Synthesis, characterization and antioxidant activities of heterocycle schiff bases derived from 4-aminoantipyrine

In this thesis, five Schiff bases of 4-aminoantipyrine drived were synthesized: 4- (2-Pyridylmethylene) amino-1-phenyl-2,3-dimethyl-5-pyrazol-one (1), (E)-1,5-dimethyl-4-((2-methyl-1H-)indol-3-yl) methyleneamino)-2-phenyl-1H-pyrazol-3(2H)–one (2), (4Z) -4 - ((thiophen-2-yl) methylenethino) -1,2-dihydro-2,3 -dimethyl-1-phenylpyrazol-5-one (3), (4E) -4 - ((1H-indol-3-yl) methyleneamino) -1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (4) and (E) -1,5-dimethyl-2-phenyl-4- (quinolin-2-ylmethyleneamino) -1H-pyrazol-3 (2H) –one (5). The structures of these synthesized Schiff bases were elucidated by 1H NMR, 13C NMR and FTIR. The antioxidant activities of synthesised compounds were carried out using different antioxidant assays such as 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, and reducing power. Trolox, BHT and BHA were used as standards. The compound 1 revealed the most antioxidant activity.