Reacción #54608

Ecuación de reacción

Et3N

MeOH

H-Glu(OBzl)-OH

Boc-Ser(Bzl)-OSu

Et3N

→

Boc-Ser(Bzl)-Glu(OBzl)-OH

Disolventes

DMF

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturato maintain
2. 2
   Otrothe reaction slightly basic
3. 3
   OtroThe clear solution was evaporated to dryness
4. 4
   Otrothe oily residue partitioned between EtOAc (1.5 liters) and 5% HOAc (2 liters)
5. 5
   LavadoThe organic layer was washed with H2O (2 times)
6. 6
   Secadodried over Na2SO4
7. 7
   Concentraciónconcentrated to a clear oil (90.0 g) which
8. 8
   workup.ADDITIONtreated with 25 ml of cyclohexylamine The solid
9. 9
   Otroformed
10. 10
    Otrowas recrystallized from MeOH and ether
11. 11
    Otroyield

Procedimiento

H-Glu(OBzl)-OH (39.4 g, 166 mmol) was stirred with Boc-Ser(Bzl)-OSu (65.0 g, 166 mmol) in 900 ml DMF overnight in the presence of Et3N (2.3 ml, 165 mmol). More Et3N was added during this time in order to maintain the reaction slightly basic. The clear solution was evaporated to dryness and the oily residue partitioned between EtOAc (1.5 liters) and 5% HOAc (2 liters). The organic layer was washed with H2O (2 times), dried over Na2SO4, and concentrated to a clear oil (90.0 g) which was taken up in 3 liters of ether and treated with 25 ml of cyclohexylamine The solid formed was recrystallized from MeOH and ether: yield, 76.2 (74.8%); mp 154°-156.5°; [α]D25 =+6.32° (c 1, MeOH).

Fuente