反应详情

85% potassium hydroxide (40.6 g) was dissolved in water (615 mL) and mixed with dioxane (103 mL). A dioxane solution (103 mL) of the compound (25.0 g) obtained in Step 1 was added dropwise to the mixture at 90° C. over 60 minutes under nitrogen atmosphere and stirred at the same temperature for 20 minutes. With cooling the reaction solution with ice-water, the pH of the solution was adjusted to 9 with concentrated hydrochloric acid, the mixture was saturated with salt, and extracted with ethyl acetate. The organic layer was combined and dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. The residue was crystallized from hexane:ether and collected by filtration to obtain the titled compound (24.6 g) as crystals.

1. extractionextracted with ethyl acetate
2. dry with materialdried over anhydrous sodium sulfate
3. customthe solvent was removed under reduced pressure
4. customThe residue was crystallized from hexane
5. filtrationether and collected by filtration