92 mg of (S)-6-chloro-N-[1-(4-fluorophenyl)ethyl]-4-(1-methyl-1H-pyrazol-4-yl)pyridine-2-amine was dissolved in 1.5 ml of tetrahydrofuran, and 17 mg of 60% sodium hydride was added thereto, and the mixture was stirred at room temperature for 10 minutes. 26 μl of methyl iodide was added thereto, and the reaction solution was subjected to microwave irradiation at 100° C. for 5 minutes. 8 mg of 60% sodium hydride and 26 μl of methyl iodide were added to the reaction solution, and the reaction solution was stirred at 130° C. for 10 minutes, and furthermore 17 mg of 60% sodium hydride and 26 μl of methyl iodide were added, and the mixture was stirred at 130° C. for 10 minutes. The reaction solution was added with water and subjected to extraction with ethyl acetate. The organic layer was washed in turn with water and brine, and then dried over magnesium sulfate. The solvent was distilled off under reduced pressure, and then the obtained residue was purified by silica gel column chromatography to obtain 62 mg of the objective compound as pale yellow oil.
