4-((6-Ethoxy-1H-indol-5-yl)oxy)pyridin-2-amine described in Production Example 15-6 (6.44 g, 23.9 mmol) was dissolved in N,N-dimethylformamide (80 mL), 50-72% oily sodium hydride (1.41 g) was added under nitrogen atmosphere at 0° C., and the mixture was stirred at mom temperature for 40 minutes. The mixture was cooled to 0° C. again, phenyl methylcarbamate described in Production Example 1-7 (5.78 g, 38.3 mmol) was added, and the mixture was stirred at room temperature for 3 hours. A saturated aqueous ammonium chloride solution, water, and ethyl acetate were added to the reaction mixture for partition. The aqueous layer was extracted with ethyl acetate and the combined organic layer was washed with water twice and then with a saturated saline solution. The organic layer was dried over anhydrous magnesium sulfate and then filtered, then the filtrate was concentrated under vacuum. A liquid mixture of diethyl ether and ethyl acetate was added to the residue, then the precipitate was collected by filteration and the resultant was washed with ethyl acetate again to obtain the title compound (4.24 g, 54%). The filtrate was purified with NH silica gel column chromatography (ethyl acetate:methanol=1:0-9:1), the target fraction was concentrated under vacuum, and then the residue was collected by filteration and washed with a liquid mixture of diethyl ether and ethyl acetate to obtain the title compound (1.58 g, 20%).
