Synthesis of functionalized benzimidazoles and quinoxalines catalyzed by sodium hexafluorophosphate bound Amberlite resin in aqueous medium

A very simple, eco-friendly, and versatile method for the selective synthesis of 1,2-disubstituted benzimidazoles and quinoxalines in water-methanol (1:1) mixture with the aid of resin bound hexafluorophosphate ion as catalyst is reported. The method is also effective for the incorporation of quinoxaline nucleus at the A ring of pentacyclic triterpenoid, friedelin. A plausible mechanism for the formation of disubstituted benzimidazole has also been suggested. (C) 2012 Elsevier Ltd. All rights reserved.