Syntheses of 6-substituted indolo[3,2-b]carbazoles, including 6-formylindolo[3,2-b]carbazole, an extremely efficient ligand for the TCDD (Ah) receptor

A number of 6-substituted indolo[3,2-b]carbazoles have been synthesized using 2,3-diindolylmethane 5 as a crucial precursor. Most notably, 6-formylindolo[3,2-b]carbazole 3 has been synthesized, and thereby a previously assigned structure has been confirmed. 6-Formylindolo[3,2-b]carbazole 3 is an extremely efficient ligand for the TCDD (Ah) receptor. A much improved synthesis of 2,3-diindolylmethane 5 has also been developed. (C) 1999 Elsevier Science Ltd. All rights reserved.