反应详情

温度

45 °C

Concentrated nitric acid (70% w/w) (0.72 mL, 11.2 mmol) in glacial acetic acid (2 mL) was added dropwise to a solution of 2,3-difluoro-4-hydroxy-benzoic acid methyl ester [Gonzales, Javier et al., PCT Int. Appl. (1999), 551 pp. WO 9901423 A1 19990114] (2 g, 10.6 mmol) in glacial acetic acid (28 mL). The mixture was stirred at 45° C. for 0.5 hour and then at room temperature overnight before it was evaporated to a quarter of the volume in vacuo. Water was added to the concentrate to give a solid precipitate which was filtered, washed with water twice and dried to give the title compound (2.2 g, 88%) as a colourless solid.

1. customat room temperature overnight before it was evaporated to a quarter of the volume in vacuo
2. additionWater was added to the
3. concentrationconcentrate
4. customto give a solid precipitate which
5. filtrationwas filtered
6. washwashed with water twice
7. customdried