反应详情

Sat. aq. K2CO3 (210 mL) was added into a solution of benzyl chloroformate (12.0 ml, 84 mmol) and crude di-tert-butyl pyrazolidine-1,5-dicarboxylate (12.74 g, assumed 46.8 mmol) in acetonitrile (137 ml) at 0° C. The reaction was allowed to warm to room temperature and was stirred for 4.5 hrs. The aqueous phase was extracted with EtOAc (3×100 mL), and the organic layers were dried over Na2SO4. The solvents were removed in vacuo, and the crude product was purified by silica gel chromatography (CombiFlash, Column: 220 g; 0-35% ethyl acetate in hexane; 60 min) to provide the desired product 1-benzyl 2,3-di-tert-butyl pyrazolidine-1,2,3-tricarboxylate (14.15 g, 74% yield) as a white solid.

1. extractionThe aqueous phase was extracted with EtOAc (3×100 mL)
2. dry with materialthe organic layers were dried over Na2SO4
3. customThe solvents were removed in vacuo
4. customthe crude product was purified by silica gel chromatography (CombiFlash, Column: 220 g; 0-35% ethyl acetate in hexane; 60 min)