Hydrochloric Acid → 7-Bromo-4,4-dimethylchroman

HRID 2415181Notes

Reaction equation

HRID 2415181 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([CH:12]=[CH:13][CH:14]=1)[O:5][CH2:6][CH2:7][C:8]([CH3:11])(O)[CH3:9].[Cl-].[Al+3].[Cl-].[Cl-].Cl>[N+](C)([O-])=O>[Br:1][C:2]1[CH:3]=[C:4]2[C:12]([C:8]([CH3:11])([CH3:9])[CH2:7][CH2:6][O:5]2)=[CH:13][CH:14]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 6451240Aluminum(III) ChlorideHCID 22640696HCID 22640696, compound

Product 1

HCID 223931007-Bromo-4,4-dimethylchromanYield 87.2%

Reagents, catalysts & solvents 1

HCID 6375NitromethaneSolvent2×

Procedure

A solution of 4-(3-bromo-phenoxy)-2-methyl-butan-2-ol (5.741 g, 22.2 mmole) in 45 mL of nitromethane was added dropwise to a suspension of aluminum chloride (4.019 g, 30.1 mmole) in 45 mL of nitromethane. The reaction mixture was stirred at room temperature for two hours and then poured onto 300 mL of ice-water. The pH was adjusted to 2.0 with 10% HCl and the product was extracted with three 100 mL portions of ether. The combined organic extracts were dried over MgSO4, filtered and concentrated in vacuo to give a purple oil. The product was purified by flash chromatography (SiO2, 1% ethyl acetate in hexanes) to yield 4.667 g of 7-bromo-4,4-dimethyl-chroman as a colorless oil, which contained about 16% of 5-bromo-4,4-dimethyl-chroman.

Workup

  1. extractionthe product was extracted with three 100 mL portions of ether
  2. dry with materialThe combined organic extracts were dried over MgSO4
  3. filtrationfiltered
  4. concentrationconcentrated in vacuo
  5. customto give a purple oil
  6. customThe product was purified by flash chromatography (SiO2, 1% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-8d69033ce4164598b6938f8a8851c628
Source dataset
uspto-grants-2004_11
Patent number
US06818652B2

Reaction notes

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