Sulfuric Acid → 4,5-Dimethylisatin

HRID 2112557Notes

Reaction equation

HRID 2112557 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]([NH:9][C:10](=[O:14])[CH:11]=NO)[CH:5]=[CH:6][C:7]=1[CH3:8].S(=O)(=O)(O)[OH:16]>O>[CH3:1][C:2]1[C:7]([CH3:8])=[CH:6][CH:5]=[C:4]2[C:3]=1[C:11](=[O:16])[C:10](=[O:14])[NH:9]2

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 6848890HCID 6848890, compound

Product 1

HCID 2665354,5-Dimethylisatin

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
85 °C

Procedure

N-(3,4-Dimethylphenyl)-2-hydroxyimino-acetamide (30 g, 0.156 mmol) was slowly added to an aqueous solution (17 ml) of concentrated sulfuric acid (85 ml), and the mixture was stirred at 85° C. for 2 hours. The obtained solution was poured into ice-cooled water, and the precipitated orange solid was filtered out. The obtained solid was dissolved in a 10% aqueous sodium hydroxide solution, activated carbon was added, and the mixture was stirred. The obtained solution was filtered, and acetic acid was used to adjust the pH to 3 to obtain 4,5-dimethyl-1H-indole-2,3-dione as crystals.

Workup

  1. additionThe obtained solution was poured into ice-
  2. filtrationthe precipitated orange solid was filtered out
  3. dissolutionThe obtained solid was dissolved in a 10% aqueous sodium hydroxide solution
  4. additionwas added
  5. stirringthe mixture was stirred
  6. filtrationThe obtained solution was filtered

Sources & evidence

ORD record
ord-3a17465761a64b39bc233e5e8b89abd6
Source dataset
uspto-grants-2009_04
Patent number
US07524841B2

Reaction notes

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