114636-37-2

108-24-7

147081-44-5

114636-37-2

Step 1: (S)-1-Boc-3-aminopyrrolidine (930 mg, 5 mmol) was dissolved in anhydrous dichloromethane (50 mL) and cooled to 0 °C. Subsequently, triethylamine (1.4 mL, 10 mmol) and acetic anhydride (567 μL, 6 mmol) were added sequentially. The reaction mixture was slowly warmed to room temperature and stirred overnight. Upon completion of the reaction, the reaction was quenched by the addition of water (20 mL) and the organic layer was separated. The aqueous layer was extracted twice with dichloromethane (10 mL × 2). The combined organic layers were washed with brine (30 mL), dried over anhydrous sodium sulfate and concentrated. The crude product was purified by silica gel column chromatography to afford the target product S-1-Boc-3-N-acetylpyrrolidine (0.69 g, 60% yield).1H NMR (CDCl3, 400 MHz): δ 6.36-6.06 (br s, 1H), 4.45-4.36 (m, 1H), 3.68-3.48 (m, 1H), 3.43- 3.30 (m, 2H), 3.24-3.08 (m, 1H), 2.14-2.04 (m, 1H), 1.95 (s, 3H), 1.90-1.73 (m, 1H), 1.42 (s, 9H).