Diethyl (ethoxymethylene)malonate → 3H-Pyrazol-3-one, 2,4-dihydro-2,5-diphenyl-

HRID 1289833Notes

Reaction equation

HRID 1289833 reaction equation
C(OC=[C:5]([C:11](OCC)=O)[C:6]([O:8]CC)=O)C.[C:16]1([NH:22][NH2:23])[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1>CO>[C:16]1([N:22]2[C:6](=[O:8])[CH2:5][C:11]([C:16]3[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=3)=[N:23]2)[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1

Participants

4

Reactant 2

HCID 6871Diethyl (ethoxymethylene)malonateHCID 7516Phenylhydrazine

Product 1

HCID 785593H-Pyrazol-3-one, 2,4-dihydro-2,5-diphenyl-Yield 175.9%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Diethyl ethoxymethylene-malonate (5.20 ml; 26 mmol) was added rapidly to 2.75 ml (28 mmol) of phenylhydrazine in 15 ml of methanol and the resulting mixture was refluxed for 4 hours. The mixture was cooled and concentrated in vacuo, and the residue was crystallized from ethanol to afford 5.82 g (97%) of 2,4-dihydro-2-phenyl-4-ethoxycarbonyl-3H-pyrazol-3-one (Formula III: R1 =Ph; R2 =H; R3 =C(O)OEt) as white needles, m.p. 106°-107° C.

Workup

  1. temperaturethe resulting mixture was refluxed for 4 hours
  2. temperatureThe mixture was cooled
  3. concentrationconcentrated in vacuo
  4. customthe residue was crystallized from ethanol

Sources & evidence

ORD record
ord-00e2325ff3f640fdb4fdaa2593a862d4
Source dataset
uspto-grants-1998_05
Patent number
US05750550

Reaction notes

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