反应详情

5-Oxo-1-[(1R)-1-phenylethyl]pyrrolidine-3-carboxylic acid tert-butyl ester (4 g, 13.82 mol) was dissolved in N,N-dimethylformamide (40 mL), and paraformaldehyde (0.83 g, 27.65 mmol) was suspended in the solution. Sodium hydride (0.60 g, 13.82 mmol) was added at room temperature, and the mixture was stirred for 30 minutes. Then, the reaction solution was poured into a 10% citric acid solution (150 mL) at 0° C. The mixture was extracted with ethyl acetate (300 mL). The organic layer was washed with water (100 mL×2) and brine (100 mL), dried over anhydrous sodium sulfate, and filtered. The solvent was evaporated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (30% ethyl acetate/hexane→80% ethyl acetate/hexane) to give 1.03 g of the title compound as a colorless solid.

1. extractionThe mixture was extracted with ethyl acetate (300 mL)
2. washThe organic layer was washed with water (100 mL×2) and brine (100 mL)
3. dry with materialdried over anhydrous sodium sulfate
4. filtrationfiltered
5. customThe solvent was evaporated under reduced pressure
6. customthe resulting residue was purified by silica gel column chromatography (30% ethyl acetate/hexane→80% ethyl acetate/hexane)