Phosphorus oxychloride → 6-Bromo-1,1,4,4,7-pentamethyl-1,4-dihydronaphthalene

HRID 1836906Notes

Reaction equation

HRID 1836906 reaction equation
[Br:1][C:2]1[C:11]([CH3:12])=[CH:10][C:9]2[C:8]([CH3:14])([CH3:13])[CH:7](O)[CH2:6][C:5]([CH3:17])([CH3:16])[C:4]=2[CH:3]=1.P(Cl)(Cl)(Cl)=O>N1C=CC=CC=1>[Br:1][C:2]1[C:11]([CH3:12])=[CH:10][C:9]2[C:8]([CH3:14])([CH3:13])[CH:7]=[CH:6][C:5]([CH3:17])([CH3:16])[C:4]=2[CH:3]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 23498899HCID 23498899, compound

Product 1

HCID 109568496-Bromo-1,1,4,4,7-pentamethyl-1,4-dihydronaphthaleneYield 87%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

To a solution of 15.3 g (51.5 mmol) of 2-bromo-3-methyl-6-hydroxy-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene in 120 ml of pyridine was added 17.9 ml (192 mmol) of phosphorus oxychloride. The reaction mixture was heated to 100°. After 6 h, cooled to room temperature and carefully poured onto ice with stirring. After 1 h, extracted with ethyl acetate, washed with 2 N HCl and brine, dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by gravity chromatography (gradient elution: hexane-10% ethyl acetate/hexane) to afford 12.5 g (87%) of 2-bromo-3,5,5,8,8-pentamethyl-5,8-dihydronaphthalene.

Workup

  1. temperatureThe reaction mixture was heated to 100°
  2. additioncarefully poured onto ice
  3. waitAfter 1 h
  4. extractionextracted with ethyl acetate
  5. washwashed with 2 N HCl and brine
  6. dry with materialdried over sodium sulfate
  7. concentrationconcentrated under reduced pressure
  8. customThe residue was purified by gravity chromatography (gradient elution: hexane-10% ethyl acetate/hexane)

Sources & evidence

ORD record
ord-06d71a715c3245eebe71754cfce36a3b
Source dataset
uspto-grants-2004_08
Patent number
US06777418B2

Reaction notes

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