Use of a novel multicomponent reaction under high pressure for the efficient construction of a new pyridazino[5,4,3-de][1,6]naphthyridine tricyclic system

Abstract

A novel multicomponent reaction between the 2-phenylhydrazono derivative 1a, malononitrile and aromatic aldehydes or acetone, carried out under high pressure, was found to generate pyridazino[5,4,3-de][1,6]naphthyridine derivatives 9a–h and 22. The structures of the products were established by using X-ray crystallographic methods. Mechanisms to account for product formation are proposed.