反应详情

Triethylamine (0.50 mL, 0.36 g, 3.6 mmol) was added to a stirred, cooled (0° C.) mixture of (S)-2-t-butoxycarbonylamino-3-(3,4-dichlorobenzyloxy)propionic acid (364 mg, 1 mmol), spiro[2H-1-benzopyran-2,4'-piperidin]-4-(3H)-one hydrochloride (U.S. Pat. No. 5,206,240, Example 67A) (254 mg, 1 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (230 mg, 1.2 mmol) and 1-hydroxybenzotriazole (162 mg, 1.2 mmol) in dimethylformamide (5 mL) and the mixture was stirred at room temperature for 2 h. Aqueous sodium hydrogen carbonate (saturated, 20 mL) and water (10 mL) were added and the mixture was extracted with ethyl acetate (3×20 mL). The combined organic fractions were washed with aqueous citric acid (10%, 2×20 mL), aqueous sodium hydrogen carbonate (saturated, 2×20 mL) and brine (20 mL), dried (MgSO4) and the solvent was evaporated under reduced pressure. The residue was purified by flash column chromatography on silica gel, eluting with CH2Cl2 /MeOH (99.5:0.5 increasing to 98:2) to give the title compound as a colorless foam (248 mg, 44%). m/e (ES+) 563 (MH+).

1. temperaturecooled
2. extractionthe mixture was extracted with ethyl acetate (3×20 mL)
3. washThe combined organic fractions were washed with aqueous citric acid (10%, 2×20 mL), aqueous sodium hydrogen carbonate (saturated, 2×20 mL) and brine (20 mL)
4. dry with materialdried (MgSO4)
5. customthe solvent was evaporated under reduced pressure
6. customThe residue was purified by flash column chromatography on silica gel
7. washeluting with CH2Cl2 /MeOH (99.5:0.5 increasing to 98:2)