Synthesis and Biological Evaluation of New Thiosubstituted Oxadiazole Derivatives of Coumarin under Solvent-Free Conditionss

A series of new thiosubstituted 1,3,4-oxadiazole derivatives of coumarin were synthesised by reaction of 7-((5-mercapto-1,3,4-oxadiazol-2-yl)methoxy)-4-methyl-2H-chromen-2-one and α-haloketones by grinding, in solvent-free conditions at room temperature. The reaction was also carried out in ethanol in reflux conditions. Shorter reaction time and better yields were observed in solvent-free conditions. The structures of the compounds were characterised by IR, NMR, elemental analysis and mass spectral data. The synthesised compounds were evaluated for their in vitro antimicrobial screening on different strains of bacteria and fungi. Most of the compounds showed good to moderate activities.