Synthetic Applications of Cyanoacetylated Bisindoles:  Synthesis of Novel Cycloheptadiindoles, Indolocarbazoles, and Related Aza Analogues

Cyclization reactions involving cyanoacetylated bisindoles have been studied, providing access to various novel cyclohepta[2,1-b:3,4-b']diindole derivatives as well as some related fused pentacyclic systems. Treatment of 3-cyanoacetyl-2,3'-diindolylmethane with methanesulfonic acid gave 6-(cyanomethyl)indolo[3,2-b]carbazole in a good yield.