Boron tribromide → 3-Bromo-5-nitrophenol

HRID 990194Notes

Reaction equation

HRID 990194 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([O:11]C)[CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[CH:7]=1.B(Br)(Br)Br>C(Cl)Cl>[Br:1][C:2]1[CH:3]=[C:4]([OH:11])[CH:5]=[C:6]([N+:8]([O-:10])=[O:9])[CH:7]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 122990761-Bromo-3-methoxy-5-nitrobenzene

Product 1

HCID 104889843-Bromo-5-nitrophenol

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
0 °C

Procedure

A solution of 3-bromo-5-nitroanisole, as described above in Step B, (2.4 g, 10.3 mmol) in methylene chloride (50 mL) was cooled to 0° C. and treated with boron tribromide (1M in CH2Cl2, 158 mL, 158 mmol), giving a clear purple solution. The reaction was warmed slowly to room temperature and stirred at room temperature overnight and heated at reflux for 2.5 hours. The reaction was poured into ice/water, the layers were separated and extracted with methylene chloride. The aqueous layer was neutralized with aqueous saturated NaHCO3 and extracted with ethyl acetate. The organic layers were combined, dried (MgSO4), filtered and concentrated in vacuo. This material was purified by column chromatography (10:1 to 5:1 hexane:ethyl acetate). The fractions containing the product contaminated with the bromoanisole were pooled, concentrated and purified using radial, thin layer chromatography (hexane to 5:1 hexane:ethyl acetate) to give 3-bromo-5-nitrophenol as a yellow solid.

Workup

  1. customgiving a clear purple solution
  2. temperatureThe reaction was warmed slowly to room temperature
  3. temperatureheated
  4. temperatureat reflux for 2.5 hours
  5. customthe layers were separated
  6. extractionextracted with methylene chloride
  7. extractionextracted with ethyl acetate
  8. dry with materialdried (MgSO4)
  9. filtrationfiltered
  10. concentrationconcentrated in vacuo
  11. customThis material was purified by column chromatography (10:1 to 5:1 hexane:ethyl acetate)
  12. additionThe fractions containing the product
  13. concentrationconcentrated
  14. custompurified

Sources & evidence

ORD record
ord-66447f540a304f5782be09430f070979
Source dataset
uspto-grants-2002_10
Patent number
US06458935B1

Reaction notes

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