Pyrazole → 1-(2-fluoro-4-nitrophenyl)-1H-pyrazole

HRID 1415892Notes

Reaction equation

HRID 1415892 reaction equation
[NH:1]1[CH:5]=[CH:4][CH:3]=[N:2]1.C(=O)([O-])[O-].[K+].[K+].[F:12][C:13]1[CH:14]=[C:15]([N+:20]([O-:22])=[O:21])[CH:16]=[CH:17][C:18]=1F>CS(C)=O.O>[F:12][C:13]1[CH:14]=[C:15]([N+:20]([O-:22])=[O:21])[CH:16]=[CH:17][C:18]=1[N:1]1[CH:5]=[CH:4][CH:3]=[N:2]1

Participants

6

Reactant 3

HCID 1048PyrazoleHCID 11430Potassium CarbonateHCID 1230531,2-Difluoro-4-nitrobenzene

Product 1

HCID 107035141-(2-fluoro-4-nitrophenyl)-1H-pyrazoleYield 87.1%

Reagents, catalysts & solvents 2

HCID 679Dimethyl SulfoxideSolventHCID 962WaterSolvent

Conditions

Temperature
90 °C

Procedure

A solution of 2.0 g (29.37 mmol) of pyrazole and 8.12 g (58.75 mmol) of potassium carbonate in 70 mL of DMSO was treated with 4.67 g (3.25 mL, 29.37 mmol) of 3, 4-difluoronitrobenzene followed by warming at 90° C. for 18 h. The solution was cooled and diluted with 100 mL water and was extracted with ethyl acetate (2×100 mL). The organic layers were extracted with water (5×100 mL) and with saturated NaCl solution (75 mL). Drying (Na2SO4) and concentration in vacuo afforded an off-white solid which was recrystallized from hot hexanes to afford 5.3 g (87%) of the title pyrazole derivative as an off-white solid, mp 128-129° C.

Workup

  1. temperatureThe solution was cooled
  2. extractionwas extracted with ethyl acetate (2×100 mL)
  3. extractionThe organic layers were extracted with water (5×100 mL) and with saturated NaCl solution (75 mL)
  4. customDrying
  5. concentration(Na2SO4) and concentration in vacuo
  6. customafforded an off-white solid which
  7. customwas recrystallized from hot hexanes

Sources & evidence

ORD record
ord-70b3fd1252024a05ba59dd02815f0739
Source dataset
uspto-grants-1999_06
Patent number
US05910504

Reaction notes

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