[C:1]([O:5][C:6](=[O:20])[CH2:7][N:8]([CH2:13][C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)[CH:9](C)[CH2:10][Cl:11])([CH3:4])([CH3:3])[CH3:2].O.[CH3:22]N(C)C=O>>[C:1]([O:5][C:6](=[O:20])[CH2:7][N:8]([CH2:13][C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1)[CH2:9][CH:10]([Cl:11])[CH3:22])([CH3:2])([CH3:3])[CH3:4]An optically-active compound of [benzyl-(2-chloro-1-methylethyl)-amino]acetic acid tert-butyl ester (172.9 g) was dissolved in N,N-dimethylformamide (520 ml), and stirred at 80° C. for 140 minutes. The reaction mixture was cooled to 0° C. Then, thereto was added water (1200 ml), and the mixture was extracted with n-hexane/ethyl acetate (2/1, 1000 ml). The organic layer was sequentially washed with water (700 ml) and saturated aqueous sodium chloride solution (400 ml), and the separated aqueous layer was extracted with n-hexane/ethyl acetate (2/1, 600 ml) again. The combined organic layer was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=50/1 to 40/1) to give the titled compound (127.0 g).
読み込み中…