Ultrasound-Promoted Mild, and Efficient Protocol for Three-Component Synthesis of 2,4,5-Trisubstituted Imidazoles Using Urea and PPh3as the Sources of Nitrogen and Organocatalyst

Substituted imidazoles have wild applications in different area of sciences and industries. In this research, the catalytic activity of PPh(3)as a cheap and efficient organocatalyst is reported for synthesis of 2,4,5-trisubstituted imidazoles. In this method, ultrasonic assisted one-pot, three-component reaction of benzil, aldehydes, urea and PPh(3)in ethylene glycol as a green solvent at room temperature has been achieved to afford the structurally diverse 2,4,5-trisubstituted imidazoles in 80-95 %. The effect of different parameters on the reaction progress was also discussed. Utilizing ultrasonic irradiation dramatically improved the reaction in terms of yields and reaction times compared to conventional heating technique. The current protocol offers many advantages such as mild reaction conditions, short reaction time, the use of non-metallic, harmless, and cheap catalyst, ease of separation and purification, simple work-up procedure, and the reactivity to all types of aldehydes particularly the aliphatic aldehydes.