Boron tribromide → 2',6'-Dichlorobiphenyl-2-ol

To a solution of 2′,6′-dichloro-1,1′-biphenyl-2-yl methyl ether (5.83 g, 0.023 mol) in anhydrous dichloromethane (100 mL) at 0° C. under nitrogen was added a solution of boron tribromide (1.0 M in dichloromethane, 27.6 mL, 0.0276 mol) dropwise over 40 minutes via a syringe pump. The reaction mixture was then stirred at room temperature for 17 hours, then quenched by the addition of absolute ethanol (50 mL). The mixture was stirred at room temperature for 1.5 hours then concentrated under reduced pressure to afford a dark oil. The oil was dissolved in 2.0 M aqueous sodium hydroxide solution (200 mL) and the resulting milky suspension extracted with diethyl ether (200 mL). The separated aqueous phase was then cooled to 0° C. and acidified to pH 1 by the addition of concentrated hydrochloric acid. The resulting milky suspension was extracted with ethyl acetate (300 mL), the separated organic phase washed with water (200 mL) and saturated brine (200 mL), dried over magnesium sulfate and concentrated under reduced pressure to afford a yellow oil. Purification by flash chromatography using a solvent gradient of 3 to 15% ethyl acetate in hexane gave 4.99 g (91%) of 2′,6′-dichloro-1,1′-biphenyl-2-ol as a white solid. MS (EI) m/z 238 (M+).

1. customquenched by the addition of absolute ethanol (50 mL)
2. stirringThe mixture was stirred at room temperature for 1.5 hours
3. concentrationthen concentrated under reduced pressure
4. customto afford a dark oil
5. extractionthe resulting milky suspension extracted with diethyl ether (200 mL)
6. temperatureThe separated aqueous phase was then cooled to 0° C.
7. additionacidified to pH 1 by the addition of concentrated hydrochloric acid
8. extractionThe resulting milky suspension was extracted with ethyl acetate (300 mL)
9. washthe separated organic phase washed with water (200 mL) and saturated brine (200 mL)
10. dry with materialdried over magnesium sulfate
11. concentrationconcentrated under reduced pressure
12. customto afford a yellow oil
13. customPurification by flash chromatography

ORD record

ord-16dfe450db58401db63c45e8bea6c427

Source dataset

uspto-grants-2008_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07365095B2