2-[N-(1,3-diamino-isopropyl)-amino]-4-phenyl-2-imidazolines and salts thereof
This invention relates to novel 2-[1,3-diamino-isopropyl)-amino]-4-phenyl-2-imidazolines and acid addition salts thereof, as well as to a method of preparing these compounds. 
     More particularly, the present invention relates to a novel class of compounds represented by the formula ##STR2## wherein R 1  is chlorine, bromine, fluorine or methyl; 
     R 2  and R 3  which may be identical to or different from each other, are each hydrogen, chlorine or methyl; 
     R 4  is hydrogen, methyl or ethyl; and 
     R 5  and R 6 , which may be identical to or different from each other, are each methyl, ethyl or alkoxy-alkyl of 2 to 4 carbon atoms, or together with each other and the nitrogen atom to which they are attached, form a 5-,6- or 7-membered heterocyle which may comprise an additional heteroatom, such as pyrrolidino, piperidino, morpholino, piperazino or hexamethyleneimino; 
     And non-toxic, pharmaceutically acceptable acid addition salts thereof. 
     The compounds embraced by formula I are cyclic guanidines which occur in tautomeric forms; they contain an asymmetric carbon atom and therefore exist as racemic mixtures or optically active antipodes. 
     The compounds of this invention may be prepared by reacting a 4-phenyl-2-imidazoline of the formula ##STR3## wherein R 1 , R 2  and R 3  have the same meanings as in formula I, and 
     X is chlorine, bromine, iodine, alkoxy of 1 to 4 carbon atoms or (alkyl of 1 to 4 carbon atoms)-mercapto, 
     with triaminoalkane of the formula ##STR4## wherein R 4 , R 5  and R 6  have the same meanings as in formula I. The reaction is preferably carried out by heating a simple mixture of the reactants, but it will also proceed in the presence of a solvent medium, such as dimethylsulfoxide, dimethylformamide, an alcohol or an ether. 
     The starting compounds of the formula II wherein X is halogen are accessible by reacting a phenyl-substituted ethylenediamine of the formula ##STR5## wherein R 1 , R 2  and R 3  have the same meanings as in formula I, with a bifunctional carbonic acid derivative, such as phosgene, a chlorocarbonic acid ester or an orthocarbonic acid ester, to form the corresponding ethyleneurea, followed by halogenation of the latter with an inorganic acid halide, such as phoshorus-oxychloride or -oxybromide, or phosphorus-pentachloride, -pentabromide or -pentaiodide, or with a thionyl halide. 
     The starting compounds of the formula II wherein X is alkylmercapto may, for example, be obtained by reacting a phenyl-substituted ethylenediamine of the formula IV with carbon disulfide to form the corresponding phenyl-substituted ethylenethiourea, followed by alkylation of the latter with an alkyl halide or an inorganic acid alkyl ester, such as dimethyl sulfate. 
     A phenyl-substituted ethylenediamine of the formula IV, in turn, may be obtained by reacting a correspondingly substituted benzaldehyde with ammonium cyanide, and hydrogenating the α-cyano-benzylamine formed thereby. 
     The compounds embraced by formula I are organic bases and therefore form acid addition salts with inorganic or organic acids. Examples of non-toxic, pharmaceutically acceptable acid addition salts are those formed with hydrochloric acid, hydrobromic acid, hydriodic acid, hydrofluoric acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, capric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, maleic acid, fumaric acid, lactic acid, tartaric acid, citric acid, malic acid, gluconic acid, benzoic acid, p-hydroxybenzoic acid, phthalic acid, cinnamic acid, salicyclic acid, ascorbic acid, 8-chlorotheophylline, methanesulfonic acid or the like. 
     The following examples illustrate the present invention and will enable others skilled in the art to understand it more completely. It should be understood, however, that the invention is not limited solely to the particular examples given below. 
    
    
     EXAMPLE 1 
     2-[N-(1,3-Bis-diethylamino-isopropyl)-amino]-4-(-2,6-dichlorophenyl)-2-imidazoline monohydrochloride 
     6.5 gm (0.022 mol) of 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and 10.65 gm (0.053 mol) of N-(1,3-bis-diethylamino-isopropyl)-amine were admixed by stirring, and the mixture was slowly heated to 100° C, whereupon a significant amount of methylmercaptan was given off and the temperature of the mixture spontaneously rose to 130° C. The reaction mixture was maintained at this temperature for 30 minutes, was then cooled to 40° C and at that temperature admixed with 15 ml of acetone. A crystalline substance separated out, which was collected and washed with a mixture of acetone and ether (1:1), yielding 4.2 gm of the hydrochloride of the formula ##STR6## After recrystallization from water, the salt had a melting point of 192° C. 
     EXAMPLE 2 
     2-[N-(1,3-Bis-diethylamino-isopropyl)-amino]-4-(2-methyl-5-chloro-phenyl)-2-imidazoline tritartrate 
     A mixture consisting of 2.77 gm (0.01 mol) of 4-(2-methyl-5-chloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride, 2.0 gm (0.01 mol) of N-(1,3-bis-diethylamino-isopropyl)-amine and 70 ml of anhydrous dimethylsulfoxide was stirred and slowly heated to 130° C. After 4 hours&#39; stirring at that temperature, 600 ml of water were added to the reaction mixture. The aqueous mixture was then fractionally extracted with ether at gradually increasing pH-values which were achieved by addition of sodium hydroxide. The fractions containing the desired compound were combined, dried and evaporated, leaving as a residue 1.7 gm of raw 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2-methyl-5-chloro-phenyl)-2-imidazoline. The raw base was purified by chromatography on a silicagel column, using acetone:benzene:methanol:concentrated ammonia (10:10:8:2) as the eluant. The eluate fractions containing the pure product were combined and evaporated, the residue was taken up in ether, and the resulting solution was admixed with ethanolic tartaric acid. The initially amorphous precipitate formed thereby was reprecipitated from ethanol/ether and then had a melting point of 85° C (decomp.); it was identified to be the tritartrate of the formula ##STR7## 
     In the following examples, whenever an oxalate was prepared, it was obtained by dissolving the free base in ether, acidifying the solution with ethereal oxalic acid, and recrystallizing the salt from ethanol. 
     EXAMPLE 3 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(4-chloro-phenyl)-2-imidazoline tritartrate, m.p. 84° C(decomp.), was prepared from 4-(4-chloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 4 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-dimethylamino-isopropyl)-amino]-4-(4-chloro-phenyl)-2-imidazoline dioxalate, m.p. 126° C, was prepared from 4-(4-chloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-dimethylamino-isopropyl)-amine. 
     EXAMPLE 5 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(4-bromo-phenyl)-2-imidazoline monohydrochloride, m.p. 140°-142° C, was prepared from 4-(4-bromo-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 6 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(4-fluoro-phenyl)-2-imidazoline monohydrochloride, m.p. 118°-120° C, was prepared from 4-(4-fluoro-phenyl)-2-methyl-mercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 7 
     Using a procedure analogous to that described in Example 2, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline tritartrate, m.p. 192° C, was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 9 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-dimorpholino-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline trioxalate, m.p. 115° C of the formula ##STR8## was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-dimorpholino-isopropyl)-amine. 
     EXAMPLE 9 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-dipyrrolidino-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline trioxalate, m.p. 228° C, of the formula ##STR9## was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-dipyrrolidino-isopropyl)-amine. 
     EXAMPLE 10 
     Using a procedure analogous to that described in Example 1, 2-[N-1,3-bis-dimethylamino-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline trioxalate, m.p. 130° C, was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-dimethylamino-isopropyl)-amine. 
     EXAMPLE 11 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,1-bis-diethylaminomethyl-ethyl)-amino-]-4-(2,6-dichloro-phenyl)-2-imidazoline tartrate, m.p. 110° C (decomp.), of the formula ##STR10## was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,1-bis-diethylaminomethylethyl)-amine. 
     EXAMPLE 12 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-di(ethoxyethyl) amino-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline, an oil, of the formula ##STR11## was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-[1,3-bis-di(ethoxyethyl)amino-isopropyl]-amine. 
     EXAMPLE 13 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,1-bis-diethylaminomethyl-n-propyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline, an oil, of the formula ##STR12## was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-[1,1-bis-(diethylaminomethyl)-n-propyl]-amine. 
     EXAMPLE 14 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-(N&#39;-methyl-piperazino)-isopropyl)-amino]4-(2,6 -dichloro-phenyl)-2-imidazoline pentaoxalate, m.p. 69° C (decomp.), of the formula ##STR13## was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-[1,3-bis-(N&#39;-methyl-piperazino)-isopropyl]-amine. 
     EXAMPLE 15 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-(N-ethoxyethyl-ethylamino)-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline, an oil, of the formula ##STR14## was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-[1,3-bis-(N-ethoxyethyl-ethylamino)-isopropyl]-amine. 
     EXAMPLE 16 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-hexamethyleneimino-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline hydrochloride, m.p. 197° C, was prepared from 4-(2,6-dichloro-phenyl)-2-methyl-mercapto-2-imidazoline hydrochloride and N-(1,3-bis-hexamethyleneimino-isopropyl)-amine. 
     EXAMPLE 17 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2,4-dichloro-phenyl)-2-imidazoline tritartrate, m.p. 135° C, was prepared from 4-(2,4-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 18 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2,6-dimethyl-phenyl)-2-imidazoline hydrochloride, m.p. 208°-210° C, was prepared from 4-(2,6-dimethyl-phenyl)-2-methyl-mercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 19 
     Using a procedure analogous to that described in Example 2, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2-methyl-4-chloro-phenyl)-2-imidazoline hydrochloride, m.p. 186° C, was prepared from 4-(2-methyl-4-chloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 20 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2-methyl-6-chloro-phenyl)-2-imidazoline hydrochloride, m.p. 194° C, was prepared from 4-(2-methyl-6-chloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethylamino-isopropyl)-amine. 
     EXAMPLE 21 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-diethylamino-isopropyl)-amino]-4-(2,4,6-trimethyl-phenyl)-2-imidazoline hydrochloride, m.p. 165° C, was prepared from 4-(2,4,6-trimethyl-phenyl)-2-methyl-mercapto-2-imidazoline hydrochloride and N-(1,3-bis-diethyl-amino-isopropyl)-amine. 
     EXAMPLE 22 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-dimorpholino-isopropyl)-amino]-4-(2,4,6-trimethyl-phenyl)-2-imidazoline trioxalate, m.p. 185° C, was prepared from 4-(2,4,6-trimethyl-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-dimorpholino-isopropyl)-amine. 
     EXAMPLE 23 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-hexamethyleneimino-isopropyl)-amino]-4-(2,4-dichloro-phenyl)-2-imidazoline oxalate, m.p. 128°-130° C, was prepared from 4-(2,4-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-bis-hexamethyleneimino-isopropyl)-amine. 
     EXAMPLE 24 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-dipiperidino-isopropyl)-amino]-4-(2,6-dichloro-phenyl)-2-imidazoline hydrochloride, m.p. 190° C, was prepared from 4-(2,6-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-(1,3-dipiperidino-isopropyl)-amine. 
     EXAMPLE 25 
     Using a procedure analogous to that described in Example 1, 2-[N-(1,3-bis-di(ethoxyethyl)amino-isopropyl)-amino]-4-(2,4-dichloro-phenyl)-2-imidazoline, an oil, was prepared from 4-(2,4-dichloro-phenyl)-2-methylmercapto-2-imidazoline hydrochloride and N-[1,3-bis-di(ethoxyethyl)amino-isopropyl]-amine. 
     The compounds of the present invention, that is those embraced by formula I above have useful pharmacodynamic properties. More particularly, they inhibit blood platelet aggregation and enhance the blood flow in warm-blooded animals, such as dogs, guinea pigs and cats. Therefore, the compounds are useful for prophylactic and therapeutic treatment of thromboembolisms and inadequate blood flow in the peripheral and cerebral blood vessels. 
     The platelet aggregation inhibiting activity of the compounds of this invention was ascertained by the method of Born, which showed that the effective concentrations are 10 -5  mol/liter and more. 
     For pharmaceutical purposes the compounds of the present invention are administered to warm-blooded animals enterally or parenterally as active ingredients in customary dosage unit compositions, that is, compositions in dosage unit form consisting essentially of an inert pharmaceutical carrier and one effective dosage unit of the active ingredient, such as tablets, coated pills, capsules, wafers, powders, solutions, suspensions, emulsions, syrups, suppositories and the like. One effective oral dosage unit of the compounds according to the present invention is from 0.00083 to 1.3 mgm/kg body weight, preferably 0.0016 to 0.33 mgm/kg body weight. 
     The following examples illustrate a few pharmaceutical dosage unit compositions comprising a compound of the present invention as an active ingredient and represent the best modes contemplated of putting the invention into practical use. The parts are parts by weight unless otherwise specified. 
     EXAMPLE 26 
     Tablets 
     The tablet composition is compounded from the following ingredients: 
     
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2-[N-(1,3-Bis-diethylamino-isopropyl)-                                    
 amino]-4-(2,6-dichloro-phenyl)-                                          
 2-imidazoline hydrochloride                                              
                             30 parts                                     
Corn starch                 160 parts                                     
Secondary calcium phosphate 250 parts                                     
Magnesium stearate           5 parts                                      
Total                       445 parts                                     
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     Preparation 
     The individual ingredients are intimately admixed with each other, the mixture is granulated in conventional manner, and the granulate is compressed into 445 mgm-tablets. Each tablet contains 30 mgm of the imidazoline compound and is an oral dosage unit composition with effective antithrombotic action. 
     EXAMPLE 27 
     Gelatin Capsules 
     The capsule filler composition is compounded from the following ingredients: 
     
         ______________________________________                                    
2-[N-(1,3-Bis-diethylamino-isopropyl)-                                    
 amino]-4-(2,4-dichloro-phenyl)-2-                                        
 imidazoline tritartrate     25 parts                                     
Corn starch                 175 parts                                     
Total                       200 parts                                     
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     Preparation 
     The ingredients are intimately admixed with each other, and 200 mgm-portions of the mixture are filled into gelatin capsules of suitable size. Each capsule contains 25 mgm of the imidazoline compound and is an oral dosage unit composition with effective antithrombotic action. 
     EXAMPLE 28 
     Hypodermic solution 
     The solution is compounded from the following ingredients: 
     
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2-[N-(1,3-Bis-diethylamino-isopropyl)-                                    
 amino]-4-(2,6-dimethyl-phenyl)-                                          
 2-imidazoline hydrochloride                                              
                            1.5 parts                                     
Sodium salt of EDTA         0.2 parts                                     
Distilled waterq.s.ad      100.0 parts                                    
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     Preparation 
     The imidazoline compound of the EDTA salt are dissolved in a sufficient amount of distilled water, the solution is diluted with additional distilled water to the indicated amount, the resulting solution is filtered until free from suspended particles, and the filtrate is filled into 2 ml-ampules under aseptic conditions. The filled ampules are then sterilized and sealed. Each ampule contains 20 mgm of the imidazoline compound, and its contents are an injectable dosage unit composition with effective antithrombotic action. 
     Analogous results are obtained when any one of the other compounds embraced by formula I or a non-toxic, pharmacologically acceptable acid addition salt thereof is substituted for the particular imiazoline compound in Examples 26 through 28. Likewise, the amount of active ingredient in these illustrative examples may be varied to achieve the dosage unit range set forth above, and the amounts and nature of the inert pharmaceutical carrier ingredients may be varied to meet the particular requirements. 
     While the present invention has been illustrated with the aid of certain specific embodiments thereof, it will be readily apparent to others skilled in the art that the invention is not limited to these particular embodiments, and that various changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claims.