反应详情

2-Chloro-nicotinic acid ethyl ester (10 g), benzo[1,3]dioxol-5-ol (sesamol, 8.2 g), and cesium carbonate (21 g) were mixed in anhydrous dioxane (40 mL) and the resulting slurry heated to reflux for 16 h. In a separate flask, lithium hydroxide (12.9 g) was dissolved in water (80 mL) with warming and then added to the refluxing mixture, which was heated for an additional 4 h. The mixture was cooled to ambient temperature and concentrated in vacuo to remove the dioxane. Concentrated hydrochloric acid was added dropwise until the pH=3. The acidified solution was then extracted with ethyl acetate (7×100 mL) to yield crude product, which was recrystallized from ethyl acetate to yield the purified title compound (10.8 g).

1. temperaturethe resulting slurry heated
2. temperatureto reflux for 16 h
3. temperaturewith warming
4. additionadded to the refluxing mixture, which
5. temperaturewas heated for an additional 4 h
6. concentrationconcentrated in vacuo
7. customto remove the dioxane
8. additionConcentrated hydrochloric acid was added dropwise until the pH=3
9. extractionThe acidified solution was then extracted with ethyl acetate (7×100 mL)
10. customto yield crude product, which
11. customwas recrystallized from ethyl acetate
12. customto yield the
13. custompurified title compound (10.8 g)