The general procedure for the synthesis of 2-bromo-3-fluoro-6-nitrophenol using 2-bromo-1,3-difluoro-4-nitrobenzene as starting material was as follows: 2-bromo-1,3-difluoro-4-nitrobenzene (10.5 g, 44.1 mmol) was dissolved in DMSO (80 mL) and stirred at room temperature. Subsequently, an aqueous solution of KOH (12.4 g, 221 mmol) was slowly added dropwise (22 mL) over 15 min. After the dropwise addition, the reaction mixture was stirred at 30 °C overnight. The reaction progress was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was acidified to pH 4 with 2N HCl and then extracted with ethyl acetate (100 mL × 2) to isolate the target product. The organic phases were combined, washed sequentially with water and saturated brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure to afford 2-bromo-3-fluoro-6-nitrophenol as a yellow solid (10.5 g, >100% yield). The structure of the product was confirmed by 1H-NMR (300 MHz, CDCl3): δ (ppm): 6.82-6.86 (m, 1H), 8.15-8.22 (m, 1H), 11.41 (brs, 1H).
