Synthesis and Antimicrobial Screening of some Mannich Bases of Isatin

A series of Mannich bases have been synthesized by treating thiourea, isatin with formaldehyde and different aromatic primary and secondary amines. The structures of compounds were established based on IR, 1H NMR and Mass spectral data. The title compounds were screened for antibacterial and antifungal activities. The compounds S₄, S₆ and S₁₀ with 1-benztriazolyl, 1-diethylamino and 1-dimethylamino substituted derivatives exhibited significant antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Klebesiella pneumonia, whereas the compounds S₄, S₆ and S₁₀ with 1-benztriazolyl, 1-piperazinyl and 1-dimethylamino substituted derivatives exhibited better antifungal activity against Aspergillus niger.