反应详情

Methyl (2S)-2-amino-3-(3,5-difluorophenyl)propanoate (XV, EXAMPLE 11, 0.300 g, 1.40 mmol, 1 equivalent) and water (10 mL) are mixed. Sodium carbonate (0.15 g, 1.40 mmol, 1 equivalent) of is added followed by benzylchloroformate (0.2 mL, 0.24 g 1.4 mmol, 1 equivalent) and the mixture stirred at 20-25° until complete as measured by HPLC. Once the reaction is complete, ethyl acetate (20 mL) is added and the phases separated. The aqueous phase is extracted with ethyl acetate (2×20 mL), and the combined organic phases are dried over sodium sulfate, filtered, and concentrated. The concentrate is crystallized from hexanes/ethyl acetate to give the title compound, mp=54°; NMR (DMSO-d6) δ 7.84, 7.28, 7.06, 4.98, 4.35, 3.68, 3.12 and 2.88.

1. customthe phases separated
2. extractionThe aqueous phase is extracted with ethyl acetate (2×20 mL)
3. dry with materialthe combined organic phases are dried over sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated
6. customThe concentrate is crystallized from hexanes/ethyl acetate