反应详情

To a solution of di-tert-butylpyrazolidine-1,5-dicarboxylate (7 g, 25.7 mmol) dissolved in 1,2-dichloroethane (DCE) (80 mL) were added HCHO (2.224 g, 69.4 mmol), sodium triacetoxyborohydride (14.71 g, 69.4 mmol), and acetic acid (8 mL). The reaction was stirred at rt for appropriate time. The solvent was then removed and the residue was diluted with DCM and saturated NaHCO3 (150 mL). The aqueous layer was extracted with DCM. The organic layer was dried over Na2SO4, filtered, and evaporated. The residue was purified by silica gel column chromatography to afford 4 g (13.97 mmol, 54.3% yield) of bis(1,1-dimethylethyl) 2-methyl-1,5-pyrazolidinedicarboxylate as a pale yellow oil. LC-MS (ES) m/e 287.1 (M+H)+.

1. customThe solvent was then removed
2. additionthe residue was diluted with DCM and saturated NaHCO3 (150 mL)
3. extractionThe aqueous layer was extracted with DCM
4. dry with materialThe organic layer was dried over Na2SO4
5. filtrationfiltered
6. customevaporated
7. customThe residue was purified by silica gel column chromatography