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A new series of indolo[1,2-c]quinazoline derivatives were prepared in good yield through reaction of 2-(o-aminophenyl)indole with a variety of arylaldehydes. The structures of the newly synthesized compounds were confirmed by IR, (1)H NMR, (13)C NMR and mass spectral studies and elemental analysis. All the title compounds were investigated for their activity against certain strains of Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis and Streptococcus pyogenes), Gram-negative bacteria (Salmonella typhimurium, Escherichia coli and Klebsiella pneumonia) and pathogenic Fungi (Aspergillus niger, Candida albicans and Trichoderma viridae). Ampicillin and ketoconazole were used as reference compounds. The results revealed that some of synthesized compounds displayed marked activity against all the tested microorganisms.

A series of 2-o-arylidineaminophenylindoles and their cyclic derivatives (indolo[1,2-c]quinazolines) were synthesized. The reactions occurred under relatively mild conditions and afforded the desired product in good yields. Molecular structures of the synthesized compounds were confirmed by IR, (1)H-NMR,( 13)C-NMR, MS spectra, and elemental analyses. Furthermore, all the final products were screened for in-vitro antibacterial activity against three Gram-positive and three Gram-negative bacteria and also tested for their inhibitory action against three strains of fungi. Compound IIc showed potent activity against all the bacterial (except S. typhimurium) and fungal strains. Especially, compounds IIi and IIj which have isoquinolyl and pyridyl substituents displayed potent antibacterial as well as antifungal activities compared to those of the respective standard drugs Ampicillin and Ketoconazole.

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.