反应详情

A solution of 7-methoxy-3-methyl-1H-quinoxalin-2-one (125 g, 631 mmol, 1.0 eq) in phosphorus oxychloride (800 mL) is heated under reflux for 1 hour. Then the reaction mixture is cooled down to room temperature and the solvent is evaporated. The residue is poured into ice water and the resulting mixture is neutralized with 20% sodium hydroxide aqueous solution. The resulting precipitate is collected by filtration, washed with water to give a crude product that is purified by column chromatography (silica gel, eluent: petroleum ether:ethyl acetate, 100:1, v/v) to afford 3-chloro-6-methoxy-2-methyl-quinoxaline as a white solid (44.4 g, 34% yield).

1. temperatureunder reflux for 1 hour
2. customthe solvent is evaporated
3. additionThe residue is poured into ice water
4. filtrationThe resulting precipitate is collected by filtration
5. washwashed with water
6. customto give a crude product that
7. customis purified by column chromatography (silica gel, eluent