Methane → 2-Cyclohexyl-1,2-dihydro-1,5-dimethyl-3H-pyrazol-3-one

HRID 1764061Notes

Reaction equation

HRID 1764061 reaction equation
[CH:1]1([N:7]2[C:11]([OH:12])=[CH:10][C:9]([CH3:13])=[N:8]2)[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1.S(OC)(O[CH3:18])(=O)=O.C(=O)([O-])[O-].[Na+].[Na+].C>O.C(Cl)Cl>[CH:1]1([N:7]2[C:11](=[O:12])[CH:10]=[C:9]([CH3:13])[N:8]2[CH3:18])[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6]1

Participants

7

Reactant 4

HCID 297MethaneHCID 6497Dimethyl SulfateHCID 10340Sodium CarbonateHCID 178429254HCID 178429254, compound

Product 1

HCID 204640012-Cyclohexyl-1,2-dihydro-1,5-dimethyl-3H-pyrazol-3-oneYield 17.9%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent

Procedure

A mixture of 2-cyclohexyl-3-hydroxy-5-methylpyrazole (16.5 g) and dimethyl sulfate (10.9 g) was heated with stirring at 150°-160° for 6 hours and then allowed to cool to room temperature. A solution of sodium carbonate (6.5 g) in water (100 ml) was added, and the reaction mixture was heated at reflux temperature for 2 hours, cooled, and extracted with chloroform. The layer was dried and concentrated to give a dark oil, which was dissolved in methylene chloride, treated with charcoal and diatomaceous earth, filtered and concentrated. The concentrate was fractionally distilled, and the portion distilling at 118°/0.020 mm Hg was further purified by column chromatography on silica gel. Elution with chloroform-ethyl acetate (7:3), chloroform-ethyl acetate gradients, ethyl acetate, and ethanol afforded product from the ethyl acetate-rich chloroform-ethyl acetate gradient fractions and the ethyl acetate and ethanol fractions as determined by thin-layer chromatography and nuclear magnetic resonance spectroscopy. Product-rich fractions which were shown by gas chromatography to be highly pure were combined and concentrated to give 2-cyclohexyl-1,5-dimethyl-1,2-dihydro-3H-pyrazol-3-one (3.0 g) as an oil. The assigned structure was confirmed by infrared and nuclear magnetic resonance spectral analysis.

Workup

  1. temperaturewas heated
  2. temperaturethe reaction mixture was heated
  3. temperatureat reflux temperature for 2 hours
  4. temperaturecooled
  5. extractionextracted with chloroform
  6. customThe layer was dried
  7. concentrationconcentrated
  8. customto give a dark oil, which
  9. filtrationfiltered
  10. concentrationconcentrated
  11. distillationThe concentrate was fractionally distilled
  12. distillationthe portion distilling at 118°/0.020 mm Hg
  13. customwas further purified by column chromatography on silica gel
  14. washElution with chloroform-ethyl acetate (7:3), chloroform-ethyl acetate gradients, ethyl acetate, and ethanol afforded product from the ethyl acetate-rich chloroform-ethyl acetate gradient fractions
  15. concentrationconcentrated

Sources & evidence

ORD record
ord-a5f0e7ff84674151a6e16109f6514978
Source dataset
uspto-grants-1978_09
Patent number
US04115096

Reaction notes

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