ONE-POT SYNTHESIS OF 2,4,5-TRISUBSTITUTED IMIDAZOLES USING [BPy]H₂PO₄, AN EFFICIENT AND RECYCLABLE CATALYST

Abstract

[BPy]H₂PO₄ was easily prepared and used as an efficient and recyclable catalyst for the one-pot synthesis of 2,4,5-trisubstituted imidazoles under solvent-free conditions in good to excellent yields. Solvent-free conditions, simple experimental and workup procedures, and the use of a nontoxic, recyclable catalyst of an environmentally benign nature are remarkable features of the procedure.

Keywords:

• 2,4,5-trisubstituted imidazoles
• [BPy]H₂PO₄
• solvent-free

ACKNOWLEDGMENT

We thank the Natural Science Foundation of Hubei Province (grants 2007ABA291, 2008CDB036) for financial support.

Notes

^a Reaction condition: benzaldehyde (5 mmol), benzil (5 mmol), ammonium acetate (10 mmol) in presence of [BPy]H₂PO₄ under solvent-free conditions.

^b Isolated yield.

^a Reaction condition: benzaldehyde (10 mmol), benzil (10 mmol), ammonium acetate (20 mmol), [BPy]H₂PO₄ (15 mol%) at 130°C under solvent-free conditions.

^b Isolated yield.

^a Reaction condition: Aromatic aldehyde (5 mmol), benzil (5 mmol), ammonium acetate (10 mmol), [BPy]H₂PO₄ (15 mol%) at 130°C under solvent-free conditions.

^b Isolated yield.