反应详情

The product of Example 10 is saponified according to the procedure of Example 2 using 5.3 g (10 mmol) of the above ester and 2M LiOH solution (12.5 ml, 2.5 eq.) in ethanol (50 ml). After stirring overnight at room temperature, the solvent is removed in vacuo and the residue diluted with water. After acidification to pH 2.5 with 0.5N KHSO4, the mixture is extracted with ethyl acetate and dried over magnesium sulfate. The drying agent is filtered and the filtrate is concentrated in vacuo. Further drying of the resultant residue at 60° (0.5 torr) gives the titled compound.

1. customthe solvent is removed in vacuo
2. additionthe residue diluted with water
3. extractionAfter acidification to pH 2.5 with 0.5N KHSO4, the mixture is extracted with ethyl acetate
4. dry with materialdried over magnesium sulfate
5. filtrationThe drying agent is filtered
6. concentrationthe filtrate is concentrated in vacuo
7. dry with materialFurther drying of the resultant residue at 60° (0.5 torr)