Synthesis of New 2,5-Di-substituted 1,3,4-Oxadiazoles Bearing 2,6-Di-tert-butylphenol Moieties and Evaluation of Their Antioxidant Activity

Abstract

Abstract:Eleven new 2,6-di-tert-butyl-4-(5-aryl-1,3,4-oxadiazol-2-yl)phenols 5a-k were synthesized by reacting aryl hydrazides with 3,5-di-tert butyl 4-hydroxybenzoic acid in the presence of phosphorus oxychloride. The resulting compounds were characterized based on their IR, 1 H-NMR, 13 C-NMR, and HRMS data. 2,2-Diphenyl-1-picrylhydrazide (DPPH) and ferric reducing antioxidant power (FRAP) assays were used to test the antioxidant properties of the compounds. Compounds 5f and 5j exhibited significant free-radical scavenging ability in both assays.

Synthesis and antioxidant activity of 1,3,4-oxadiazoles and their diacylhydrazine precursors derived from phenolic acids

“…23 A series of 2,5-disubstituted 1,3,4-oxadiazole antioxidants incorporating phenol moiety was prepared by reacting aryl hydrazides with substituted 4hydroxybenzoic acids in the presence of phosphorus oxychloride. 20 Nieddu et al performed a synthesis of cytotoxic unsymmetrical 1,3,4-oxadiazoles also using POCl 3 as cyclodehydration agent. 21 For cyclization of our 1,2-diacylhydrazines containing more phenolic hydroxyl groups, thionyl chloride was the best choice, and for this purpose, we modied literature procedure for the synthesis 1,3,4-oxadiazoles containing adamantane ring 19 replacing solvent and excluding base during the preparation of 1,2-diacylhydrazines as well as excluding toluene in the next cyclization step.…”

New Hydrazones Bearing Thiazole Scaffold: Synthesis, Characterization, Antimicrobial, and Antioxidant Investigation

“…In this case, we can speak of oxidative stress, a phenomenon involved in the onset and progression of over 100 diseases (cancer, cardiovascular diseases, neurodegenerative disorders, rheumatoid arthritis, etc.). Antioxidants are molecules, natural or synthetic, capable of interacting with free radicals and stopping their chain reactions before essential vital molecules are damaged [6][7][8].…”

Synthesis and Antioxidant Ability of New 5-amino-1,2,4-Triazole Derivatives Containing 2,6-dimethoxyphenol

“…This stability increases with the extent of delocalization and enhances the antioxidant ability 9,10 . As such, many synthesized compounds containing long chain resonance exhibited significant antioxidant activity.…”