Leflunomide → 5-Methyl-4-(4-trifluoromethylphenyl)aminothiocarbonylisoxazole

HRID 863609Notes

Reaction equation

HRID 863609 reaction equation
[CH3:1][C:2]1[O:6][N:5]=[CH:4][C:3]=1[C:7]([NH:9][C:10]1[CH:15]=[CH:14][C:13]([C:16]([F:19])([F:18])[F:17])=[CH:12][CH:11]=1)=O.COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:29])=CC=1>C1(C)C=CC=CC=1>[CH3:1][C:2]1[O:6][N:5]=[CH:4][C:3]=1[C:7]([NH:9][C:10]1[CH:15]=[CH:14][C:13]([C:16]([F:19])([F:18])[F:17])=[CH:12][CH:11]=1)=[S:29]

Participants

4

Reactant 2

HCID 3899LeflunomideHCID 87949Lawesson's reagent

Product 1

HCID 158588075-Methyl-4-(4-trifluoromethylphenyl)aminothiocarbonylisoxazoleYield 64.9%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of 24 grams of 5-methyl-4-(4-trifluoromethyl-phenyl)aminocarbonylisoxazole and 39 grams of Lawesson's reagent [2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide] in 400 ml of toluene was refluxed for three hours. Upon cooling of mixture to room temperature, all the solid was filtered off and the filtrate was concentrated. The resulting crude product from the filtrate was then purified on a silica gel column with 3% methanol in dichloromethane to yield 16.5 grams of 5-methyl-4-(4-trifluoromethylphenyl)aminothiocarbonylisoxazole.

Workup

  1. filtrationall the solid was filtered off
  2. concentrationthe filtrate was concentrated
  3. customThe resulting crude product from the filtrate was then purified on a silica gel column with 3% methanol in dichloromethane

Sources & evidence

ORD record
ord-265988c89b964ceabf298e9ead7fe463
Source dataset
uspto-grants-1998_02
Patent number
US05721277

Reaction notes

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