Synthesis of 9-aminoellipticine (9-amino-5,11-dimethyl-6H-pyrido[4,3-b]carbazole) and related compounds

Abstract

Attempts to prepare 9-nitroellipticine from 2-{1-[3-(1-methoxyethyl)-4-pyridyl]ethylidene}-5-nitroindolin-3-one have been unsuccessful. On the other hand 9-aminoellipticine has been prepared by ring closure of 5-acetamido-2-{1-[3-(1-methoxyethyl)-4-pyridyl]ethyl}indole. The mechanism of the reduction of alkylideneindolinones by sodium borohydride is discussed and an anomalous nitration reaction of indoles in concentrated sulphuric acid is reported.