Sodium Phosphate, Dibasic → 1-tert-Butyloxycarbonyl-3-bromo-4-oxopiperidine

Participants

Reaction Conditions

Reaction Steps

A solution of 32.5 g (163 mmol) of tert-butyl 4-oxo-piperidine-1-carboxylate in 200 ml of chloroform was treated with 24.0 g (168 mmol) of disodium hydrogen phosphate and cooled to 5° C. A solution of 27.9 g (175 mmol) of bromine in 75 ml of chloroform was added dropwise during 1 hour, thereafter the reaction mixture was warmed to room temperature and stirred for 18 hours. The reaction mixture was worked-up by extraction with ice-water and methylene chloride, the organic phase was dried over magnesium sulphate, filtered and the solvent was distilled off in a water-jet vacuum. The crude product (38 g) was chromatographed on silica gel with methylene chloride and ethyl acetate as the eluent. The thus-obtained product was recrystallized from ethyl acetate and n-hexane. There were obtained 19.1 g (42% of theory) of tert-butyl 3-bromo-4-oxo-piperidine-1-carboxylate as a pale yellow solid; MS: 277, 279 (M)+.

Provenance & Evidence