N1-Methyl-5-(2-amino-5-cyano-4-pyridyl)oxy-1H-1-indolecarboxamide (20 mg) synthesized in Example 215 was suspended in tetrahydrofuran (0.5 ml) at room temperature; triethylamine (0.121 ml, 0.868 mmol) and phenyl chloroformate (0.08 ml, 0.633 mmol) was added thereto while stirring; and the reaction mixture was stirred at room temperature for 2 hours. Water was added to the reaction mixture; this was subjected to extraction with ethyl acetate, washed with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. N,N-Dimethylformamide and pyrrolidine (0.013 ml) was added to a portion of the residue (14 mg); and the reaction mixture was stirred overnight. The reaction mixture was partitioned between ethyl acetate and water; and the organic layer was dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (Fuji Silysia NH, ethyl acetate-methanol). The resultant was washed with a solvent mixture (ether: hexane=1:1) to yield the title compound as crystals (6 mg).
