Sulfuric Acid → 3-Hydroxy-2-methylbenzoic Acid

HRID 1250085Notes

Reaction equation

HRID 1250085 reaction equation
N[C:2]1[C:3]([CH3:11])=[C:4]([CH:8]=[CH:9][CH:10]=1)[C:5]([OH:7])=[O:6].S(=O)(=O)(O)[OH:13].N([O-])=O.[Na+].NC(N)=O>O.[OH-].[Na+]>[OH:13][C:2]1[C:3]([CH3:11])=[C:4]([CH:8]=[CH:9][CH:10]=1)[C:5]([OH:7])=[O:6]

Participants

7

Reactant 4

HCID 1118Sulfuric Acid2×HCID 1176UreaHCID 27336993-Amino-2-methylbenzoic acidHCID 23668193Sodium Nitrite

Product 1

HCID 2520233-Hydroxy-2-methylbenzoic AcidYield 100%

Reagents, catalysts & solvents 2

HCID 14798Sodium HydroxideCatalystHCID 962WaterSolvent3×

Conditions

Temperature
90 °C

Procedure

A solution of 3-amino-2-methylbenzoic acid (43.1 g, 285 mmol), water (700 mL), and sulfuric acid (55 mL) was briefly heated to give a clear solution and then cooled to a temperature below 5° C. A solution of sodium nitrite (21 g, 300 mmol) in a minimal amount of water was added in portions while maintaining the internal temperature below 7° C. After stirring for about 30 minutes in an ice bath, urea (7 g) was added to discharge the excess nitrile. A chilled solution of 98% sulfuric acid (240 mL) in water (1000 mL) was added to the diazonium solution, and the combined reaction mixture was heated slowly to 90° C. Solid sodium hydroxide (410 mg) was slowly added. The mixture was extracted with ethyl acetate, and the organic layer was dried over sodium sulfate and evaporated to give 3-hydroxy-2-methylbenzoic acid as a yellow solid (44.4 g,˜100%).

Workup

  1. customto give a clear solution
  2. temperaturecooled to a temperature below 5° C
  3. temperaturewhile maintaining the internal temperature below 7° C
  4. customthe combined reaction mixture
  5. extractionThe mixture was extracted with ethyl acetate
  6. dry with materialthe organic layer was dried over sodium sulfate
  7. customevaporated

Sources & evidence

ORD record
ord-0c235ae9d031437e971834df4baa50ac
Source dataset
uspto-grants-2002_01
Patent number
US06335459B1

Reaction notes

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