Studies in the imidazole series

By quaternization of 1-alkyl(aryl, aralkyl)-2-methyl-4, 5-diarylimidazoles with -bromo ketones and by subsequent cyclization of the quaternary salts of imidazole, a number of arylpyrrolo[1,2-a]imida~ zoles were obtained. A study was made of the effect of different bases on the process of cyclization and the yield of pyrroloimidazole derivatives. The structure was established of certain intermediate products of the reaction involving the closure of the pyrrole ring.For Part XXXVI, see [11].     

Studies in the imidazole series

Imidazo[1,2-f]xanthine derivatives were synthesized by the reaction of 8-methylmercaptotheophylline with-haloketones and subsequent heating of the 7-acylalkyl-8-methylmercaptotheophyllines with ammonia and primary amines.See [1] for communication LIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 686–688, May, 1971.     

Studies in the imidazole series

The reaction of 2-mercaptobenzimidazole and 5, 6-dimethyl-2-mercaptobenzimidazole with -halogenoketones has given a series of 2--oxoalkylthio- and 2--oxoaralkylthiobenzimidazoles—intermediate products for the synthesis of thiazolo[3,2-a]benzimidazoles. The compounds obtained exhibit the phenomenon of ring-chain tautomerism.For part XXXV, see [6].     

Studies in the imidazole series

6,7-Dimethylbenzimidazo[2,1-b]thiazolid-3-one was synthesized, and its reactions with aldehydes, isatin, nitroso compounds, and arene diazonium salts were studied. As a result, ylidene and imino derivatives and azo coupling products were obtained. According to the IR spectra, the azo coupling products have 6,7-dimethylbenzimidazo[2,1-b]thiazolidine-2,3-dione 2-arylhydrazone structures.See [1] for communication LVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 822–825, June, 1971.     

Studies in the imidazole series

A new synthesis of derivatives of thiazolo[3,2-a]benzimidazoles based on 2-halogenobenzimidazoles has been performed. The reaction of 2-chlorobenzimidazole with -halogeno ketones and the subsequent heating of the resulting 1-acylmethyl-2-chlorobenzimidazoles with thiourea has given 1-acylmethyl-2-mercaptobenzimidazoles. The cyclization of the latter under the action of mineral acids or water-abstracting agents has given a series of 2-alkyl-, 2-aryl-, and 2-heteryl-substituted thiazolo[3,2-a]benzimidazoles.For Communication XLIX, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 6, pp. 827–831, June, 1970.     

Studies on the imidazole series

The reaction of 2-mercaptoimidazole and its 4(5)-aryl- and 4,5-diaryl-substituted derivatives with -halogenoketones has yielded a number of alkyl-, acyl-, and aryl-substituted imidazo[2,1-b]thiazoles.For part XLV, see [1].     

Investigations in the imidazole series

A number of 2-acyl(2-acyl-3-alkyl)imidazo[2,1-b]thiazoles and previously unknown 2-acyl-(2-acyl-3-alkyl)imidazolino[2,1-b]thiazoles were obtained by the reaction of 2-acylmethylmercapto derivatives of imidazole and imidazoline with acylating agents.See [1] for communication XLVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 389–392, March, 1971.     

Research in the imidazole series

It was established that the reaction of 8-theophylline with α-halo ketones gives 8-acylalkylthiotheophyllines or their cyclization products-thiazolo[2,3-f]xanthine derivatives — depending on the conditions used to carry out the reaction and the structure of the halo ketones. Derivatives of two new heterocyclic systemscy-clopentathiazolo[2,3-f]purine and benzothiazolo[2,3-f]purine-were synthesized from 2-bromocyclopentadienone and cyclohexanone. The structure and the conditions for the cyclization of 8-acylalkylthiotheophyllines to three(four)-ring compounds were studied. The structure of the thiazolo[2.3-f]xanthines was proved by reductive desulfuration to 1,3,7-trialkylxanthines.     

Research in the imidazole series

The hydrolysis of 7-cyano derivatives of pyrrolo[1,2-a]imidazole in 85–90% sulfuric acid at 100°C gives amides of pyrroloimidazole-7-carboxylic acids. Under more severe conditions, the resulting carboxylic acids are decarboxylated to the corresponding pyrroloimidazole derivatives with a free 7 position.See [1] for communication XC.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1658–1659, December, 1976.     

Research in the imidazole series

The Mannich reaction in the 6-aryl-7-cyanopyrrolo[1,2-a] imidazole series was studied, and the corresponding 5-dialkylaminomethyl derivatives of this heterocycle were obtained.See [1] for communication LXXXIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1552–1553, November, 1976.     

Research in the imidazole series

The reduction of pyrrolo[1,2-a]imidazole-2-one and pyrrolo[1,2-a]benzimidazole derivatives, which leads to the formation of 2,3-dihydropyrrolo[1,2-a]imidazole derivatives and derivatives of the previously unknown 1,2,3,3a-tetrahydropyrrolo[1,2-a]benzimidazole, was studied. A method was developed for the preparation of 5- and 7-amino derivatives of pyrrolo[1,2-a]imidazole by reduction of the corresponding nitroso- and arylazo-substituted pyrrolo[1,2-a]-imidazoles.See [1] for communication XCI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 225–228, February, 1977.     

Research in the imidazole series

The synthesis of 9-acyl- and 8-alkyl-9-acyl-substituted naphth[1,24,5]imidazo[2,1-b]thiazoles was accomplished by the reaction of 2-acylmethylthionaphth[1,2-d]imidazole with acylating agents and of 2-mercaptonaphth[1,2-d]imidazole with 3-chloro-2,4-pentanedione.See [1] for communication LXVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 30–32, January, 1972.     

Research in the imidazole series

2-Alkyl(aryl, hetaryl)-6,8-dimethylthiazolo[2,3-f]xanthines were synthesized from 8-bromotheophylline and -halo ketones with subsequent replacement of the bromine atom by sulfur and cyclization of the resulting 7-acylmethyl-8-thiotheophyllines under the influence of dehydrating agents.See [1] for communication LXXXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1121–1123, August, 1975.     

Research in the imidazole series

It was established on the basis of an investigation of the mass spectra that in the reaction of 2-chlorobenzimidazoles with unsymmetrical olefin oxides and secondary β -halo alcohols, of the two possible isomers only 1-[β-alkyl(aryl)-β-hydroxyethyl] derivatives of benzimidazole are formed.     

Investigations in the imidazole series

Imidazo[1,2-a]imidazole derivatives were synthesized by the reaction of 1-acylmethyl-2-bromo-4,5-diphenylimidazoles with ammonia and primary amines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1243–1247, September, 1971.     

Investigations in the imidazole series

The reactions of 2-mercaptonaphth[1,2-d]imidazole with 1,2-dichloro- and 1,2-dibromoethanes and the cyclization of 3-(-hydroxyethyl)- and 2-(-hydroxyethyl)mercaptonaphth[1,2-d]imidazoles were studied. 2,3-Dihydro derivatives of naphth[1,2-d]imidazo[1,2-b]thiazole and naphth[1,2-d]imidazo[3,2-b]thiazole were obtained.See [1] for communication LXX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 257–259, February, 1972.     

Investigations in the imidazole series

Purinyl(theophyllinyl)-8-mercapto aldehydes and their acetals were synthesized by the reaction of 8-thio derivatives of purine and theophylline with -halo aldehydes and their acetals. The IR spectra demonstrated that the indicated aldehydes exist in the solid state as tautomeric forms — 3-hydroxy derivatives of thiazolino[2,3-f]purines(xanthines). Dehydration of the latter gave thiazolo[2,3-f]purine, 6,8-dimethylthiazolo[2,3-f]xanthine, and their 2-alkyl-substituted derivatives. The structures of the three-ring compounds were established by reductive desulfuration to 7-alkyl-substituted purines and theophyllines.See [1] for communication LXXVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 996–999, July, 1972.     

Investigations in the imidazole series

The reaction of 2-aminobenzothiazole and its 6-substituted derivatives with-bromomethyl alkyl (aryl, heteryl) ketones was investigated in detail. Under mild conditions, 3-acylmethyl-2-iminobenzothiazolines were isolated. Their structures were established, and their properties and the conditions for cyclization to imidazo[2,1-b]benzothiazole derivatives were studied.See [1] for communication LXXVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1271–1274, September, 1972.     

Investigations in the imidazole series

2,3-Dihydro derivatives of naphth[1,2-d]imidazo[3,2-b]imidazole were synthesized by the reaction of 2-chloro-3-(-haloalkyl)naphth[1,2-d]imidazole with ammonia and primary amines and by the reaction of 2-chloro-3-(-hydroxyaIkyl)naphth[1,2-d]imidazole with ammonia and amines with subsequent cyclization of the resulting 2-amino(alkylamino, arylamino)-3-(-hydroxyalkyl)naphth[1,2-d]imidazoles under the influence of thionyl chloride or phosphorus oxychloride. Dihydro derivatives of the condensed naphth[1,2-d]imidazo[3,2-b]imidazole system have not been described in the literature.See [1] for communication LX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1125–1127, August, 1971.     

Investigations in the imidazole series

The synthesis of derivatives of 2,3-dihydropyrrolo[1,2-a]imidazole from 1,2-dialkylimidazolines or 1,2-diarylkylimidazolines and phenacyl bromides with subsequent heating of the 1,2-disubstituted 3-phenacyl-imidazolinium bromides in aqueous or ethanolic solution in the presence of bases has been effected.For part XXXVIII, see [7].