Efficient synthesis of 2-arylindoles, 2-arylimidazo[1,2-a]pyridines and 2-arylquinoxalines, and their bis-derivatives using [Hmim]OTf ionic liquid supported on nano-silica as a reusable catalyst

An efficient and facile method for the synthesis of 2-arylindoles, 2-arylimidazo[1,2-a]pyridines and 2-arylquinoxalines by the reaction of various α-bromo ketones with anilines, 2-aminopyridine and 1,2-phenylenediamine, respectively, in the presence of N-methylimidazolium trifluoromethanesulfonate ionic liquid supported on nano-silica ([Hmim]OTf@nano-SiO2) as a reusable catalyst under solvent-free conditions has been developed. The bis-derivatives of these compounds were also prepared efficiently, for the first time, using this catalytic system. All products were obtained in high yields and in short reaction times.