Synthesis, characterization and antimicrobial activity evaluation of new imidazo [2,1-b][1,3,4]thiadiazole derivatives

Imidazo[2,1-b][1,3,4]thiadiazoles (4a-g) were synthesized from 3,4,5-trimethoxy benzoic acid and thiosemicarbazide. Reaction of 4 with Vilsmeier-Haack reagent yielded imidazo [2,1-b][1,3,4] thiadiazole–5-carbaldehyde derivatives (5a-g). Obtained imidazo[2,1-b][1,3,4] thiadia zoles-5-carbaldehydes were subjected to Knoevenagel condensation with 2-(2,4-dioxothia zolidin-3-yl)acetic acid (1) and 2-(4-oxo-2-thioxothiazolidin-3-yl)acetic (2) in the presence of catalytic amount of piperidine and acetic acid to afford imidazo[2,1-b][1,3,4]thiadiazoles (6a-g) and (7a-g), respectively. The structures of the newly synthesized compounds were confirmed by IR, NMR and elemental analyses. All compounds were screened for their antibacterial and antifungal activities. Some of the compounds displayed good antibacterial and antifungal activity.