Synthesis and Antioxidant of Some New Pyrazolo[1,5-a]pyrimidine, Pyrazolo[5,1-b]quinazoline and Imidazo[1,2-b]pyrazole Derivatives Incorporating Phenylsulfonyl Moiety

The synthesis and antioxidant of some new pyrazole analogs were described. It is achieved by the reaction of phenyl-4-(phenylsulfonyl)-1H-pyrazole-3,5-diamine (3) with different bifunctional reagents. The free radical-induced damage and the protective effects of the newly synthesized pyrazoles were studied. These new compounds inhibit the free radical-induced oxidative hemolysis of red blood cells effectively. It was found that these compounds effectively inhibit the free radical-induced oxidative hemolysis of red blood cells. Compound 5, which contain phenolic group, and 17, which bear sulfur, nitrogen atoms, and benzothiazole ring, respectively displayed high antioxidant activity. Analogs 15, 11, 10, and 9 were proved to exhibit antioxidative activity. Structures of new pyrazoles were confirmed by spectroscopic and elemental analyses and have been screened for their antioxidant activity.