                   C.sub.28 H.sub.30 BN.sub.3 O.sub.2                     
                            74.5                                          
                               6.7                                        
                                 9.3                                      
                                   74.6                                   
                                      6.5                                 
                                        9.3                               
D-35  330                                                                 
         19,700                                                           
               222-222.5                                                  
                   C.sub.28 H.sub.27 BF.sub.3 N.sub.3 O.sub.2             
                            66.5                                          
                               5.4                                        
                                 8.3                                      
                                   66.6                                   
                                      5.4                                 
                                        8.3                               
D-36  347                                                                 
         20,000                                                           
             214.5-224.5                                                  
                   C.sub.30 H.sub.32 BN.sub.3 O                           
                            78.1                                          
                               7.0                                        
                                 9.1                                      
                                   77.5                                   
                                      7.3                                 
                                        8.8                               
D-37  350                                                                 
         14,500                                                           
             201.5-212.5                                                  
                   C.sub.30 H.sub.29 BF.sub.3 N.sub.3 O                   
                            69.9                                          
                               5.7                                        
                                 8.2                                      
                                   69.6                                   
                                      5.7                                 
                                        8.1                               
__________________________________________________________________________
 *All compounds were also characterized by 300 MHz .sup.1 H NMR, IR, and  
 FDMS.                                                                    
 **Measured in CH.sub.2 Cl.sub.2.                                         
 
    
     From Tables II, III, AND IV it is apparent that close agreement between the calculated and found elemental content of the compounds was observed. The peak absorption (λ max ) of the compounds was measured in dichloromethane. The extinction coefficient (ε), in liters/mole-cm was measured in solution at the peak absorption. 
     EXAMPLES 29 through 35 
     A series of negative working photoresist compositions PR-1 each containing 0.02 millimole of a different dye being tested as a photosensitizer were prepared. 
     PR-1 was formulated as follows: 
     
         ______________________________________                                    
2.34    g           Binder A                                              
1.17    g           Monomer A                                             
1.17    g           Monomer B                                             
0.012   g           Inhibitor A                                           
0.077   g           Activator A                                           
0.02    mmol        Photosensitizer                                       
10.32   g           Solvent (Dichloromethane)                             
______________________________________                                    
 
    
     Binder A exhibited the following structure ##STR10## 
     Monomer A exhibited the following structure ##STR11## 
     Monomer B exhibited the following structure ##STR12## 
     Inhibitor A exhibited the following structure ##STR13## 
     Activator A was 1-methoxy-4-phenylpyridinium tetrafluoroborate. 
     Each of the photoresist compositions was coated on a copper sheet using a 0.3 mm coating knife and dried for 10 minutes at about 70° C. A transparent polypropylene cover sheet was then placed over the coating. 
     Since PR-1 without the photosensitizer coinitiator responds to ultraviolet exposures, shorter wavelengths were removed during exposure using filters. Speicifically, wavelengths below the absorption peak of the photosensitizer dye were removed using a W-2A Wratten® filter capable of filtering 99.9 percent of radiation of less than 400 nm in wavelength. 
     To determine the degree of effectiveness of the photosensitizer exposure of each coated sample was undertaken through a Kodak T-14® step tablet having 14 equal increment density steps ranging in density from essentially zero to 2.1. Three minute exposures were undertaken using a Nu-arc FT32L® flip-top platemaker equipped with a 4000 watt pulsed Xenon lamp. After exposure the samples were baked for 10 minutes at 70° C. and spray developed for two minutes. Development was undertaken using 1,1,1-trichloroethane as a developer. Response was measured in terms of the number of stepped exposure areas (steps) in which the photoresist was retained following exposure. For example, a photoresist sample which was retained following exposure and development on 10 steps, but was absent from the remaining four steps was assigned a step rating of 10. If partial retention of the photoresist was observed on the eleventh step, this was indicated by assigning a plus rating--i.e., 10+. On the other hand, where the photoresist retention was deemed just barely adequate to merit the step rating, this was indicated by assigning a minus rating--i.e., 10-. 
     Results with the various dyes are indicated below in Table V, which reports the absorption peak of the dye in the coating and the step range of response. Activator A exhibited a reduction potential of -0.75 volt, and each of the dye photosensitizers exhibited a reduction potential less than 0.1 volt more positive than the reduction potential of Activator A. 
     When control formulations of PR-1 were prepared varied only by omitting the dye, so that Activator A was the sole initiator present, performance of the procedure described above and including the filtering used with the dyes resulted in no imaging response being observed. This showed the activator to be ineffective to impart sensitivity to the photoresist in the blue portion of the spectrum. 
     The dyes employed as photosensitizers, their reduction potentials. (Er), maximum absorption wavelengths (λmax), and the number of steps of retained photoresist after development are shown in Table V. 
     
                       TABLE V                                                     
______________________________________                                    
Dye           λmax (nm)                                            
                        Steps                                             
______________________________________                                    
D-2           523       8                                                 
D-6           610       .sup. 9.sup.+                                     
D-7           616       .sup. 9.sup.+                                     
D-8           483       8                                                 
 D-11         584        10.sup.+                                         
 D-16         548       5                                                 
 D-19         475       6                                                 
______________________________________                                    
 
    
     By comparing the maximum absorption wavelengths of the dyes in solution in Table V with the maximum absorption wavelengths of the dyes in the photoresist it is apparent that the maximum absorption wavelength was bathochromically shifted in the imaging composition. All of the dyes of the invention tested in the photoresist composition PR-1 were found to be useful as photosensitizers. 
     The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.