反应详情

0.439 g (1.85 mmol) of N-benzyloxycarbonyl-2(S)-aminobutyric acid prepared as in Example 3 a) is dissolved, under nitrogen, in tetrahydrofuran (50 ml) and the solution is cooled in an ice/water bath. 0.213 g (1.85 mmol) of N-ethylmorpholine is added, followed by 0.253 g (1.85 mmol) of isobutyl chloroformate. After 45 minutes, 0.378 g (1.85 mmol) of the compound obtained in step b) is added and stirring is continued for 12 hours. The suspension is poured into CH2Cl2 (100 ml) and the mixture is washed with 10% citric acid (3×100 ml) and then with 5% NaHCO3 (3×100 ml). After drying and evaporation, a white solid is obtained which crystallizes from CCl4.

1. temperaturethe solution is cooled in an ice/water bath
2. waitis continued for 12 hours
3. washthe mixture is washed with 10% citric acid (3×100 ml)
4. customAfter drying
5. customevaporation
6. customa white solid is obtained which
7. customcrystallizes from CCl4