Réaction #7381

Équation de réaction

Thionyl chloride

D-glutamic acid

potassium hydrogen carbonate

benzyl chloroformate

ethyl acetate

→

title compound

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

Solvants

methanol

water

Conditions de réaction

Traitement

1. 1
   Températurethe mixture subsequently heated
2. 2
   Températureunder reflux for 16 h
3. 3
   TempératureOn cooling
4. 4
   Concentrationthe mixture was concentrated under reduced pressure
5. 5
   Autrethe residue azeotroped with toluene
6. 6
   Autreto give a white solid
7. 7
   workup.ADDITIONwas added
8. 8
   LavageThe separated organic phase was washed with water
9. 9
   Séchagedried (over magnesium sulphate)
10. 10
    Concentrationconcentrated under reduced pressure
11. 11
    Autreto provide a yellow oil
12. 12
    AutreThis oil was purified
13. 13
    Lavageflash column chromatography (silica, eluting with cyclohexane:ethyl acetate 2:1)

Mode opératoire

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.

Source