反应详情

Boc-Ser(Bzl)-Ser(Bzl)-Glu(OBzl)-OH (71.6 g, 104 mmol) was treated with 2.7 liters of freshly prepared 3.9 N HCl in THF for 45 minutes. The mixture was evaporated to dryness and the residue evaporated twice more with THF to give a solid mass (59.3 g; mp 161°-165°). It was collected and washed with ether and stirred in 500 ml of DMF with Boc-Thr(Bzl)-OSu (38.2 g, 94 mmol) in the presence of Et3N (25 ml) at 0° for 1 hour and then at 25° for 15 hours. More Et3N (14.5 ml) was added in serveral portions during this time to maintain the reaction slightly basic. Some insoluble matter formed was filtered off and the filtrate evaporated to an oil which was dissolved in EtOAc (1.5 liters), washed with 5% HOAc, H2O (2 times), dried (Na2SO4), and evaporated to a solid mass. The product was recrystallized from EtOAc and petroleum ether to yield, 64.8 g (78.1%); mp 115°-118°; [α]D25 =+11.64° (c 1, DMSO).

1. customThe mixture was evaporated to dryness
2. customthe residue evaporated twice more with THF
3. customto give a solid mass (59.3 g; mp 161°-165°)
4. customIt was collected
5. washwashed with ether
6. temperatureto maintain
7. customthe reaction slightly basic
8. customSome insoluble matter formed
9. filtrationwas filtered off
10. customthe filtrate evaporated to an oil which
11. dissolutionwas dissolved in EtOAc (1.5 liters)
12. washwashed with 5% HOAc, H2O (2 times)
13. dry with materialdried (Na2SO4)
14. customevaporated to a solid mass
15. customThe product was recrystallized from EtOAc and petroleum ether
16. customto yield