反应详情

温度

23 °C

20.0 g (86 mmol, 1 equiv.) of Boc-L-asparagine was dissolved in 120 mL of dry pyridine and 20.0 g (97 mmol, 1.3 equiv.) of dicyclohexylcarbodiimide dissolved in 60 mL of dry pyridine was added dropwise over a period of 30 minutes. The reaction was stirred for 3 hours at 23° C. and filtered through a 2 μm nylon filter. The filtrate was concentrated in vacuo on a rotary evaporator and 100 mL of water was added. The pH was adjusted to 10 with 40% NaOH (aq.) and the solution filtered through a 2 μm nylon filter once again. The filtrate was passed through a 120 mL bed of Dowex 50X8-400 ion exchange resin and the resin washed with four column volumes of 1:1 methanol:water. The filtrate was concentrated in vacuo to yield 17.5 g (95% yield) of the title compound as a white solid. 1H-NMR (CD3OD): 4.40 p.p.m (m, 1H); 2.95 p.p.m. (m, 2H); 1.40 p.p.m. (s, 9H).

1. additionwas added dropwise over a period of 30 minutes
2. filtrationfiltered through a 2 μm nylon
3. filtrationfilter
4. concentrationThe filtrate was concentrated in vacuo on a rotary evaporator and 100 mL of water
5. additionwas added
6. filtrationthe solution filtered through a 2 μm nylon
7. filtrationfilter once again
8. washthe resin washed with four column volumes of 1:1 methanol
9. concentrationThe filtrate was concentrated in vacuo