反应详情

温度

0 °C

Benzyloxycarbonylserine (8.4 g; 35 mmoles), N-ethylpiperidine (4.9 ml) and pyridine (3.5 ml) in dichlormethane (100 ml) cooled to -20° C. are treated under constant stirring with pivaloylchloride (4.4 ml); the mixture is stirred and cooled (0° C.) a further 8 minutes. After that, within 2 to 3 minutes, a solution of asparaginyl-phenylalanine methyl ester, liberated from its hydrobromide (13.1 g; 35 mmoles) by the addition of N-ethylpiperidine (4.9 ml), in dichloromethane (100 ml) is added. The reaction mixture is stirred for 2 hours at room temperature and evaporated. The noncrystalline residue is dissolved in ethyl acetate and the solution is successively washed with 1 M hydrochloric acid, water, 5% sodium hydrogencarbonate and water, dried over anhydrous sodium sulfate, and evaporated, after which the residue is crystallized from methanol. The yield is 9.1 g (51%), m.p. 180°-183° C. A sample is recrystallized from the same solvent and has m.p. 184°-186° C. Rf 0.71/S1, 0.82/S2. [α]D20 -13.8° (c 0.2; methanol). Composition: C25H30N4O8.

1. additionare treated
2. additionis added
3. stirringThe reaction mixture is stirred for 2 hours at room temperature
4. customevaporated
5. dissolutionThe noncrystalline residue is dissolved in ethyl acetate
6. washthe solution is successively washed with 1 M hydrochloric acid, water, 5% sodium hydrogencarbonate and water
7. dry with materialdried over anhydrous sodium sulfate
8. customevaporated
9. customafter which the residue is crystallized from methanol
10. customA sample is recrystallized from the same solvent