Synthesis of 5,6-dimethyl-9-methoxy-1-phenyl-6H-pyrido[4,3-b]carbazole derivatives and their cytotoxic activity

Starting from 2-(6-methoxy-1-methyl-9H-carbazol-2-yl)ethylamine 7 and mixed anhydrides of 4-nitrobenzoic acid or 4-methoxybenzoic acid, the corresponding 5,6-dimethyl-9-methoxy-1-(4-substituted phenyl)-6H-pyrido[4,3-b]carbazoles 11a-b, 5,6-dimethyl-9-bydroxy-1-(4-substituted phenyl)-6Hpyrido[4,3-b]carbazoles 12a, 12c, and their quaternary salts 13a-d were obtained. The four new pyridocarbazole derivatives 12a-c and 13d satisfy the international activity criterion for synthetic compounds, namely an ID50 value lower then 4 mu g/mL in preliminary in vitro cytotoxic activity screening against the A549 cell line (non-small cell lung cancer).