Sulfuric Acid → 5-Amino-1-(2,3,5,6-tetrafluoro-4-trifluoromethylphenyl)pyrazole

HRID 257315Notes

Reaction equation

HRID 257315 reaction equation
[NH2:1][C:2]1[N:6]([C:7]2[C:12]([F:13])=[C:11]([F:14])[C:10]([C:15]([F:18])([F:17])[F:16])=[C:9]([F:19])[C:8]=2[F:20])[N:5]=[CH:4][C:3]=1C(OCC)=O.S(=O)(=O)(O)O>O>[NH2:1][C:2]1[N:6]([C:7]2[C:12]([F:13])=[C:11]([F:14])[C:10]([C:15]([F:18])([F:17])[F:16])=[C:9]([F:19])[C:8]=2[F:20])[N:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 139337085-Amino-4-ethoxycarbonyl-1-(2,3,5,6-tetrafluoro-4-trifluoromethyl-phenyl)-pyrazole

Product 1

HCID 139337095-Amino-1-(2,3,5,6-tetrafluoro-4-trifluoromethylphenyl)pyrazoleYield 2.5%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
130 °C

Procedure

A stirred mixture of 18.6 grams (0.500 mole) of ethyl 5-amino-1-(2,3,5,6-tetrafluoro-4-trifluoromethylphenyl)pyrazole-4-ylcarboxylate, 23 mL of water, and 23 mL of sulfuric acid was heated at 130° C. for six hours. After the reaction mixture was cooled, 75 mL of crushed ice was added. A solid had formed and was collected by filtration; the filtrate was saved. This solid was washed with water and diethyl ether, allowed to dry, and set aside for further purification. To the filtrate was added an aqueous sodium hydroxide solution until a pH of 9.0 was obtained. A solid formed and was collected by filtration. This solid was washed with water and dried to yield 3.8 grams of 5-amino-1-(2,3,5,6-tetrafluoro-4-trifluoromethylphenyl)pyrazole, m.p. 102.5°-104.5° C. The nmr spectrum was consistent with the proposed structure.

Workup

  1. temperatureAfter the reaction mixture was cooled
  2. customA solid had formed
  3. filtrationwas collected by filtration
  4. washThis solid was washed with water and diethyl ether
  5. customto dry
  6. customset aside for further purification
  7. additionTo the filtrate was added an aqueous sodium hydroxide solution until a pH of 9.0
  8. customwas obtained
  9. customA solid formed
  10. filtrationwas collected by filtration
  11. washThis solid was washed with water
  12. customdried

Sources & evidence

ORD record
ord-c2b66b43e60f47908aa0c722ac001c29
Source dataset
uspto-grants-1993_11
Patent number
US05262382

Reaction notes

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