反应详情

(R)-diethyl 2-t-butyloxycarbonylamino-2-carbamoylsuccinate (590 mg) obtained in Example 15 was dissolved in acetone (6 mL) and water (6 mL), the solution was added with potassium carbonate (295 mg), the mixture was stirred for 6 hours, 1 mol/L hydrochloric acid was poured to the mixture, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and then dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the residue was subjected to silica gel column chromatography, in which elution was performed with n-hexane/ethyl acetate (1:1) for purification, and then recrystallized from ethyl acetate/n-hexane to obtain the title compound (450 mg, yield: 88%) as colorless crystals. Optical rotation [α]D25 was −39.1° (c 0.50, ethanol). 1H NMR (CDCl3) δ (ppm): 8.50 (1H, br), 5.99 (1H, br), 4.32 (2H, q, J=7.2 Hz), 3.16 (2H, m), 1.44 (9H, s), 1.30 (3H, t, J=7.2 Hz)

1. extractionthe mixture was extracted with ethyl acetate
2. washThe extract was washed with saturated brine
3. dry with materialdried over anhydrous magnesium sulfate
4. customThe solvent was evaporated under reduced pressure
5. washthe residue was subjected to silica gel column chromatography, in which elution
6. customwas performed with n-hexane/ethyl acetate (1:1) for purification
7. customrecrystallized from ethyl acetate/n-hexane