Potassium Carbonate → 10-bromo-5-methyl-2-(3-pyridylmethyloxy)-4H-pyrido[3,2,1-jk]carbazole-4-one

10-bromo-2-hydroxy-5-methyl-4H-pyrido[3,2,1-jk]carbazole-4-one (350 mg) obtained in Example 49 was suspended in dimethyl sulfoxide (14 ml), and potassium carbonate (440 mg) was added to the suspension. The mixture was stirred at room temperature for 30 minutes and 3-picolylchloride hydrochloride (190 mg) was added to the mixture. The mixture was stirred at room temperature for 12 hours, and the reaction mixture was poured into ice water (500 ml). The crystals precipitated 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 (270 mg, 60%).