Lithium Hydroxide → 3-Fluoro-5-methylbenzoic acid

HRID 732007Notes

Reaction equation

HRID 732007 reaction equation
[OH-].[Li+].C[O:4][C:5](=[O:14])[C:6]1[CH:11]=[C:10]([CH3:12])[CH:9]=[C:8]([F:13])[CH:7]=1>O1CCCC1>[F:13][C:8]1[CH:7]=[C:6]([CH:11]=[C:10]([CH3:12])[CH:9]=1)[C:5]([OH:14])=[O:4]

Participants

4

Reactant 2

HCID 3939Lithium HydroxideHCID 44203100Benzoic acid, 3-fluoro-5-methyl-, methyl ester

Product 1

HCID 27784473-Fluoro-5-methylbenzoic acidYield 98.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
75 °C

Procedure

0.5 N Lithium hydroxide (7.4 ml, 3.7 mmol) was added to a solution 3-fluoro-5-methyl-benzoic acid methyl ester (520 mg, 3.1 mmol) in tetrahydrofuran (7.4 ml). The reaction was stirred at 75° C. for 2 h and then the solvent was removed in vacuo. The residue was dissolved in a small amount of water and then acidified (pH about 2) by the addition of 10% HCl (aq.). Following extraction of the aqueous layer with ethyl acetate, the organic layer was then washed with water and saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated to afford 469 mg (98%) of 3-fluoro-5-methyl-benzoic acid as a white solid. 1H NMR (DMSO), d (ppm): 7.62 (s, 1H), 7.45 (d, 1H), 7.32 (d, 1H), 2.38 (s, 3H).

Workup

  1. customthe solvent was removed in vacuo
  2. dissolutionThe residue was dissolved in a small amount of water
  3. additionby the addition of 10% HCl (aq.)
  4. extractionextraction of the aqueous layer with ethyl acetate
  5. washthe organic layer was then washed with water and saturated brine
  6. dry with materialdried over anhydrous sodium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated

Sources & evidence

ORD record
ord-f40495955b4041e4819098903f9dab84
Source dataset
uspto-grants-2009_09
Patent number
US07585881B2

Reaction notes

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