Boron tribromide → 1-Benzyl-2-ethyl-1H-indol-4-OL

HRID 495610Notes

Reaction equation

HRID 495610 reaction equation
[CH2:1]([C:3]1[N:4]([CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)[C:5]2[C:10]([CH:11]=1)=[C:9]([O:12]C)[CH:8]=[CH:7][CH:6]=2)[CH3:2].B(Br)(Br)Br>C(Cl)Cl>[CH2:1]([C:3]1[N:4]([CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)[C:5]2[C:10]([CH:11]=1)=[C:9]([OH:12])[CH:8]=[CH:7][CH:6]=2)[CH3:2]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 99432411-Benzyl-2-ethyl-4-methoxy-1H-indole

Product 1

HCID 98164161-Benzyl-2-ethyl-1H-indol-4-OLYield 54%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

3.1 g (11.7 mmol) of 2-ethyl-4-methoxy-1-(phenylmethyl)-1H-indole was O-demethylated by treating it with 48.6 mL of 1M BBr3 in methylene chloride with stirring at room temperature for 5 hours, followed by concentration at reduced pressure. The residue was dissolved in ethyl acetate, washed with brine and dried (MgSO4). After concentrating at reduced pressure, the residue was chromatographed on silica gel eluting with 20% EtOAc/hexane to give 1.58 g (54% yield) of 2-ethyl-4-hydroxy-1-(phenylmethyl)-1H-indole, mp, 86-90° C.

Workup

  1. concentrationfollowed by concentration at reduced pressure
  2. dissolutionThe residue was dissolved in ethyl acetate
  3. washwashed with brine
  4. dry with materialdried (MgSO4)
  5. concentrationAfter concentrating at reduced pressure
  6. customthe residue was chromatographed on silica gel eluting with 20% EtOAc/hexane

Sources & evidence

ORD record
ord-d39e691b54f34bbba8d306e2918205bb
Source dataset
uspto-grants-2005_09
Patent number
US06939890B2

Reaction notes

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