反应详情

The above-described product 19a (1 g, 3.9 mmol) was dissolved in dichloromethane (4 mL), and then anhydrous potassium carbonate (0.6 g) was added thereto. Then, Cbz-Cl (1.863 g, 1.537 mL) was slowly dropped, at a rate of 1-2 drops per second, into the mixture maintained in an ice-salt bath. The resultant mixture was reacted for 4 hours at room temperature. After completion of the reaction, water was added into the reaction mixture, followed by extraction with ethyl acetate. The combined ethyl acetate phase was evaporated in vacuum to get a crude product, which was recrystallized with acetone to afford the product 20a (1.235 g) as a white solid, with a yield of 80.8%.

1. temperaturemaintained in an ice-salt bath
2. additionwas added into the reaction mixture
3. extractionfollowed by extraction with ethyl acetate
4. customThe combined ethyl acetate phase was evaporated in vacuum
5. customto get a crude product, which
6. customwas recrystallized with acetone