Hydrochloric Acid → 4-Fluorosalicylic acid

HRID 2229539Notes

Reaction equation

HRID 2229539 reaction equation
F[C:2]1[CH:10]=[C:9]([F:11])[CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].[OH-:12].[Na+].Cl>CN1CCN(C)C1=O.O>[F:11][C:9]1[CH:10]=[C:2]([OH:12])[C:3](=[CH:7][CH:8]=1)[C:4]([OH:6])=[O:5]

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 741022,4-Difluorobenzoic acid

Product 1

HCID 676614-Fluorosalicylic acidYield 68.1%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 66611,3-Dimethyl-2-imidazolidinoneSolvent

Conditions

Temperature
135 °C

Procedure

A solution of 2,4-difluorobenzoic acid (100 g, 0.63 mol) in 1,3-dimethyl-2-imidazolidinone (1,400 mL, 0.45 M) was treated with sodium hydroxide (88 g, 2.2 mol) and heated to 135° C. After stirring for 4 h, the solution was cooled 0° C., dissolved in water (100 mL), and transferred to a 5 L Erlenmeyer flask and carefully treated with aq HCl (2,800 mL, 2 N). After filtering off the crude product, the precipitate was dissolved in ethyl acetate, dried over sodium sulfate and decolorizing charcol, and filtered. The solution was concentrated under reduced pressure and recrystallized from ethyl acetate and heptane to give 4-fluorosalicylic acid (2 crops, 67 g, 68%) as off-white needles. mp: 188-189° C.; Rf 0.26 (20% methanol in dichloromethane).

Workup

  1. temperaturethe solution was cooled 0° C.
  2. filtrationAfter filtering off the crude product
  3. dissolutionthe precipitate was dissolved in ethyl acetate
  4. dry with materialdried over sodium sulfate
  5. filtrationfiltered
  6. concentrationThe solution was concentrated under reduced pressure
  7. customrecrystallized from ethyl acetate and heptane

Sources & evidence

ORD record
ord-2460b238fde54cbca2e974e36ffeb2ba
Source dataset
uspto-grants-2002_07
Patent number
US06420426B1

Reaction notes

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