γ-Carbolines and their hydrogenated derivatives. 2.* Hydrogenated derivatives of γ-carbolines: methods of synthesis (review)

Abstract

Published data on methods for the synthesis of dihydro-, tetrahydro-, and hexahydro-γ-carbolines are reviewed.

A Unified Approach to the Isomeric α-, β-, γ-, and δ-Carbolines via their 6,7,8,9-Tetrahydro Counterparts

“…A multitude of methods has been established for the synthesis of the carbolines, including classical ones involving Graebe–Ullmann, Fischer indolization, Bischler–Napieralski, and Pictet–Spengler reactions. , Variations on the Cadogan syntheses of carbazoles are also known, as are routes involving the annulation of pyridines onto indoles, ,, including through Diels–Alder and electrocyclization processes. Generally speaking, though, “customized” approaches are required for the assembly of each of the α-, β-, γ-, and δ-carboline frameworks, thus prompting the search for more general routes to them .…”