Phosphorus oxychloride → 5-Chloro-1-methyl-3-phenyl-1H-pyrazole

HRID 918343Notes

Reaction equation

HRID 918343 reaction equation
P(Cl)(Cl)([Cl:3])=O.[CH3:6][N:7]1[C:11](=O)[CH:10]=[C:9]([C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)[NH:8]1>O>[Cl:3][C:11]1[N:7]([CH3:6])[N:8]=[C:9]([C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)[CH:10]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 27635041-methyl-3-phenyl-1H-pyrazol-5-ol

Product 1

HCID 126657925-Chloro-1-methyl-3-phenyl-1H-pyrazoleYield 66.4%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a solution of phosphorous oxychloride (2,015 g, 19 moles) is added solid 1-methyl-3-phenylpyrazolin-5-one (2,073 g, 11.9 moles) with stirring and warming. At 100°C. the mixture becomes homogeneous. The reflux temperature rises from 119°C. to 143°C. over a period of 30 hours. After cooling the mixture is poured into ice and water (8 l) with stirring. After 4 hours the slurry is filtered and the filter cake added to 4 l of water containing 1.5 l of 10% sodium hydroxide solution with stirring. Removal of the solid by filtration followed by a recrystallization from hexane yields 1,523 g of product, having a melting point ranging from 61°C. to 62°C.

Workup

  1. temperaturewarming
  2. customAt 100°C.
  3. temperatureAfter cooling the mixture
  4. stirringwith stirring
  5. filtrationAfter 4 hours the slurry is filtered
  6. additionthe filter cake added to 4 l of water containing 1.5 l of 10% sodium hydroxide solution
  7. stirringwith stirring
  8. customRemoval of the solid
  9. filtrationby filtration
  10. customfollowed by a recrystallization from hexane

Sources & evidence

ORD record
ord-766a9dfd5a8448389a96c9eb0de06da4
Source dataset
uspto-grants-1976_07
Patent number
US03970754

Reaction notes

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