Potassium Nitrate → 4,6-dimethyl-5-nitro-2,3-dihydro-1H-indole-2,3-dione

HRID 235293

Reaction equation

HRID 235293 reaction equation
[CH3:1][C:2]1[CH:10]=[C:9]([CH3:11])[CH:8]=[C:7]2[C:3]=1[C:4](=[O:13])[C:5](=[O:12])[NH:6]2.[N+:14]([O-])([O-:16])=[O:15].[K+]>OS(O)(=O)=O>[CH3:1][C:2]1[C:10]([N+:14]([O-:16])=[O:15])=[C:9]([CH3:11])[CH:8]=[C:7]2[C:3]=1[C:4](=[O:13])[C:5](=[O:12])[NH:6]2

Participants

4

Reactant 2

HCID 24434Potassium NitrateHCID 23861614,6-dimethyl-1H-indole-2,3-dione

Product 1

HCID 233544354,6-dimethyl-5-nitro-2,3-dihydro-1H-indole-2,3-dioneYield 77.2%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

The method of Cheesman, G. W. H.; J. Chem. Soc. 1170 (1962), was adapted. 4,6-Dimethylisatin (89 mg, 0.50 mmol) was dissolved in concentrated H2SO4 (1.0 mL) at 0° C. for 30 min with stirring, then KNO3 (55 mg, 0.55 mmol, Baker) was added to this solution. The mixture was stirred at 25° C. for 24 h. It was then poured into ice water (5 g). The resulting precipitate was collected by filtration. The precipitate was dissolved in 1N KOH (5 mL) and the small amount of solid was removed by filtration, then the filtrate was acidified to pH 2 with 4N HCl (~1 mL) to give a yellow precipitate. The solid was collected by filtration and was washed with water (2×1 mL), then it was dried in the air at 50° C. for 4 h affording pure (by NMR) title compound (85 mg, 77%) as a yellow powder. Crystallization from acetone/water gave crystals. Mp 278°-80° C. (dec.). IR (KBr, cm-1): 3452, 3225, 2931, 1780, 1742, 1635, 1608, 1535. 1H NMR (DMSO-d6): δ 11.357 (s, 1H), 6.771 (s, 1H), 2.389 (s, 3H), 2.305 (s, 3H). Purity >97.5% by HPLC.

Workup

  1. stirringThe mixture was stirred at 25° C. for 24 h
  2. filtrationThe resulting precipitate was collected by filtration
  3. dissolutionThe precipitate was dissolved in 1N KOH (5 mL)
  4. customthe small amount of solid was removed by filtration
  5. customto give a yellow precipitate
  6. filtrationThe solid was collected by filtration
  7. washwas washed with water (2×1 mL)
  8. customit was dried in the air at 50° C. for 4 h

Sources & evidence

ORD record
ord-a01efeeec5694493b00ed9c8dc9b8df2
Source dataset
uspto-grants-1997_01
Patent number
US05597922

Linked notes

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