3-Bromo-2,6-difluorobenzonitrile synthesis

Yield: 71%

Reaction Conditions:

with potassium bromate;sulfuric acid at 35;Inert atmosphere;

Steps:

1.1 Preparation of 3-bromo-2,6-difluorophenyl nitrile
2 L four-necked flask, 600mL60% sulfuric acid was added, with stirring was added 2,6-difluorobenzonitrile 139.0g (1.0mol), in N₂Under protection, control of the reaction temperature below 35°C, points added 250.5g of KBrO3 10 portions(1.5mol), TLC monitoring, the reaction 5-6 days, until starting material disappeared point, the reaction was stopped, the ice preparation 800mL20% saline solution, the reaction mixture was poured into iced brine.After settlement products, quickly suction filtration to give a crude orange product with CCl₄The crude product was dissolved, respectively, with 5% NaHSO₃Solution, saturated Na₂CO₃Solution was washed with water until the solution was neutral, dried over anhydrous sodium sulfate, the solution was filtered, 60 water bath rotary evaporation to give a pale yellow liquid was cooled to a standstill for some time as a pale yellow solid, distillation under reduced pressure, condensed steam heated, oil bath was raised to 90 deg.] C, taking the temperature of 58-62°C steam fraction, and cooled to obtain a white solid product, 71% yield.

References:

Tianjin Normal University;SONG, FANBO;ZHANG, ZHONGBIAO;LI, HUAYUN;TANG, HONGYING;WANG, ZHIQIANG;SONG, AIRU CN104004016, 2016, B Location in patent:Paragraph 0043; 0044; 0045