Sulfuric Acid → 3-Methylsalicylic Acid

HRID 1636437Notes

Reaction equation

HRID 1636437 reaction equation
[CH3:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:4]([C:5]([OH:7])=[O:6])[C:3]=1N.S(=O)(=O)(O)[OH:13].N([O-])=O.[Na+]>O>[CH3:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:4]([C:5]([OH:7])=[O:6])[C:3]=1[OH:13]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 781012-Amino-3-methylbenzoic acidHCID 23668193Sodium Nitrite

Product 1

HCID 67383-Methylsalicylic Acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
0 °C

Procedure

3-methylanthranilic acid (12.5 g) was added slowly with stirring to sulfuric acid (61 ml: 7.5M) cooled to 0° C. A solution of sodium nitrite (5.7 g) in water (19 ml) was added dropwise maintaining the temperature below 5° C. The mixture was stirred for half an hour at room temperature and heated at 79-80° C. for one hour then cooled. Water was added and the mixture allowed to stand over the weekend. The mixture was filtered and the precipitate collected and washed with water. It was dissolved in ethyl acetate and the solution washed with water, stirred with barium chloride for 2 hours to remove any residual sulfuric acid, filtered, washed with water, dried and evaporated under reduced pressure to give 3-methylsalicylic acid, m.p. 160-2° C.

Workup

  1. temperaturemaintaining the temperature below 5° C
  2. temperatureheated at 79-80° C. for one hour
  3. temperaturethen cooled
  4. filtrationThe mixture was filtered
  5. customthe precipitate collected
  6. washwashed with water
  7. dissolutionIt was dissolved in ethyl acetate
  8. washthe solution washed with water
  9. stirringstirred with barium chloride for 2 hours
  10. customto remove any residual sulfuric acid
  11. filtrationfiltered
  12. washwashed with water
  13. customdried
  14. customevaporated under reduced pressure

Sources & evidence

ORD record
ord-37cb0704c2674e50832d2fde01fa616d
Source dataset
uspto-grants-2000_03
Patent number
US06034121

Reaction notes

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