Synthesis of various 1‐alkylbenzimidazole derivatives directly from 2‐alkylaminonitroarenes via a two‐step, one‐pot procedure

Abstract

N‐Alkyl‐2‐nitroanilines deoxygenated with tributylphosphine form intermediate 2‐(alkylamino)aryliminophosphoranes, which were subjected, without isolation, to various cyclocondensation reactions with CS2, CO2, alkyl isocyanates, acyl chlorides, anhydrides, or esters. A simple, convenient, one‐pot procedure provided derivatives of unsymmetrically substituted 1‐alkylbenzimidazoles functionalized at C2 in good to excellent yields. The method does not require the use of metals, sensitive catalysts, or pressure.