Synthesis of 2-aryl-1-arylmethyl-1H-benzimidazoles using chlorosulfonic acid at room temperature

Abstract Chlorosulfonic acid (ClSO 3 H) used to be a catalyst for the synthesis of 2-aryl-1-arylmethyl-1 H -benzimidazoles which was efficiently simple and convenient. This method afforded short reaction time, easy workup, moderate to excellent isolated yields which make this protocol practical and economically attractive.