GENERAL STEPS: N,N'-dimethylethylenediamine (5.00 g, 57 mmol) was dissolved in dichloromethane (25 mL) and the solution was cooled to 0 °C. In another vessel, di-tert-butyl dicarbonate (5.00 g, 22 mmol) was dissolved in dichloromethane (25 mL), and the solution was subsequently added dropwise slowly to the reaction flask, maintaining the temperature at 0°C. After the dropwise addition, the reaction mixture was gradually warmed to room temperature and stirring was continued overnight. Upon completion of the reaction, the reaction was quenched with deionized water (20 mL) and extracted with dichloromethane (40 mL x 2). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated. The crude product obtained was purified by silica gel column chromatography using methanol/dichloromethane (1/20, V/V) as eluent to finally obtain the target compound tert-butyl methyl (2-(methylamino)ethyl)carbamate (4.37 g, 81%) as a colorless oil. Its structure was confirmed by 1H NMR (400 MHz, CDCl3) and HRMS (ESI): 1H NMR δ 3.39-3.36 (m, 2H, CH2), 2.95-2.90 (s, 3H, CH3), 2.76 (m, 2H, CH2), 2.48 (s, 3H, CH3), 1.48 (s, 9H, (CH3)3); HRMS (ESI) m/z [M + H]+ Calculated value: C9H21N2O2+ 189.1603, measured value: 189.1601.
