4-Piperidinecarboxamide → benzyl 4-(aminocarbonyl)tetrahydro-1(2H)-pyridinecarboxylate

To a solution of piperidine-4-carboxamide (5 g, 39 mmol) and benzylchloroformate (5.54 mL, 39 mmol) in a mixture of water (30 mL) and acetone (40 mL), NaOH 1N (39 mL, 39 mmol) was added dropwise, while maintaining the pH between 6 and 8. The mixture was stirred at r.t. for 3 h; then acetone was evaporated and the resulting precipitate filtered and dried at 70° C. under reduced pressure, giving 7.75 g of benzyl-4-carbamoylpiperidine-1-carboxylate (76%).