[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[C:19]([CH3:20])=[CH:18][C:17](Br)=[CH:16][N:15]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].O.N.[CH3:24][N:25](C)C=O>[C-]#N.[Zn+2].[C-]#N>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[C:19]([CH3:20])=[CH:18][C:17]([C:24]#[N:25])=[CH:16][N:15]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2]Under a nitrogen stream, 4-(5-bromo-3-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (3.13 g) was dissolved in N,N-dimethylformamide (30 mL), zinc cyanide (1.03 g) and tetrakistriphenylphosphine palladium(0) (0.51 g) were added, and the mixture was stirred at 120° C. for 4 hr. After completion of the reaction, to the reaction mixture was added water/saturated aqueous ammonium chloride solution/28% aqueous ammonia (4:4:1), and the mixture was extracted with ethyl acetate. The organic layer was washed with water and saturated brine, and the solvent was evaporated. The obtained residue was purified by column chromatography (hexane:ethyl acetate) to give the title compound (2.46 g).
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