New Approach to Biologically Active Indolo[2,3‐ b ]quinoxaline Derivatives through Intramolecular Oxidative Cyclodehydrogenation

A convenient synthetic protocol to antiviral agent B‐220 and a series of similar indolo[2,3‐ b ]quinoxaline derivatives has been developed. This synthetic approach is based on Buchwald‐Hartwig cross‐coupling and subsequent annulation by intramolecular oxidative cyclodehydrogenation. For the first time, 6 H ‐indolo[2,3‐ b ]quinoxaline amine derivatives were evaluated for antimycobacterial activity. The moderate bacteriostatic effect against Mycobacterium tuberculosis H 37 Rv was found. A plausible mechanism of antibacterial action was elucidated by the molecular docking.