Sulfuric Acid → 3-Hydroxy-2-methylbenzoic Acid

HRID 1457174Notes

Reaction equation

HRID 1457174 reaction equation
[CH3:1][C:2]1[C:10](N)=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].S(=O)(=O)(O)[OH:13].N([O-])=O.[Na+]>O>[CH3:1][C:2]1[C:10]([OH:13])=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5]

Participants

5

Reactant 3

HCID 1118Sulfuric Acid2×HCID 27336993-Amino-2-methylbenzoic acidHCID 23668193Sodium Nitrite

Product 1

HCID 2520233-Hydroxy-2-methylbenzoic AcidYield 69%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
90 °C

Procedure

To a cold (0° C.) suspension of 0.54 g (3.3 mmol) of 2-methyl-3-aminobenzoic acid in 5 mL of water containing 0.65 mL of concentrated sulfuric acid, was added 0.25 g (3.6 mmol) of solid sodium-nitrite. After approximately 15 minutes the reaction mixture was poured into 20 mL of warm water containing 4 mL of concentrated sulfuric acid. The resultant reaction mixture was heated slowly to 90° C., resulting in gas evolution. After the gas evolution ceased, the solution was cooled to room temperature and extracted with ethyl acetate. The organic layers were combined, washed with 0.5N hydrochloric acid, dried and concentrated under reduced pressure. The crude residue was purified by rapid filtration through silica gel (eluent of 5% methanol in methylene chloride) to yield 350 mg of a white solid (m.p. 137°-138° C.).

Workup

  1. customThe resultant reaction mixture
  2. customresulting in gas evolution
  3. temperaturethe solution was cooled to room temperature
  4. extractionextracted with ethyl acetate
  5. washwashed with 0.5N hydrochloric acid
  6. customdried
  7. concentrationconcentrated under reduced pressure
  8. filtrationThe crude residue was purified by rapid filtration through silica gel (eluent of 5% methanol in methylene chloride)

Sources & evidence

ORD record
ord-33176ceabf844e578bd2761f511e941c
Source dataset
uspto-grants-1998_12
Patent number
US05846993

Reaction notes

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