Synthesis and antimicrobial activity of some novel derivatives of 7-hydroxy-4- methyl coumarin

Some novel derivatives of 7-hydroxy-4-methyl coumarin were synthesized. The title compounds were obtained by the reaction of 7-hydroxy-4-methyl coumarin with ethylchloroacetate in the presence of potassium carbonate in acetone afforded ethyl-2-(4-methyl-2-oxo-2H-chromen-7-yloxy)acetate, which react with hydrazine hydrate in ethanol afforded 2-(4-methyl-2-oxo-2H-chromen-7-yloxy)acetohydrazide. Hydrazide was considered as the key intermediate for some novel compounds (MK1-MK6). The reaction of hydrazide with acetyl acetone and ethyl acetoacetate gave 7-(2-(3,5-dimethyl-1H-pyrazol-1-yl)-2-oxoethoxy)-4-methyl-2Hchromen-2-one (MK-1) and 1-(2-(4-methyl-2-oxo-2H-chromen-7-yloxy)icetyl)-3-methyl-1H-pyrazol-5(4H)-one (MK-2). Also reaction of hydrazide with isatin lead to the formation of 2-(4-methyl-2-oxo-2H-chromen-7-yloxy)-N’-(2-oxoindolin-3-ylidene) acetohydrazide (MK-3).The other derivatives MK-4, MK-5 and MK-6 were obtained by treating the hydrazide with phthalic, maleic and succinic anhydrides respectively. The structures of these compounds were established on the basis of IR and 1H-NMR spectral analysis. Compounds (MK1-MK6) were screened for their antimicrobial activity. All compounds exhibit significant antimicrobial activity as compared to standard drug.