Boron tribromide → 5-Bromo-4'-fluoro[1,1'-biphenyl]-2-ol

A mixture of 4′-fluoro[1,1′-biphenyl]-2-yl methyl ether (107 g), pyridinium hydrobromide perbromide (34.0 g) and water-acetic acid-diethyl ether mixed solution (1:4:5, 500 ml) was stirred for 18 h at room temperature. Hypowater was added to the reaction mixture and the mixture was concentrated. The resulting crystals were collected by filtration to give a crude product (15.2 g) of 5-bromo-4′-fluoro[1,1′-biphenyl]-2-yl methyl ether as a yellow solid. To a solution of this product (14.1 g) in dichloromethane (150 ml) was added dropwise a solution of boron tribromide (5.69 ml) in dichloromethane (40 ml) at −78° C., and the mixture was stirred at room temperature ifor 18 h. The reaction mixture was poured into ice and the organic layer was separated, neutralized with aqueous sodium hydrogen carbonate, washed with brine and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure and the residue was purified by silica gel chomatography (eluent;hexane→hexane:ethyl acetate=5:1) to give the title compound (13.2 g) as a colorless oil.

1. additionHypowater was added to the reaction mixture
2. concentrationthe mixture was concentrated
3. filtrationThe resulting crystals were collected by filtration
4. customto give a crude product (15.2 g) of 5-bromo-4′-fluoro[1,1′-biphenyl]-2-yl methyl ether as a yellow solid
5. stirringthe mixture was stirred at room temperature ifor 18 h
6. additionThe reaction mixture was poured into ice
7. customthe organic layer was separated
8. washwashed with brine
9. dry with materialdried over anhydrous sodium sulfate
10. customThe solvent was evaporated under reduced pressure
11. customthe residue was purified by silica gel chomatography (eluent;hexane→hexane:ethyl acetate=5:1)

ORD record

ord-e53c52d973644b8ea6ee279585f6bab4

Source dataset

uspto-grants-2003_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06518257B1