4-Bromo-1H-indole-3-carbaldehyde → 4-Bromo-3-methyl-1H-indole

HRID 475266Notes

Reaction equation

HRID 475266 reaction equation
[Br:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[C:4]([CH:11]=O)=[CH:5][NH:6]2.[H-].[H-].[H-].[H-].[Li+].[Al+3]>C1COCC1>[Br:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[C:4]([CH3:11])=[CH:5][NH:6]2

Participants

4

Reactant 2

HCID 27631784-Bromo-1H-indole-3-carbaldehydeHCID 21226445Aluminium lithium hydride

Product 1

HCID 529877044-Bromo-3-methyl-1H-indoleYield 75.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a refluxing solution of 4-bromo-1H-indole-3-carbaldehyde (644 mg, 2.87 mmol) in dry THF (20 mL) was added LiAlH4 (218 mg, 5.75 mmol) in several small portions. Heating at reflux was continued for 1 h, the reaction cooled to RT and quenched with water (220 μL), 15% aq. NaOH (w/w, 220 μL), and water (650 μL). The resulting precipitate was filtered and the filtrate was concentrated under reduced pressure to dryness. To the residue was added aq. NaOH (10 mL) and the solution twice extracted with DCM (2×10 mL). The combined extracts were dried (MgSO4), filtered and concentrated in vacuo to afford 454 mg (75%) of 4-bromo-3-methyl-1H-indole (230) as light brown oil: MS (ESI) m/z=210.1 [M+1]+

Workup

  1. temperatureHeating
  2. temperatureat reflux
  3. customquenched with water (220 μL), 15% aq. NaOH (w/w, 220 μL), and water (650 μL)
  4. filtrationThe resulting precipitate was filtered
  5. concentrationthe filtrate was concentrated under reduced pressure to dryness
  6. additionTo the residue was added aq. NaOH (10 mL)
  7. extractionthe solution twice extracted with DCM (2×10 mL)
  8. dry with materialThe combined extracts were dried (MgSO4)
  9. filtrationfiltered
  10. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-272d18d441bf4f5abccf56b9955905a0
Source dataset
uspto-grants-2014_01
Patent number
US08637537B2

Reaction notes

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