反应详情

温度

-13 °C

A solution of 2,5-difluorophenol (5 g, 38.4 mmol) in acetic acid (10 mL) was added slowly to a mixture of concentrated nitric acid (10 mL) and acetic acid (10 mL) cooled in an acetonitrile/dry ice bath in a manner that temperature did not exceed −18° C. After everything was added, solution was kept at −30° C. for 30 minutes, stirred at −13° C. for 30 minutes, and then at 0° C. for 1 hour. Solution was transferred into a separatory funnel, diluted with methylene chloride, and extracted three times with water. Organic phase was dried over magnesium sulfate, filtered, and concentrated. Residue was purified by column chromatography on SiO2 (hexane/acetyl acetate 1:1) to give 2,5-difluoro-4-nitro-phenol as a yellow solid (1.74 g, 26%). 1HNMR (MeOD, 400 MHz) δ 7.97-7.93 (m, 1H), 6.95-6.91 (m, 1H), 6.17 (s, 1H).

1. temperaturecooled in an acetonitrile/dry ice bath in a manner that temperature
2. customdid not exceed −18° C
3. additionAfter everything was added
4. waitat 0° C. for 1 hour
5. customSolution was transferred into a separatory funnel
6. extractionextracted three times with water
7. dry with materialOrganic phase was dried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated
10. customResidue was purified by column chromatography on SiO2 (hexane/acetyl acetate 1:1)