Hydrofluoric Acid → 6,7-Dichloro-2,3-dihydro-4H-1-benzopyran-4-one

HRID 871057Notes

Reaction equation

HRID 871057 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([CH:11]=[CH:12][C:13]=1[Cl:14])[O:5][CH2:6][CH2:7][C:8]([OH:10])=O.F>>[Cl:14][C:13]1[CH:12]=[C:11]2[C:4](=[CH:3][C:2]=1[Cl:1])[O:5][CH2:6][CH2:7][C:8]2=[O:10]

Participants

3

Reactant 2

HCID 14917Hydrofluoric AcidHCID 8193113-(3,4-Dichlorophenoxy)propanoic acid

Product 1

HCID 126644086,7-Dichloro-2,3-dihydro-4H-1-benzopyran-4-one

Procedure

500 mg of 3-(3,4-dichlorophenoxy)propionic acid, is stirred in 50 ml. of liquid hydrogen fluoride surrounded by a solid carbon dioxide/acetone bath. This slurry is allowed to stir overnight without replenishing the cooling bath. The hydrogen fluoride is removed by a stream of air. The residual solid was then dissolved in ether and washed with 10% aqueous sodium carbonate solution. The organic layer is dried over anhydrous magnesium sulphate and the solvent is evaporated to give the required chromanone with sufficient purity.

Workup

  1. customThe hydrogen fluoride is removed by a stream of air
  2. dissolutionThe residual solid was then dissolved in ether
  3. washwashed with 10% aqueous sodium carbonate solution
  4. dry with materialThe organic layer is dried over anhydrous magnesium sulphate
  5. customthe solvent is evaporated

Sources & evidence

ORD record
ord-744efed30757469a8349614f11740e36
Source dataset
uspto-grants-2015_03
Patent number
US08969573B2

Reaction notes

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