Nitric Acid → 4,5-Difluoro-2-nitrobenzoic acid

HRID 982199Notes

Reaction equation

HRID 982199 reaction equation
[F:1][C:2]1[CH:3]=[C:4]([CH:8]=[CH:9][C:10]=1[F:11])[C:5]([OH:7])=[O:6].CCCC(O[C@@]1(C(COC(C)=O)=O)[C@@]2(C)C[C@H](O)[C@]3(F)[C@]4(C)C(=CC(C=C4)=O)[C@@H](F)C[C@H]3[C@@H]2CC1)=O.[N+:48]([O-])([OH:50])=[O:49]>S(=O)(=O)(O)O>[N+:48]([C:8]1[CH:9]=[C:10]([F:11])[C:2]([F:1])=[CH:3][C:4]=1[C:5]([OH:7])=[O:6])([O-:50])=[O:49]

Participants

5

Reactant 3

HCID 944Nitric AcidHCID 991663,4-Difluorobenzoic acidHCID 443936Difluprednate

Product 1

HCID 42196304,5-Difluoro-2-nitrobenzoic acidYield 77.4%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Conditions

Temperature
0 °C

Procedure

Into 100 ml of 96% sulfuric acid was placed 3,4-difluorobenzoic acid (11.95 g, 0.0756 mol). The solution was stirred at room temperature until the DFBA was dissolved, and then cooled to 0° C. Nitric acid (7.9 g of 90% fuming) was added dropwise to the cooled mixture. After addition, the solution was warmed to room temperature and stirred until completion of the reaction. After pouring on to 500 g of ice water, the solids were filtered and washed with water. After drying, 11.88 g of 2-nitro-4,5-difluorobenzoic acid was isolated. The material was identified by GCMS and 19F NMR analysis. An additional 2.41 g of product was obtained by extraction of the acid washes and removal of the solvent.

Workup

  1. dissolutionwas dissolved
  2. additionAfter addition
  3. temperaturethe solution was warmed to room temperature
  4. filtrationthe solids were filtered
  5. washwashed with water
  6. customAfter drying

Sources & evidence

ORD record
ord-33f2cf8e11134ed781d8c2541eb06aa4
Source dataset
uspto-grants-1991_02
Patent number
US04994606

Reaction notes

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