Facile Synthesis of 3-Arylidene-3H-1,4-benzodiazepines by a Sequential Ugi/Staudinger/Aza-Wittig Reaction

Abstract

<i>N</i>-[2-(Alkylamino)-1-(2-azidophenyl)-2-oxoethyl]-<i>N</i>-(3-oxoprop-1-en-2-yl)amides, obtained from the Ugi reaction of a vinyliminophosphorane, 2-azidobenzaldehyde, a carboxylic acid, and an alkyl isocyanide, reacted with triphenylphosphine to give various 3-arylidene-3<i>H</i>-1,4-benzodiazepine in good yields via sequential Staudinger and intramolecular aza-Wittig reaction.