Three component one pot synthesis of 5-substituted 1-Aryl-2,3- diphenyl imidazoles: A novel class of promising antioxidants

A novel series of structurally diverse 5-Substituted 1-Aryl-2,3-diphenyl imidazoles (2a-j) was synthesized by treatment of benzoin (1) with 4-hydroxy aniline, substituted benzaldehydes and NH₄OAc in polyethylene glycol (PEG-400) under reflux condition in excellent yields. The newly synthesized compounds were characterized by spectral and elemental analysis and screened for their antioxidant properties by employing three in vitro assays like 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) assay and iron reducing power assay. Ascorbic acid was used as a standard antioxidant and the comparative study with newly synthesized compounds was also done. Among the analogues compounds 2e, 2g and 2j bearing hydroxy and methoxy groups on 2-substituted phenyl moiety respectively showed predominant antioxidant activity.