反应 #84040

反应方程式

Methyl chloroformate

NaOH

L-Leucine

sodium carbonate

→

(S)-2-(methoxycarbonylamino)-4-methylpentanoic acid

反应条件

后处理

1. 1
   其他reach room temperature
2. 2
   其他The reaction mixture is separated with ether (3×50 mL)
3. 3
   其他the aqueous layer is contained in a round bottom flask
4. 4
   温度cooled over an ice-water bath
5. 5
   workup.ADDITIONConcentrated HCl (aq) is added drop wise until pH 2
6. 6
   其他is brought to room temperature
7. 7
   萃取extracted with 2-Me-THF (3×50 mL)
8. 8
   干燥dried (MgSO4)
9. 9
   其他the solids removed by filtration
10. 10
    其他the solvents of the filtrate removed under reduced pressure
11. 11
    其他The compound was purified by silicagel chromatography with gradient elution from CH2Cl2 to CH2Cl2/MeOH/acetic acid 17/2/1
12. 12
    workup.ADDITIONFractions containing product
13. 13
    其他the solvent were removed in vacuum
14. 14
    其他resulting in N-methoxycarbonyl-L-leucine (1.9 g, 32%)

实验过程

An aqueous NaOH (1M, 2.6 mL) solution is added, while stirring, to L-Leucine (4 g, 30.5 mmol) in a round bottom flask (250 mL). To this solution was added sodium carbonate (1.62 g, 15.2 mmol). The flask is cooled to 0° C. in an ice-water bath. Methyl chloroformate (2.6 mL, 33.5 mmol) is added drop wise and the reaction mixture is allowed to stir for 15 hours and reach room temperature. The reaction mixture is separated with ether (3×50 mL), and the aqueous layer is contained in a round bottom flask and cooled over an ice-water bath. Concentrated HCl (aq) is added drop wise until pH 2. The reaction mixture is brought to room temperature and extracted with 2-Me-THF (3×50 mL). The organic layers are pooled, dried (MgSO4), the solids removed by filtration, and the solvents of the filtrate removed under reduced pressure. The compound was purified by silicagel chromatography with gradient elution from CH2Cl2 to CH2Cl2/MeOH/acetic acid 17/2/1. Fractions containing product were combined and the solvent were removed in vacuum, resulting in N-methoxycarbonyl-L-leucine (1.9 g, 32%).

来源