Acetone → 7-fluoro-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

HRID 2356972Notes

Reaction equation

HRID 2356972 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:10])[CH3:9])=[C:4]([OH:11])[CH:3]=1.[CH3:12][C:13]([CH3:15])=O.N1CCCC1>C1C=CC=CC=1>[F:1][C:2]1[CH:3]=[C:4]2[C:5]([C:8](=[O:10])[CH2:9][C:13]([CH3:15])([CH3:12])[O:11]2)=[CH:6][CH:7]=1

Participants

5

Reactant 3

HCID 180AcetoneHCID 31268PyrrolidineHCID 27373264'-Fluoro-2'-hydroxyacetophenone

Product 1

HCID 152053737-fluoro-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-oneYield 53%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

1-(4-Fluoro-2-hydroxy-phenyl)-ethanone (5.0 g, 32.44 mmol), acetone (11.92 mL, 162.2 mmol) and pyrrolidine (2.7 mL, 32.44 mmol) were dissolved in 20 mL benzene, and the reaction mixture was refluxed for four hours. The reaction mixture was cooled to room temperature and partitioned between ethyl acetate and 1 N HCl. The organic layer was dried over MgSO4, and solvent was evaporated under reduced pressure. The resulting residue was chromatographed (15% ethyl acetate in hexanes eluting through silica) and solvent was removed to yield 3.33 g (17.16 mg, 53%) of 7-fluoro-2,2-dimethyl-chroman-4-one as an oil. MS: 195 (M+H)+.

Workup

  1. temperaturethe reaction mixture was refluxed for four hours
  2. custompartitioned between ethyl acetate and 1 N HCl
  3. dry with materialThe organic layer was dried over MgSO4, and solvent
  4. customwas evaporated under reduced pressure
  5. customThe resulting residue was chromatographed (15% ethyl acetate in hexanes eluting through silica) and solvent
  6. customwas removed

Sources & evidence

ORD record
ord-16cd407b8a214e20b9c488b3c105df9a
Source dataset
uspto-grants-2010_07
Patent number
US07759389B2

Reaction notes

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