Hydrogen Bromide → 3H-Pyrazol-3-one, 2,4-dihydro-2-(2-hydroxyphenyl)-5-methyl-

HRID 1722726Notes

Reaction equation

HRID 1722726 reaction equation
C[O:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[N:9]1[C:13](=[O:14])[CH2:12][C:11]([CH3:15])=[N:10]1.Br>C(O)(=O)C>[OH:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[N:9]1[C:13](=[O:14])[CH2:12][C:11]([CH3:15])=[N:10]1

Participants

4

Reactant 2

HCID 260Hydrogen BromideHCID 10236079HCID 10236079, compound

Product 1

HCID 103079173H-Pyrazol-3-one, 2,4-dihydro-2-(2-hydroxyphenyl)-5-methyl-Yield 71%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

An amount of 1.80 g of 1-(2-methoxyphenyl)-3-methyl-2-pyrazolin-5-one was added into a mixture of 18 ml of 47% hydrobromic acid and 18 ml of acetic acid, and the mixture were refluxed under stirring for 6.5 hours. After evaporation of the solvent, an aqueous NaHCO3 solution was added to the residue to adjust to pH 4 and the mixture was extracted with ethyl acetate. The organic layer was dried and concentrated, followed by recrystallization of the residue from ethanol to give 1.19 g of 1-(2-hydroxyphenyl)-3-methyl-2-pyrazolin-5-one (Compound No. 44) as colorless crystals.

Workup

  1. temperaturethe mixture were refluxed
  2. customAfter evaporation of the solvent
  3. additionan aqueous NaHCO3 solution was added to the residue
  4. extractionthe mixture was extracted with ethyl acetate
  5. customThe organic layer was dried
  6. concentrationconcentrated
  7. customfollowed by recrystallization of the residue from ethanol

Sources & evidence

ORD record
ord-3dde50694f304f07809b35be699507cd
Source dataset
uspto-grants-1989_08
Patent number
US04857542

Reaction notes

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