Hydrochloric Acid → 3H-Pyrazol-3-one, 2,4-dihydro-2,5-diphenyl-

HRID 1289834Notes

Reaction equation

HRID 1289834 reaction equation
[C:1]1([N:7]2[C:11](=[O:12])[CH:10](C(OCC)=O)[CH:9]=[N:8]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[OH-].[K+].Cl>C(O)C.O>[C:1]1([N:7]2[C:11](=[O:12])[CH2:10][C:9]([C:1]3[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=3)=[N:8]2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 14797Potassium HydroxideHCID 12298630HCID 12298630, compound

Product 1

HCID 785593H-Pyrazol-3-one, 2,4-dihydro-2,5-diphenyl-Yield 50.8%

Reagents, catalysts & solvents 1

HCID 19096565Water ethanolSolvent

Procedure

To a mixture of 2,4-dihydro-2-phenyl-4-ethoxycarbonyl-3H-pyrazol-3-one (5.8 g; 25 mmol) in 16 ml of ethanol/water (1:1) 4 g of KOH was added and the resulting mixture was heated at reflux for 4 hours. The mixture was cooled in an ice/bath, conc. HCl solution was added (until pH=1-2), and the resulting mixture was refluxed overnight. The reaction mixture was cooled, concentrated in vacuo, and the residue was dissolved in water. The aqueous layer was extracted with ethyl acetate (2×), the combined organic layer was dried over magnesium sulfate and concentrated in vacuo. The residual yellow oil was purified by silica gel column chromatography (25-30% ethyl acetate/hexane) to afford 1.5 g (38%) of 2,4-dihydro-2-phenyl-3H-pyrazol-3-one (Formula III: R1 =Ph; R2 =H; R3 =H) as a solid, m.p. 113°-114° C.

Workup

  1. additionwas added
  2. temperaturethe resulting mixture was heated
  3. temperatureat reflux for 4 hours
  4. temperatureThe mixture was cooled in an ice/bath
  5. temperaturethe resulting mixture was refluxed overnight
  6. temperatureThe reaction mixture was cooled
  7. concentrationconcentrated in vacuo
  8. dissolutionthe residue was dissolved in water
  9. extractionThe aqueous layer was extracted with ethyl acetate (2×)
  10. dry with materialthe combined organic layer was dried over magnesium sulfate
  11. concentrationconcentrated in vacuo
  12. customThe residual yellow oil was purified by silica gel column chromatography (25-30% ethyl acetate/hexane)

Sources & evidence

ORD record
ord-1262b97fd52444d8bbe88543feb97844
Source dataset
uspto-grants-1998_05
Patent number
US05750550

Reaction notes

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