Synthesis and antimicrobial studies of novel methylene bridged benzisoxazolyl imidazo[2,1-b][1,3,4]thiadiazole derivatives.

Novel methylene bridged benzisoxazolyl imidazo[2,1-b][1,3,4]thiadiazoles (3a-f) were synthesized from benzisoxazolyl-3-acetic acid and thiosemicarbazide. Reaction of 3 with bromine in glacial acetic acid in the presence of anhydrous sodium acetate yielded the corresponding 5-bromo derivatives (4a-f). While compound 3 furnished the 5-nitroso derivatives (5a-f) on refluxing with sodium nitrite solution. Thiocyanato derivatives (6a-f) were obtained by treating the imidazothiadiazole 3 with bromine and potassium thiocyanate in glacial acetic acid at room temperature. The structures of the newly synthesized compounds were confirmed by IR, NMR, mass and elemental analysis. All the compounds were screened for their antibacterial and antifungal activities. Some of the compounds displayed very good antibacterial and antifungal activity.