Boron tribromide → 2-Fluoro-5-nitrophenol

HRID 218530Notes

Reaction equation

HRID 218530 reaction equation
B(Br)(Br)Br.[F:5][C:6]1[CH:11]=[CH:10][C:9]([N+:12]([O-:14])=[O:13])=[CH:8][C:7]=1[O:15]C>C(OCC)(=O)C>[F:5][C:6]1[CH:11]=[CH:10][C:9]([N+:12]([O-:14])=[O:13])=[CH:8][C:7]=1[OH:15]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 144519681-Fluoro-2-methoxy-4-nitrobenzene

Product 1

HCID 234981002-Fluoro-5-nitrophenol

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

116 ml (116 mmol) of boron tribromide (1 molar solution in dichloromethane) are added dropwise at −10° C. over a period of 1 h to a solution of 5.00 g (29.2 mmol) of 1-fluoro-2-methoxy-4-nitrobenzene at such a rate that the temperature does not exceed −5° C. The solution is left at 0° C. for 5 h, then added slowly to 600 ml of ice-water and diluted with 100 ml of ethyl acetate. After phase separation, the aqueous phase is extracted twice with ethyl acetate. The combined organic phases are dried over sodium sulfate. After filtration, the solvents are removed under reduced pressure. The residue is purified by chromatography on silica gel (10:1 cyclohexane/ethyl acetate). This affords 1.45 g (30% of theory) of the desired compound.

Workup

  1. customdoes not exceed −5° C
  2. customAfter phase separation
  3. extractionthe aqueous phase is extracted twice with ethyl acetate
  4. dry with materialThe combined organic phases are dried over sodium sulfate
  5. filtrationAfter filtration
  6. customthe solvents are removed under reduced pressure
  7. customThe residue is purified by chromatography on silica gel (10:1 cyclohexane/ethyl acetate)

Sources & evidence

ORD record
ord-4ce511ad68cd444fbc1213dc2ef767a3
Source dataset
uspto-grants-2012_06
Patent number
US08198267B2

Reaction notes

Loading…