Synthesis and evaluation of mannich bases of benzimidazo [1,2-c] quinazolin- 6[5h]-thione for antimicrobial activity

The intermediate Benzimidazo[1,2-c] quinazolin-6[5H]-thione [1] was obtained by cyclization of 2-[2'- aminophenyl] benzimidazole with carbon disulfide. Mannich base [2a-d] of compound [1] was obtained on treatment with Para formaldehyde and secondary aliphatic amines, similarly treatment of [1] with different ketones afforded respective mannich bases [3 e-h]. All derivatives synthesized were characterized from IR and 1HNMR spectral data's. Moderate anti bacterial activity was exhibited from 2a-d and from 3f, 3h against S. aureus, E. coli, and E. fecalis but very negligent activity were seen from these compounds when screened against P aeruginosa