10314-98-4

498-94-2

501-53-1

10314-98-4

NaHCO3 (1.5 eq.) and Na2CO3 (1.5 eq.) were added to 4-piperidinecarboxylic acid (1.29 g, 10 mmol) in a mixed solvent of acetonitrile/water (2:3, 0.1 M) and the pH was adjusted to 10-11. The reaction mixture was cooled down to 0 °C and then benzyl chloroformate (1.42 mL, 1.7 g, 10 mmol) was slowly added dropwise. After the dropwise addition, the reaction solution was stirred at room temperature for 2 hours. Upon completion of the reaction, the reaction mixture was acidified to pH ~2-3 by dropwise addition of aqueous 1N HCl. Subsequently, acetonitrile was removed by evaporation under reduced pressure, and the aqueous phase was extracted with ethyl acetate (3 x 30 mL). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give 1-(benzyloxycarbonyl)piperidine-4-carboxylic acid in quantitative yield, and the product was used directly in the next step of the reaction.