2-Hetarylimidazoles quaternization

Quaternization of 2-hetarylimidazoles by the action of methyl iodide in anhydrous benzene was performed. The reaction involving 1-methyl-2-pyridyl-1H-imidazoles was studied in detail. Relative rate of 2-hetarylimidazoles quaternization changes in parallel with their basicity. The alkylation of aza group was found to be very sensitive to steric factors. The methylation of 1-methyl-2-(3-pyridyl)-1H- and 1-methyl-2-(4- pyridyl)-1H-imidazoles was accompanied with the formation of isomeric quaternary imidazole and pyridine salts.