Tetrabutylammonium bromide (TBAB) in isopropanol: An efficient, novel, neutral and recyclable catalytic system for the synthesis of 2,4,5-trisubstituted imidazoles

A simple, efficient and eco-friendly procedure has been developed using tetrabutylammonium bromide (TBAB, 10 mol%) as novel neutral ionic liquid catalyst for the synthesis of 2,4,5-triaryl imidazoles by a three-component, one-pot condensation of benzil, aryl aldehydes and ammonium acetate in refluxing isopropanol. The present methodology offers several advantages such as excellent yields, shorter reaction times (15–30 min) and environmentally benign milder reaction conditions; moreover, the catalyst in isopropanol solvent exhibited reusable activity.