Synthesis and Antioxidant Activity of Some New Thiazolyl-Pyrazolone Derivatives.

3-Methyl-1-thiocarbamoyl-2-pyrazolin-5-one has been utilized as a core for the synthesis of some 1-(thiazol-2-yl)-pyrazolin-5-one derivatives through diazo-coupling reaction and/or followed by with some α-halogenated reagents such as bromoacetone, phenacyl bromide, and ethyl bromoacetate. Base prompted addition of the core compound to an equimolar amount of phenyl isothiocyanate furnished 3-methyl-4-phenylthiocarbamoyl-1-thiocarbamoyl-2-pyrazolin-5-one which undergoes with α-halogenated reagents at the more reactive phenylthiocarbamoyl moiety to afford the corresponding 4-(thiazol-2-yl)-1-thiocarbamoyl-2-pyrazolin-5-ones. The new synthesized thiazolyl-pyrazolone compounds were evaluated for their potential antioxidant activity by using (ABTS Radical Cation Decolorization Assay). [ABSTRACT FROM AUTHOR]