Preparation of Fully Substituted 1,3,4-Oxadiazole Derivatives from N-Isocyaniminotriphenylphosphorane, (E)-Cinnamic Acids, Chloroacetone and Primary Amines

Young Researchers Club, Zanjan Branch, Islamic Azad University, Zanjan, IranReceived June 5, 2011, Accepted June 29, 2011The 1:1 imine intermediate generated by the addition of primary amine to chloroacetone is trapped by N-isocyaniminotriphenylphosphorane in the presence of ( E)-cinnamic acids and the corresponding iminophosphoraneintermediate was formed. Disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittigreaction of the iminophosphorane intermediate. The reactions were completed in neutral conditions at roomtemperature. The disubstituted 1,3,4-oxadiazole derivatives were produced in excellent yields.Key Words : N-Isocyaniminotriphenylphosphorane, Chloroacetone, (E)-Cinnamic acid, 1,3,4-Oxadiazole,aza-Wittig reactionIntroductionRecently, multicomponent condensation reactions (MCRs)have become one of the most powerful methods for thesynthesis of small molecule libraries, due to the fact thatproducts are formed in a single step by simultaneous reactionsof several reagents and the molecular diversity required forsuch combinatorial libraries can be achieved by simplyvarying each component.