Boron tribromide → 5-(1-Hexyl-cyclopentyl)resorcinol

HRID 269431Notes

Reaction equation

HRID 269431 reaction equation
C[O:2][C:3]1[CH:4]=[C:5]([C:11]2([CH2:16][CH2:17][CH2:18][CH2:19][CH2:20][CH3:21])[CH2:15][CH2:14][CH2:13][CH2:12]2)[CH:6]=[C:7]([O:9]C)[CH:8]=1.B(Br)(Br)Br>C(Cl)Cl>[CH2:16]([C:11]1([C:5]2[CH:4]=[C:3]([OH:2])[CH:8]=[C:7]([CH:6]=2)[OH:9])[CH2:15][CH2:14][CH2:13][CH2:12]1)[CH2:17][CH2:18][CH2:19][CH2:20][CH3:21]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 220662791-(3,5-Dimethoxyphenyl)-1-hexyl-cyclopentane

Product 1

HCID 109233555-(1-Hexyl-cyclopentyl)resorcinolYield 90%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 1-(3,5-dimethoxyphenyl)-1-hexyl-cyclopentane (1 equiv.) in dry methylene chloride (0.04M) at −78° C. under an argon atmosphere was added boron tribromide (2.5 equiv., 1M solution in methylene chloride). Following the addition, the reaction temperature was gradually raised over a period of 3 h to −20° C. Stirring was continued at that temperature until completion of the reaction. Unreacted boron tribromide was destroyed by addition of methanol and ice at 0° C. The resulting mixture was warmed at room temperature, stirred for 40 min and the solvent was removed in vacuo. The residual oil was diluted with ethyl acetate and the solution was washed with saturated sodium bicarbonate, water and brine. The organic layer was dried over MgSO4, filtered and concentrated under reduced pressure. Purification by flash column chromatography (40% diethyl ether-petroleum ether as eluent) afforded the title compound in 90% yield.

Workup

  1. additionthe addition
  2. temperaturethe reaction temperature was gradually raised over a period of 3 h to −20° C
  3. customwas continued at that temperature until completion of the reaction
  4. customUnreacted boron tribromide was destroyed by addition of methanol and ice at 0° C
  5. stirringstirred for 40 min
  6. customthe solvent was removed in vacuo
  7. additionThe residual oil was diluted with ethyl acetate
  8. washthe solution was washed with saturated sodium bicarbonate, water and brine
  9. dry with materialThe organic layer was dried over MgSO4
  10. filtrationfiltered
  11. concentrationconcentrated under reduced pressure
  12. customPurification by flash column chromatography (40% diethyl ether-petroleum ether as eluent)

Sources & evidence

ORD record
ord-cfb9367364a94727bfe71d5c22e9c932
Source dataset
uspto-grants-2008_11
Patent number
US07446229B2

Reaction notes

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