Highly efficient, one-pot, solvent-free synthesis of tetrasubstituted imidazoles using HClO4–SiO2 as novel heterogeneous catalyst

Highly efficient, one-pot, four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles was reported the condensation of various aldehydes, benzil, aliphatic or aromatic primary amines and ammonium acetate under solvent free conditions using perchloric acid adsorbed on silica gel (HClO4–SiO2) as catalyst in excellent yields. HClO4–SiO2 exhibited remarkable catalytic activity with respect to the reaction time (2–20 min), amount of catalyst. Present protocol with HClO4–SiO2 catalyst is convincingly superior to the recently reported catalytic methods.

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