Phosphorus tribromide → 4-(2-Bromoethyl)benzonitrile

HRID 1584167Notes

Reaction equation

HRID 1584167 reaction equation
P(Br)(Br)[Br:2].[C:5]([C:7]1[CH:15]=[CH:14][C:10]([CH2:11][CH2:12]O)=[CH:9][CH:8]=1)#[N:6]>C(Cl)(Cl)(Cl)Cl>[C:5]([C:7]1[CH:15]=[CH:14][C:10]([CH2:11][CH2:12][Br:2])=[CH:9][CH:8]=1)#[N:6]

Participants

4

Reactant 2

HCID 24614Phosphorus tribromideHCID 28008154-(2-Hydroxyethyl)benzonitrile

Product 1

HCID 128865484-(2-Bromoethyl)benzonitrile

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent2×

Procedure

A solution of phosphorus tribromide (5 g) in carbon tetrachloride (10 ml) was added, dropwise, to a solution of 4-cyanophenethyl alcohol (8.06 g) in carbon tetrachloride (60 ml). The mixture was heated under reflux for 4 hours. On cooling to room temperature, the mixture was poured onto ice (200 g). the layers were separated and the organic layer was washed with 10% aqueous sodium carbonate (50 ml) and brine (50 ml), dried (MgSO4) and concentrated in vacuo to give a colourless oil which solidified on standing. The solid was chromatographed on silica eluting with ethyl acetate containing hexane (20%). The fractions containing the less polar (higher Rf) produce were combined and concentrated in vacuo to give 4-cyanophenethyl bromide as a yellow oil which solidified on standing, yield 8.9 g. The fractions containing the more polar (lower Rf) product were combined and concentrated in vacuo to give the title compound as a colourless solid, yield 0.47 g, m.p. 152-153°.

Workup

  1. temperatureThe mixture was heated
  2. temperatureunder reflux for 4 hours
  3. additionthe mixture was poured onto ice (200 g)
  4. customthe layers were separated
  5. washthe organic layer was washed with 10% aqueous sodium carbonate (50 ml) and brine (50 ml)
  6. dry with materialdried (MgSO4)
  7. concentrationconcentrated in vacuo
  8. customto give a colourless oil which
  9. customThe solid was chromatographed on silica eluting with ethyl acetate
  10. additioncontaining hexane (20%)
  11. additionThe fractions containing the less polar (higher Rf)
  12. customproduce
  13. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-5713f234d2b64d02a1e31354558eb471
Source dataset
uspto-grants-1999_08
Patent number
US05932594

Reaction notes

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