10315-07-8

24228-40-8

10315-07-8

(b) Synthesis of 1-benzyl-4-piperidinecarboxylic acid: 4N aqueous sodium hydroxide solution (35 mL) was added to a solution of ethyl 1-benzyl-4-piperidinecarboxylate (16.1 g, 65.1 mmol) in tetrahydrofuran (70 mL). The reaction mixture was stirred at room temperature and 1,4-dioxane (70 mL) was added and stirring was continued overnight. Upon completion of the reaction, the pH of the reaction solution was adjusted to 7 with 2 N hydrochloric acid. subsequently, the solvent was removed by distillation under reduced pressure. The obtained residue was suspended in ethanol and the solid was collected by filtration. Finally, the filtrate was concentrated under reduced pressure to afford 1-benzyl-4-piperidine carboxylic acid (13.6 g, 95% yield).