Synthesis of 5-chloro-7-azaindoles by Fischer reaction

Abstract

[Figure not available: see fulltext.] A simple and effective method on the basis of Fischer reaction in polyphosphoric acid is proposed for the synthesis of previously unknown heterocyclic structures that contain the 5-chloro-1H-pyrrolo[2,3-b]pyridine system. This method can be used for the synthesis of 3-substituted and 2,3-disubstituted 5-chloro-7-azaindoles with alkyl and aryl substituents.