反应详情

To a solution of 23 (0.36 g, 1.05 mmol) in MeOH (10 mL) and water (2 ml), lithium hydroxide (0.05 g, 2.11 mmol) was added. The reaction mixture was refluxed for 6 h and was then concentrated under reduced pressure to provide a residue. The residue was dissolved in water. 3N HCl was added up to acidic pH and the mixture was extracted with EtOAc (20 mL×3). The combined organic layer was dried over anhydrous MgSO4 and concentrated under reduced pressure to give a brown residue, which was recrystallized by EtOH to afford 24 (0.2 g). 1H NMR (500 MHz, CD3OD): δ 6.46 (d, J=15.8 Hz, 1H), 7.62-7.69 (m, 4H), 7.81 (s, 1H), 7.81 (d, J=16.0 Hz, 1H), 7.95 (d, J=8.4 Hz, 1H), 8.12 (d, J=7.3 Hz, 2H), 8.21 (s, 1H).

1. temperatureThe reaction mixture was refluxed for 6 h
2. concentrationwas then concentrated under reduced pressure
3. customto provide a residue
4. extractionthe mixture was extracted with EtOAc (20 mL×3)
5. dry with materialThe combined organic layer was dried over anhydrous MgSO4
6. concentrationconcentrated under reduced pressure
7. customto give a brown residue, which
8. customwas recrystallized by EtOH