反应详情

温度

10 °C

The product from Example 52B (1.35 g, 5 mmol) in methanol (12 mL) was treated with concentrated sulfuric acid (2 mL) and heated to gentle reflux. After 2 hours, additional sulfuric acid was added (1 mL) and heating was continued for another 2 hours. The mixture was concentrated under vacuum and the residue was diluted with water (15 mL). The mixture was cooled to 10° C., filtered, and the filter cake washed with water (5 mL) and dried to provide the title compound. 1H NMR (CDCl3) δ 3.42 (s, 2H); 3.55 (s, 2H); 3.74 (s, 3H); 6.65 (m, 1H); 7.22-7.31 (m, 2H), 7.44 (m, 1H).

1. temperatureheated to gentle reflux
2. temperatureheating
3. waitwas continued for another 2 hours
4. concentrationThe mixture was concentrated under vacuum
5. additionthe residue was diluted with water (15 mL)
6. filtrationfiltered
7. washthe filter cake washed with water (5 mL)
8. customdried