A general and practicable synthesis of polycyclic heteroaromatic compounds. Part 1. Use of a putative quinolone-quinone-methide in the synthesis of polycyclic heteroaromatic compounds

Abstract

A general and straightforward new synthesis of polycyclic heteroaromatic compounds has been developed. In the synthesis a putative quinolone-quinone-methide is generated in the presence of an aniline. The ensuing reaction results in a polycyclic heteroaromatic product. In the most useful approach, a hemiacetal (25) is prepared in one step from the parent quinolone and this is heated in the presence of an aromatic amine to produce the polycyclic heteroaromatic compound in good yield. The regiospecificity of the reaction is the opposite to that expected in the Skraup synthesis with respect to the quinone-methide component. With respect to the aniline component, however, regiospecificity is the same as in the Skraup synthesis.