Sulfuric Acid → Benzenesulfonic acid, 5-amino-2-methoxy-

HRID 2082551Notes

Reaction equation

HRID 2082551 reaction equation
[S:1](=[O:5])(=O)([OH:3])[OH:2].[CH3:6][O:7][C:8]1[CH:13]=[CH:12][C:11]([NH2:14])=[CH:10][CH:9]=1.OS(O)(=O)=O.O=S(=O)=O>>[CH3:6][O:7][C:8]1[CH:13]=[CH:12][C:11]([NH2:14])=[CH:10][C:9]=1[S:1]([OH:3])(=[O:5])=[O:2]

Participants

4

Reactant 3

HCID 1118Sulfuric Acid2×HCID 7732P-AnisidineHCID 24681Fuming sulfuric acid

Product 1

HCID 80945Benzenesulfonic acid, 5-amino-2-methoxy-Yield 97%

Procedure

123 parts of fused p-anisidine are added dropwise over 30 minutes to 240 parts of 100% sulfuric acid, while keeping the temperature at 55°-60° C. After stirring for 15 minutes the p-anisidine is completely dissolved. This sulfuric acid solution is then run into 242 parts of 66% oleum over 30 minutes, while keeping the temperature at 30°-40° C. by cooling with an ice bath. Stirring is continued for 30 minutes at 40° C., after which time no more educt can be detected by HPLC. The batch is poured into 1000 parts of ice/water and the precipitated 4-methoxyaniline-3-sulfonic acid is filtered with suction and washed with 500 parts of ice/water, affording 179 parts of moist 97.0% 4-methoxyaniline-3-sulfonic acid, corresponding to a yield of 85%, based on p-anisidine. No more p-anisidine and no more 4-methoxyaniline-2-sulfonic acid is detectable by HPLC (<0.1%).

Workup

  1. customat 55°-60° C
  2. dissolutionis completely dissolved
  3. customat 30°-40° C.
  4. temperatureby cooling with an ice bath
  5. filtrationthe precipitated 4-methoxyaniline-3-sulfonic acid is filtered with suction
  6. washwashed with 500 parts of ice/water

Sources & evidence

ORD record
ord-8fc6e9f29d6d4eeab8de724de4ad59b4
Source dataset
uspto-grants-1993_02
Patent number
US05189206

Reaction notes

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