Synthesis and Characterisation of Coumarin Analogues Using Palladium Catalyst and their Free Radical Scavenging Activity

Coumarins are naturally and synthetically derived compounds containing oxygen. In this work, coumarin analogues were synthesised by Suzuki cross-coupling reaction using boronic acid in the presence of a palladium catalyst with a base. The synthesised compounds were screened for free radical scavenging activity by the DPPH method. The synthesised compound Ethyl 6-(4-fluorophenyl)-8-formyl-2-oxo-2H-chromene-3-carboxylate showed a better inhibition percentage than ethyl 6-(3,5-dimethylphenyl)-8-formyl-2-oxo-2H-chromene-3-carboxylate. The compound Ethyl 6-(4-fluorophenyl)-8-formyl-2-oxo-2H-chromene-3-carboxylate showed 80% inhibition while Ethyl 6-(3,5-dimethylphenyl)-8-formyl-2-oxo-2H-chromene-3-carboxylate showed 75% inhibition.