2-Methoxy-3-methyl-1-butene → Ethyl 1-(2,4-dichlorophenyl)-5-(propan-2-yl)-1H-pyrazole-3-carboxylate

HRID 467260Notes

Reaction equation

HRID 467260 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[NH:9][N:10]=[C:11](Cl)[C:12]([O:14][CH2:15][CH3:16])=[O:13].C(=O)([O-])O.[K+].CO[C:25]([CH:27]([CH3:29])[CH3:28])=[CH2:26]>O>[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[N:9]1[C:25]([CH:27]([CH3:29])[CH3:28])=[CH:26][C:11]([C:12]([O:14][CH2:15][CH3:16])=[O:13])=[N:10]1

Participants

5

Reactant 3

HCID 1428832-Methoxy-3-methyl-1-buteneHCID 516893Potassium BicarbonateHCID 2771526Ethyl 2-chloro-2-[2-(2,4-dichlorophenyl)hydrazinylidene]acetate

Product 1

HCID 11099468Ethyl 1-(2,4-dichlorophenyl)-5-(propan-2-yl)-1H-pyrazole-3-carboxylate

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

1550 g of ethyl 2-chloroglyoxalate 2,4-dichlorophenylhydrazone are dissolved in 1000 g of 2-methoxy-3-methylbut-1-ene and a total of 600 g of potassium hydrogen-carbonate in 500 ml of water is added continuously at 70°-80° C. such that a pH of about 8-8.5 is always maintained. After a total reaction time of 4 hours, the excess enol ether (465 g) is distilled off and the reaction mixture is adjusted to a pH of 0.5 using 190 ml of hydrochloric acid. After heating to reflux for 1 hour, the mixture is cooled to room temperature and the precipitated crystallizate is filtered off with suction.

Workup

  1. temperatureis always maintained
  2. distillationAfter a total reaction time of 4 hours, the excess enol ether (465 g) is distilled off
  3. temperatureAfter heating
  4. temperatureto reflux for 1 hour
  5. filtrationthe precipitated crystallizate is filtered off with suction

Sources & evidence

ORD record
ord-f53b75b9387a472bb694456327685ef2
Source dataset
uspto-grants-1992_10
Patent number
US05159086

Reaction notes

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