Ultrasound based method for one-pot synthesis of substituted imidazoles using SiO2-OSbCl2 as highly effective and reusable catalyst

A simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (SiO2-OSbCl2) as a catalyst in ethanol at moderate temperature. Operational simplicity, practicability and applicability to various substrates make this method an interesting alternative to previously applied procedures. From the environmental standpoint, this eco-friendly green catalyst is stable, highly active, easy to prepare and handle.