Synthesis and antimicrobial evaluation of some fused heterocyclic [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives.

A series of fused 1,2,4-triazoles with diphenylsulfone moiety are prepared utilizing 4-amino-5-[4-(4-X-phenylsulfonyl)phenyl]-4H-1,2,4-triazole-3-thiol 1 (X=H, Br). The latter on reaction with aromatic isothiocyanate in DMF, aromatic acid in POCl3 and CDI in dioxane gives five membered fused triazole derivatives 2a-c, 3a-c, 4a-g, 5a-g and 6a,b. The structures of newly synthesized compounds were confirmed on the basis of their elemental analysis and spectral data results (IR, 1H-and 13C NMR). New synthesized compounds were screened for their antimicrobial activities. The preliminary results revealed that some of the compounds exhibited promising antimicrobial activities.