4-BROMO-2,3-DIFLUOROBENZOIC ACID synthesis

Yield:194804-91-6 97%

Reaction Conditions:

Stage #1:1-bromo-2,3-difluorobenzene with n-butyllithium;diisopropylamine in tetrahydrofuran;hexane at -78 - 0; for 1 h;
Stage #2:carbon dioxide in tetrahydrofuran;hexane at 20; for 1 h;

Steps:

2
Diisopropylamine (1.5 mL, 11 mmol) is dissolved in THF (8.0 mL), and n-butyllithium (2.69 M hexane solution, 4.1 mL, 11 mmol) is added dropwise thereto at 0 ° C.The mixture was stirred for 15 minutes. After stirring, this was cooled to -78 ° C. 1-Bromo-2,3-difluorobenzene (1.1 mL, 10 mmol) dissolved in THF (10 mL) was added dropwise to the cooled solution, and the mixture was stirred for 1 hour to obtain a reaction mixture. After stirring, dry ice (excess amount) was added to the reaction mixture, the temperature was raised to room temperature, and the mixture was stirred for 1 hour. 6.0M hydrochloric acid (5 mL) was added to the reaction mixture, and the reaction product was extracted with diethyl ether (20 mL × 2). After washing the reaction product with distilled water (20 mL) and saturated brine (20 mL), the organic layer was dried over magnesium sulfate and concentrated under reduced pressure to obtain a white solid.

References:

Tosoh Corp;Sagami Chemical Research Institute;Inoue, Munenobu;Araki, Keisuke;Ogawa, Hiroshi;Kobayashi, Wataru JP2015/151350, 2015, A Location in patent:Paragraph 0071-0075

FullText