反应详情

A solution of Z-Asp(OtBu)-OSu (115.6 g; 0.275 mol) in DMF (1.16 L) was stirred at 0° in a 3 L, 3-necked round bottom flask fitted with a mechanical stirrer and thermometer. The H-Leu-Lys(Boc)-OH (89.86 g; 0.250 mol) was added followed by Et3N (35.2 mL; 0.25 mol). The reaction mixture was stirred at 0° for 0.5 h and at 25° for 1.5 h. Additional Et3N (17 mL) was added (to maintain pH 8) and the reaction mixture stirred at 25° for 20 H. The reaction mixture was evaporated, dissolved in EtOAc (3 L), washed with 1M citric acid (3×1 L), H2O (3×1 L), dried (MgSO4) and evaporated in vacuo. The residual paste was dissolved in anhydrous ether (5 L) and stirred magnetically while DCHA (53.5 mL; 0.268 mol) was added slowly. After standing in the cold room (20 h) the white salt was collected and washed with anhydrous ether (2×0.5 L) and petroleum ether (2×0.5 L). Yield: 177 g (84%); m.p. 173°-174°; [α]D25 -12.57° (c 1, MeOH).

1. customfitted with a mechanical stirrer
2. temperature(to maintain pH 8)
3. stirringthe reaction mixture stirred at 25° for 20 H
4. customThe reaction mixture was evaporated
5. dissolutiondissolved in EtOAc (3 L)
6. washwashed with 1M citric acid (3×1 L), H2O (3×1 L)
7. dry with materialdried (MgSO4)
8. customevaporated in vacuo
9. dissolutionThe residual paste was dissolved in anhydrous ether (5 L)
10. additionwas added slowly
11. customAfter standing in the cold room (20 h)
12. customwas collected
13. washwashed with anhydrous ether (2×0.5 L) and petroleum ether (2×0.5 L)