反应详情

To a suspension of N-[2-(ethoxycarbonyl)butyl]alanine (2.2 g, 10 mmol) and potassium carbonate (2.2 g, 16 mmol) in a mixture of acetone (30 mL) and water (2.5 mL) was added benzyl chloroformate (2.0 mL, 2.4 g, 14 mmol) at 0-5° C. After stirring for 2 h at ambient temperature the solid was filtered off, the solvent was evaporated, the residue was stirred with cold aqueous sodium hydroxide solution [prepared from ice (20 g) and aqueous sodium hydroxide solution (1N, 40 mL)] and extracted with ethyl acetate (40 mL). The aqueous layer was acidified with an aqueous solution of hydrochloric acid 1/1 (20 mL) and the mixture was extracted with ethyl acetate (40 mL). After drying and evaporation N-[2-(ethoxycarbonyl)butyl]-N-benzyloxycarbonylalanine (1.66 g, 47%) was obtained as a yellow oil which can be used in the next reaction without further purification.

1. filtrationwas filtered off
2. customthe solvent was evaporated
3. stirringthe residue was stirred with cold aqueous sodium hydroxide solution [prepared from ice (20 g) and aqueous sodium hydroxide solution (1N, 40 mL)]
4. extractionextracted with ethyl acetate (40 mL)
5. extractionthe mixture was extracted with ethyl acetate (40 mL)
6. customAfter drying
7. customevaporation N-[2-(ethoxycarbonyl)butyl]-N-benzyloxycarbonylalanine (1.66 g, 47%)
8. customwas obtained as a yellow oil which
9. customcan be used in the next reaction without further purification