Microwave-assisted preparation of polysubstituted imidazoles using Zingiber extract synthesized green Cr 2 O 3 nanoparticles.

Cr 2 O 3 nanoparticles were prepared using Zingiber officinal extract which were used as an efficient and reusable catalyst in the practical synthesis of polysubstituted imidazoles by means of a convenient reaction of aromatic aldehydes with ammonium acetate and benzil under microwave irradiation and H 2 O as solvent. The structure of the compounds was studied by IR and 1 H-NMR spectrum. The most important benefits of this process are operational simplicity, reasonable reaction times, and excellent yield of products. The results show that the optimal conditions for the formation of imidazole derivatives are as follow: power of 400 W, reaction time of 4-9 min, H 2 O as a solvent, and 15 mmol of catalyst amount.