反应详情

A mixture of 7-fluoro-quinoxalin-2-ol (2.60 g, 15.84 mmol, 1.0 eq) and phosphorus oxychloride (50 mL, 536.4 mmol, 34.0 eq) is refluxed for 1 hour, then concentrated, diluted with water (60 mL), basified to pH 7 by adding saturated sodium hydrogen carbonate aqueous solution, and extracted with ethyl acetate (3×100 mL). The combined organic layers are dried over sodium sulfate, filtered and concentrated to give a crude that is purified by column chromatography (silica gel, eluent: ethyl acetate:petroleum ether, 1:20, v/v) to afford 2-chloro-7-fluoro-quinoxaline as a white solid (2.50 g, 84% yield).

1. temperatureis refluxed for 1 hour
2. concentrationconcentrated
3. additiondiluted with water (60 mL)
4. additionby adding saturated sodium hydrogen carbonate aqueous solution
5. extractionextracted with ethyl acetate (3×100 mL)
6. dry with materialThe combined organic layers are dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated
9. customto give a crude that
10. customis purified by column chromatography (silica gel, eluent