反应详情

Boc-Thr(Bzl)-Lys(Z)-OH (14.0 g, 24.5 mmol) was treated with 500 ml of 4.0 N HCl in THF for 30 minutes, evaporated to dryness, and re-evaporated twice with fresh THF. The oily residue solidified when treated with ether. The dried powder (11.4 g, 21.6 mmol) of the dipeptide hydrochloride salt was then dissolved in 140 ml DMF, cooled to 0°, and treated with Boc-Thr(Bzl)-OSu (8.8 g, 21.6 mmol) followed by 3.5 ml of Et3N. A few drops of Et3N was added to maintain a slightly basic condition while the mixture was stirred for an additional 24 hours at 25°. It was acidified with 5 ml of HOAc and then diluted with a large volume of water. The solid crude product precipitated was collected, dissolved in EtOAc, washed with H2O, dried over Na2SO4, and evaporated to dryness, leaving a glassy solid mass. Crystallized from EtOAc and petroleum ether: yield, 13.8 g (83.7%); mp 110°- 112°; [α]D25 =+19.45° (c 1, EtOAc).

1. customevaporated to dryness
2. customre-evaporated twice with fresh THF
3. additiontreated with ether
4. temperaturecooled to 0°
5. temperatureto maintain a slightly basic condition while the mixture
6. customThe solid crude product precipitated
7. customwas collected
8. dissolutiondissolved in EtOAc
9. washwashed with H2O
10. dry with materialdried over Na2SO4
11. customevaporated to dryness
12. customleaving a glassy solid mass
13. customCrystallized from EtOAc and petroleum ether
14. customyield