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

SYNTHESIS AND EVALUATION OF ANTITUBERCULAR AND ANTI FUNGAL ACTIVITY OF SOME NOVEL 6-(4-SUBSTITUTED ARYL)-2-(3,5-DIMETHYL-1H-PYRAZOL-1-YL) IMIDAZO[2,1-B] [1,3,4] THIADIAZOLE DERIVATIVES

ABSTRACT The 6-(4-substituted aryl)-2-(3,5-dimethyl-1H-pyrazol-1-yl)imidazo[2,1-b][1,3,4]thiadiazole (2a to f) were prepared by treating 2-amino-5-(3,5-dimethyl-H-pyrazole-1yl)-1,3,4-thiadiazole with appropriate α-haloaryl ketones. The reaction 2 with morpholine using formaldehyde, acetic acid in methanol yielded the corresponding 5- morpholin-4-ylmethyl derivatives (3a-e). While compound 2 also produces the 5- pyrrolidine-4-ylmethyl derivatives (4a-e) by reaction with pyrrolidine using formaldehyde, acetic acid in methanol. The 5- piperidin-4-ylmethyl derivatives (5a-e) were obtained by treating compound 2 with piperidine using formaldehyde, acetic acid in methanol. The structures of the newly synthesized compounds confirmed by IR, NMR and Mass spectra. All the compounds were screened for antitubercular and antifungal activity. Some of the compound displayed very good antitubercular and antifungal activity. Keywords: 2-Amino-5-(3,5-dimethyl-H-pyrazole-1yl)-1,3,4-thiadiazole; Imidazo[2,1-b][1,3,4] thiadiazole; Antitubercular activity; Antifungal activity