Triethylamine → Ethyl 1-(2,4-dichlorophenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate

HRID 1731272Notes

Reaction equation

HRID 1731272 reaction equation
Cl.[Cl:2][C:3]1[CH:8]=[C:7]([Cl:9])[CH:6]=[CH:5][C:4]=1[NH:10][NH2:11].C(N(CC)CC)C.C(O[CH:22]=[C:23]([C:29]([C:31]([F:34])([F:33])[F:32])=O)[C:24]([O:26][CH2:27][CH3:28])=[O:25])C>C(O)C>[F:32][C:31]([F:33])([F:34])[C:29]1[N:10]([C:4]2[CH:5]=[CH:6][C:7]([Cl:9])=[CH:8][C:3]=2[Cl:2])[N:11]=[CH:22][C:23]=1[C:24]([O:26][CH2:27][CH3:28])=[O:25]

Participants

5

Reactant 3

HCID 8471TriethylamineHCID 2723905(2,4-Dichlorophenyl)hydrazine monohydrochlorideHCID 4685753Ethyl 2-(ethoxymethylene)-4,4,4-trifluoro-3-oxobutanoate

Product 1

HCID 13537978Ethyl 1-(2,4-dichlorophenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Conditions

Temperature
-10 °C

Procedure

2,4-Dichlorophenylhydrazine hydrochloride salt (15.68 grams, 0.068 mole) was dissolved in a minimum amount of ethanol and the solution was cooled to -10° C. Triethylamine (9.44 ml., 0.068 mole) was added followed by ethyl (ethoxymethylene)trifluoroacetoacetate (16.27 grams, 0.068 mole). The addition of this last reactant was made over thirty minutes, keeping the reaction temperature below -10° C. The reaction mixture was allowed to rise to room temperature overnight (about 16 hours). The solvent was removed in vacuo and the resiude was dissolved in equal parts of ethyl acetate and water. The organic phase was separated, washed with 1N HCl, water, saturated sodium bicarbonate solution, water, and brine. It was then dried and evaporated to 7.85 grams of an oil which slowly crystallized. The 5-(trifluoromethyl)-1-(2,4-dichlorophenyl)-1H-pyrazole-4-carboxylic acid, ethyl ester, was recrystallized from petroleum ether, mp=81°-83° C.

Workup

  1. additionThe addition of this last reactant
  2. waitwas made over thirty minutes
  3. customthe reaction temperature below -10° C
  4. custom(about 16 hours)
  5. customThe solvent was removed in vacuo
  6. dissolutionthe resiude was dissolved in equal parts of ethyl acetate and water
  7. customThe organic phase was separated
  8. washwashed with 1N HCl, water, saturated sodium bicarbonate solution, water, and brine
  9. customIt was then dried
  10. customevaporated to 7.85 grams of an oil which
  11. customslowly crystallized
  12. customThe 5-(trifluoromethyl)-1-(2,4-dichlorophenyl)-1H-pyrazole-4-carboxylic acid, ethyl ester, was recrystallized from petroleum ether, mp=81°-83° C.

Sources & evidence

ORD record
ord-47b1543290cd48e589867a2916aa9a56
Source dataset
uspto-grants-1986_11
Patent number
US04620865

Reaction notes

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