The synthesis of pyridines, quinolines and other related systems by the vilsmeier and the reverse vilsmeier method

Abstract

Quinolines, pyridines, thienopyridines, quinolones, isoquinolones, naphthyridines and related systems can be made efficiently from acylamides under Vilsmeier conditions. This review focusses on the application of both the Vilsmeier and the Reverse Vilsmeier approach. In the former method the acylamide becomes a nucleophile and is the source of the nitrogen and the 2,3-carbons of the resulting heterocycle while in the latter the acylamide reacts as an electrophile which yields the product heterocycle by reaction with an electron-rich alkene or its equivalent. This 'alkene' can be an enamine, a vinyl ester, an amide, or a masked nucleophilic alkene such as a ketone or an 'active' methyl or methylene group as in an α-substituted acetic acid. © 1993.