反应详情

5 g (9.8 mmole) of the methyl ester from Example 6 was placed in a 250 ml round bottom flask and warmed in 100 ml of methyl alcohol to effect dissolution. After cooling to room temperature, 7.5 ml of 2M LiOH was added and the reaction mixture stirred for 3 hours. Solvent was stripped on the rotary evaporator and water added. The solution was acidified to pH 2 with hydrochloric acid, and the resultant gummy mass was extracted with ethyl acetate-ether, washed once with water then with brine, and dried over Na2SO4. After filtration, the solvent was removed on the rotary evaporator under vacuum at room temperature. Recrystalization form ethyl alcohol gave 3.84 g (79% yield), mp 66°-68° C., of the title compound. Calc: C, 69.86; H, 7.76; Found: C, 70.05; H, 7.68.

1. dissolutiondissolution
2. customSolvent was stripped on the rotary evaporator and water
3. additionadded
4. extractionthe resultant gummy mass was extracted with ethyl acetate-ether
5. washwashed once with water
6. dry with materialwith brine, and dried over Na2SO4
7. filtrationAfter filtration
8. customthe solvent was removed on the rotary evaporator under vacuum at room temperature
9. customRecrystalization
10. customform ethyl alcohol
11. customgave 3.84 g (79% yield), mp 66°-68° C.