Boron tribromide → 3,5-Difluoro-4-(4-trifluoromethyl-pyrazol-1-yl)-phenol

HRID 537587Notes

Reaction equation

HRID 537587 reaction equation
[F:1][C:2]1[CH:7]=[C:6]([O:8]C)[CH:5]=[C:4]([F:10])[C:3]=1[N:11]1[CH:15]=[C:14]([C:16]([F:19])([F:18])[F:17])[CH:13]=[N:12]1.B(Br)(Br)Br>ClCCl>[F:1][C:2]1[CH:7]=[C:6]([OH:8])[CH:5]=[C:4]([F:10])[C:3]=1[N:11]1[CH:15]=[C:14]([C:16]([F:18])([F:19])[F:17])[CH:13]=[N:12]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 681564661-(2,6-Difluoro-4-methoxy-phenyl)-4-trifluoromethyl-1H-pyrazole

Product 1

HCID 681573243,5-Difluoro-4-(4-trifluoromethyl-pyrazol-1-yl)-phenolYield 88%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

1-(2,6-Difluoro-4-methoxy-phenyl)-4-trifluoromethyl-1H-pyrazole (278 mg, 0.999 mmol) was dissolved in dichloromethane (3 mL). Boron tribromide (20.0 mL, 1.0 M in DCM, 20.0 mmol) was added and the reaction was refluxed. At 42 h, the reaction was cooled in an ice bath and slowly quenched with methanol. The combined materials were then concentrated and partitioned between ethyl acetate and sat. NaHCO3. The aqueous layer was extracted with ethyl acetate and the combined organics dried over MgSO4. Purification by silica gel flash chromatography (ethyl acetate in heptane) gave 3,5-difluoro-4-(4-trifluoromethyl-pyrazol-1-yl)-phenol (0.231 g, 88%) as a tan oil that solidified upon standing. 1H NMR (400 MHz, CDCl3, δ): 7.99 (s, 1H) 7.90 (s, 1H) 6.50-6.60 (m, 2H); MS (M+1): 265.2.

Workup

  1. temperaturethe reaction was refluxed
  2. temperaturethe reaction was cooled in an ice bath
  3. customslowly quenched with methanol
  4. concentrationThe combined materials were then concentrated
  5. custompartitioned between ethyl acetate and sat. NaHCO3
  6. extractionThe aqueous layer was extracted with ethyl acetate
  7. dry with materialthe combined organics dried over MgSO4
  8. customPurification by silica gel flash chromatography (ethyl acetate in heptane)

Sources & evidence

ORD record
ord-679c7fa0320345289ee3550da2fcf721
Source dataset
uspto-grants-2014_10
Patent number
US08859591B2

Reaction notes

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