Carbon Dioxide → 6-Bromo-2,3-difluorobenzoic acid

Temperatur

-78 °C

A solution of 1.6M butyllithium in hexane (60 mL, 96 mmol) was diluted with tetrahydrofuran (180 mL) under an argon atmosphere, and cooled to −78° C. To the solution, were added dropwise 2,2,6,6-tetramethylpiperidine (16.2 g, 116 mmol) and subsequently 4-bromo-1,2-difluorobenzene (15.4 g, 80 mmol), and the mixture was stirred at the same temperature for 2 hours. The solution was carefully poured onto crushed dry ice, and the mixture was allowed to warm to room temperature. The solution was concentrated under reduced pressure, and the residue was poured into water. After the solution was washed with diethylether, the aqueous layer was made acidic by the addition of 6N hydrochloric acid, and organic matter was extracted with dichloromethane. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give the title compound (10.8 g, 57% yield).

1. additionThe solution was carefully poured
2. temperatureto warm to room temperature
3. concentrationThe solution was concentrated under reduced pressure
4. additionthe residue was poured into water
5. washAfter the solution was washed with diethylether
6. additionthe aqueous layer was made acidic by the addition of 6N hydrochloric acid, and organic matter
7. extractionwas extracted with dichloromethane
8. washThe extract was washed with saturated brine
9. dry with materialdried over anhydrous magnesium sulfate
10. concentrationconcentrated under reduced pressure

ORD-Eintrag

ord-f2347a8cfb674342bc9bcef92b938f7e

Quelldatensatz

uspto-grants-2005_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06949648B2