Potassium Carbonate → 9-bromo-2-(3-hydroxypropyloxy)-5-(3-pyridylmethyl)-4H-pyrido [3,2,1-jk]carbazole-4-one

9-bromo-2-hydroxy-5-(3-pyridylmethyl)-4H-pyrido[3,2,1-jk]carbazole-4-one (400 mg) produced in Example 102 was suspended in dimethyl sulfoxide (40 ml). After adding potassium carbonate (540 mg), the mixture was stirred at room temperature for 30 minutes, and 3-bromo-1-propanol (0.3 ml) was added. After stirring at room temperature for 12 hours, the reaction mixture was poured into ice water (100 ml) and the crystals precipitated were recovered by filtration. The thus obtained crude crystals were washed with water, ethanol and ether in succession and recovered by filtration to obtain the title compound (177 mg, 72%).