Dimethyl Sulfate → 1-Methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one

HRID 485681

Reaction equation

HRID 485681 reaction equation
N1C(=O)C=[CH:3]N1.[C:7]1([N:13]2[C:17](=[O:18])[CH:16]=[CH:15][NH:14]2)[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1.S(OC)(OC)(=O)=O>C1(C)C=CC=CC=1>[CH3:3][N:14]1[CH:15]=[CH:16][C:17](=[O:18])[N:13]1[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1

Participants

5

Reactant 3

HCID 6497Dimethyl SulfateHCID 3513171H-Pyrazol-3-olHCID 27487101-phenyl-1H-pyrazol-5-ol

Product 1

HCID 146200001-Methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
50 °C

Procedure

The pyrazolinone prepared as described above in (a) (1.153 g, 7.2 mmol) in dry toluene (3 ml) was treated with dimethyl sulphate (8 mmol, 750 μl) and the whole refluxed under nitrogen for 5 hours. The reaction mixture was then allowed to cool and in doing so separated into two phases. The upper consisting mainly of toluene was carefully pipetted off and discarded. The remaining layer was then treated with water (1 ml), the whole warmed with stirring to 50° C. and then treated with 40% sodium hydroxide solution (1 ml) and stirred at 50° C. for a further 30 minutes. The resultant solution was subsequently extracted with three portions of benzene. The first two extracts were found to contain two products which has spectral properties consistent with 2-methyl-1-phenyl-3-pyrazolin-5-one and 2,4-dimethyl-1-phenyl-3-pyrazolin-5-one. These were separated by chromatography on silica (ethyl acetate) to give 2-methyl-1-phenyl-3-pyrazolin-5-one (95 mg). The third extracton (above) consisted solely of 2-methyl-1-phenyl-3-pyrazolin-5-one (208 mg) (Total yield, 24%). νmax (CHCl3) 1655, 1595, 1550, 1495 cm-1. δ(D6Acetone) 3.11 (3H, s, --NMe), 5.44 (1H, d, J4 Hz, C4 proton), 7.47 (5H, m, phenyl protons), 7.83 (1H, d, J4 Hz, C3 proton). Found: M+ 174.0798; C10H10N2O requires M; 174.0794.

Workup

  1. temperaturethe whole refluxed under nitrogen for 5 hours
  2. temperatureto cool
  3. customin doing so separated into two phases
  4. additionThe remaining layer was then treated with water (1 ml)
  5. temperaturethe whole warmed
  6. additiontreated with 40% sodium hydroxide solution (1 ml)
  7. stirringstirred at 50° C. for a further 30 minutes
  8. extractionThe resultant solution was subsequently extracted with three portions of benzene
  9. customThese were separated by chromatography on silica (ethyl acetate)

Sources & evidence

ORD record
ord-44fc1f7af76e42bb9e8884210dfb514b
Source dataset
uspto-grants-1985_08
Patent number
US04537886

Linked notes

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