General procedure: 6-amino-1-hexanol (5.0 g, 42.7 mmol) was dissolved in a solvent mixture of tetrahydrofuran (50 mL) and water (15 mL), and benzyl chloroformate (7.3 mL, 51.2 mmol) was added slowly and dropwise at 0°C. The pH of the reaction solution was adjusted to 8-9 by adding 1N sodium hydroxide solution (12 mL). Under the condition of maintaining the temperature of the reaction system at 0 °C, 1N sodium hydroxide solution (12 mL) was slowly added to adjust the pH of the reaction solution to 8-9, a process that took about 30 min. Subsequently, the reaction mixture was continued to be stirred at room temperature for 30 minutes. Upon completion of the reaction, the reaction was extracted with ether (30 mL x 3), the organic phases were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting crude product was recrystallized by solvent recrystallization of a mixture of dichloromethane and hexane to afford N-Cbz-6-amino-1-hexanol as a white crystalline solid (3.85 g, 90% yield). The structure of the product was confirmed by 1H NMR and 13C NMR: 1H NMR (400 MHz, CDCl3): δ7.34 (m, 5H, Ar-H), 5.07 (s, 2H, PhCH2), 4.73 (br, 1H, NH), 3.61 (t, J=6.4Hz, 2H, CH2O), 3.16 (dt, J=6.8,6.8 Hz, 2H, NCH2), 1.61-1.32 (m, 8H, CH2); 13C NMR (100 MHz, CDCl3): δ 156.4 (C=O), 136.6,128.5,128.1 (Ar-C), 66.6 (PhCH2), 62.7 (CH2OH), 40.9 (NHCH2), 32.5 ( CH2CH2OH), 29.9 (NHCH2CH2), 26.3 (CH2CH2CH2OH), 25.3 (NCH2CH2CH2).
