Diethyl Ether → Benzyl 3-methyl-4-oxopiperidine-1-carboxylate

Participants

Reaction Steps

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.

Provenance & Evidence