A microwave-assisted facile synthesis of novel coumarin derivatives containing cyanopyridine and furan as antimicrobial agents

In this paper, we have described the microwave-assisted method for the synthesis of novel 4-(substitutedphenyl)-2-(furan-2-ylmethyleneamino)-6-(2-oxo-2H-chromen-3-yl)nicotinonitriles (5a-m). Compound (I) 3-acetyl-2H-chromen-2-one was reacted with aromatic aldehydes, malononitrile and ammonium acetate in microwave conditions afforded compounds 3a-m, which on further microwave irradiation at 300 W for 8-10 min in the presence of trace amount of ZnCl2 furnished 5a-m. Structures of synthesized compounds have been confirmed by IR, 1H NMR, 13C NMR and mass spectra. Antimicrobial activity of the compounds was studied against several bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes) and fungi (Candida albicans, Aspergillus niger, Aspergillus clavatus) by using the serial broth dilution method. Five compounds 5d, 5f, 5j, 5k and 5l were found to possess high activity comparable to ampicillin at 50 μg/ml against E. coli and P. aeruginosa.