反应详情

To a solution of (RS)-4-oxo-pyrrolidine-1,3-dicarboxylic acid 1-tert-butyl ester 3-ethyl ester (commercial; 1 g, 3.9 mmol) in EtOH (15 mL) were added benzylamine (0.85 mL, 7.77 mmol) and AcOH (0.45 mL, 7.77 mmol) and the mixture was stirred 3 h at rt. Sodium cyanoborohydride (0.98 g, 15.5 mmol) was then added at rt and the mixture was heated to 75° C. for 5 h, then 15 h to 50° C. and again 1 h to 75° C. The mixture was concentrated under reduced pressure, water was added and the mixture extracted 3× with EA. The combined org. extracts were washed with brine dried over MgSO4 and concentrated under reduced pressure. The residue was purified by CC (Hep/EA from 2:1 to 1:1) to afford the title intermediate as a yellow oil (0.73 g, 54%).

1. temperaturethe mixture was heated to 75° C. for 5 h
2. concentrationThe mixture was concentrated under reduced pressure, water
3. additionwas added
4. extractionthe mixture extracted 3× with EA
5. washextracts were washed with brine
6. dry with materialdried over MgSO4
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by CC (Hep/EA from 2:1 to 1:1)