反应详情

10 g (23.56 mmols) of Ddz-Gly-Ile-OMe were dissolved in a mixture of 24 ml of dioxane and 8 ml of water and titrated with 1 N NaOH against thymolphthalein as indicator. Over 23 ml were consumed depending on the acetic acid content. After neutralization with citric acid, the dioxane was distilled off. The residue was taken up in water and a pH of 3 was adjusted at 0° C. with 2 N citric acid. If necessary, the aqueous phase was again acidified to pH 3 and extracted with ethyl acetate. The combined ethyl acetate extracts were shaken once with water, dried over Na2SO4, concentrated and dried again in a high vacuum. An amorphous substance was obtained. Yield 8.9 g (92%), m.p. 80°-90° C.

1. customOver 23 ml were consumed
2. distillationAfter neutralization with citric acid, the dioxane was distilled off
3. customwas adjusted at 0° C. with 2 N citric acid
4. extractionextracted with ethyl acetate
5. dry with materialdried over Na2SO4
6. concentrationconcentrated
7. customdried again in a high vacuum
8. customAn amorphous substance was obtained