Acetic Acid → 4-Aminoindole

HRID 1275667Notes

Reaction equation

HRID 1275667 reaction equation
C(O)(=O)C.[N+:5]([C:8]1[CH:16]=[CH:15][CH:14]=[C:13]2[C:9]=1[CH:10]=[CH:11][NH:12]2)([O-])=O>C(O)C.[Fe]>[NH2:5][C:8]1[CH:16]=[CH:15][CH:14]=[C:13]2[C:9]=1[CH:10]=[CH:11][NH:12]2

Participants

5

Reactant 2

HCID 176Acetic AcidHCID 1457664-Nitro-1H-indole

Product 1

HCID 5834314-AminoindoleYield 99.9%

Reagents, catalysts & solvents 2

HCID 23925IronCatalystHCID 702EthanolSolvent

Procedure

Iron powder (1.20 g, 21.58 mmol) and acetic acid (2.47 mL, 43.19 mmol) are added to a solution of 4-nitroindole (1.0 g, 6.17 mmol) in ethanol (20 mL). The resulting suspension is heated to reflux for 14 hours. The ethanol is removed by rotary evaporation and the residue is partitioned between water and ethyl acetate. The ethyl acetate layer is dried over magnesium sulfate, filtered, and the solvents removed by rotary evaporation. The crude residue is purified via silica gel column chromatography using 1% methanol/methylene chloride as the eluent. The appropriate fractions are combined and the solvents removed by rotary evaporation to yield 0.815 g of 4-aminoindole as an orange solid (82% yield).

Workup

  1. temperatureThe resulting suspension is heated
  2. temperatureto reflux for 14 hours
  3. customThe ethanol is removed by rotary evaporation
  4. customthe residue is partitioned between water and ethyl acetate
  5. dry with materialThe ethyl acetate layer is dried over magnesium sulfate
  6. filtrationfiltered
  7. customthe solvents removed by rotary evaporation
  8. customThe crude residue is purified via silica gel column chromatography
  9. customthe solvents removed by rotary evaporation

Sources & evidence

ORD record
ord-dadd5e7ae0bb4626bc1879c77e198bc9
Source dataset
uspto-grants-2000_12
Patent number
US06162818

Reaction notes

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