One-Pot Synthesis of 2,4,5-Trisubstituted Imidazoles Using MoO₃/SiO₂, an Efficient and Recyclable Catalyst

Abstract

A simple one-pot synthesis has been developed for the synthesis of 2,4,5-trisubstituted imidazoles using an efficient and recyclable MoO₃/SiO₂ solid acid catalyst by condensation of benzil or benzoin, benzaldehyde, and ammonium acetate in acetonitrile as a solvent. Using this solid catalyst, the reactions could be carried out under mild reaction conditions with very good yield of imidazoles, up to 95%. This catalyst could be recycled very easily, which makes this methodology environmentally benign.

Keywords:

• Benzil/benzoin
• cyclocondensation
• imidazoles
• MoO₃/SiO₂
• one-pot
• solid acid

ACKNOWLEDGMENT

S. V. B. and S. V. N. are thankful to DST, New Delhi, for financial support (SR/FTP/CS-82/2007).

Notes

^a Reaction conditions: Temperature 80 °C, benzil or benzoin/aldehyde/NH₄OAc:1:1:2.5 mmol.

^b Isolated yield of product using benzil.

^c Isolated yield of product using benzoin.

^d Isolated yield of product after first recycle.

^e Isolated yield of product after second recycle.