Novel Cyclization of Vinyl Nitrene into 1-Azaphenalene

Article abstract of DOI:10.1246/cl.1987.883

Thermal reaction of 2H-azirines, bearing a methoxy or methylthio group at the neighboring position to azirine ring, was studied.In thermolysis of ethyl 2-(2-methoxynaphth-1-yl)-2H-azirine-3-carboxylate, attack of the vinyl nitrene at the peri position to form a 1-azaphenalene ring was observed.In thermal reaction of its thio analogue, 1-azaphenalene was also formed, but a naphthotiazine formed by the attack of vinyl nitrene at the sulfur atom was the major product.Mechanisms and differences of the reactions depending on O and S are discussed.