Antioxidant activity of some (7-hydroxy-2-oxo-2H-chromen-4-yl) acetic acid derivatives

A series of coumarin Schiff bases (7-(arylidenehydrazinocarbonylmethoxy)-2-oxo-2H-chromen-4-yl]acetic acid arylidenehydrazide) (4a-k) and N-(2-aryl-4-oxothiazolidin-3-yl)-2-{[4-(2-aryl-4-oxothiazolidin-3-yl)carbamoylmethyl]-2-oxo-2H-chromen-7-yloxy}-acetamides (5a-k) were synthesized and evaluated for their antioxidant activity (scavenging of 1,1-diphenyl-2-picryhydrazyl radical and phosphomolybdenum method). Compounds with 3,4-dihydroxyphenyl and 2,5-dihidroxyphenyl ring showed the best 1,1-diphenyl-2-picryhydrazyl (DPPH) scavenging activity, whereas the best activity investigated by phosphomolybdenum method was found for the compounds with 2,5-dihidroxydiphenyl ring