10-bromo-2-hydroxy-4H-pyrido[3,2,1-jk]carbazole-4-one (300 mg) obtained in Example 59 was suspended in dimethyl sulfoxide (20 ml), and potassium carbonate (400 mg) was added to the suspension. The mixture was stirred at room temperature for 30 minutes and 3-picolylchloride hydrochloride (180 mg) was added and the mixture was stirred at room temperature for 12 hours. The reaction mixture was poured into ice water (100 ml), and the precipitated crystals were recovered by filtration. The resulting crude crystals were washed with methanol and ether in succession, and recovered by filtration to obtain the title compound (200 mg, 52%).
