One-pot synthesis of tri- and tetrasubstituted imidazoles using nano-LaMnO3 perovskite-type oxide as reusable heterogeneous catalyst in solvent-free condition

A convenient synthetic method for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetra substituted imidazole derivatives, has been developed via one-pot condensation reaction in solvent-free condition when aldehyde, ammonium acetate/amine, and 1,2-diketone are reacted using 0.8 mol% of NP-LaMnO3 at 80 °C under solvent free conditions. Catalyst could be recovered and reused in five reaction cycles without any loss of its activities, giving a total turnover number (TON) = 594 and turn over frequency (TOF) = 71 h−1. High yield, little catalyst loading, elimination of solvent, simple workup, recovery and reusability of the catalyst are some of the impressive features of the present method.