Sulfuric Acid → 3-Hydroxy-2-methylbenzoic Acid

HRID 400269Notes

Reaction equation

HRID 400269 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 solution. 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 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 solution
  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 5% methanol in methylene chloride)

Sources & evidence

ORD record
ord-0b47e0ee29e94990870f668d60458b2f
Source dataset
uspto-grants-1998_10
Patent number
US05827891

Reaction notes

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