反应详情

Nα -Benzyloxycarbonyl-D-alanyl-L-leucine methyl ester is prepared from 8.92 g. (40 mmol) of Nα -benzyloxycarbonyl-D-alanine, 7.28 g. (40 mmol) of L-leucine methyl ester hydrochloride and 5.4 g. (40 mmol) of 1-hydroxybenztriazole dissolved in 120 ml. of dimethylformamide. The solution is cooled and treated with 5.6 ml. (40 mmol) of triethylamine and then with 8.64 g. of dicyclohexylcarbodiimide. The reaction is stirred with cooling for several hours and then allowed to come to room temperature in the ice bath. It is stirred overnight at room temperature and filtered. The filtrate is evaporated at reduced pressure and the residue dissolved in 400 ml. of ethyl acetate and washed three times with 5 percent sodium bicarbonate solution, dilute hydrochloric acid, saturated salt solution, dried over magnesium sulfate and evaporated. The residue is crystallized from ether-petroleum ether, re-dissolved in ether, filtered and crystallized by addition of petroleum ether; 12.88 g.; m.p. 65°-68° C.

1. temperatureThe solution is cooled
2. additiontreated with 5.6 ml
3. temperaturewith cooling for several hours
4. stirringIt is stirred overnight at room temperature
5. filtrationfiltered
6. customThe filtrate is evaporated at reduced pressure
7. dissolutionthe residue dissolved in 400 ml
8. washof ethyl acetate and washed three times with 5 percent sodium bicarbonate solution, dilute hydrochloric acid, saturated salt solution
9. dry with materialdried over magnesium sulfate
10. customevaporated
11. customThe residue is crystallized from ether-petroleum ether
12. dissolutionre-dissolved in ether
13. filtrationfiltered
14. customcrystallized by addition of petroleum ether