Nano zirconia catalysed one-pot synthesis of some novel substituted imidazoles under solvent-free conditions

A highly efficient method for the synthesis of substituted imidazoles from a multicomponent reaction of isatin derivatives with ammonium acetate and aromatic aldehydes under solvent-free conditions has been established. The reaction is supposed to proceed via nano ZrO2-catalyzed C=O bond activation, followed by the formation of a diamine intermediate and its condensation with ZrO2 activated isatin derivatives. Because of the simple and readily available starting materials, the ease of operation, and the high bioactivity of imidazoles, this strategy can be broadly applied to medical chemistry. The recyclability of the nano ZrO2 catalyst is another advantage of the proposed methodology.