CONVENTIONAL AND MICROWAVE ASSISTED SYNTHESIS OF SOME NEW DERIVATIVES OF COUMARIN CONTAINING PYRAZOLINE AND INVESTIGATION OF THEIR ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES

Pyrazoline derivatives, being used as potential medicinal agents, 3-Acetyl-2H-chromen-2one (I) was prepared by Knoevenagel condensation of salicyladehyde with ethylacetoacetate in presence of piperidine. A series of 3-[(2E)-3-substituted-prop-2-enoyl]-2H-chro men-2-one derivatives (II a-h) were prepared by Claisen-Schmidt condensation of 3-acetyl coumarin with aromatic aldehydes. Treatment of 3-substituted cinnamoylcoumarin with hydrazine hydrate in the presence of ethanol gave [5-substitutedphenyl]-4, 5-dihydro-1H-pyrazol-3-yl]-2H-chromen-2-one (III a-h). Title compound were synthesized by conventional as well as by microwave assisted method. The structures of the newly synthesized compounds were confirmed by IR and ¹H-NMR spectroscopy. All the synthesized compounds were tested for their antibacterial and antifungal activities using cup-plate-agar-diffusion method. The antibacterial activity screening revels that the compound III b has comparable activity and compound III c shows moderate activity as that of standard ampicillin against gram positive and gram negative bacteria. All synthesized compounds were found to be inactive as antifungal against Candida albicans.