Potassium Carbonate → 4-Fluoro-2-[(4-fluorophenyl)sulfanyl]benzoic acid

HRID 2083769Notes

Reaction equation

HRID 2083769 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([SH:8])=[CH:4][CH:3]=1.I[C:10]1[CH:18]=[C:17]([F:19])[CH:16]=[CH:15][C:11]=1[C:12]([OH:14])=[O:13].C(=O)([O-])[O-].[K+].[K+]>N1C=CC=CC=1>[F:19][C:17]1[CH:18]=[CH:10][C:11]([C:12]([OH:14])=[O:13])=[C:15]([S:8][C:5]2[CH:6]=[CH:7][C:2]([F:1])=[CH:3][CH:4]=2)[CH:16]=1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 677894-FluorothiophenolHCID 125201644-Fluoro-2-iodobenzoic acid

Product 1

HCID 203574664-Fluoro-2-[(4-fluorophenyl)sulfanyl]benzoic acid

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent2×

Procedure

To a solution of 3.28 g. (0.0256 mol) of p-fluorothiophenol and 6.8 g. (0.0256 mol) of 2-iodo-4-fluorobenzoic acid in 40 ml. of pyridine is added 3.54 g. (0.0256 mol) of potassium carbonate at room temperature with stirring. Additional pyridine is added to dissolve the precipitate and then 1.54 g. of cuprous chloride is added. The mixture is refluxed overnight, cooled, poured into ice-water, stirred and filtered. The aqueous solution is acidified, filtered and the solid dissolved in 5% sodium bicarbonate solution, then extracted with ether. The aqueous solution is acidified, extracted with ether, and the dried extract is concentrated to give 4-fluoro-2-(4-fluorophenylthio)benzoic acid, m.p. 209°-218° C. The latter (3.0 g., 0.0113 mol) is cyclized by heating for one hour with 45 g. of concentrated sulfuric acid to obtain 2,6-difluorothioxanthone, m.p. 205°-210° C.

Workup

  1. dissolutionto dissolve the precipitate
  2. temperatureThe mixture is refluxed overnight
  3. temperaturecooled
  4. filtrationfiltered
  5. filtrationfiltered
  6. dissolutionthe solid dissolved in 5% sodium bicarbonate solution
  7. extractionextracted with ether
  8. extractionextracted with ether
  9. extractionthe dried extract
  10. concentrationis concentrated

Sources & evidence

ORD record
ord-198857c359c34b04a8b3e9f1a04b569d
Source dataset
uspto-grants-1978_04
Patent number
US04086350

Reaction notes

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