Cornforth reagent → 1-(5-Bromo-2-fluorophenyl)butan-1-one

HRID 1880371Notes

Reaction equation

HRID 1880371 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]([F:13])=[C:6]([CH:8]([OH:12])[CH2:9][CH2:10][CH3:11])[CH:7]=1.[Cr](O[Cr]([O-])(=O)=O)([O-])(=O)=O.[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1>C(Cl)Cl>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([F:13])=[C:6]([C:8](=[O:12])[CH2:9][CH2:10][CH3:11])[CH:7]=1

Participants

4

Reactant 2

HCID 2724130Cornforth reagentHCID 63894506HCID 63894506, compound

Product 1

HCID 529838151-(5-Bromo-2-fluorophenyl)butan-1-oneYield 75.1%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 1-(5-bromo-2-fluoro-phenyl)-butan-1-ol (6.2 g, 25 mmol) in dry CH2Cl2 (60 mL) were added pyridinium dichromate (19.0 g, 50.3 mmol) and molecular sieves powder (1.24 g) at room temperature and stirred overnight. The reaction mixture was filtered through diatomaceous earth and washed with diethyl ether (200 mL). The combined CH2Cl2 and ether layers were dried over anhydrous Na2SO4, filtered and concentrated to give a crude product, which was purified by column chromatography using 5% ethyl acetate/pet-ether as eluents to afford 1-(5-bromo-2-fluorophenyl)butan-1-one (4.6 g, 75%) as a syrup. 1H NMR (CDCl3): δ 8.0 (m, 1H), 7.5-7.6 (m, 1H), 7.0 (t, 1H), 2.9-3.0 (m, 2H), 1.7 (q, 2H), 1.0 (t, 3H).

Workup

  1. filtrationThe reaction mixture was filtered through diatomaceous earth
  2. washwashed with diethyl ether (200 mL)
  3. dry with materialThe combined CH2Cl2 and ether layers were dried over anhydrous Na2SO4
  4. filtrationfiltered
  5. concentrationconcentrated
  6. customto give a crude product, which
  7. customwas purified by column chromatography

Sources & evidence

ORD record
ord-6cd28482d45f45ab948fa08ae00df467
Source dataset
uspto-grants-2012_11
Patent number
US08318762B2

Reaction notes

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