Synthesis of functionalized benzo[f]2H-chromenes and evaluation of their antimicrobial activities

Knoevenagel cyclocondensations of α-hydroxy naphthaldehyde with β-oxodithioesters and ketene dithioacetals yielded 2 H -benzo[ f ]chromene-2-thiones and 2 H -benzo[ f ]chromen-2-ones, respectively, in high yields. The newly synthesized compounds were evaluated for antifungal and antibacterial activities. Among them, compounds (2-furyl)(3-thioxo-3 H -benzo[ f ]chromen-2-yl)methanone and phenyl(3-oxo-3 H -benzo[ f ]chromen-2-yl)methanone exhibited excellent antifungal activity against tested fungi Curvularia lunata and Fusarium moniliforme . The highest antibacterial activity against the tested bacteria Escherichia coli and Staphylococcus aureus was observed for (4-chlorophenyl)(3-oxo-3 H -benzo[ f ]chromen-2-yl)methanone. The results of antimicrobial screening demonstrate that (2-furyl)(3-thioxo-3 H -benzo[ f ]chromen-2-yl)methanone, phenyl(3-oxo-3 H -benzo[ f ]chromen-2-yl)methanone, and (4-chlorophenyl)(3-oxo-3 H -benzo[ f ]chromen-2-yl)methanone are promising as antimicrobial drugs.