反应详情

温度

0 °C

44 ml of 100% nitric acid, 44 ml of 97% sulfuric acid and 44 ml of trifluoroacetic anhydride are added in succession to a solution, cooled to 0° C., of 22 g (100.8 mmol) of 2,3-dimethoxy-quinoxaline-5-carbaldehyde in 88 ml of trifluoroacetic acid. The mixture is maintained at 0° C. for 2 hours and is then carefully poured onto a mixture of 4N NaOH and ice. The temperature should not exceed 20° C. The mixture is extracted with ethyl acetate. The organic phase is washed with an aqueous 1 N NaOH solution, water and brine and dried over sodium sulfate. Crystallization of the crude product yields the title compound in the form of light-yellow crystals. M.p.: 147-149° C.; TLC (EtOAc/hexane 1:3): Rf =0.25.

1. customexceed 20° C
2. extractionThe mixture is extracted with ethyl acetate
3. washThe organic phase is washed with an aqueous 1 N NaOH solution, water and brine
4. dry with materialdried over sodium sulfate
5. customCrystallization of the crude product