Dimethylacetamide → 2,4,5-Trifluorobenzoic acid

HRID 2253939Notes

Reaction equation

HRID 2253939 reaction equation
[F:1][C:2]1[C:10]([F:11])=[CH:9][C:8]([F:12])=[C:4]([C:5]([OH:7])=[O:6])[C:3]=1C(O)=O.CC(N(C)C)=O>O>[F:12][C:8]1[CH:9]=[C:10]([F:11])[C:2]([F:1])=[CH:3][C:4]=1[C:5]([OH:7])=[O:6]

Participants

4

Reactant 2

HCID 31374DimethylacetamideHCID 10130673HCID 10130673, compound

Product 1

HCID 5211702,4,5-Trifluorobenzoic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A 250 mL single-neck flask equipped with a condenser and a magnetic stirrer was charged with 30.00 g of 3,4,6-trifluorophthalic acid, and 200 mL of dimethyl acetamide. The reaction mixture was then heated with stirring for 29.2 hr. at a bath temperature of 127° C. The flask was then allowed to cool to room temperature and the contents were poured into 500 mL of water, and extracted with 4×200 mL of ethyl acetate. The combined organic extracts were washed with water (2×200 mL), dried over magnesium sulfate, filtered, and the solvent removed on a rotary evaporator followed by drying at the pump overnight. The crude product was then dissolved in 25 mL of ethyl acetate and introduced at the top of a silica column (4.5 cm ID×56 cm, flushed with hexane). The product was then eluted with 90:10 hexane:ethyl acetate under a slight nitrogen pressure, and the fractions (500 mL each) were monitored by gas chromatography. The fractions containing the product were combined, the solvent removed on a rotary evaporator, and then dried at the pump overnight to give 2,4,5-trifluorobenzoic acid as a light yellow solid. Recrystallization of the product from toluene (50 mL, ca. 60° C.) gave a white product (65.0% overall yield).

Workup

  1. customA 250 mL single-neck flask equipped with a condenser and a magnetic stirrer
  2. temperatureThe reaction mixture was then heated
  3. customtemperature of 127° C
  4. extractionextracted with 4×200 mL of ethyl acetate
  5. washThe combined organic extracts were washed with water (2×200 mL)
  6. dry with materialdried over magnesium sulfate
  7. filtrationfiltered
  8. customthe solvent removed on a rotary evaporator
  9. customby drying at the pump overnight
  10. dissolutionThe crude product was then dissolved in 25 mL of ethyl acetate
  11. additionintroduced at the top of a silica column (4.5 cm ID×56 cm, flushed with hexane)
  12. washThe product was then eluted with 90:10 hexane
  13. additionThe fractions containing the product
  14. customthe solvent removed on a rotary evaporator
  15. customdried at the pump overnight

Sources & evidence

ORD record
ord-a1b1f4e25b00462480fada0bef5e817b
Source dataset
uspto-grants-1993_08
Patent number
US05233085

Reaction notes

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