Synthesis, structure and reactivity of 1-(4-nitrobenzyl)-2-chloromethyl benzimidazole

The synthesis of 1-(4-nitrobenzyl)-2-chloromethyl benzimidazole, which undergoes a nucleophilic substitution with pyridine in the absence of additional base, is reported. The key steps are the reaction of 1,2-phenylenediamine to give exclusively the mono-substituted product and the avoidance of minor by-products via the use of glycolic acid for the cyclisation step. The X-ray structures of 1-(4-nitrobenzyl)-2-chloromethyl benzimidazolium chloride and 1-[1-(4-nitrobenzyl)benzimidazol-2-ylmethyl]pyridinium chloride are presented.