876379-22-5

501-53-1

216854-23-8

876379-22-5

To a 200 mL round bottom flask was added (S)-3-Boc-aminopiperidine (2.02 g, 10.09 mmol) followed by dichloromethane (40 mL) as solvent. Triethylamine (2.25 mL, 16.1 mmol) was added dropwise to the system under stirring. The resulting colorless solution was cooled to 0 °C and then benzyl chloroformate (1.70 mL, 11.9 mmol) was added slowly and dropwise. The reaction mixture was stirred at 0 °C and gradually warmed to room temperature. After completion of the reaction (monitored by TLC), the mixture was extracted by partitioning with dichloromethane and water. The aqueous phase was further extracted with dichloromethane and the combined organic phases were washed with saturated brine and dried over anhydrous sodium sulfate. After filtration, the organic phase was concentrated under reduced pressure to afford (S)-1-Cbz-3-N-Boc-aminopiperidine as a colorless viscous oil, which was crystallized after standing under vacuum (3.35 g, 99% yield).