Sulfuric Acid → 2-Chloro-5-Fluorobenzaldehyde

HRID 1700758Notes

Reaction equation

HRID 1700758 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([F:8])=[CH:4][C:3]=1[CH3:9].S(=O)(=O)(O)[OH:11].[Cr](O)(O)(=O)=O>C(OC(=O)C)(=O)C>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([F:8])=[CH:4][C:3]=1[CH:9]=[O:11]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 24425Chromic AcidHCID 1184752-Chloro-5-fluorotoluene

Product 1

HCID 27791842-Chloro-5-Fluorobenzaldehyde

Reagents, catalysts & solvents 1

HCID 7918Acetic AnhydrideSolvent2×

Procedure

To a solution of 2-chloro-5-fluorotoluene (5.0 g) in acetic anhydride (40 ml) was added dropwise under ice-cooling concentrated sulfuric acid (40 ml), and then added dropwise a solution of anhydrous chromic acid (9.3 g) in acetic anhydride (40 ml) for 2 hours. The mixture was stirred at the same temperature for 1 hour, poured into ice-water and extracted with diethylether. The organic layer was washed with sodium carbonate solution, water and saturated brine and dried with magnesium sulfate. Under reduced pressure, the solvent was evaporated, and the residue was dissolved in tetrahydrofuran (10 ml). To the mixture were added water (4 ml) and concentrated sulfuric acid (4 ml), and the mixture was stirred at 100° C. for 30 minutes and cooled. The reaction solution was extracted with ethyl acetate. The organic layer was washed with sodium carbonate solution, water and saturated brine and dried with magnesium sulfate. Under reduced pressure, the solvent was evaporated to give the residue, which was subjected to silica gel column chromatography to give 2-chloro-5-fluorobenzaldehyde (1.6 g).

Workup

  1. extractionextracted with diethylether
  2. washThe organic layer was washed with sodium carbonate solution, water and saturated brine
  3. dry with materialdried with magnesium sulfate
  4. customUnder reduced pressure, the solvent was evaporated
  5. dissolutionthe residue was dissolved in tetrahydrofuran (10 ml)
  6. additionTo the mixture were added water (4 ml) and concentrated sulfuric acid (4 ml)
  7. stirringthe mixture was stirred at 100° C. for 30 minutes
  8. temperaturecooled
  9. extractionThe reaction solution was extracted with ethyl acetate
  10. washThe organic layer was washed with sodium carbonate solution, water and saturated brine
  11. dry with materialdried with magnesium sulfate
  12. customUnder reduced pressure, the solvent was evaporated
  13. customto give the residue, which

Sources & evidence

ORD record
ord-3dc7d39afae048f1b85e407f8da4d3f9
Source dataset
uspto-grants-2002_02
Patent number
US06350749B1

Reaction notes

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