Synthesis and biological evaluation of 3-thiosemicarbazoneacetyl coumarin derivatives as antioxidant

This work describes the synthesis and characterization of three 3-acetyl coumarin thiosemicarbazone derivatives. These compounds are: Semicarbazone -2- methyl- 3-coumarenyl ketone(1),3-oxo-3-[({-2-[1-(2-oxo-2H-chromin-3-yl) ethylidene] hydrazinyl}carbonothioyl) amino] propanoic acid (2), 2-[(coumarin-3-yl)-1H,3-5-6-trehydro-4-thiooxo-1,2diazine] (3).The first compound was prepared by reacting 3-acetylcoumarin with thiosemicarbazide via schiff's base reaction. Then this compound: Semicarbazone -2- methyl- 3-coumarinyl ketonereacted with malonic acid and ethylacetoacetate respectively. Compound 2 is with amide group and compound 3 is with a specific heterocycle. The structural formulas of synthetic compounds was characterized by the available spectra infrared (FT-IR) and mass spectroscopic LC-MS. In addition to various physical available means such as melting points and Rf (using thin layer chromatography). The antioxidant activity of each of the prepared compounds were evaluated in vitro via the quantitative 2,2-diphenyl-1-picrylhydrazyl (DPPH)radical scavenging activity method. All of the synthesized products showed a good antioxidant effectiveness and there is a relationship between the concentration of DPPH and its antioxidant effect. Compound 2 and 3, which known as 3-oxo-3-[({-2-[1-(2-oxo-2H-chromen-3-yl) ethylidene] hydrazinyl}carbonothioyl) amino] propanoic acid , 2-[(coumaren-3-yl)-1H,3-5-6-trehydro-4-thiooxo-1,2diazine], show medium antioxidant activity 66% compared with the first prepared compound Semicarbazone -2- methyl- 3-coumarinyl ketone 34%.