反应详情

3-(Acetylthio)propanoic acid (2.96 g) and 1,1'-carboxyldiimidazole (3.24 g) are dissolved in 20 ml of dry tetrahydrofuran with stirring at room temperature. After twenty minutes, a solution of glycolic acid (1.52 g) and 2.80 ml of triethylamine in 15 ml of dry tetrahydrofuran are added. The reaction mixture is stored overnight at room temperature. The tetrahydrofuran is removed in vacuo, the crude residue taken up into ethyl acetate, washed with 1N hydrochloric acid and three times with water, dried over magnesium sulfate and the O-(3-acetylthiopropanoyl)glycolic acid is concentrated to dryness in vacuo, yield 3.9 g. This is dissolved in ether and dicyclohexylamine is added. The dicyclohexylamine salt precipitates, yield 2.85 g.; m.p. 150-157° . The salt is converted to the free acid by adding to ethyl acetate and adding 10% potassium bisulfate solution, yield 1.5 g.

1. waitAfter twenty minutes
2. customThe tetrahydrofuran is removed in vacuo
3. washwashed with 1N hydrochloric acid and three times with water
4. dry with materialdried over magnesium sulfate
5. concentrationthe O-(3-acetylthiopropanoyl)glycolic acid is concentrated to dryness in vacuo, yield 3.9 g
6. dissolutionThis is dissolved in ether
7. additiondicyclohexylamine is added
8. customThe dicyclohexylamine salt precipitates
9. additionby adding to ethyl acetate
10. additionadding 10% potassium bisulfate solution, yield 1.5 g