General procedure for the synthesis of tert-butyl 4-amino-4-methylpiperidine-1-carboxylate from the compound (CAS: 236406-14-7): a mixture of the compound of formula LE (2.48 g, 7.11 mmol) with 10% palladium carbon (200 mg, Sigma-Aldrich) in methanol (20 mL) was subjected to an atmosphere of hydrogen at about 250 °C The reaction was stirred for 16 hours. Upon completion of the reaction, the Pd/C catalyst was removed by filtration and the filtrate was concentrated under reduced pressure to give 1.37 g of the compound of formula LF as a light-colored viscous oil (90.2% yield). The structure of tert-butyl 4-amino-4-methylpiperidine-1-carboxylate, compound of formula LF, was confirmed using 1H NMR. The 1H NMR data of compound LF were as follows: δH (400 MHz, CDCl3): 3.47-3.49 (4H, m), 1.47-1.61 (4H, m), 1.46 (9H, s), 1.31-1.42 (2H, m), 1.15 (3H, s).
