To a solution of tert-butyl (5-(4-chloro-2-((4-cyanophenyl)amino)pyrimidin-5-yl)-4-pentyn-1-yl)carbamate (T5, 30 mg) and pyrazole (7 mg) in N-methylpyrrolidone (1 mL), cesium carbonate (71 mg) was added at room temperature, and the mixture was stirred at 60° C. for 3 hours. The reaction mixture was cooled to room temperature, and then water and ethyl acetate were added to the reaction mixture. The organic layer was separated, washed with saturated aqueous sodium chloride, and then dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography (eluent, 90 to 40% hexane in ethyl acetate) to obtain tert-butyl (5-(2-((4-cyanophenyl)amino)-4-(1H-pyrazol-1-yl)pyrimidin-5-yl)-4-pentyn-1-yl)carbamate (T7, 20 mg).
