6-acetyl-5-hidroxy-4-methylcoumarin was prepared by cyclic reaction of 2,4-dihidroxyacetophenon with ethyl acetoacetate. The product was then transformed by condensation with aromatic aldehydes to form a series of new α,β-unsaturated ketones (7 compounds). Structure of these products was confirmed by IR, 1H NMR, 13C NMR, HSQC, HMBC spectroscopic data. Biological activities of these compounds have been inves.