Sulfuric Acid → 5-bromo-6-methoxy-1H-indole-2,3-dione

HRID 245148Notes

Reaction equation

HRID 245148 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([NH:8][C:9](=[O:13])/[CH:10]=N/O)=[CH:4][C:3]=1[O:14][CH3:15].[OH:16]S(O)(=O)=O>>[Br:1][C:2]1[CH:7]=[C:6]2[C:5](=[CH:4][C:3]=1[O:14][CH3:15])[NH:8][C:9](=[O:13])[C:10]2=[O:16]

Participants

3

Reactant 2

HCID 1118Sulfuric AcidHCID 14595057(2E)-N-(4-bromo-3-methoxyphenyl)-2-hydroxyiminoacetamide

Product 1

HCID 145950615-bromo-6-methoxy-1H-indole-2,3-dione

Conditions

Temperature
80 °C

Procedure

Concentrated H2SO4 (400 mL) was heated to 50° C. and portions of (2E)-N-[4-bromo-3-(methyloxy)phenyl]-2-(hydroxyimino)ethanamide (75 g, 275 mmol) were added while keeping the internal temperature below 70° C. After complete addition, the mixture was heated to 80° C. for 1 h, then poured into ice, filtered and washed with H2O to yield 5-bromo-6-(methyloxy)-1H-indole-2,3-dione (75 g) of a red solid. MS (m/z) 257.9 (M+H+).

Workup

  1. customthe internal temperature below 70° C
  2. additionAfter complete addition
  3. additionpoured into ice
  4. filtrationfiltered
  5. washwashed with H2O

Sources & evidence

ORD record
ord-e7ddd712c7ca4b06a283fb359913762b
Source dataset
uspto-grants-2014_02
Patent number
US08658636B2

Reaction notes

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