Symmetric and nonsymmetric diindolocarbazoles were successfully synthesized for the first time by a Cadogan ring closure using N-alkyl-2, 7-disubstituted carbazole precursors. Cyclization reaction on N-alkyl-2, 7-di (2'-nitrophenyl) carbazole derivatives is not regioselective and produced a separable mixture of symmetric and nonsymmetric diindolocarbazoles. A carbazole derivative with methyl protective groups at the 1-and 8- ...
