反应详情

Methyl chloroformate (2.6 mL, 33 mmol) was added dropwise to a stirred suspension of 2-Amino-4-methanesulfonyl-butyric acid (5.03 g, 27.8 mmol) and NaOH (5 N in H2O, 13.3 mL, 66.6 mmol) in THF (50 mL). After stirring at room temperature for 9 h, additional methyl chloroformate (5.2 mL, 66.6 mmol) and NaOH (5 N in H2O, 30 mL, 150 mmol) were added. After another 14 h, the reaction mixture was poured into H2O. The aqueous phase was washed with DCM 2× then acidified to pH 1 with 10% HCl. The acidified aqueous phase was extracted 3× with EtOAc. The combined organics were dried over MgSO4, filtered and concentrated to provide 4-Methanesulfonyl-2-methoxycarbonylamino-butyric acid (970 mg, 15%).

1. waitAfter another 14 h
2. washThe aqueous phase was washed with DCM 2×
3. extractionThe acidified aqueous phase was extracted 3× with EtOAc
4. dry with materialThe combined organics were dried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated