Hydrogen Bromide → 4-Bromo-2-(3,4-dichloro-phenyl)-2-methyl-butyric acid methyl ester

HRID 734275Notes

Reaction equation

HRID 734275 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C:9]2([CH3:15])[CH2:13][CH2:12][O:11][C:10]2=[O:14])[CH:5]=[CH:6][C:7]=1[Cl:8].[BrH:16].S(Cl)(Cl)=O.[CH3:21]O>C(O)(=O)C>[CH3:21][O:11][C:10](=[O:14])[C:9]([C:4]1[CH:5]=[CH:6][C:7]([Cl:8])=[C:2]([Cl:1])[CH:3]=1)([CH3:15])[CH2:13][CH2:12][Br:16]

Participants

6

Reactant 4

HCID 260Hydrogen Bromide2×HCID 887MethanolHCID 24386Thionyl ChlorideHCID 578435633-(3,4-Dichloro-phenyl)-3-methyl-dihydro-furan-2-one

Product 1

HCID 578435734-Bromo-2-(3,4-dichloro-phenyl)-2-methyl-butyric acid methyl esterYield 94%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent3×

Procedure

To a mixture of 3.3 g (13.5 mmol) 3-(3,4-dichloro-phenyl)-3-methyl-dihydro-furan-2-one in 15 mL acetic acid was added 48 mL HBr (33%) in acetic acid and after 63 h 20 mL HBr (33%) in acetic acid and stirred for another 21 h at room temperature. The mixture was pored onto ice-water and extracted with ethyl ether. The combined organic phases were washed with NaCl aq. sat., dried with Na2SO4, filtered and evaporated to dryness. The residue was taken up in 150 mL toluene and 6.5 mL (89 mmol) thionylchloride were added. The mixture was heated to 75° C. for 4 h, cooled to 0° C., treated with 20 mL methanol and allowed to stand for 16 h at room temperature. The mixture was evaporated to dryness and subjected to column chromatography on silica eluting with a gradient formed from ethyl acetate and heptane. The product containing fractions were evaporated to yield 4.32 g (94%) of the title compound as light yellow oil. MS(m/e): 341.9 (MH+).

Workup

  1. extractionextracted with ethyl ether
  2. washThe combined organic phases were washed with NaCl aq. sat.
  3. dry with materialdried with Na2SO4
  4. filtrationfiltered
  5. customevaporated to dryness
  6. temperatureThe mixture was heated to 75° C. for 4 h
  7. temperaturecooled to 0° C.
  8. waitto stand for 16 h at room temperature
  9. customThe mixture was evaporated to dryness
  10. customformed from ethyl acetate and heptane
  11. additionThe product containing fractions
  12. customwere evaporated

Sources & evidence

ORD record
ord-620e8a12eebc407abc4a12c58ab7b414
Source dataset
uspto-grants-2009_09
Patent number
US07592345B2

Reaction notes

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