c) Synthesis of 2-(methoxymethyl)piperidine hydrochloride: to a solution of tert-butyl 2-(methoxymethyl)-1-piperidine carboxylate (464 mg, 2.02 mmol) in dichloromethane (10 mL) was added a dioxane solution (5.06 mL, 20.23 mmol) in 2 M HCl. The reaction mixture was stirred at 25°C for 20 hours. Upon completion of the reaction, the mixture was partitioned between water and dichloromethane. The aqueous phase was separated, concentrated, followed by azeotropic removal of residual water with toluene and further drying under high vacuum for 5 h. 2-(Methoxymethyl)piperidine hydrochloride (259.5 mg, 99%) was obtained as a light yellow solid.LCMS (ES) m/z 130 (M + H)+; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.39-1.52 ( m, 2H), 1.58 (br.s, 1H), 1.67-1.81 (m, 3H), 2.83 (br.s, 1H), 3.17 (br.s, 2H), 3.31 (s, 3H), 3.46-3.53 (m, 2H), 8.86 (br.s, 2H).
