A New synthesis of highly functionalized 1- azadienes

Multicomponent reactions (MCRs) have attracted much attention in combinatorial chemistry. Of importance in this area are the isocyanide-based MCRs such as the versatile Ugi and Passerini reactions1. The addition of nucleophilic carbenes such as isocyanides to dialkyl acetylenedicarboxylates has been investigated in detail2. The reaction of 1-azadienes with various chiral dienophiles, which leads to substituted pyridines, have been reported3. We report here an efficient synthesis of 1-azadienes, minor amounts of ketenimines using alkyl isocyanides 1, dialkylacetylenedicarboxylates 2, and 2-hydroxy pyridine. The structure of 3 was deduced from IR, 1H NMR, 13C NMR spectra.