反应详情

To a mechanically stirred mixture of benzylchloroformate (33.1 mL, 232 mmol, 105 mol %), sodium bicarbonate (37.2 g, 442 mmol, 200 mol %), ether (250 mL), and water (250 mL) is added. 3-methyl-4-piperidone hydrobromide salt (42.9 g, 221 mmol) in portions over 10 min. The resultant mixture is stirred for 2 h and the organic phase separated. The aqueous phase is extracted with ether (2×150 mL) and the combined organics dried (MgSO4), filtered, and concentrated to an oily residue. This residue crystallized on standing at 23° C. and was recrystallized from hexanes/ethyl acetate to give N-benzyloxycarbonyl-3-methyl-4-piperidone as a solid: 51.2 g; 93%; mp 33°-35° C.

1. additionis added
2. customthe organic phase separated
3. extractionThe aqueous phase is extracted with ether (2×150 mL)
4. dry with materialthe combined organics dried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated to an oily residue
7. customThis residue crystallized
8. customon standing at 23° C.
9. customwas recrystallized from hexanes/ethyl acetate