Phosphorus oxychloride → 2-Chloro-7-fluoroquinoxaline

Participants

Reaction Steps

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).

Provenance & Evidence