Synthesis of tri and four substituted imidazoles derivatives using zinc oxid nanotubes modified by SiO2 as a powerful and reusable catalyst

In recent years, zinc oxid nanotubes have attracted much attention. The direct use of , zinc oxid nanotubes modified by SiO2 as recoverable catalysts for organic reactions is very rare. The catalysts were characterized by XRD. The average particle size of ZnO catalysts is 57 nm and there are highdensity defects on nanotubes surfaces . A simple and efficient method for the imidazol derivatives synthesis from the condensation benzil and ammonium acetate with substituted aromatic aldehydes in the presence of a catalytic amount zinc oxid nanotubes modified by SiO2 is described. The reason proposed for higher catalytic activity of zinc oxid nanotubes modified by SiO2 is a combination effect of the small particle size and high-density surface defects. The practical and simple method led to excellent yields of the tri and four substituted imidazoles derivatives under mild conditions and within short times.