4-Benzensulfonylmethyl-4-hydroxy-piperidine TFA (B-1) Diisopropylethylamine (28.3 mL, 162.75 mmol) and di-t-butyl dicarbonate (28.4 g, 130.02 mmol) were added in sequence to a mixture of piperidone hydrate hydrochloride (12) (10.0 g, 65.1 mmol) in methanol (50 mL). The mixture was stirred at room temperature for 20 hours. After that, removed the solvent and the remaining was separated with ether and 1 M KHSO
4 solution. The organic layer was washed with brine and saturated NaHCO
3. Finally, N-Boc-2-piperidone was obtained after purification.
