Brønsted acidic ionic liquid catalyzed an efficient and eco-friendly protocol for the synthesis of 2,4,5-trisubstituted-1H-imidazoles under solvent-free conditions

A simple, highly efficient and eco-friendly protocol for the synthesis of 2,4,5-trisubstituted-1 H -imidazoles via one-pot three component condensation of benzil/benzoin, aldehydes and ammonium acetate under solvent-free conditions has been achieved utilizing Brønsted acidic ionic liquid, (4-sulfobutyl)tris(4-sulfophenyl) phosphonium hydrogen sulfate as catalyst. The remarkable features of this methodology are excellent yields in shorter reaction times, cleaner reaction profile, and environmentally benign nature, use of non-toxic, readily synthesizable, inexpensive and recyclable catalyst.