Methanesulfonic Acid → 5-Methoxy-6-methylindoline-2,3-dione

HRID 1157442Notes

Reaction equation

HRID 1157442 reaction equation
ON=[CH:3][C:4]([NH:6][C:7]1[CH:12]=[CH:11][C:10]([O:13][CH3:14])=[C:9]([CH3:15])[CH:8]=1)=[O:5].CS(O)(=O)=[O:18]>>[CH3:14][O:13][C:10]1[CH:11]=[C:12]2[C:7](=[CH:8][C:9]=1[CH3:15])[NH:6][C:4](=[O:5])[C:3]2=[O:18]

Participants

3

Reactant 2

HCID 6395Methanesulfonic AcidHCID 713346932-hydroxyimino-N-(4-methoxy-3-methylphenyl)acetamide2×

Product 1

HCID 543291845-Methoxy-6-methylindoline-2,3-dioneYield 77%

Procedure

2-Hydroxyimino-N-(4-methoxy-3-methylphenyl)acetamide (0.5 g, 2.4 mmol) was added portionwise to concentrated methanesulfonic acid (1.5 mL). The 2-hydroxyimino-N-(4-methoxy-3-methylphenyl)acetamide was added over a period of 45 min in order to keep the reaction temperature between 65 to 70° C. After addition, the mixture was stirred for 10 min and then poured onto ice (10 g). The resulting aqueous solution was extracted with ethyl acetate (3×50 mL). Combined organic layers were dried (Na2SO4), filtered and concentrated in vacuo. The crude product was purified by column chromatography on silica gel with petroleum ether:ethyl acetate (20:1, v/v) as eluent to afford 5-methoxy-6-methyl-1H-indole-2,3-dione (350 mg, 1.8 mmol, 77%).

Workup

  1. custombetween 65 to 70° C
  2. additionAfter addition
  3. additionpoured onto ice (10 g)
  4. extractionThe resulting aqueous solution was extracted with ethyl acetate (3×50 mL)
  5. dry with materialCombined organic layers were dried (Na2SO4)
  6. filtrationfiltered
  7. concentrationconcentrated in vacuo
  8. customThe crude product was purified by column chromatography on silica gel with petroleum ether:ethyl acetate (20:1

Sources & evidence

ORD record
ord-d21d2f10338542aaafa2cfd338b1d777
Source dataset
uspto-grants-2010_10
Patent number
US07807686B2

Reaction notes

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