Synthesis, antibacterial, antifungal and anti-HIV evaluation of Schiff and Mannich bases of isatin derivatives with 3-amino-2-methylmercapto quinazolin-4(3H)-one

Isatin (Indole 2,3-dione), its 5-chloro and 5-bromo derivatives were added to 3-amino-2-methylmercapto quinazolin-4(3H)-one to form Schiff bases and the N-Mannich bases of these compounds were synthesized by reacting with formaldehyde and several secondary amines. Their chemical structures have been confirmed by means of their IR, ${}^1\text{H}$-NMR data and by elemental analysis. Investigation of antimicrobial activity of compounds was done by an agar dilution method against 26 pathogenic bacteria, 8 pathogenic fungi and anti-HIV activity against replication of HIV-1 (III B) in MT-4 cells. Among the compounds tested 5-chloro-3-(3′,4′-dihydro-2′-methylmercapto-4′-oxoquinazolin-3′-yl)-1-morpholino methyl imino isatin was the most active antimicrobial agent.