Facile Synthesis of 4-Arylidene-1H-imidazol-5(4H)-ones by an Ugi–Aza-Wittig Sequence

Abstract

Vinyl azides, obtained from the Ugi-type reaction of 2-azido-3-arylacrylic acid, secondary amine, aldehyde, and isocyanide, react with triphenylphosphine to give a variety of 4-arylidene-1<i>H</i>-imidazol-5(4<i>H</i>)-ones in high yields via sequential Staudinger and intramolecular aza-Wittig reaction.