SYNTHESIS AND ANTIOXIDANT ACTIVITY OF NOVEL 4,8-DISUBSTITUTED-3,4-DIHYDRO-6-METHYL-IMIDAZO[1,5-b][1,

Abstract

Purpose: The main objective of the present research study is to synthesize series of novel 4,8-disubstituted disubstituted-3,4-dihydro-6-methyl-imidazo[1,5-b][1,2,4]triazin-2(8H)-one derivatives (5a-5f) and evaluate them for their antioxidant effect. Methods: The said compounds were synthesized in total three steps viz Earlenmeyer-Azlactone synthesis, followed by reaction with substituted and unsubstituted 2, 4-dinitrophenylhydrazine and lastly reaction with chloracetamide. In vitro antioxidant study was performed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay using various concentrations such as 10, 20, 30, 40 and 50 µg/mL. Synthesis of compounds was confirmed by melting point, HPTLC, FTIR, 1H NMR, 13C NMR and LC-MS. The obtained results (IC50 values) were compared with standard antioxidant agent ascorbic acid. Results: The IC50 values were compared with standard antioxidant ascorbic acid. Compound 5a, 5b and 5c showed very higher significant activity (p<0.01), 5d showed significant activity while compound 5e and 5f showed marginally significant activity. Conclusion: Compounds bearing electron donating group showed higher antioxidant effect as compared to the compounds with electron withdrawing groups.