A. M. Demchenko

Antimicrobial and tuberculostatic activity of 5-aryl(hetaryl)-1,3,4-oxadiazole-2-thiones and their derivatives

As is known, some 5-R-1,3,4-oxadiazole-2-thione derivatives possess antimicrobial properties [ 1 3 ] and some 1,3,4-oxadiazole derivatives are used as antituberculous drugs [ 4 10]. In the search for new antimicrobial and tuberculostatic agents, we have employed the interaction of 5-aryl(hetaryl)1,3,4-oxadiazole-2-thiones ( I a I c ) [11] with substituted phenacyl bromides to obtain a series of new 5-aryl(hetaryl)2-(phenacylthio)1,3,4-oxadiazoles ( I I a IIc).

6-Arylamino-3-methyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines: Novel N-Arylamidine Structures

We propose a method for obtaining derivatives of 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine by alkylation of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol by substituted α-chloroacetanilides, followed by cyclization of the intermediate by phosphorus oxychloride.

Synthesis and Properties of 1,3-Diaryl-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium Bromides

It has been established that the condensation of 3-(4-methoxyphenylamino)-5,6-dihydro-2H-1,4-oxazine with substituted phenacyl bromides occurs at the exocyclic nitrogen atom with formation of 3-aryl-3-hydroxy-1-(4-methoxyphenyl)-2,5,6,8-tetrahydro-3H-imidazo[2,1-c]-1,4-oxazinium bromides. By treatment of the latter with acetic anhydride 3-aryl-1-(4-methoxyphenyl)-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium bromides are formed. The structures of the compounds synthesized were determined via1H NMR spectroscopy and X-ray diffraction.

Synthesis of 3-Alkyl-6-aryl(arylamino)-7H-[1,2,4]triazolo- [3,4-b][1,3,4]thiadiazines

Starting from 5-alkyl-4-amino-4H-1,2,4-triazole-3-thiols and substituted chloroacetanilides, the corresponding (5-alkyl-4-amino-4H-1,2,4-triazol-3-ylsulfanyl)acetanilides were synthesized. The products underwent intramolecular cyclization in boiling phosphoryl chloride to afford 3-alkyl-6-arylamino-7H-[1,2,4]-triazolo[3,4-b][1,3,4]thiadiazines. 3-Alkyl-6-aryl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine hydrobromides were obtained by reaction of 5-alkyl-4-amino-4H-1,2,4-triazole-3-thiols with substituted phenacyl bromides.

Synthesis and Transformations of 3-Ethoxycarbonyl-2-(N-R-thioureido)thiophenes

Abstract3-Ethoxycarbonyl-2-(N-R-thioureido)-4,5,6,7-tetrahydrobenzo[b]thiophenes were obtained by the reaction of 2-amino-3-ethoxycarbonyl-4,5,6,7-tetrahydrobenzo[b]thiophene with isothiocyanates and of 3-ethoxycarbonyl-2-isothiocyanato-4,5,6,7-tetrahydrobenzo[b]thiophene with primary and secondary amines. The cyclization paths of the products leading to derivatives of thieno[2,3-d]pyrimidine and thieno[2,3-d]-1,3-thiazine were studied. The corresponding S-substituted derivatives were obtained by the alkylation of 3-R-2-thioxo-3,4,5,6,7,8-hexahydrobenzo[b]thieno[2,3-d]pyrimidin-4-ones.

The Reaction of 5-Aryl(hetaryl)-2-aroylmethylthio-1,3,4-oxadiazoles with Aryldiazonium Tetrafluoroborates

Abstract5-Aryl(hetaryl)-2-aroylmethylthio-1,3,4-oxadiazoles behave as CH acids and readily react with aryldiazonium tetrafluoroborates at the active methylene group to give azo coupling products. The spectroscopic properties of the compounds synthesized have been studied.

On the reaction of 2-phenylaminothiazoline withα-halogenoketones

It was established that the alkylation of 2-phenylaminothiazoline with substituted phenacyl bromides proceeds at the exocyclic nitrogen atom with the formation of 5-aryl-7-phenyl-2,3-dihydroimidazo[2,1-b]thiazolium bromides. In order to confirm the structure of the last, the reductive desulfurization of one of them (Ar=p-chlorophenyl) was accomplished using Raney nickel. It was shown that dequaternization of the resulting 1-phenyl-3-ethyl-4-(p-chlorophenyl)imidazolium bromide to 1-phenyl-4-(p-chlorophenyl)imidazole, identical to the sample obtained by direct synthesis, thereby occurs.

Synthesis and study of the analgesic and antiinflammatory activity of imidazo[2,1-b]thiazolium bromides

As is known, the class of imidazo[2,1-b]thiazole derivatives contains compounds possessing analgesic [1] and antiinflammatory [24] activity. In continuation of previous investigations [5, 6], we have synthesized a series of 2phenylimino-3-phenacyl-4-methylthiazoline hydrobromides ( I Ia l id ) using reactions of 2-phenylamino-4-methylthiazole (I) with aromatic o~-halogenoketones. Upon boiling these salts in a 48% aqueous hydrobromic acid solution, we have isolated 3-methyl-6-(p-tolyl)-7-phenylimidazo[2, l-b] thiazolium bromide (Ill). At the same time, boiling salts Ila lid in acetic anhydride leads to 3,6-dimethyl-5-(p-R-benzoyl)-7phenylimidazo[2,1-b]thiazolium bromides OVa IVd).

Imidazo[2,1-b]thiazolium salts based on 2-phenylamino-4-methylthiazole

Alkylation of 2-phenylamino-4-methylthiazole with substituted phenacyl bromides led to the synthesis of hydrobromides of 2-phenylimino-3-(p-R-phenacyl)-4-methylthiazoles. It was shown that, depending on the conditions of the cyclization of the last, 3-methyl-6-aryl-7-phenyl- or 3-methyl-5-aroyl-6-alkyl-7-phenylimidazo[2,1-b]thiazolium bromides can be synthesized. The spectral characteristics of the compounds synthesized were studied.

UNEXPECTED DESTRUCTION OF TRIAZOLE RING BY THE ACTION OF DEHYDROACETIC ACID

Dehydroacetic acid displays properties of a ketone in its reactions with aldehydes and dimethyl acetal of DMF [1, 2], while this acid reacts with different amines to give the corresponding derivatives of 3-acetyl-6methyl-2-(R-amino)-4-pyranone [3]. We attempted to carry out the condensation of dehydroacetic acid with 4-amino-5-trifluoromethyl-4H1,2,4-triazole-3-thiol (1). The spectral data showed that N,N-di(3-acetyl-6-methyl-4-oxo-4H-2-pyranyl)hydrazine (3) was obtained instead of the expected 3-acetyl-6-methyl-2-(3-mercapto-5-trifluoromethyl-4H-1,2,4-triazol-4ylamino)-4H-4-pyranone (2).