Thiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidine and [1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidine derivatives
FIELD OF THE INVENTION 
     This invention relates to triazolopyrimidine derivatives and physiologically acceptable salts thereof which are useful as anti-allergic agent. 
     BACKGROUND OF THE INVENTION 
     It is well known that a chemical mediator released by antigen-antibody reaction, e.g., histamine, plays an important role in inducing allergy. Typical known agents having an inhibitory activity on release of chemical mediators include sodium cromoglycate as disclosed in British Pat. No. 1,144,906. This compound, however, is not effective in oral administration and is generally administered by inhalation or by other topical applications as an aqueous solution thereof. Apparently, the inhalation has difficulty in administering the compound to infants or children and, moreover, can not be administered to patients sensitive to irritation caused by powder, and the topical application of aqueous solution is limited only to nasal cavity. Thus, development of excellent anti-allergic agents which can be administered orally has long been desired. 
     As a result of extensive studies on compounds having an anti-allergic activity, the present inventors found that the triazolopyrimidine derivatives of the present invention represented by the formula (I) below exhibit an excellent anti-allergic activity. 
     The condensed ring included in the compounds of this invention, i.e., thiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidine and [1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidine, are novel condensed ring which have been first synthesized by the present inventors, and the compounds represented by the formula (I) having various substituents thereon are novel compounds. 
     The compounds represented by the formula (I) of this invention have the following characteristics: 
     (a) These compounds exhibit an inhibitory activity on release of chemical mediators induced by the antigen-antibody reaction, not only release of histamine which has been well known as a chemical mediator, but also release of a so-called &#34;slow reacting substance of anaphylaxis&#34; (SRS-A) which has recently been known to play an important role as a chemical mediator in the attack of asthma. 
     (b) These compounds exhibit such inhibitory activity in oral administration. 
     SUMMARY OF THE INVENTION 
     An object of this invention is therefore to provide a novel type of compounds having an anti-allergic activity. 
     Another object of the present invention is to provide a novel type of compounds which are useful for treatment and prophylaxis of allergic diseases such as bronchial asthma, allergic gastro-intestinal disorders, allergic rhinitis, hay fever, urticaria and the like. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The triazolopyrimidine compounds according to the present invention are represented by the formula (I) ##STR1## wherein: A represents CH or N; 
     R represents an aryl group or a heterocyclic group, each of which may be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkylene group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylenedioxy group having 1 to 8 carbon atoms and a halogen atom; and 
     X represents a single bond, an alkylene group having 1 to 10 carbon atoms or an alkenylene group having 2 to 10 carbon atoms, each of which may be bonded to the substituent R or the condensed ring via an oxygen atom or a sulfur atom and may be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an aryl group and a heterocyclic group; 
     and physiologically acceptable salts thereof. 
     Examples of alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl groups and the like. 
     Examples of aryl group include phenyl, biphenyl, naphthyl groups and the like. 
     Examples of heterocyclic group include furyl, thienyl, pyridyl, isochromanyl, chromanyl, chromenyl, benzodioxanyl, thiazolyl, isothiazolyl, thiadiazolyl, imidazolyl, pyrazolyl, triazolyl, pyrimidinyl, morpholinyl, pyrazinyl, pyridazinyl, pyrrolidinyl, piperidinyl, piperazinyl, homopiperazinyl, pyrrolyl, pyrrolinyl, imidazolyl, imidazolidinyl, oxazolinyl, oxazolidinyl, tetrazolyl, thiazolidinyl, indolyl, quinolyl, naphthyridinyl, quinazolinyl, pteridinyl, isobenzofuranyl, carbazolyl, acridinyl, xanthenyl, phenoxazinyl, perimidinyl group and the like. 
     The term &#34;alkylene group&#34; as used herein means a methylene or polymethylene group which may be substituted with one or more alkyl groups, and examples thereof include methylene, ethylene, trimethylene, heptamethylene, decamethylene, propylene, butylene, amylene, hexylene groups and the like. 
     Examples of cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl groups and the like, which may be substituted with one or more alkyl groups, and the like. 
     The term &#34;alkenylene group&#34; as used herein means a group formed by removing two hydrogen atoms from alkene, and examples thereof include vinylene, propenylene, butenylene, 1-pentenylene, 2-pentenylene, 2-methyl-1-butenylene, 2-methyl-2-butenylene, 1-hexenylene, 2,3-dimethyl-2-butenylene groups and the like. 
     Of the compounds according to the present invention, compounds of the formula (I) wherein X represents an alkylene group and R represents a phenyl group which may be substituted with one or more substituents selected from the group consisting of an alkyl group, an alkoxy group and a halogen atom are preferred from the standpoint of their anti-allergic activity. Most preferred compounds are those of the formula (I) wherein X represents an ethylene group and R represents a phenyl group, a halophenyl group or an alkylphenyl group. 
     Although the compounds of the formula (I) are represented as their 1H-9-oxo compounds for the sake of convenience, it is to be understood that these compounds have the following tautomers (I&#39;), (I&#34;) and (I&#34;&#39;), which are within the scope of this invention. ##STR2## 
     The compounds of the formula (I) can be prepared according to the following reaction scheme: ##STR3## wherein A, R and X are as defined above. 
     The compound of the formula (I) can be prepared by diazotizing a compound of the formula (II) or a salt thereof with a nitrite in an acid. Examples of the acid include inorganic acids such as hydrochloric acid, hydrobromic acid and the like, organic acids such as acetic acid, propionic acid and the like, and a mixture thereof. Examples of the nitrite include sodium nitrite, potassium nitrite, etc. In the diazotizing reaction, the nitrite is used in at least an equimolar amount to the compound of the formula (II), and the acid is usually used in a large excess amount to the compound of the formula (II). The reaction can be generally carried out under ice-cooling or at a temperature up to room temperature (about 1° to 30° C.) for a period of from about 30 minutes to about 10 hours. 
     Alternatively, the above diazotization can be carried out by reacting a compound of the formula (II) with a nitrous acid ester such as isoamyl nitrite, tert-butyl nitrite, etc. in a solvent such as dimethylformamide, etc. 
     The compounds of the formula (I) can also be prepared according to the following reaction scheme: ##STR4## wherein A, R and X are as defined above. In this process, the compound of the formula (I) can be prepared by reacting a compound of the formula (III) or a tautomer thereof represented by the formula (IV) or a mixture thereof with a cyanoacetic acid ester such as methyl cyanoacetate, ethyl cyanoacetate and the like, in a solvent such as methanol, ethanol, etc. in the presence of an alkali such as sodium alkoxide, i.e., sodium methoxide or sodium ethoxide. The reaction can be carried out at a temperature in the range of from room temperature to a boiling point of the solvent used for a period of from about 30 minutes to about 10 hours. 
     The starting materials of the formulae (II), (III) and (IV) used in the above-described processes are novel compounds and can be prepared by the following processes: ##STR5## wherein A, R and X are as defined above. 
     Some of the compounds represented by the formula (V) are also novel compounds which can be prepared according to a known procedure for preparing thiadiazole derivatives as disclosed in, for example, Japanese Patent Application (OPI) No. 177997/83 (the term &#34;OPI&#34; as used herein means an unexamined published patent application) or a known procedure for preparing thiazole derivatives as disclosed in, for example, Ya. G. Balon, M. D. Shul&#39;man, N. V. Kuznetsov; Zh. Org. Khim., Vol. 15, No. 11, p2351, 1979. 
     The above processes for preparing the starting materials are hereinafter described in detail. 
     The compound of the formula (VI) can be prepared by reacting a compound of the formula (V) with a malonic acid ester, preferably 2,4,6-trichlorophenyl malonate, in the presence or absence of an inert solvent, for example, Dowtherm A, etc. The reaction can be carried out at a temperature of from about 100° to about 250° C. for a period of from about 30 minutes to about 10 hours. 
     The compound of the formula (VII) can be prepared by reacting the compound of the formula (VI) with fuming nitric acid in the presence or absence of an inert solvent, for example, acetic acid, diethyl ether, etc. The reaction can be carried out under ice cooling or at a temperature up to about 80° C. for a period of from about 30 minutes to about 15 hours. 
     The compound of the formula (VIII) can be prepared by reacting the compound of the formula (VII) with phosphorus oxychloride in the presence of an acid acceptor and in the presence or absence of a solvent. Preferred acid acceptors include an organic base such as dimethylaniline, diethylaniline, tripropylamine, etc. The reaction can be carried out at a temperature of from room temperature to about 100° C. for a period of from about 30 minutes to about 5 hours. 
     The compound of the formula (IX) can be prepared by reacting the compound of the formula (VIII) with ammonia in the presence or absence of a solvent, for example, an alcohol, dimethylformamide, dioxane and the like. The reaction can be carried out under ice cooling or at a temperature up to about 80° C. for a period of from about 30 minutes to about 5 hours. 
     The starting compound of the formula (II) can be prepared by subjecting the compound of the formula (IX) to a usual reduction reaction, for example, catalytic reduction using palladium or reduction using a metal and an acid such as tin and hydrochloric acid. 
     The starting materials of the formulae (III) and (IV) which exist as tautomers can be prepared by reacting the compound of the formula (V) with an alkali and p-toluenesulfonyl azide in the presence or absence of a solvent such as dichloromethane. 
     Examples of salts of the compounds represented by the formula (I) include alkali metal salts such as sodium and potassium salts, alkaline earth metal salts such as calcium salt, and amine salts such as ammonium, tris(hydroxymethyl)aminomethane and N-methylglucamine salts, and the like. 
     The excellent anti-allergic activity of the compounds of this invention has been confirmed by evaluating an inhibitory activity on release of histamine and SRS-A induced by passive peritoneal anaphylaxis (PPA) reaction in rat as well as an inhibitory activity on passive cutaneous anaphylaxis (PCA) reaction in rats. As a result of these tests, it has been found that the compounds of this invention inhibit not only the release of histamine but also the release of SRS-A to a significant degree in the PPA reaction, and also inhibit the PCA reaction to a significant degree in oral administration of the compounds. Thus, the compounds of this invention have been found to possess a strong anti-allergic activity and, therefore, are useful as anti-allergic agent in oral administration. 
     In contrast, sodium cromoglycate which has been known as an anti-allergic agent having an inhibitory activity on release of chemical mediators did not inhibit the release of SRS-A in the PPA reaction and also did not inhibit the PCA reaction in oral administration. 
     These anti-allergic activities are described in more detail in Test Examples hereinafter described. 
     The compounds of the formula (I) and the salts thereof can be generally administered orally at a dose level of from about 150 mg to about 600 mg, 2 to 3 times per day for adult human, in a form of pharmaceutical preparation such as tablets, capsules, syrups and the like. 
     The compounds of the formula (I) are relatively of low toxicity, and LD 50  values determined in rats by oral administration are higher than 2 g/kg for the compounds of Examples 1, 9, 17, 18, 20, 21, 23, 42, 47, 48, 49, 50, 53, 54 and 55. 
    
    
     The present invention is further described in more detail by the following Examples, Reference Examples and Test Examples, but the present invention is not limited thereto. 
     EXAMPLE 1 
     6-(4-tert-Butylphenyl)-[1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one 
     1.0 of 6,7-diamino-2-(4-tert-butylphenyl)-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one was suspended in a mixture of 20 ml of concentrated hydrochloric acid and 20 ml of water, and 2 ml of an aqueous solution containing 0.70 g of sodium nitrite was added dropwise thereto while cooling below 5° C. and stirring. The mixture was stirred at that temperature for 1.5 hours and then diluted with water. The resulting precipitate was filtered and recrystallized from chloroform-ethanol to obtain 0.88 g of the titled compound as pale yellow prisms. Melting Point: 293°-296° C. (decomposition). 
     In the same manner as described in Example 1, each of the following compounds represented by the formula (I) of Examples 2 to 8 was prepared. 
     
         ______________________________________                                    
Example                                                                   
No.    A      RX               Melting point (°C.)                 
______________________________________                                    
2      N                                                                  
               ##STR6##        269-271                                    
3      N                                                                  
               ##STR7##        285-287                                    
4      N                                                                  
               ##STR8##        &gt;300                                       
5      CH                                                                 
               ##STR9##        305-307                                    
6      CH                                                                 
               ##STR10##       &gt;300                                       
7      CH                                                                 
               ##STR11##       &gt;300                                       
8      CH                                                                 
               ##STR12##       &gt;300                                       
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     EXAMPLE 9 
     6-(2-Phenylethyl)-[1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one 
     10.7 g of 7-amino-6-nitro-2-(2-phenylethyl)-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one was suspended in 130 ml of dioxane, and 18 g of tin powder was added thereto. Then, 22 ml of concentrated hydrochloric acid was added dropwise to the gentle refluxing suspension. The gentle refluxing was further continued and, after confirming disappearance of the starting material, any insoluble material was removed by filtration. The filtrate was concentrated, and the precipitate was separated by filtration and suspended in 300 ml of concentrated hydrochloric acid-water (1:1 by volume). 20 ml of an aqueous solution containing 6.2 g of sodium nitrite was then added dropwise to the suspension at a temperature below 5° C. and, after stirring the mixture at 5° C. for 3 hours, the precipitate was separated by filtration. After washing with water and drying, the precipitate was recrystallized from chloroform-ethanol to obtain 5.3 g of the titled compound. Melting point: 295°-296° C. 
     In the same manner as described in Example 9, each of the following compounds represented by the formula (I) of Examples 10 to 79 was prepared. 
     
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                                   Melting                                
Example                            Point                                  
No.    A      RX                   (°C.)                           
______________________________________                                    
10     N                                                                  
               ##STR13##           &gt;300                                   
11     N                                                                  
               ##STR14##           276-278                                
12     N                                                                  
               ##STR15##           &gt;300                                   
13     N                                                                  
               ##STR16##           296-298                                
14     N                                                                  
               ##STR17##           290-292                                
15     N                                                                  
               ##STR18##           296-299                                
16     N                                                                  
               ##STR19##           &gt;300                                   
17     N                                                                  
               ##STR20##           &gt;300                                   
18     N                                                                  
               ##STR21##           &gt;300                                   
19     N                                                                  
               ##STR22##           &gt;300                                   
20     N                                                                  
               ##STR23##           &gt;300                                   
21     N                                                                  
               ##STR24##           &gt;300                                   
22     N                                                                  
               ##STR25##           &gt;300                                   
23     N                                                                  
               ##STR26##           &gt;300                                   
24     N                                                                  
               ##STR27##           &gt;300                                   
25     N                                                                  
               ##STR28##           280-283                                
26     N                                                                  
               ##STR29##           295-297                                
27     N                                                                  
               ##STR30##           &gt;300                                   
28     N                                                                  
               ##STR31##           253-256                                
29     N                                                                  
               ##STR32##           225-230                                
30     N                                                                  
               ##STR33##           &gt;300                                   
31     N                                                                  
               ##STR34##           270-273                                
32     N                                                                  
               ##STR35##           &gt;300                                   
33     N                                                                  
               ##STR36##           &gt;300                                   
34     N                                                                  
               ##STR37##           &gt;300                                   
35     N                                                                  
               ##STR38##           &gt;300                                   
36     N                                                                  
               ##STR39##           298-303                                
37     N                                                                  
               ##STR40##           297-300                                
38     N                                                                  
               ##STR41##           &gt;300                                   
39     N                                                                  
               ##STR42##           &gt;300                                   
40     N                                                                  
               ##STR43##           260-280 (not clear)                    
41     N                                                                  
               ##STR44##           &gt;300                                   
42     N                                                                  
               ##STR45##           &gt;300                                   
43     N                                                                  
               ##STR46##           267 (decompo- sition) (not clear)      
44     N                                                                  
               ##STR47##           &gt;300                                   
45     N                                                                  
               ##STR48##           285-288                                
46     N                                                                  
               ##STR49##           &gt;300                                   
47     N                                                                  
               ##STR50##           &gt;300                                   
48     N                                                                  
               ##STR51##           277-279                                
49     N                                                                  
               ##STR52##           276-278                                
50     N                                                                  
               ##STR53##           284-285                                
51     N                                                                  
               ##STR54##           285-287                                
52     N                                                                  
               ##STR55##           270-272                                
53     N                                                                  
               ##STR56##           284-286                                
54     N                                                                  
               ##STR57##           277-279                                
55     N                                                                  
               ##STR58##           290-292                                
56     N                                                                  
               ##STR59##           295-297                                
57     N                                                                  
               ##STR60##           265-267                                
58     N                                                                  
               ##STR61##           276-278                                
59     N                                                                  
               ##STR62##           297-302                                
60     N                                                                  
               ##STR63##           265-267                                
61     N                                                                  
               ##STR64##           279-281                                
62     N                                                                  
               ##STR65##           &gt;300                                   
63     N                                                                  
               ##STR66##           &gt;300                                   
64     N                                                                  
               ##STR67##           &gt;300                                   
65     N                                                                  
               ##STR68##           &gt;300                                   
66     N                                                                  
               ##STR69##           283-285                                
67     N                                                                  
               ##STR70##           &gt;300                                   
68     N                                                                  
               ##STR71##           &gt;300                                   
69     N                                                                  
               ##STR72##           245-248 (decompo- sition)              
70     N                                                                  
               ##STR73##           249-251                                
71     N                                                                  
               ##STR74##           288-290                                
72     N                                                                  
               ##STR75##           228-230                                
73     CH                                                                 
               ##STR76##           270-275                                
74     CH                                                                 
               ##STR77##           &gt;300                                   
75     CH                                                                 
               ##STR78##           &gt;300                                   
76     CH                                                                 
               ##STR79##           250-253 (decompo- sition)              
77     CH                                                                 
               ##STR80##           232-233 (decompo- sition)              
78     N                                                                  
               ##STR81##           273-276                                
79     N                                                                  
               ##STR82##           212-214                                
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     EXAMPLE 80 
     6-(4-Methylphenyl)-[1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one monohydrate 
     3.12 g of ethyl cyanoacetate was added to 15 ml of an ethanol solution containing 1.88 g of sodium ethoxide and, after stirring, 3.0 g of 2-azido-5-(4-methylphenyl)-1,3,4-thiadiazole was added to the solution. The mixture was stirred at room temperature for 20 minutes and then gently refluxed for 2 hours. After allowing to cool, the precipitate was separated by filtration, washed with ethanol and added to dilute hydrochloric acid. The resulting precipitate was separated by filtration and washed with water to obtain 2.54 g of the titled compound as a colorless powder. Melting Point: higher than 300° C. 
     In the same manner as described in Example 80, each of the following compounds represented by the formula (I) of Examples 81 to 84 was prepared. 
     
         ______________________________________                                    
Example                                                                   
No.    A      RX               Melting Point (°C.)                 
______________________________________                                    
81     N                                                                  
               ##STR83##       &gt;300                                       
82     N                                                                  
               ##STR84##       250-253                                    
83     N                                                                  
               ##STR85##       284-287                                    
84     CH                                                                 
               ##STR86##       &gt;300                                       
______________________________________                                    
 
    
     EXAMPLE 85 
     6-(4-tert-Butylphenyl)-[1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one tris(hydroxymethyl)aminomethane salt. 
     A mixture of 0.80 g of the product obtained in Example 1 and 0.296 g of tris(hydroxymethyl)aminomethane was heated in ethanol. After allowing the mixture to cool, the resulting precipitate was separated by filtration to obtain 0.861 g of the titled compound. Melting Point: 160°-165° C. (not clear). 
     EXAMPLE 86 
     6-(4-Methoxyphenyl)-[1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one tris(hydroxymethyl)aminomethane salt. 
     In the same manner as described in Example 85, the titled compound was prepared from the product obtained in Example 3 and tris(hydroxymethyl)aminomethane. Melting Point: 160°-165° C. (not clear). 
     EXAMPLE 87 
     6-(2-Phenylethyl)-[1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one sodium salt monohydrate 
     22.35 g of the product obtained in Example 9 was suspended in 300 ml of water, and 79 ml of a 1N aqueous solution of sodium hydroxide was added to the suspension, followed by stirring for 1 hour. Any insoluble material was separated by filtration, and the filtrate was concentrated under reduced pressure to a volume of about 100 ml. 500 ml of isopropanol was added to the concentrate and, after allowing the mixture to stand under ice-cooling, the precipitate formed was separated by filtration, washed with isopropanol and dried under reduced pressure at 80° C. for 4 hours to obtain 19.4 g of the titled compound as a pale yellow substance. Melting Point: higher than 300° C. (with loss of water of crystallization at about 150° C.). 
     NMR (δ in D 2  O): 2.6-3.3 (4H, m), 6.90 (5H, s). 
     EXAMPLE 88 
     6-(2-Phenylethyl)-[1,3,4]thiadiazolo[3,2-a][1,2,3]triazolo[4,5-d]pyrimidin-9(1H)-one potassium salt sesquihydrate 
     The titled compound was obtained in the same manner as described in Example 87 using the product obtained in Example 9 and a 1N aqueous solution of potassium hydroxide, but air-drying the product for 3 days. Melting Point: higher than 300° C. (with loss of water of crystallization at about 90° C.). 
     NMR (δ in D 2  O): 2.6-3.3 (4H, m), 6.90 (5H, s). 
     EXAMPLE 89 
     6-(2-Phenylethyl)-[1,3,4[thiadiazolo[3,2-a][1,2,3]triazolo[4,5-]pyrimidin-9(1H)-one lithium salt dihydrate 
     The titled compound was obtained in the same manner as described in Example 87 using the product obtained in Example 9 and a 1N aqueous solution of lithium hydroxide, but air-drying the product for 3 days. Melting Point: 247°-255° C. (decomposition and with loss of water of crystallization at about 150° C.). 
     NMR (δ in D 2  O): 2.6-3.3 (4H, m), 6.90 (5H, s). 
     Syntheses of the starting materials of the formulae (II), (III), (IV) and (IX) used in the above Examples are described in the following Reference Examples. In these Reference Examples, the substituents A, R and X of the starting materials are identical to those in the compounds of the formula (I) of Examples having the corresponding number. 
     SYNTHESIS OF STARTING COMPOUND OF FORMULA (II) 
     REFERENCE EXAMPLE 1 
     6,7-Diamino-2-(4-tert-butylphenyl)-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one 
     (i) A mixture of 9.3 g of 2-amino-5-(4-tert-butylphenyl)-1,3,4-thiadiazole, 20 g of 2,4,6-trichlorophenyl malonate and 50 ml of Dowtherm A was heated at a temperature of 120° to 130° C. for 2 hours. After allowing the mixture to cool, the precipitate was separated by filtration, washed successively with isopropanol and diethyl ether to obtain 11.6 g of 2-(4-tert-butylphenyl)-7-hydroxy-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one as a colorless, crystalline powder having a melting point of 265° to 268° C. (decomposition). 
     Elemental Analysis for C 15  H 15  N 3  O 2  S: Calc&#39;d: C: 59.78; H: 5.02; N: 13.94. Found: C: 60.19; H: 5.34; N: 13.62. 
     (ii) 10.0 g of 2-(4-tert-butylphenyl)-7-hydroxy-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one was suspended in 100 ml of acetic acid, and 15 ml of fuming nitric acid was added dropwise to the suspension while maintaining the temperature at 80° C. After completion of the reaction, the mixture was cooled and the precipitate was separated by filtration to obtain 7.1 g of 2-(4-tert-butylphenyl)-7-hydroxy-6-nitro-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one as pale yellow prisms having a melting point of 245° to 246° C. (decomposition). 
     Elemental Analysis for C 15  H 14  N 4  O 4  S: Calc&#39;d: C: 52.01; H: 4.07; N: 16.18.  Found: C: 52.08; H: 4.43; N: 16.18. 
     (iii) 6.0 g of 2-(4-tert-butylphenyl)-7-hydroxy-6-nitro-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one was added to a mixture of 25 ml of phosphorus oxychloride and 4 ml of diethylaniline, and the resulting mixture was heated at a temperature of 70° to 80° C. for 2 hours. After cooling, the precipitate formed was filtered, washed successively with water, isopropanol and diethyl ether to obtain 4.3 g of 2-(4-tert-butylphenyl)-7-chloro-6-nitro-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one as crystals having a melting point of 245° to 248° C. 
     Elemental Analysis for C 15  H 13  ClN 4  O 3  S: Calc&#39;d: C: 49.38; H: 3.32; N: 15.36. Found: C: 49.02; H: 3.27; N: 15.48. 
     (iv) 1.9 g of 2-(4-tert-butylphenyl)-7-chloro-6-nitro-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one was suspended in a mixture of 20 ml of ethanol and 10 ml of dimethylformamide, and 5 ml of concentrated aqueous ammonia was added dropwise to the suspension while maintaining at a temperature of 60° C. to 70° C. After heating at that temperature for 2 hours, the mixture was cooled and the precipitate formed was separated by filtration to obtain 1.3 g of 7-amino-2-(4-tert-butylphenyl)-6-nitro-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one as pale yellow prisms having a melting point higher than 300° C. 
     Elemental Analysis for C 15  H 15  N 5  O 3  S: Calc&#39;d: C: 52.16; H: 4.38; N: 20.28. Found: C: 51.23; H: 4.62; N: 20.37. 
     (v) 2.75 g of 7-amino-2-(4-tert-butylphenyl)-6-nitro-5H-[1,3,4] thiadiazolo[3,2-a]pyrimidin-5-one was dissolved in 200 ml of warmed dimethylformamide, and 20 ml of acetic acid and 2.0 g of 5% palladium-carbon were added to the solution. Catalytic reduction was carried out at a temperature of 40° to 60° C. After the calculated amount of hydrogen was absorbed, the catalyst was removed by filtration while hot, and the filtrate was concentrated under reduced pressure. The precipitate formed was separated by filtration to obtain 2.0 g of 6,7-diamino-2-(4-tert-butylphenyl)-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidin-5-one as yellow needles. 
     Elemental Analysis for C 15  H 17  N 5  OS: Calc&#39;d: C: 57.12; H: 5.43; N: 22.21. Found: C: 57.06; H: 5.33; N: 22.21. 
     In the same manner as described in Reference Example 1, each of the compounds represented by the formula (II) of Reference Examples 2 to 7 was prepared. In these compounds of the formula (II), the substituents A, R and X are the same as those of Examples 2 to 7, respectively. 
     
         ______________________________________                                    
Compound of                                                               
Reference Example                                                         
                Melting Point (°C.)                                
______________________________________                                    
2               279-282                                                   
3               &gt;300                                                      
4               293-296                                                   
                (decomposition)                                           
5               255-258                                                   
6               270-275                                                   
7               265-275                                                   
______________________________________                                    
 
    
     REFERENCE EXAMPLE 8 
     6,7-Diamino-2-phenyl-5H-thiazolo[3,2-a]pyrimidin-5-one 
     (i) In the same manner as described in steps (i), (ii), (iii) and (iv) of Reference Example 1, 7-amino-6-nitro-2-phenyl-5H-thiazolo[3,2-a]pyrimidin-5-one having a melting point of 291°-294° C. was obtained. 
     (ii) 2.0 g of 7-amino-6-nitro-2-phenyl-5H-thiazolo[3,2-a]pyrimidin-5-one was suspended in 50 ml of 90% dioxane, and 3.0 g of tin powder and 5 ml of concentrated hydrochloric acid were added thereto, followed by stirring the mixture at 80° to 90° C. for 30 minutes. Any insoluble material was removed by filtration, and the filtrate was concentrated. After cooling, the precipitate formed was separated by filtration and added to concentrated aqueous ammonia. The precipitate was separated by filtration and recrystallized from dimethylformamide to obtain 6,7-diamino-2-phenyl-5H-thiazolo[3,2-a]pyrimidin-5-one as yellow needles having a melting point higher than 300° C. 
     Elemental Analysis for C 12  H 10  N 4  OS: Calc&#39;d: C: 55.80; H: 3.90; N: 21.69. Found: C: 56.01; H: 4.09; N: 21.60. 
     In the same manner as described in steps (i), (ii), (iii) and (iv) of Reference Example 1, each of the compounds represented by the formula (IX) of Reference Examples 9 to 79 was obtained. In these compounds, the substituents A, R and X are the same as those of Examples 9 to 79, respectively. 
     
         ______________________________________                                    
Compound of                                                               
Reference Example                                                         
                Melting Point (°C.)                                
______________________________________                                    
 9              268-270                                                   
10              &gt;300                                                      
11              279-285                                                   
12              &gt;300                                                      
13              &gt;300                                                      
14              &gt;300                                                      
15              &gt;295                                                      
16              280-286                                                   
17              &gt;300                                                      
18              &gt;280                                                      
                (not clear)                                               
19              282-284                                                   
20              &gt;300                                                      
21              &gt;300                                                      
22              &gt;290                                                      
                (not clear)                                               
23              &gt;300                                                      
24              &gt;300                                                      
25              292-296                                                   
26              &gt;300                                                      
27              &gt;300                                                      
28              272-275                                                   
29              281-284                                                   
30              &gt;300                                                      
31              &gt;300                                                      
32              &gt;300                                                      
33              &gt;300                                                      
34              &gt;300                                                      
35              &gt;300                                                      
36              &gt;300                                                      
37              240-248                                                   
38              &gt;300                                                      
39              &gt;300                                                      
40              &gt;300                                                      
41              &gt;300                                                      
42              286-289                                                   
43              258-261                                                   
44              298-300                                                   
45              285-287                                                   
46              286-287                                                   
47              &gt;300                                                      
48              264-268                                                   
49              262-264                                                   
50              273-274                                                   
51              264-267                                                   
52              254- 257                                                  
53              260-264                                                   
54              248-249                                                   
55              248-250                                                   
56              272-273                                                   
57              220-222                                                   
58              252-260                                                   
                (decomposition)                                           
59              &gt;300                                                      
60              252-255                                                   
61              249-252                                                   
62              &gt;300                                                      
63              287-290                                                   
64              267-268                                                   
65               274                                                      
                (decomposition)                                           
66              249-251                                                   
67              &gt;300                                                      
68              269-271                                                   
69               243                                                      
                (decomposition)                                           
70              150-155                                                   
71              200-202                                                   
72              234-237                                                   
73              &gt;300                                                      
74               280                                                      
                (decomposition)                                           
75              290-297                                                   
76              218-223                                                   
77              215-218                                                   
78              235-243                                                   
79              180-187                                                   
                (not clear)                                               
______________________________________                                    
 
    
     REFERENCE EXAMPLE 80 
     2-Azido-5-(4-methylphenyl)-1,2,4-thiadiazole 
     A mixture of 3.67 g of 2-amino-5-(4-methylphenyl)-1,3,4-thiadiazole, 3.89 g of p-toluenesulfonyl azide, 0.68 g of tetrabutylammonium hydrogensulfate, 40 ml of a 40% aqueous sodium hydroxide solution and 60 ml of dichloromethane was vigorously stirred at room temperature. After 2 hours, cold water and dichloromethane were added to the mixture, and any insoluble material was removed by filtration. The dichloromethane layer was washed with water, dried and dichloromethane was distilled off. The resulting residue was recrystallized from methanol to obtain 3.02 g of the titled compound as colorless crystals having a melting point of 129° to 130° C. (decomposition). 
     Elemental Analysis for C 9  H 7  N 5  S: Calc&#39;d: C: 49.76; H: 3.25; N: 32.24. Found: C: 49.96; H: 3.33; N: 32.51. 
     REFERENCE EXAMPLE 81 
     2-Azido-5-(3-pyridyl)-1,3,4-thiadiazole 
     The titled compound was obtained from 2-amino-5-(3-pyridyl)-1,3,4-thiadiazole in the same manner as described in Reference Example 80. Melting Point: 121°-123° C. (decomposition). 
     REFERENCE EXAMPLES 82 AND 83 
     In the same manner as described in Reference Example 80, each of the compounds represented by the formula (IV) of Reference Examples 82 and 83 was obtained. 
     
         ______________________________________                                    
Compound of                                                               
Reference Example                                                         
                Melting Point (°C.)                                
______________________________________                                    
82              129-131                                                   
83              113-114                                                   
______________________________________                                    
 
    
     REFERENCE EXAMPLE 84 
     2-Azido-5-styrylthiazole 
     The titled compound was prepared from 2-amino-5-styrylthiazole in the same manner as described in Reference Example 80. Melting Point: 112°-130° C. (decomposition). 
     Some of the starting compounds having the formula (V) are novel compounds and their melting points are identified as follows. The substituents A, R and X in the following compounds are identical to those in the compounds of the formula (I) of Examples having the corresponding number. 
     
         ______________________________________                                    
Starting Compound of                                                      
Formula (V)    Melting point (°C.)                                 
______________________________________                                    
 2             215-217                                                    
 5             175-180                                                    
 6             198-200                                                    
 7             -270                                                       
               (not clear, decomposition)                                 
10             220-222                                                    
18             237-239                                                    
19             195-199                                                    
20             273-278                                                    
22             241-243                                                    
25             221-225                                                    
27             206-209                                                    
28             203-205                                                    
29             235-239                                                    
30             237-238                                                    
31             195-197                                                    
32             207-209                                                    
33             255-260                                                    
34             251-253                                                    
35             250-253                                                    
36             265-270                                                    
37             213-215                                                    
38             263-267                                                    
39             224-226                                                    
40             172-174                                                    
41             230-233                                                    
43              223                                                       
48             193-194                                                    
49             173.5-174.5                                                
50             -214                                                       
               (not clear)                                                
51             167-168                                                    
52             212-213                                                    
54             170-172                                                    
55             219-221                                                    
56             199-201                                                    
58             -230                                                       
               (not clear)                                                
59             192-194                                                    
65              219                                                       
67             220-223                                                    
68             205-207                                                    
69              222                                                       
71             167-169                                                    
73             198-206                                                    
74             81-82                                                      
75             153-156                                                    
76             135-137                                                    
77             110-111                                                    
78             196-198                                                    
79             164-165                                                    
83             181-188                                                    
84             -254                                                       
               (not clear)                                                
______________________________________                                    
 
    
     Elemental analysis and infrared absorption specrum of the compounds of the formula (I) described in Examples are shown below. 
     
         __________________________________________________________________________
Compound          Elemental Analysis                                      
of                % (calc&#39;d)/(found)                                      
                            IR Absorption Spectrum                        
Example                                                                   
      Formula     C  H   N  (KBr) cm.sup.-1                               
__________________________________________________________________________
 1    C.sub.15 H.sub.14 N.sub.6 OS                                        
                  55.20                                                   
                     4.32                                                 
                         25.75                                            
                            3140                                          
                               3060                                       
                                  2940                                    
                                     1735                                 
                                        1690                              
                  55.39                                                   
                     4.54                                                 
                         25.82                                            
                            1550                                          
                               1480                                       
                                  1430                                    
                                     1255                                 
                                        1190                              
 2    C.sub.14 H.sub.12 N.sub.6 OS                                        
                  53.83                                                   
                     3.87                                                 
                         26.91                                            
                            3050                                          
                               2850                                       
                                  1720                                    
                                     1670                                 
                                        1550                              
                  54.27                                                   
                     4.08                                                 
                         26.93                                            
                            1520                                          
                               1490                                       
                                  1290                                    
                                     1255                                 
                                        1190                              
 3    C.sub.12 H.sub.8 N.sub.6 O.sub.2 S                                  
                  45.69                                                   
                     3.83                                                 
                         25.66                                            
                            3070                                          
                               1695                                       
                                  1600                                    
                                     1530                                 
                                        1495                              
      C.sub.3 H.sub.7 NO.H.sub.2 O                                        
                  45.40                                                   
                     3.56                                                 
                         25.59                                            
                            1440                                          
                               1310                                       
                                  1260                                    
                                     1175                                 
                                        835                               
 4    C.sub.10 H.sub.5 N.sub.7 OS                                         
                  43.48                                                   
                     2.17                                                 
                         35.50                                            
                            3080                                          
                               1700                                       
                                  1565                                    
                                     1515                                 
                                        1470                              
      1/4H.sub.2 O                                                        
                  43.88                                                   
                     2.25                                                 
                         34.97                                            
                            1455                                          
                               1430                                       
                                  1235                                    
                                     990                                  
                                        775                               
 5    C.sub.15 H.sub.13 N.sub.5 OS                                        
                  57.86                                                   
                     4.21                                                 
                         22.50                                            
                            3160                                          
                               3100                                       
                                  2950                                    
                                     1690                                 
                                        1570                              
                  57.78                                                   
                     4.33                                                 
                         22.33                                            
                            1520                                          
                               1470                                       
                                  1240                                    
                                     1150                                 
                                        770                               
 6    C.sub.16 H.sub.15 N.sub.5 OS                                        
                  58.25                                                   
                     4.74                                                 
                         21.23                                            
                            3160                                          
                               3100                                       
                                  2950                                    
                                     1685                                 
                                        1570                              
      1/4H.sub.2 O                                                        
                  58.73                                                   
                     5.16                                                 
                         20.98                                            
                            1525                                          
                               1465                                       
                                  1240                                    
                                     1150                                 
                                        770                               
 7    C.sub.18 H.sub.17 N.sub.5 OS                                        
                  60.74                                                   
                     4.95                                                 
                         19.67                                            
                            3160                                          
                               3100                                       
                                  2910                                    
                                     1685                                 
                                        1560                              
      1/4H.sub.2 O                                                        
                  60.62                                                   
                     4.89                                                 
                         19.35                                            
                            1520                                          
                               1460                                       
                                  1240                                    
                                     1150                                 
                                        755                               
 8    C.sub.12 H.sub.7 N.sub.5 OS                                         
                  53.01                                                   
                     3.46                                                 
                         25.19                                            
                            3080                                          
                               2920                                       
                                  2780                                    
                                     1710                                 
                                        1565                              
      1/2C.sub.3 H.sub.7 NO                                               
                  53.02                                                   
                     3.79                                                 
                         24.89                                            
                            1510                                          
                               1450                                       
                                  1395                                    
                                     1235                                 
                                        755                               
 9    C.sub.13 H.sub.10 N.sub.6 OS                                        
                  52.34                                                   
                     3.38                                                 
                         28.17                                            
                            3140                                          
                               3080                                       
                                  1700                                    
                                     1565                                 
                                        1520                              
                  52.50                                                   
                     3.56                                                 
                         28.20                                            
                            1470                                          
                               1265                                       
                                  1000                                    
                                     970                                  
                                        770                               
10    C.sub.16 H.sub.14 N.sub.6 OS                                        
                  56.79                                                   
                     4.17                                                 
                         24.84                                            
                            3130                                          
                               3070                                       
                                  2940                                    
                                     1740                                 
                                        1700                              
                  56.51                                                   
                     4.31                                                 
                         24.65                                            
                            1555                                          
                               1530                                       
                                  1480                                    
                                     1420                                 
                                        1190                              
11    C.sub.13 H.sub.10 N.sub.6 O.sub.3 S                                 
                  47.27                                                   
                     3.05                                                 
                         25.44                                            
                            1725                                          
                               1635                                       
                                  1570                                    
                                     1530                                 
                                        1510                              
                  47.18                                                   
                     3.34                                                 
                         25.10                                            
                            1470                                          
                               1270                                       
                                  1235                                    
                                     1080                                 
                                        990                               
12    C.sub.12 H.sub.6 N.sub.6 O.sub.3 S                                  
                  46.51                                                   
                     3.38                                                 
                         25.31                                            
                            3420                                          
                               1730                                       
                                  1650                                    
                                     1560                                 
                                        1525                              
      C.sub.3 H.sub.7 NO                                                  
                  46.23                                                   
                     3.30                                                 
                         25.22                                            
                            1485                                          
                               1445                                       
                                  1270                                    
                                     1245                                 
                                        1030                              
13    C.sub.11 H.sub.5 FN.sub.6 OS                                        
                  45.83                                                   
                     1.75                                                 
                         29.16                                            
                            3060                                          
                               1690                                       
                                  1580                                    
                                     1520                                 
                                        1470                              
                  46.29                                                   
                     2.24                                                 
                         28.90                                            
                            1440                                          
                               1250                                       
                                  895                                     
                                     800                                  
                                        760                               
14    C.sub.11 H.sub.5 ClN.sub.6 OS                                       
                  43.36                                                   
                     1.65                                                 
                         27.58                                            
                            3400                                          
                               3150                                       
                                  1710                                    
                                     1550                                 
                                        1525                              
                  43.85                                                   
                     1.94                                                 
                         27.15                                            
                            1415                                          
                               1240                                       
                                  1190                                    
                                     1170                                 
                                        670                               
15    C.sub.11 H.sub.5 ClN.sub.6 OS                                       
                  43.36                                                   
                     1.65                                                 
                         27.58                                            
                            2830                                          
                               1725                                       
                                  1680                                    
                                     1585                                 
                                        1550                              
                  43.47                                                   
                     1.95                                                 
                         27.65                                            
                            1520                                          
                               1475                                       
                                  1255                                    
                                     1190                                 
                                        1080                              
16    C.sub.11 H.sub.4 Cl.sub.2 N.sub.6 OS                                
                  38.96                                                   
                     1.19                                                 
                         24.78                                            
                            3060                                          
                               2850                                       
                                  1725                                    
                                     1685                                 
                                        1550                              
                  39.36                                                   
                     1.58                                                 
                         24.72                                            
                            1520                                          
                               1470                                       
                                  1195                                    
                                     990                                  
                                        965                               
17    C.sub.9 H.sub.4 N.sub.6 O.sub.2 S                                   
                  41.54                                                   
                     1.55                                                 
                         32.30                                            
                            3100                                          
                               1680                                       
                                  1565                                    
                                     1510                                 
                                        1470                              
                  41.69                                                   
                     1.92                                                 
                         32.05                                            
                            1250                                          
                               1225                                       
                                  870                                     
                                     780                                  
                                        750                               
18    C.sub.10 H.sub.6 N.sub.6 O.sub.2 S                                  
                  44.13                                                   
                     2.67                                                 
                         29.92                                            
                            2980                                          
                               2880                                       
                                  1690                                    
                                     1575                                 
                                        1530                              
      1/4C.sub.3 H.sub.7 NO                                               
                  44.12                                                   
                     2.76                                                 
                         29.98                                            
                            1480                                          
                               1260                                       
                                  1240                                    
                                     1010                                 
                                        895                               
19    C.sub.11 H.sub.8 N.sub.6 O.sub.2 S                                  
                  45.83                                                   
                     2.80                                                 
                         29.15                                            
                            3080                                          
                               1720                                       
                                  1640                                    
                                     1525                                 
                                        1470                              
                  45.97                                                   
                     2.99                                                 
                         28.71                                            
                            1410                                          
                               1370                                       
                                  1235                                    
                                     750                                  
                                        730                               
20    C.sub.13 H.sub.12 N.sub.6 O.sub. 2 S                                
                  49.98                                                   
                     3.87                                                 
                         26.91                                            
                            3180                                          
                               3080                                       
                                  1710                                    
                                     1565                                 
                                        1530                              
                  49.37                                                   
                     3.96                                                 
                         26.47                                            
                            1510                                          
                               1250                                       
                                  1000                                    
                                     890                                  
                                        800                               
21    C.sub.9 H.sub.3 ClN.sub.6 O.sub.2 S                                 
                  39.19                                                   
                     2.74                                                 
                         26.66                                            
                            3090                                          
                               1735                                       
                                  1665                                    
                                     1600                                 
                                        1545                              
      C.sub.3 H.sub.7 NO                                                  
                  39.53                                                   
                     2.82                                                 
                         26.86                                            
                            1510                                          
                               1460                                       
                                  1200                                    
                                     1010                                 
                                        970                               
22    C.sub.13 H.sub.10 N.sub.6 O.sub.2 S                                 
                  49.67                                                   
                     3.21                                                 
                         26.74                                            
                            3140                                          
                               3090                                       
                                  2930                                    
                                     1705                                 
                                        1570                              
                  49.30                                                   
                     3.26                                                 
                         26.43                                            
                            1545                                          
                               1525                                       
                                  1155                                    
                                     1005                                 
                                        890                               
23    C.sub.9 H.sub.4 N.sub.6 OS.sub.2                                    
                  39.39                                                   
                     1.70                                                 
                         29.80                                            
                            3000                                          
                               1695                                       
                                  1565                                    
                                     1530                                 
                                        1450                              
      1/8C.sub.2 H.sub.5 OH                                               
                  39.02                                                   
                     1.83                                                 
                         29.81                                            
                            1410                                          
                               1245                                       
                                  1230                                    
                                     970                                  
                                        720                               
24    C.sub.9 H.sub.4 N.sub.6 OS.sub.2                                    
                  39.12                                                   
                     1.46                                                 
                         30.42                                            
                            3060                                          
                               1680                                       
                                  1570                                    
                                     1520                                 
                                        1470                              
                  39.52                                                   
                     2.09                                                 
                         30.23                                            
                            1405                                          
                               1235                                       
                                  1230                                    
                                     845                                  
                                        730                               
25    C.sub.10 H.sub.6 N.sub.6 OS.sub.2                                   
                  41.37                                                   
                     2.08                                                 
                         28.95                                            
                            3400                                          
                               2760                                       
                                  1710                                    
                                     1560                                 
                                        1510                              
                  41.37                                                   
                     2.19                                                 
                         29.00                                            
                            1480                                          
                               1450                                       
                                  1410                                    
                                     1245                                 
                                        1170                              
26    C.sub.10 H.sub.6 N.sub.6 OS.sub.2                                   
                  41.37                                                   
                     2.08                                                 
                         28.95                                            
                            3150                                          
                               3080                                       
                                  1690                                    
                                     1570                                 
                                        1530                              
                  41.49                                                   
                     2.50                                                 
                         28.71                                            
                            1500                                          
                               1440                                       
                                  1235                                    
                                     875                                  
                                        750                               
27    C.sub.11 H.sub.8 N.sub.6 OS.sub.2                                   
                  43.41                                                   
                     2.65                                                 
                         27.62                                            
                            3080                                          
                               2920                                       
                                  1725                                    
                                     1650                                 
                                        1580                              
                  43.50                                                   
                     3.26                                                 
                         27.70                                            
                            1525                                          
                               1490                                       
                                  1475                                    
                                     1415                                 
                                        750                               
28    C.sub.13 H.sub.12 N.sub.6 OS.sub.2                                  
                  46.97                                                   
                     3.64                                                 
                         25.29                                            
                            2940                                          
                               2850                                       
                                  1720                                    
                                     1670                                 
                                        1540                              
                  46.85                                                   
                     3.64                                                 
                         24.96                                            
                            1520                                          
                               1490                                       
                                  1430                                    
                                     1250                                 
                                        1160                              
29    C.sub.13 H.sub.12 N.sub.6 OS.sub.2                                  
                  46.97                                                   
                     3.64                                                 
                         25.29                                            
                            2950                                          
                               2640                                       
                                  1740                                    
                                     1540                                 
                                        1270                              
                  47.46                                                   
                     3.98                                                 
                         25.55                                            
                            1235                                          
                               1205                                       
                                  1190                                    
                                     1170                                 
                                        750                               
30    C.sub.11 H.sub.8 N.sub.6 OS.sub.2                                   
                  42.16                                                   
                     2.90                                                 
                         26.82                                            
                            3480                                          
                               2720                                       
                                  1720                                    
                                     1570                                 
                                        1510                              
      1/2H.sub.2 O                                                        
                  42.28                                                   
                     2.88                                                 
                         26.82                                            
                            1475                                          
                               1235                                       
                                  1170                                    
                                     980                                  
                                        590                               
31    C.sub.12 H.sub.10 N.sub.6 OS.sub.2                                  
                  46.07                                                   
                     4.38                                                 
                         25.05                                            
                            2920                                          
                               1735                                       
                                  1650                                    
                                     1570                                 
                                        1535                              
      C.sub.3 H.sub.7 NO                                                  
                  46.11                                                   
                     4.39                                                 
                         25.08                                            
                            1510                                          
                               1475                                       
                                  1440                                    
                                     1385                                 
                                        870                               
32    C.sub.9 H.sub.3 ClN.sub.6 OS.sub.2                                  
                  37.55                                                   
                     3.00                                                 
                         25.54                                            
                            2700                                          
                               1730                                       
                                  1640                                    
                                     1580                                 
                                        1530                              
      C.sub.3 H.sub.7 NO                                                  
                  37.84                                                   
                     2.83                                                 
                         25.46                                            
                            1500                                          
                               1475                                       
                                  1425                                    
                                     1385                                 
                                        1240                              
33    C.sub.12 H.sub.8 N.sub.6 OS.sub.2                                   
                  45.56                                                   
                     2.55                                                 
                         26.57                                            
                            3180                                          
                               1710                                       
                                  1565                                    
                                     1530                                 
                                        1500                              
                  45.54                                                   
                     2.69                                                 
                         26.22                                            
                            1475                                          
                               1435                                       
                                  1415                                    
                                     1230                                 
                                        1160                              
34    C.sub.14 H.sub.13 N.sub.5 O.sub.3 S.sub.2                           
                  47.58                                                   
                     3.71                                                 
                         23.78                                            
                            3170                                          
                               3120                                       
                                  1695                                    
                                     1570                                 
                                        1540                              
      1/2H.sub.2 O                                                        
                  47.53                                                   
                     3.56                                                 
                         23.64                                            
                            1505                                          
                               1430                                       
                                  1245                                    
                                     1005                                 
                                        770                               
35    C.sub.13 H.sub.10 N.sub.6 OS.sub.2                                  
                  47.42                                                   
                     3.39                                                 
                         24.58                                            
                            3170                                          
                               1710                                       
                                  1690                                    
                                     1560                                 
                                        1530                              
      1/4C.sub.2 H.sub.5 OH                                               
                  46.91                                                   
                     3.23                                                 
                         24.50                                            
                            1510                                          
                               1470                                       
                                  1440                                    
                                     1230                                 
                                        735                               
36    C.sub.14 H.sub.12 N.sub.6 OS.sub.2                                  
                  48.84                                                   
                     3.82                                                 
                         24.14                                            
                            3400                                          
                               2910                                       
                                  1730                                    
                                     1640                                 
                                        1555                              
      1/4C.sub.3 H.sub.7 NO                                               
                  48.89                                                   
                     4.31                                                 
                         24.15                                            
                            1515                                          
                               1450                                       
                                  1380                                    
                                     1250                                 
                                        1205                              
37    C.sub.12 H.sub.11 N.sub.7 O.sub.2 S                                 
                  42.98                                                   
                     3.91                                                 
                         29.24                                            
                            3100                                          
                               2950                                       
                                  1730                                    
                                     1705                                 
                                        1570                              
      H.sub.2 O   43.33                                                   
                     3.59                                                 
                         29.28                                            
                            1550                                          
                               1530                                       
                                  1450                                    
                                     1230                                 
                                        910                               
38    C.sub.14 H.sub.8 N.sub.6 O.sub.2 S                                  
                  51.59                                                   
                     3.21                                                 
                         25.23                                            
                            3050                                          
                               1730                                       
                                  1635                                    
                                     1555                                 
                                        1530                              
      1/2C.sub.3 H.sub.7 NO                                               
                  51.90                                                   
                     3.46                                                 
                         25.11                                            
                            1510                                          
                               1470                                       
                                  1450                                    
                                     1230                                 
                                        755                               
39    C.sub.14 H.sub.10 N.sub.6 O.sub.2 S                                 
                  51.52                                                   
                     3.09                                                 
                         25.76                                            
                            3050                                          
                               1735                                       
                                  1555                                    
                                     1530                                 
                                        1515                              
                  51.67                                                   
                     2.72                                                 
                         25.55                                            
                            1470                                          
                               1450                                       
                                  1270                                    
                                     1235                                 
                                        755                               
40    C.sub.14 H.sub.10 N.sub.6 O.sub.2 S                                 
                  51.30                                                   
                     3.75                                                 
                         25.09                                            
                            1705                                          
                               1560                                       
                                  1520                                    
                                     1260                                 
                                        1230                              
      1/2 C.sub.3 H.sub.7 NO                                              
                  51.55                                                   
                     3.52                                                 
                         24.24                                            
                            1150                                          
                               1100                                       
                                  995                                     
                                     965                                  
                                        745                               
41    C.sub.13 H.sub.8 N.sub.6 O.sub.3 S                                  
                  47.73                                                   
                     3.18                                                 
                         24.96                                            
                            3040                                          
                               1700                                       
                                  1560                                    
                                     1530                                 
                                        1490                              
      1/2C.sub.3 H.sub.7 NO                                               
                  47.93                                                   
                     3.06                                                 
                         24.95                                            
                            1270                                          
                               1260                                       
                                  1240                                    
                                     1090                                 
                                        765                               
42    C.sub.12 H.sub.8 N.sub.6 OS                                         
                  50.69                                                   
                     2.84                                                 
                         29.56                                            
                            3150                                          
                               1705                                       
                                  1570                                    
                                     1530                                 
                                        1490                              
                  50.59                                                   
                     2.93                                                 
                         29.57                                            
                            1150                                          
                               970                                        
                                  770                                     
                                     695                                  
                                        610                               
43    C.sub.16 H.sub.16 N.sub.6 OS                                        
                  55.71                                                   
                     4.82                                                 
                         24.36                                            
                            3155                                          
                               2950                                       
                                  1720                                    
                                     1710                                 
                                        1625                              
      1/4H.sub.2 O                                                        
                  55.92                                                   
                     4.73                                                 
                         24.25                                            
                            1575                                          
                               1530                                       
                                  1480                                    
                                     1130                                 
                                        770                               
44    C.sub.13 H.sub.10 N.sub.6 O.sub.2 S                                 
                  49.67                                                   
                     3.21                                                 
                         26.74                                            
                            3150                                          
                               1710                                       
                                  1570                                    
                                     1530                                 
                                        1510                              
                  49.74                                                   
                     3.34                                                 
                         26.63                                            
                            1470                                          
                               1250                                       
                                  1140                                    
                                     1020                                 
                                        970                               
45    C.sub.12 H.sub.7 FN.sub.6 OS                                        
                  47.68                                                   
                     2.33                                                 
                         27.80                                            
                            3050                                          
                               1705                                       
                                  1600                                    
                                     1570                                 
                                        1525                              
                  47.85                                                   
                     2.44                                                 
                         27.53                                            
                            1500                                          
                               1470                                       
                                  1230                                    
                                     1215                                 
                                        1110                              
46    C.sub.12 H.sub.7 ClN.sub.6 OS                                       
                  45.21                                                   
                     2.21                                                 
                         26.77                                            
                            3140                                          
                               1710                                       
                                  1570                                    
                                     1530                                 
                                        1490                              
                  45.29                                                   
                     2.37                                                 
                         26.44                                            
                            1475                                          
                               1150                                       
                                  970                                     
                                     770                                  
                                        610                               
47    C.sub.11 H.sub.6 N.sub.6 OS                                         
                  48.88                                                   
                     2.24                                                 
                         31.10                                            
                            3060                                          
                               3030                                       
                                  1690                                    
                                     1575                                 
                                        1520                              
                  48.79                                                   
                     2.55                                                 
                         30.79                                            
                            1480                                          
                               1440                                       
                                  1240                                    
                                     990                                  
                                        770                               
48    C.sub.14 H.sub.12 N.sub.6 OS                                        
                  53.83                                                   
                     3.87                                                 
                         26.91                                            
                            3180                                          
                               1700                                       
                                  1560                                    
                                     1515                                 
                                        1470                              
                  53.62                                                   
                     3.99                                                 
                         26.43                                            
                            1450                                          
                               1140                                       
                                  990                                     
                                     770                                  
                                        740                               
49    C.sub.14 H.sub.12 N.sub.6 OS                                        
                  53.83                                                   
                     3.87                                                 
                         26.91                                            
                            3140                                          
                               2900                                       
                                  1710                                    
                                     1570                                 
                                        1550                              
                  53.86                                                   
                     4.03                                                 
                         26.88                                            
                            1530                                          
                               1475                                       
                                  1210                                    
                                     970                                  
                                        770                               
50    C.sub.14 H.sub.12 N.sub.6 OS                                        
                  53.83                                                   
                     3.87                                                 
                         26.91                                            
                            3210                                          
                               1705                                       
                                  1560                                    
                                     1520                                 
                                        1470                              
                  53.76                                                   
                     4.18                                                 
                         26.57                                            
                            1445                                          
                               1230                                       
                                  1220                                    
                                     995                                  
                                        770                               
51    C.sub.14 H.sub.12 N.sub.6 O.sub.2 S                                 
                  51.21                                                   
                     3.68                                                 
                         25.59                                            
                            3150                                          
                               1710                                       
                                  1590                                    
                                     1570                                 
                                        1540                              
                  51.19                                                   
                     3.92                                                 
                         25.31                                            
                            1525                                          
                               1270                                       
                                  1250                                    
                                     1160                                 
                                        1030                              
52    C.sub.14 H.sub.12 N.sub.6 O.sub.2 S                                 
                  51.21                                                   
                     3.68                                                 
                         25.59                                            
                            3150                                          
                               1700                                       
                                  1560                                    
                                     1520                                 
                                        1500                              
                  51.25                                                   
                     3.76                                                 
                         25.48                                            
                            1470                                          
                               1260                                       
                                  1235                                    
                                     970                                  
                                        800                               
53    C.sub.13 H.sub.9 FN.sub.6 OS                                        
                  49.36                                                   
                     2.87                                                 
                         26.57                                            
                            3160                                          
                               1690                                       
                                  1550                                    
                                     1510                                 
                                        1490                              
                  49.30                                                   
                     3.06                                                 
                         26.63                                            
                            1210                                          
                               1045                                       
                                  990                                     
                                     810                                  
                                        750                               
54    C.sub.13 H.sub.9 ClN.sub.6 OS                                       
                  46.92                                                   
                     2.73                                                 
                         25.26                                            
                            3060                                          
                               1710                                       
                                  1570                                    
                                     1550                                 
                                        1530                              
                  46.93                                                   
                     2.87                                                 
                         25.30                                            
                            1475                                          
                               970                                        
                                  890                                     
                                     865                                  
                                        770                               
55    C.sub.13 H.sub.9 ClN.sub.6 OS                                       
                  46.92                                                   
                     2.73                                                 
                         25.26                                            
                            3150                                          
                               1700                                       
                                  1560                                    
                                     1520                                 
                                        1480                              
                  46.68                                                   
                     2.99                                                 
                         24.80                                            
                            1210                                          
                               1085                                       
                                  970                                     
                                     805                                  
                                        765                               
56    C.sub.13 H.sub.8 Cl.sub.2 N.sub.6 OS                                
                  42.52                                                   
                     2.20                                                 
                         22.89                                            
                            3130                                          
                               1700                                       
                                  1560                                    
                                     1520                                 
                                        1455                              
                  42.44                                                   
                     2.35                                                 
                         22.83                                            
                            1210                                          
                               1125                                       
                                  985                                     
                                     970                                  
                                        820                               
57    C.sub.19 H.sub.14 N.sub.6 OS                                        
                  58.15                                                   
                     4.11                                                 
                         21.42                                            
                            3170                                          
                               1715                                       
                                  1700                                    
                                     1555                                 
                                        1515                              
      H.sub.2 O   58.66                                                   
                     3.89                                                 
                         21.05                                            
                            1480                                          
                               1465                                       
                                  740                                     
                                     690                                  
                                        590                               
58    C.sub.14 H.sub.12 N.sub.6 OS                                        
                  53.83                                                   
                     3.87                                                 
                         26.91                                            
                            3150                                          
                               1705                                       
                                  1570                                    
                                     1525                                 
                                        1490                              
                  53.88                                                   
                     3.96                                                 
                         26.54                                            
                            1470                                          
                               1135                                       
                                  980                                     
                                     765                                  
                                        695                               
59    C.sub.15 H.sub.14 N.sub.6 OS                                        
                  55.20                                                   
                     4.32                                                 
                         25.75                                            
                            3150                                          
                               2940                                       
                                  1710                                    
                                     1560                                 
                                        1515                              
                  55.56                                                   
                     4.38                                                 
                         25.89                                            
                            1470                                          
                               1430                                       
                                  1140                                    
                                     760                                  
                                        690                               
60    C.sub.14 H.sub.12 N.sub.6 OS                                        
                  53.83                                                   
                     3.87                                                 
                         26.91                                            
                            3130                                          
                               1710                                       
                                  1570                                    
                                     1525                                 
                                        1490                              
                  53.58                                                   
                     3.93                                                 
                         24.48                                            
                            1470                                          
                               1445                                       
                                  970                                     
                                     770                                  
                                        745                               
61    C.sub.15 H.sub.14 N.sub.6 OS                                        
                  55.20                                                   
                     4.32                                                 
                         25.75                                            
                            3140                                          
                               2920                                       
                                  1700                                    
                                     1560                                 
                                        1520                              
                  54.91                                                   
                     4.27                                                 
                         25.36                                            
                            1485                                          
                               1470                                       
                                  1445                                    
                                     770                                  
                                        745                               
62    C.sub.13 H.sub.8 N.sub.6 OS                                         
                  52.49                                                   
                     3.12                                                 
                         27.83                                            
                            3400                                          
                               3120                                       
                                  3060                                    
                                     1700                                 
                                        1610                              
      1/4C.sub.3 H.sub. 7 NO                                              
                  52.57                                                   
                     3.49                                                 
                         27.25                                            
                            1565                                          
                               1520                                       
                                  1470                                    
                                     970                                  
                                        770                               
63    C.sub.19 H.sub.12 N.sub.6 OS                                        
                  60.54                                                   
                     3.34                                                 
                         22.30                                            
                            3130                                          
                               1715                                       
                                  1690                                    
                                     1540                                 
                                        1490                              
      1/4H.sub.2 O                                                        
                  60.28                                                   
                     3.54                                                 
                         22.24                                            
                            1435                                          
                               1255                                       
                                  1190                                    
                                     1140                                 
                                        770                               
64    C.sub.12 H.sub.8 N.sub.6 O.sub.2 S                                  
                  48.07                                                   
                     3.09                                                 
                         27.48                                            
                            3180                                          
                               1710                                       
                                  1560                                    
                                     1530                                 
                                        1485                              
      1/4C.sub.3 H.sub.7 NO                                               
                  47.77                                                   
                     2.93                                                 
                         27.33                                            
                            1245                                          
                               1230                                       
                                  1210                                    
                                     1170                                 
                                        760                               
65    C.sub.16 H.sub.16 N.sub.6 O.sub.2 S                                 
                  53.92                                                   
                     4.53                                                 
                         23.58                                            
                            2970                                          
                               1720                                       
                                  1560                                    
                                     1530                                 
                                        1510                              
                  54.74                                                   
                     4.90                                                 
                         22.87                                            
                            1250                                          
                               1230                                       
                                  1185                                    
                                     1170                                 
                                        825                               
66    C.sub.12 H.sub.7 FN.sub.6 O.sub.2 S                                 
                  45.28                                                   
                     2.22                                                 
                         26.41                                            
                            3200                                          
                               1730                                       
                                  1565                                    
                                     1400                                 
                                        1250                              
                  45.45                                                   
                     2.42                                                 
                         26.57                                            
                            1230                                          
                               1205                                       
                                  1170                                    
                                     830                                  
                                        770                               
67    C.sub.12 H.sub.7 ClN.sub.6 O.sub.2 S                                
                  43.05                                                   
                     2.11                                                 
                         25.11                                            
                            3150                                          
                               1710                                       
                                  1565                                    
                                     1530                                 
                                        1490                              
                  43.47                                                   
                     2.53                                                 
                         24.85                                            
                            1240                                          
                               1220                                       
                                  1170                                    
                                     1060                                 
                                        820                               
68    C.sub.16 H.sub.14 N.sub.6 O.sub.2 S                                 
                  54.22                                                   
                     3.98                                                 
                         23.72                                            
                            3200                                          
                               1725                                       
                                  1710                                    
                                     1575                                 
                                        1565                              
                  53.98                                                   
                     4.06                                                 
                         23.35                                            
                            1550                                          
                               1495                                       
                                  1260                                    
                                     1235                                 
                                        1170                              
69    C.sub.17 H.sub.18 N.sub.6 O.sub.2 S                                 
                  54.59                                                   
                     5.33                                                 
                         22.37                                            
                            2960                                          
                               1710                                       
                                  1580                                    
                                     1555                                 
                                        1530                              
      1/2C.sub.3 H.sub.7 NO                                               
                  54.15                                                   
                     4.94                                                 
                         22.45                                            
                            1510                                          
                               1245                                       
                                  1185                                    
                                     1155                                 
                                        775                               
70    C.sub.12 H.sub.8 N.sub.6 OS.sub.2                                   
                  45.30                                                   
                     2.55                                                 
                         26.57                                            
                            3130                                          
                               1690                                       
                                  1550                                    
                                     1515                                 
                                        1465                              
                  45.63                                                   
                     2.60                                                 
                         26.41                                            
                            1430                                          
                               1225                                       
                                  1210                                    
                                     1000                                 
                                        760                               
71    C.sub.16 H.sub.16 N.sub.6 OS.sub.2                                  
                  51.59                                                   
                     4.33                                                 
                         22.57                                            
                            3150                                          
                               2950                                       
                                  1720                                    
                                     1710                                 
                                        1565                              
                  51.58                                                   
                     4.26                                                 
                         23.04                                            
                            1525                                          
                               1480                                       
                                  1235                                    
                                     1105                                 
                                        825                               
72    C.sub.13 H.sub.10 N.sub.6 OS.sub.2                                  
                  47.49                                                   
                     3.25                                                 
                         24.62                                            
                            3400                                          
                               3130                                       
                                  1700                                    
                                     1600                                 
                                        1560                              
      1/4C.sub.2 H.sub.5 OH                                               
                  47.50                                                   
                     3.31                                                 
                         24.54                                            
                            1520                                          
                               1470                                       
                                  1425                                    
                                     1225                                 
                                        730                               
73    C.sub.13 H.sub.8 ClN.sub.5 O.sub.2 S                                
                  46.96                                                   
                     2.77                                                 
                         20.29                                            
                            3080                                          
                               1720                                       
                                  1710                                    
                                     1635                                 
                                        1590                              
      1/4C.sub.2 H.sub.5 OH                                               
                  47.22                                                   
                     2.55                                                 
                         20.20                                            
                            1520                                          
                               1490                                       
                                  1460                                    
                                     1280                                 
                                        1265                              
74    C.sub.10 H.sub.5 N.sub.5 O.sub.2 S                                  
                  46.52                                                   
                     2.45                                                 
                         26.50                                            
                            1695                                          
                               1575                                       
                                  1525                                    
                                     1485                                 
                                        1240                              
      1/4C.sub.3 H.sub.7 NO                                               
                  46.39                                                   
                     2.40                                                 
                         26.26                                            
                            985                                           
                               965                                        
                                  750                                     
                                     740                                  
                                        590                               
75    C.sub.10 H.sub.5 N.sub.5 OS.sub.2                                   
                  43.97                                                   
                     2.28                                                 
                         24.42                                            
                            3170                                          
                               3080                                       
                                  1680                                    
                                     1570                                 
                                        1520                              
      1/4C.sub.2 H.sub.5 OH                                               
                  43.53                                                   
                     2.12                                                 
                         24.64                                            
                            1465                                          
                               1235                                       
                                  1140                                    
                                     765                                  
                                        730                               
76    C.sub.14 H.sub.11 N.sub.5 OS                                        
                  56.55                                                   
                     3.73                                                 
                         23.55                                            
                            2730                                          
                               1725                                       
                                  1570                                    
                                     1520                                 
                                        1460                              
                  56.64                                                   
                     3.93                                                 
                         23.28                                            
                            1345                                          
                               1330                                       
                                  1040                                    
                                     770                                  
                                        740                               
77    C.sub.14 H.sub.10 ClN.sub.5 OS                                      
                  50.68                                                   
                     3.04                                                 
                         21.11                                            
                            3100                                          
                               1685                                       
                                  1570                                    
                                     1520                                 
                                        1460                              
                  50.57                                                   
                     3.18                                                 
                         20.99                                            
                            1420                                          
                               1340                                       
                                  1320                                    
                                     1230                                 
                                        770                               
78    C.sub.13 H.sub.9 ClN.sub.6 OS                                       
                  46.92                                                   
                     2.72                                                 
                         25.26                                            
                            3170                                          
                               1700                                       
                                  1555                                    
                                     1520                                 
                                        1475                              
                  47.15                                                   
                     3.04                                                 
                         24.98                                            
                            1445                                          
                               1125                                       
                                  1035                                    
                                     770                                  
                                        740                               
79    C.sub.19 H.sub.22 N.sub.6 O.sub.2 S                                 
                  57.27                                                   
                     5.56                                                 
                         21.09                                            
                            2950                                          
                               1705                                       
                                  1575                                    
                                     1530                                 
                                        1480                              
                  57.16                                                   
                     5.57                                                 
                         21.11                                            
                            1450                                          
                               1265                                       
                                  1120                                    
                                     975                                  
                                        775                               
80    C.sub.12 H.sub.8 N.sub.6 OS                                         
                  47.68                                                   
                     3.33                                                 
                         27.80                                            
                            3480                                          
                               1720                                       
                                  1575                                    
                                     1530                                 
                                        1500                              
      H.sub.2 O   47.79                                                   
                     3.45                                                 
                         27.85                                            
                            1475                                          
                               1230                                       
                                  985                                     
                                     745                                  
                                        600                               
81    C.sub.10 H.sub.5 N.sub.7 OS                                         
                  44.59                                                   
                     2.34                                                 
                         35.08                                            
                            1730                                          
                               1675                                       
                                  1600                                    
                                     1570                                 
                                        1545                              
      1/4H.sub.2 O                                                        
                  44.46                                                   
                     2.24                                                 
                         35.32                                            
                            1525                                          
                               1480                                       
                                  1240                                    
                                     1170                                 
                                        745                               
82    C.sub.15 H.sub.14 N.sub.6 OS                                        
                  55.20                                                   
                     4.32                                                 
                         25.75                                            
                            3100                                          
                               2960                                       
                                  1735                                    
                                     1580                                 
                                        1525                              
                  55.13                                                   
                     4.29                                                 
                         26.03                                            
                            1470                                          
                               1240                                       
                                  990                                     
                                     750                                  
                                        630                               
83    C.sub.15 H.sub.12 N.sub.6 OS                                        
                  55.54                                                   
                     3.73                                                 
                         25.91                                            
                            2930                                          
                               1710                                       
                                  1560                                    
                                     1525                                 
                                        1480                              
                  55.70                                                   
                     3.94                                                 
                         25.50                                            
                            1420                                          
                               1240                                       
                                  1160                                    
                                     825                                  
                                        750                               
84    C.sub.14 H.sub.9 N.sub.5 OS                                         
                  56.94                                                   
                     3.07                                                 
                         23.71                                            
                            3100                                          
                               2880                                       
                                  1685                                    
                                     1670                                 
                                        1545                              
                  56.64                                                   
                     3.32                                                 
                         22.96                                            
                            1310                                          
                               1150                                       
                                  940                                     
                                     775                                  
                                        750                               
85    C.sub.19 H.sub.25 N.sub.7 O.sub.4 S                                 
                  49.99                                                   
                     5.74                                                 
                         21.48                                            
      1/2H.sub.2 O                                                        
                  50.24                                                   
                     6.00                                                 
                         21.25                                            
86    C.sub.16 H.sub.19 N.sub.7 O.sub.5 S                                 
                  42.01                                                   
                     5.07                                                 
                         21.14                                            
      2H.sub.2 O  42.01                                                   
                     4.64                                                 
                         21.97                                            
87    C.sub.13 H.sub.9 NaN.sub.6 OS                                       
                  46.15                                                   
                     3.28                                                 
                         24.84                                            
      H.sub.2 O   45.86                                                   
                     3.40                                                 
                         24.80                                            
88    C.sub.13 H.sub.9 KN.sub.6 OS1.5H.sub.2 O                            
                  42.96                                                   
                     3.33                                                 
                         23.13                                            
                  42.76                                                   
                     3.40                                                 
                         23.23                                            
89    C.sub.13 H.sub.9 LiN.sub.6 OS                                       
                  45.88                                                   
                     3.85                                                 
                         24.70                                            
      2H.sub.2 O  45.58                                                   
                     3.80                                                 
                         24.55                                            
__________________________________________________________________________
 
    
     The pharmacological test examples and the anti-allergic activity of the compounds of this invention are described hereinafter in detail. 
     TEST EXAMPLE 1 
     (i) Preparation of Antiserum 
     1 mg of egg albumin dissolved in 0.2 ml of saline was intramuscularly administered to each of Sprague-Dawley male rats weighing 300 to 350 g (Charles River Japan Inc.), and then 1 ml of a suspension of sterilized Bordetella pertussis (2×10 10  cells) in saline was administered intraperitoneally to the rats. After 14 days, blood was drawn from the rats to obtain an antiserum. The PCA titer of this serum was found to be about 1:64 to 128 when measured with the 48 hours PCA in rats. 
     (ii) Passive Peritoneal Anaphylaxis (PPA) Test 
     The test was conducted according to the method of Orange et al [Orange, R. P., Stechschulte, D. J., Austen, K. F., J. Immunol., 105, pp1087-1095 (1970)]. Sprague-Dawley male rats weighing 250 to 400 g (5 rats per group) were passively sensitized by administering 5 ml of 5-fold dilution antiserum (prepared by diluting the above antiserum with saline). 2 hours later, 5 ml of an egg albumin solution prepared by dissolving 2 mg of egg albumin in phosphate buffered saline containing 0.9 mM of calcium chloride was administered intraperitoneally to the rats. After 5  minutes, the rats were sacrificed by decapitation, and peritoneal fluid was pooled and centrifuged at 300×G at 4° C. for 10 minutes. Then, amounts of SRS-A and histamine in the supernatant were determined. 
     The quantitative determination of SRS-A was carried out according to the method of Stechschulte et al [Stechschulte, D. J., Auste, K. F., Bloch, K. J., J. Exp. Med., 125, pp127-147 (1967)] using a guinea pig ileum specimen in the presence of mepyramine and atropine. The amount of SRS-A was expressed in terms of unit, i.e., one unit of SRS-A activity was defined as the concentration required to produce a contraction of guinea pig ileum equal in amplitude to that produced by 5 ng of histamine, and the total released amount of SRS-A per rat (unit/rat) was calculated. 
     The quantitative determination of histamine was carried out according to the method of Shore et al [Shore, P. A., Bunkhalter, A. H., Cohn, V. H., J. Pharmacol. Exp. Ther., 127, pp182-186 (1959)], and the total released amount of histamine per rat (μg/rat) was calculated. 
     In this test, the test compound of this invention was administered as follows. 2 mg of a test compound was dissolved in 10 ml of phosphate buffered saline containing 0.9 mM of calcium chloride, an equimolar amount of sodium hydroxide to test compound, 2% of dimethyl sulfoxide and 2% of ethanol, and the solution was administered intraperitoneally to the rats at a dose of 1 mg/kg 30 seconds before the injection of egg albumin for inducing PPA. For a control group, the same solution without test compound and sodium hydroxide was administered. 
     The inhibitory activity on release of histamine and SRS-A by the PPA reaction in the treated group was calculated by the following formula: ##EQU1## wherein: a represents a mean value of released amount in the control group. 
     b represents a mean value of released amount in the treated group. 
     c represents a mean value of spontaneously released amount. 
     The inhibitory activities of the compounds of this invention determined by the above tests are shown in Table 1. 
     
                       TABLE 1                                                     
______________________________________                                    
Compound of     Inhibition (%)                                            
Example         Histamine SRS-A                                           
______________________________________                                    
 1              83        64                                              
 2              85        52                                              
 3              93        42                                              
 8              83        37                                              
 9              80        50                                              
11              89        66                                              
12              87        52                                              
17              82        55                                              
23              84        51                                              
27              81        63                                              
32              87        63                                              
33              82        70                                              
35              88        45                                              
36              83        41                                              
41              91        62                                              
42              99        54                                              
43              75        59                                              
44              81        70                                              
57              86        61                                              
62              94        55                                              
66              89        47                                              
80              91        42                                              
82              82        52                                              
DSCG*           93         0                                              
______________________________________                                    
 *DSCG Sodium Cromoglycate (administered at 1 mg/kg of body weight)       
 
    
     TEST EXAMPLE 2 
     PCA Test 
     In this test, the antiserum described in Test Example 1 was used after it was diluted with saline so as to provide a blue spot having a diameter of about 10 mm in the following control group. 
     Sprague-Dowley male rats weighing about 180 g (5 rats per group) were sensitized by injecting 0.05 ml of the diluted antiserum into the shaved dorsal skin. 48 hours later, the animals were challenged with 1 ml of saline containing 5 mg of egg albumin and 5 mg of Evans blue dye administered via a tail vein. 30 minutes later, the rats were sacrificed by decapitation. The dorsal skin was removed, and the long and short axis of the each wheal was measured. 
     In this test, the test compound was administered as follows. 20 mg of a test compound was suspended in a 0.5% CMC aqueous solution, and the suspension was administered to each of the rats in an amount of 20 mg/kg 30 minutes before the antigen challenge. For a control group, only a 0.5% CMC solution was administered. 
     The inhibitory activity on the PCA reaction in the treated group was calculated by the following formula: ##EQU2## wherein: a represents a mean value of blue spot area in the control group. 
     b represents a mean value of blue spot area in the treated group. 
     The inhibitory activity of the compounds of this invention determined by the above test are shown in Table 2. 
     
                       TABLE 2                                                     
______________________________________                                    
Compound of                                                               
Example       Inhibition (%)                                              
______________________________________                                    
 1            46                                                          
 6            36                                                          
 7            40                                                          
 9            52                                                          
11            32                                                          
12            36                                                          
13            34                                                          
17            50                                                          
21            35                                                          
23            31                                                          
24            45                                                          
28            34                                                          
29            39                                                          
31            32                                                          
32            35                                                          
33            47                                                          
35            45                                                          
36            40                                                          
39            38                                                          
42            48                                                          
45            57                                                          
47            38                                                          
64            33                                                          
69            34                                                          
73            48                                                          
75            32                                                          
80            31                                                          
83            44                                                          
DSCG*          8                                                          
______________________________________                                    
 *DSCG Sodium Cromoglycate (administered at 100 mg/kg of body weight)     
 
    
     Example of preparations containing the compound of this invention are described hereinafter. 
     PREPARATION EXAMPLE 1 
     Tablets each containing 50 mg of the compound of the present invention are prepared from the following formulation. 
     
         ______________________________________                                    
Compound of Present Invention*                                            
                     50     mg                                            
Lactose              35     mg                                            
Starch               24.5   mg                                            
Magnesium Stearate   0.5    mg                                            
Total                110    mg per tablet                                 
______________________________________                                    
 
    
     PREPARATION EXAMPLE 2 
     A syrup preparation containing 10 mg of the compound of the present invention per ml was prepared from the following formulation. 
     
         ______________________________________                                    
Compound of Present Invention*                                            
                      1000    mg                                          
Polysolbate 80        1000    mg                                          
Syrup                  quantum sufficient                                 
Total                 100     ml                                          
______________________________________                                    
 *6-(2-Phenylethyl)-[1,3,4]thiadiazolo[3,2a][1,2,3triazolo[4,5d]pyrimidin9
1H)-one                                                                   
 
    
     While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.