[CH2:1]([C@H:3]1[N:6]([C:7]2[CH:12]=[CH:11][C:10]([C:13]([F:16])([F:15])[F:14])=[CH:9][CH:8]=2)[C:5](=[O:17])[CH2:4]1)[CH3:2].Cl.[CH2:19](O)[CH3:20].[OH2:22]>C(OCC)(=O)C>[F:14][C:13]([F:16])([F:15])[C:10]1[CH:11]=[CH:12][C:7]([NH:6][C@H:3]([CH2:1][CH3:2])[CH2:4][C:5]([O:17][CH2:19][CH3:20])=[O:22])=[CH:8][CH:9]=1To 200 mg (0.822 mmol) of (R)-4-ethyl-1-[4-(trifluoromethyl)phenyl]-2-azetidinone produced in Example 6, 2.0 g (16.45 mmol) of 30 wt % hydrogen chloride/ethanol solution was added dropwise for 5 minutes. On completion of the addition, the resulting solution was heated to 40° C. and stirred for 14 hours. Water (5 mL) was added to the solution and extraction with ethyl acetate was carried out. The extracted organic layer was washed with saturated brine and the product was dried with anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure to obtain ethyl (R)-3-[4-(trifluoromethyl) phenylamino]-pentanoate as a yellow oil (193.8 mg, crude yield: 82%). 1H-NMR (CDCl3, 400 MHz/ppm): 6 0.98 (3H, t), 1.23 (3H, t), 1.55-1.71 (2H, m), 2.53 (2H, m), 3.75-3.82 (1H, m), 4.11 (2H, q), 6.61 (2H, d), 7.38 (2H, d)
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