Selective one-pot synthetic method for imidazole and benzimidazole derivatives

A novel and-selective one-pot synthetic method of imidazole and benzimidazole derivatives has been developed. Three series of target compounds,14(omega-haloalkyl) imidazoles 3a-3e, bis-imidazoles 5a-5b and tri-imidazoles 6a-6b have been synthesized by the selective quaterisation of H-1-imidazole-1-propanenitrile (1) with alpha,omega-dihalide, bis (bromomethyl) benzene or tri (bromomethyl) benzene to obtain imidazolium salts, following by Hoffmann-type elimination. Similarly, benzimidazole analogues 7 and 8 were also prepared. It is found that important factors affecting this selective quaterisation are the solvent, temperature, structure and amount of halides.