GENERAL STEPS: 1-Boc-4-piperidinyl-N-methylamide (68 mg, 0.28 mmol) was dissolved in methanol (2 mL) and cooled to 0°C. A 1,4-dioxane solution (2 mL) of 4 M hydrogen chloride was slowly added. The reaction mixture was stirred at 0°C for 15 minutes and then gradually warmed to room temperature and continued stirring for 3 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The crude product was purified by SCX-2 column chromatography, eluting first with methanol and then with 0.5 M ammonia in methanol solution to afford N-methylpiperidine-4-carboxamide as a colorless oil (41 mg, 99% yield). The product was detected by infrared spectroscopy (CHCl3) with characteristic absorption peaks of 1308, 2948, 1663, 1525, 1227, 1119 cm-1; mass spectrometry (ESI) analysis showed that the theoretical value of the [M+H]+ ion peak of C7H15N2O was 143.1179 and the measured value was 143.1178.
