反应详情

Methyl 3,3-bis(ethoxycarbonyl)-4-[2',5'-dimethoxy-4'-(4"-methoxy-3"-phthalido)] phenylbutyrate III) (25 g., 0.046 mole) is taken up in tetrahydrofuran (200 ml.) and methanol (200 ml.); an aqueous solution of potassium hydroxide (3.35 g., 0.060 mole, 200 ml.) is added thereto. The mixture is heated under reflux for 4 days and the solvent substantially removed thereafter by evaporation under reduced pressure. The residue is acidified with dilute aqueous hydrochloric acid (1 N, 100 ml.) and extracted with methylenechloride (300 ml.) the organic phase is washed with water (100 ml.), dried over anhydrous magnesium sulfate, filtered, and the solvent removed from the filtrate under reduced pressure to yield 3,3-Bis(ethoxycarbonyl)-4-[2',5'-dimethoxy-4'-(4"-methoxy-3"-phthalido)] phenylbutyric acid, (IV) m.p. 105°-109° C., I.R. (Nujol), 2600, 2800 (broad for CO2H), 1750 (CO of the lactone), 1730 (CO of the ester), 1698 (CO of the CO2H) cm-1.

1. temperatureThe mixture is heated
2. temperatureunder reflux for 4 days
3. customthe solvent substantially removed
4. customby evaporation under reduced pressure
5. extractionextracted with methylenechloride (300 ml.) the organic phase
6. washis washed with water (100 ml.)
7. dry with materialdried over anhydrous magnesium sulfate
8. filtrationfiltered
9. customthe solvent removed from the filtrate under reduced pressure