反应详情

To a solution of the ketal of step D (11.5 g, 43.3 mmol) in THF (100 mL) was added 3N HCl (75 mL) and the solution stirred overnight at rt. The pH of the solution was adjusted to ˜11 by the addition of 3N NaOH solution. After removal of most of the THF by rotary evaporation, the aqueous was extracted with CH2Cl2 (3×). The combined extracts were dried (MgSO4), filtered, and concentrated to give the title compound as a yellow solid; yield 8.2 g, 37.1 mmol, 86%; 1H NMR (CDCl3) δ 8.26 (s, 1H), 7.75 (d, 1H), 6.73 (d, 1H), 3.91 (s, 3H), 2.91 (m, 2H), 2.78 (s, 1H), 2.32 (m, 2H), 2.21 (m, 4H); MS m/z=222.1.

1. customAfter removal of most of the THF
2. customby rotary evaporation
3. extractionthe aqueous was extracted with CH2Cl2 (3×)
4. dry with materialThe combined extracts were dried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated