反应详情

温度

20 °C

4-Methylmorpholine (12.62 g, 124.8 mmol), Boc-Leucine monohydrate (29.92, 120.0 mmol) and HOBt (1.62 g, 12.0 mmol) were added to a solution of H-Leu-OMe.HCl (21.80 g, 120.0 mmol) in ethyl acetate (205 g). A solution of DCC (29.71 g, 144.0 mmol) in ethyl acetate (25.0 g) was added at 0 to 5° C. over 30 min and the resulting mixture was stirred over 2 h at a maximum temperature of 20° C. The resulting urea was removed by filtration and washed with ethyl acetate and the combined organic filtrate was extracted with successive portions of 5% aq. K2CO3 and 5% aq. KHSO4. The organic layer was dried (MgSO4), concentrated in vacuo, and the residual solid was recrystallized from petroleum ether (bp 100-125° C.) to give Boc-Leu-Leu-OMe (38.6 g, 89.8%).

1. customThe resulting urea was removed by filtration
2. washwashed with ethyl acetate
3. extractionthe combined organic filtrate was extracted with successive portions of 5% aq. K2CO3 and 5% aq. KHSO4
4. dry with materialThe organic layer was dried (MgSO4)
5. concentrationconcentrated in vacuo
6. customthe residual solid was recrystallized from petroleum ether (bp 100-125° C.)