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-1H-imidazol-5(4H)-ones in high yields via sequential Staudinger and intramolecular aza-Wittig reaction.
Key words
1
H-imidazol-5(4
H)-ones - Ugi reaction - aza-Wittig reaction - iminophosphoranes - azides