Reaktion #7381

Reaktionsgleichung

Thionyl chloride

D-glutamic acid

potassium hydrogen carbonate

benzyl chloroformate

ethyl acetate

→

title compound

Dimethyl (2R)-2-{[(benzyloxy)carbonyl]amino}pentanedioate

Lösungsmittel

methanol

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture subsequently heated
2. 2
   Temperaturunder reflux for 16 h
3. 3
   TemperaturOn cooling
4. 4
   Einengenthe mixture was concentrated under reduced pressure
5. 5
   Sonstigethe residue azeotroped with toluene
6. 6
   Sonstigeto give a white solid
7. 7
   workup.ADDITIONwas added
8. 8
   WaschenThe separated organic phase was washed with water
9. 9
   Trocknendried (over magnesium sulphate)
10. 10
    Einengenconcentrated under reduced pressure
11. 11
    Sonstigeto provide a yellow oil
12. 12
    SonstigeThis oil was purified
13. 13
    Waschenflash column chromatography (silica, eluting with cyclohexane:ethyl acetate 2:1)

Vorschrift

Thionyl chloride (30 ml) was added to a cooled solution of D-glutamic acid (33.2 g) in methanol (250 ml) and the mixture subsequently heated under reflux for 16 h. On cooling, the mixture was concentrated under reduced pressure and the residue azeotroped with toluene to give a white solid. This was stirred with ethyl acetate, water and potassium hydrogen carbonate at 0° C. while benzyl chloroformate (30 ml) was added. The mixture was warmed to room temperature and stirred for 5 h. The separated organic phase was washed with water, dried (over magnesium sulphate) and concentrated under reduced pressure to provide a yellow oil. This oil was purified using flash column chromatography (silica, eluting with cyclohexane:ethyl acetate 2:1) to give the title compound (22.45 g) as an oil.

Quelle