SYNTHESIS AND ANTIMICROBIAL TESTING OF 4H-1,2,4-TRIAZOLE, 1,2,4-TRIAZOLO[3,4-B][1,3,4]THIADIAZOLE AND 1,2,4-TRIAZOLO[3,4-B]THIADIAZINE DERIVATIVES OF 1-H-BENZIMIDAZOLE

Three novel series of benzimidazole derivatives namely 6-substituted 3 -[1-(2-alkyl-1 l)methyl]-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines 5a-h , 6-substituted 3-[1-(2-alkyl-1H-benzimidazolyl)methyl]-7 H-1,2,4-tria zolo[3,4-b]-[1,3,4]thiadiazines 6a-j and 6-thioxo-3-[1-(2-alkyl-1 -dih ydro-1,2,4-triazolo[3,4-b][1,3,4]-thiadiazoles 7a, b have been prepare d by cyclization of the key intermediate 1-[(4-amino-5-mercapto-4 H-1, 2,4-triazol-3-yl)methyl]-2-alkyl-1 H-benzimidazoles 3a, b. Furthermore , 1-[(4-arylideneamino-5-mercapto-4 H-1,2,4-triazol-3-yl)-methyl]-2-al kyl-1 H-benzimidazoles 4a-h have been prepared and some of them were c yclized to 6-substituted 3-[1-(2-alkyl-1 l)methyl]-1,2,4-triazolo[3,4- b][1,3,4]thiadiazoles 5d, h using thionyl chloride. The prepared compo unds were tested for antimicrobial activity in vitro; they showed mode rate activity.