Chemistry of 6H-pyrido[4,3-b]carbazoles. Part 7. The synthesis of 8,9-benzoellipticine (benzo[h]pyrido[4,3-b]carbazole) and some 5-alkyl derivatives of the pyrido[4,3-b]carbazole system

Abstract
Various known procedures have been utilized to synthesize benzo[h]pyrido[4,3-b]carbazole (8,9-benzoellipticiene) and derivatives of the pyrido[4,3-b]carbazole system with extended alkyl substituents attached to position 5. A comparison is made between the various synthetic methods available for the synthesis of ellipticine derivative of interest as anticancer agents.