Visible‐Light‐Induced Multicomponent Synthesis of Tetrasubstituted Imidazoles

2,4-Dinitrophenol mediated photochemical coupling of α-keto vinyl azides, anilines and aldehydes for the synthesis of tetrasubstituted imidazoles is presented. 2,4-DNP acts as a photosensitizer as well as Bronsted acid catalyst in the overall reaction and hence it finds its applicability as a photocatalyst for metal free synthesis of therapeutically important complex molecule.

Abstract

An efficient visible light photocatalyzed one-pot, three-component synthesis of tetrasubstituted imidazoles was developed. Catalytic amount of 2,4-dinitrophenol (2,4-DNP) was necessary for the successful coupling of anilines, aldehydes and α-keto vinyl azides to yield imidazoles in the presence of 7 W blue LED light. The scope of the reaction was demonstrated by synthesizing a series of highly functionalized imidazoles in excellent yields (75–86%). Control experiments were carried out and a mechanistic rationalization of the three-component reaction was proposed.

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