反应详情

To a solution of the crude ester (416 g, 1.77 mol) prepared in Example 2 in EtOH (1 L), was added a solution of NaOH (142 g, 3.54 mol) in water (1.5 L). The reaction mixture was heated to reflux, during which time the color changed to dark red, and the reaction became homogeneous. After 1 h, the reaction was cooled to rt, and the EtOH was removed under reduced pressure. The remaining basic aqueous layer was washed with Et2O (3×500 mL), then acidified with HCl (conc. aqueous solution) to pH˜4 at which point an oily residue formed. The mixture was then extracted with Et2O (4×500 mL), the combined extracts washed with water (2×300 mL) and brine, and then dried over Na2SO4. Filtration and evaporation of the solvents under reduced pressure gave the title compound (305 g, 83%) as a yellow solid after drying for 12 h under vacuum. 1H NMR (CDCl3) δ 7.34 (d, 1H), 6.71 (s, 1H), 6.65 (dd, 1H), 3.71 (s, 3H), 3.47 (m, 1H), 2.80 (m, 3H), 2.35 (m, 2H), 1.71 (m, 1H). MS (Cl) m/z 207 [M+H]+.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux, during which time the color
3. customthe EtOH was removed under reduced pressure
4. washThe remaining basic aqueous layer was washed with Et2O (3×500 mL)
5. customformed
6. extractionThe mixture was then extracted with Et2O (4×500 mL)
7. washthe combined extracts washed with water (2×300 mL) and brine
8. dry with materialdried over Na2SO4
9. filtrationFiltration and evaporation of the solvents under reduced pressure