Reacción #7381

Ecuación de reacción

Thionyl chloride

D-glutamic acid

potassium hydrogen carbonate

benzyl chloroformate

ethyl acetate

→

title compound

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

Disolventes

methanol

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe mixture subsequently heated
2. 2
   Temperaturaunder reflux for 16 h
3. 3
   TemperaturaOn cooling
4. 4
   Concentraciónthe mixture was concentrated under reduced pressure
5. 5
   Otrothe residue azeotroped with toluene
6. 6
   Otroto give a white solid
7. 7
   workup.ADDITIONwas added
8. 8
   LavadoThe separated organic phase was washed with water
9. 9
   Secadodried (over magnesium sulphate)
10. 10
    Concentraciónconcentrated under reduced pressure
11. 11
    Otroto provide a yellow oil
12. 12
    OtroThis oil was purified
13. 13
    Lavadoflash column chromatography (silica, eluting with cyclohexane:ethyl acetate 2:1)

Procedimiento

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.

Fuente