p-Hydrazinobenzenesulphonamide → Enflicoxib

HRID 276140

Reaction equation

HRID 276140 reaction equation
[O-]CC.[Na+].[F:5][C:6]([F:20])([F:19])[C:7](=O)[CH:8]=[CH:9][C:10]1[CH:15]=[CH:14][C:13]([F:16])=[CH:12][C:11]=1[F:17].[NH2:21][S:22]([C:25]1[CH:30]=[CH:29][C:28]([NH:31][NH2:32])=[CH:27][CH:26]=1)(=[O:24])=[O:23]>C(O)C>[NH2:21][S:22]([C:25]1[CH:26]=[CH:27][C:28]([N:31]2[CH:9]([C:10]3[CH:15]=[CH:14][C:13]([F:16])=[CH:12][C:11]=3[F:17])[CH2:8][C:7]([C:6]([F:20])([F:19])[F:5])=[N:32]2)=[CH:29][CH:30]=1)(=[O:24])=[O:23]

Participants

5

Reactant 3

HCID 78105p-HydrazinobenzenesulphonamideHCID 2723922Sodium ethoxideHCID 69533569HCID 69533569, compound

Product 1

HCID 9953093EnflicoxibYield 65%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

In a flask with an inert atmosphere sodium ethoxide (0.53 g, 7.72 mmoles) is dissolved in 45 ml of ethanol. 1,1,1-trifluoro-4-(2,4-difluorophenyl)-3-butene-2-one (prepared according to method E-1) (0.913 g, 3.86 mmoles) and 4-(aminosulphonyl)phenylhydrazine chlorohydrate (0.87 g, 3.87 mmoles) are added and the mixture was refluxed for 16 hours. The mixture was cooled, evaporated to dryness, cold water added, and the mixture acidified by adding acetic acid and the precipitated solid filtered. This solid was redissolved in ether, treated with active C, filtered and the solvent eliminated with a rotovapor. The resulting residue was crystallised from ethyl ether-petrol ether (50:50) to give 1-(4-aminosulphonylphenyl)-5-(2,4-difluorophenyl)-4,5-dihydro-3-trifluoromethyl-1H-pyrazole (1.02 g, yield: 65%) in the form of a solid m.p.=160-2° C.

Workup

  1. temperaturethe mixture was refluxed for 16 hours
  2. temperatureThe mixture was cooled
  3. customevaporated to dryness, cold water
  4. additionadded
  5. additionby adding acetic acid
  6. filtrationthe precipitated solid filtered
  7. dissolutionThis solid was redissolved in ether
  8. additiontreated with active C
  9. filtrationfiltered
  10. customThe resulting residue was crystallised from ethyl ether-petrol ether (50:50)

Sources & evidence

ORD record
ord-9c9a8dfdafa14f3ba84ff28ef6abe2d0
Source dataset
uspto-grants-2002_03
Patent number
US06353117B1

Linked notes

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