Pyrazole → 1-(3-Bromophenyl)-1H-pyrazole

HRID 881975Notes

Reaction equation

HRID 881975 reaction equation
[H-].[Na+].[NH:3]1[CH:7]=[CH:6][CH:5]=[N:4]1.[Br:8][C:9]1[CH:14]=[CH:13][CH:12]=[C:11](F)[CH:10]=1>CN(C=O)C>[Br:8][C:9]1[CH:10]=[C:11]([N:3]2[CH:7]=[CH:6][CH:5]=[N:4]2)[CH:12]=[CH:13][CH:14]=1

Participants

5

Reactant 3

HCID 1048PyrazoleHCID 140821-Bromo-3-fluorobenzeneHCID 24758Sodium hydride

Product 1

HCID 71278041-(3-Bromophenyl)-1H-pyrazoleYield 47.9%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent2×

Procedure

To a suspension of sodium hydride (3.52 g, 88 mmol) in DMF (40 ml), was added pyrazole (3.0 g, 44 mmol) in portions. After stirring at room temperature for 30 minutes, 1-bromo-3-fluorobenzene (9.3 g, 53 mmol) in DMF (20 ml) was added dropwise and the resulting mixture was stirred for 2 hours at 130° C. The mixture was cooled and quenched by the addition of a saturated aqueous NH4Cl solution and extracted with ethyl acetate. The organic layer was washed with brine, dried over Na2SO4 and concentrated under reduced pressure. The residue was purified using normal phase chromatography, eluting with petroleum ether containing 10% ethyl acetate to give 1-(3-bromophenyl)-1H-pyrazole (4.7 g) as yellow solid.

Workup

  1. stirringthe resulting mixture was stirred for 2 hours at 130° C
  2. temperatureThe mixture was cooled
  3. customquenched by the addition of a saturated aqueous NH4Cl solution
  4. extractionextracted with ethyl acetate
  5. washThe organic layer was washed with brine
  6. dry with materialdried over Na2SO4
  7. concentrationconcentrated under reduced pressure
  8. customThe residue was purified
  9. washeluting with petroleum ether containing 10% ethyl acetate

Sources & evidence

ORD record
ord-104a73e2b85e4058b713d4205888236d
Source dataset
uspto-grants-2015_03
Patent number
US08993757B2

Reaction notes

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