Carbon Dioxide → 4-Bromo-2,5-difluorobenzoic acid

Temperatur

-78 °C

A solution of 1,4-dibromo-2,5-difluorobenzene (640 mg, 2.35 mmol) in dry diethyl ether (10 mL) cooled in a dry ice-acetone bath was treated dropwise with 2.5 M n-butyllithium in hexanes (1.04 mL, 2.59 mmol). The solution was stirred at −78° C. for 30 min, then was treated with a piece of dry ice. The cooling bath was removed after 5 min and the mixture was stirred for another 30 min while warming to room temperature. The mixture was diluted with EtOAc and water. The organic phase was separated and washed twice with saturated aqueous NaHCO3. The combined aqueous phases were acidified with 1M aqueous HCl, extracted twice with DCM, and the combined organic phases were dried and concentrated to give 4-bromo-2,5-difluorobenzoic acid as a white solid (297 mg, 53% yield).

1. customThe cooling bath was removed after 5 min
2. stirringthe mixture was stirred for another 30 min
3. temperaturewhile warming to room temperature
4. additionThe mixture was diluted with EtOAc and water
5. customThe organic phase was separated
6. washwashed twice with saturated aqueous NaHCO3
7. extractionextracted twice with DCM
8. customthe combined organic phases were dried
9. concentrationconcentrated

ORD-Eintrag

ord-5e76969404fd4db6871fcd7917306608

Quelldatensatz

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09334290B2