Methyl Ethyl Ketone → 5-Bromo-2,3-dimethyl-1H-indole

HRID 404274Notes

Reaction equation

HRID 404274 reaction equation
[CH3:1][C:2](=O)[CH2:3][CH3:4].Cl.[Br:7][C:8]1[CH:13]=[CH:12][C:11]([NH:14]N)=[CH:10][CH:9]=1>CCO>[Br:7][C:8]1[CH:13]=[C:12]2[C:11](=[CH:10][CH:9]=1)[NH:14][C:3]([CH3:4])=[C:2]2[CH3:1]

Participants

4

Reactant 2

HCID 6569Methyl Ethyl KetoneHCID 121574-Bromophenylhydrazine hydrochloride

Product 1

HCID 127930975-Bromo-2,3-dimethyl-1H-indoleYield 67%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Following a published procedure (Gundersen, E. G. U.S. Patent App. Publ. US 2005/070592) 2-Butanone (0.11 mL, 1.278 mmol) was added to a solution of 4-bromophenylhydrazine hydrochloride (0.300 g, 1.342 mmol in EtOH (3.8 mL). The mixture was heated to reflux for 22 h, concentrated in vacuo, and partitioned between EtOAc and 1N HCl. The organic layer was washed with H2O and saturated aqueous NaHCO3, dried over Na2SO4, filtered, and concentrated. The crude residue was purified by chromatography (SiO2, 0-20% EtOAc/Hexane) to afford the desired indole as a pink powder (200 mg, 67%).

Workup

  1. temperatureThe mixture was heated
  2. temperatureto reflux for 22 h
  3. concentrationconcentrated in vacuo
  4. custompartitioned between EtOAc and 1N HCl
  5. washThe organic layer was washed with H2O and saturated aqueous NaHCO3
  6. dry with materialdried over Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated
  9. customThe crude residue was purified by chromatography (SiO2, 0-20% EtOAc/Hexane)

Sources & evidence

ORD record
ord-a77b45717ef348488aa1730458407939
Source dataset
uspto-grants-2014_06
Patent number
US08748473B2

Reaction notes

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