反応 #54611

反応方程式

ether

H-Asp(OBzl)-Thr(Bzl)-Ser(Bzl)-Ser(Bzl)-Glu(OBzl)-OH

Boc-Val-OSu

HCl

→

Boc-Val-Asp(OBzl)-Thr(Bzl)-Ser(Bzl)-Ser(Bzl)-Glu(OBzl)-OH

溶媒

DMF

THF

THF

Et3N

Et3N

反応条件

後処理

1. 1
   その他a white solid powder was obtained (44.0 g, mp 179°-184°)
2. 2
   温度cooled to 0°
3. 3
   workup.ADDITIONwas added in several portions
4. 4
   温度maintaining
5. 5
   その他the reaction slightly basic
6. 6
   その他The insoluble matter was removed by filtration
7. 7
   その他the filtrate evaporated to dryness
8. 8
   workup.DISSOLUTIONThe oily residue was dissolved in CH2Cl2
9. 9
   洗浄washed with 5% HOAc, H2O
10. 10
    乾燥dried (Na2SO4)
11. 11
    その他evaporated to a smaller volume (0.5 liter) when
12. 12
    workup.ADDITIONtreated with petroleum ether
13. 13
    その他The product crystallized slowly during overnight
14. 14
    その他It was recrystallized from THF and i-PrOH
15. 15
    その他to yield

実験手順

Boc-Asp(OBzl)-Thr(Bzl)-Ser(Bzl)-Ser(Bzl)-Glu(OBzl)-OH (50.0 g, 46 mmol) was deprotected with HCl (4.15 N) in THF and worked up as usual to give 45.4 g of white solid. It was dissolved in THF (1.5 liters) and treated with ether (7 liters). On standing at 0° overnight a white solid powder was obtained (44.0 g, mp 179°-184°). Part of this material, HCl.H-Asp(OBzl)-Thr(Bzl)-Ser(Bzl)-Ser(Bzl)-Glu(OBzl)-OH (43.7 g, 42.7 mmol) was then dissolved in 500 ml of DMF, cooled to 0°, and treated with Boc-Val-OSu (15.4 g, 49 mmol) and Et3N (10 ml). The mixture was stirred for 15 hours during which time more Et3N (7.9 ml) was added in several portions maintaining the reaction slightly basic. The insoluble matter was removed by filtration and the filtrate evaporated to dryness. The oily residue was dissolved in CH2Cl2, washed with 5% HOAc, H2O, dried (Na2SO4), and evaporated to a smaller volume (0.5 liter) when treated with petroleum ether. The product crystallized slowly during overnight standing. It was recrystallized from THF and i-PrOH to yield, 26.3 g (51.4%); mp 174°-177°; α]D25 =+0.84° (c, 1, THF).

出典