Mono and bis-6-arylbenzimidazo[1,2-c]quinazolines: a new class of antimicrobial agents.

With the aim of obtaining novel biologically active compounds, we have synthesized a series of mono, bis-2-o-arylideneaminophenylbenzimidazoles and a second series of corresponding mono, bis-6-arylbenzimidazo[1,2-c]quinazolines respectively. The target benzimidazo[1,2-c]quinazoline compounds were obtained by the condensation of 2-(o-aminophenyl)benzimidazole with mono and di carbonyl compounds, followed by oxidative cyclisation of the resulting mono and bis-2-o-arylideneaminophenylbenzimidazoles.All the products were characterized via IR, (1)H NMR, (13)C NMR, MS and elemental analysis. The antimicrobial activities of all quinazolines against various bacteria and fungi were evaluated. Among the compounds tested IVd, IVe exhibited good antibacterial and antifungal activities while IIIb, IIIc also showed notable antimicrobial activity with reference to standard drugs Ampicillin and Ketoconazole respectively.