Efficient Method for the Synthesis of 2,4,5-Triarylimidazoles Using an S-Zr/MCM-41 Catalyst

A novel and efficient method for the synthesis of 2,4,5-trisubstituted imidazoles has been developed using MCM-41-supported sulfated zirconia (S-Zr/MCM-41) as a heterogeneous catalyst. The approach involves a one-pot, thee-component reaction between benzoin, aromatic aldehydes, and ammonium acetate as the nitrogen source. MCM-41-supported ZrO₂ was synthesized and subsequently modified by sulfate impregnation. The prepared catalyst was thoroughly characterized by IR spectroscopy, XRD, SEM-EDX, TEM, and TGA analyses. The synthesis was performed in ethanol under reflux at 80°C using the catalyst, leading to the formation of corresponding 2,4,5-triaryl-1H-imidazoles in excellent yields. Reaction conditions were further optimized by varying catalyst loading and solvent choice. Remarkably high product yields, ranging from 90–96%, were achieved within 40 min.