one-pot preparation of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles using poly(4-vinylpyridinium butane sulfonic acid) hydrogen sulfate, as an efficient heterogeneous poly(ionic liquid) solid acid catalyst under solvent-free conditions

one-pot preparation of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles has been conducted in the presence of poly(4-vinylpyridinium butane sulfonic acid) hydrogen sulfate, p(4vpbsa)hso4, as an efficient dual acidic catalyst under solvent-free conditions. reusability of the catalyst, easy work-up procedure, eco-friendly reaction conditions, short reaction times and high yields of the products illustrate the utility of this approach.