Sodium Hydroxide → Ddz-Gly-Ile-OH

Participants

Reaction Steps

10 g (23.56 mmoles) of Ddz-Gly-Ile-OMe are dissolved in a mixture of 24 ml of dioxane and 8 ml of water and are titrated with 1 N NaOH against thymolphthalein as the indicator. The consumption depends on the ethyl acetate content but is more than 23 ml. After neutralization with citric acid, the dioxane is distilled off. The residue is taken up in water and brought to pH 3 with 2 N citric acid at 0° C. The oil which precipitates is extracted with ethyl acetate. The aqueous phase is again acidified to pH 3 if necessary and is extracted with ethyl acetate. The combined ethyl acetate extracts are extracted by shaking once with water, dried over Na2SO4 and concentrated. The residue is dried in a high vacuum. The substance becomes amorphous.

Provenance & Evidence