Acetophenone → Phenacyl bromide

HRID 1373781Notes

Reaction equation

HRID 1373781 reaction equation
[C:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)(=[O:3])[CH3:2].[Br-:10].[Br-].[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.C([N+](CCCC)(CCCC)CCCC)CCC.C([N+](CCCC)(CCCC)CCCC)CCC>CO.C(Cl)Cl>[Br:10][CH2:2][C:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)=[O:3]

Participants

4

Reactant 2

HCID 7410AcetophenoneHCID 23500184Tetra-n-butylammonium tribromide

Product 1

HCID 6259Phenacyl bromideYield 60.2%

Reagents, catalysts & solvents 1

HCID 21226129Dichloromethane methanolSolvent

Procedure

The product from Step B (52 mmol) was treated with tetrabutylammonium tribromide (25.5 g, 52.9 mmol) in methanol/methylene chloride (1/3, 240 ml) under nitrogen. After stirring 3 days at room temperature, the solvents were removed in vacuo, and the residue dissolved in diethyl ether (200 ml), washed with water (4×50 ml), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. Purification by column chromatography on silica gel (120 g) eluting with hexanes/ethyl acetate (30/1) afforded the desired □-bromoacetophenone (6.23 g) as a crystalline solid: 1H NMR (300 MHz, CDCl3) δ 7.70–7.81 (m, 2H), 7.55 (t, J=7.7 Hz, 1H), 4.39 (s, 2H); CI MS m/z=251 [C8H5BrClFO+H]+.

Workup

  1. customthe solvents were removed in vacuo
  2. dissolutionthe residue dissolved in diethyl ether (200 ml)
  3. washwashed with water (4×50 ml)
  4. dry with materialdried over anhydrous sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated in vacuo
  7. customPurification by column chromatography on silica gel (120 g)
  8. washeluting with hexanes/ethyl acetate (30/1)

Sources & evidence

ORD record
ord-7539c65abf654b6fb51c91c2096bf424
Source dataset
uspto-grants-2007_01
Patent number
US07163949B1

Reaction notes

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