Mannich bases and novel benzothiazole derivatives of imidazo[2,1-b][1,3,4]thiadiazoles and their biological evaluation

A series of 2,6-disubstituted imidazo[2,1-b][1,3,4]thiadiazoles, their new Mannich bases and novel benzothiazole derivatives were synthesized. The structures of all the synthesized compounds were established by analytical and spectral data. All the compounds were screened for their antitubercular activity against Mycobacterium tuberculosis H₃₇Rv using the BACTEC 460 radiometric system and antibacterial activity against E. coli and B. cirrhosis, antifungal activity against A. niger and P. worthmanni. Among the tested compounds Mannich bases 3e, 3f and 4 g and 5-carbaldehyde derivative 6d have shown excellent inhibition (99, 99, 97 and 95%, respectively) against M. tuberculosis. Mannich bases in general have also shown impressive antifungal activity.