4-Fluorobenzene-1,2-dicarboxylic acid → 1,3-Isobenzofurandione, 5-fluoro-

HRID 256142Notes

Reaction equation

HRID 256142 reaction equation
[Mn]([O-])(=O)(=O)=O.[K+].[F:7][C:8]1[CH:9]=[C:10]([C:17]([OH:19])=[O:18])[C:11](=[CH:15][CH:16]=1)[C:12]([OH:14])=O.[K]>>[F:7][C:8]1[CH:9]=[C:10]2[C:17](=[O:18])[O:19][C:12](=[O:14])[C:11]2=[CH:15][CH:16]=1

Participants

4

Reactant 3

HCID 153124-Fluorobenzene-1,2-dicarboxylic acidHCID 516875Potassium PermanganateHCID 5462222Potassium

Product 1

HCID 675721,3-Isobenzofurandione, 5-fluoro-

Procedure

Diazotization (i) and conversion (ii) to the tetrafluoroborate followed by pyrolysis in benezene of that derivative (Balz-Schieman reaction) gives 3,4-dimethylfluorobenzene. This is oxidized by aqueous potassium permanganate to 4-fluorophthalic acid, monopotassium salt. Vacuum distillation of the latter in the presence of sulfuric acid yields 4-fluorophthalic anhydride. Treatment of the anhydride with urea in boiling chlorobenzene yields the imide which is converted with concentrated ammonium hydroxide to the diamide. Finally, dehydration of the diamide with thionyl chloride in dimethylformamide gives 4-fluorophthalonitrile.

Workup

  1. distillationVacuum distillation of the latter in the presence of sulfuric acid

Sources & evidence

ORD record
ord-6c66da9abd3f463688415b93ca7b11eb
Source dataset
uspto-grants-1987_10
Patent number
US04701396

Reaction notes

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