Ethyl 5-methoxyindole-2-carboxylate → Ethyl 5-hydroxy-1H-indole-2-carboxylate

HRID 1582631Notes

Reaction equation

HRID 1582631 reaction equation
B(Br)(Br)Br.C[O:6][C:7]1[CH:8]=[C:9]2[C:13](=[CH:14][CH:15]=1)[NH:12][C:11]([C:16]([O:18][CH2:19][CH3:20])=[O:17])=[CH:10]2>ClCCl>[OH:6][C:7]1[CH:8]=[C:9]2[C:13](=[CH:14][CH:15]=1)[NH:12][C:11]([C:16]([O:18][CH2:19][CH3:20])=[O:17])=[CH:10]2

Participants

4

Reactant 2

HCID 20926Ethyl 5-methoxyindole-2-carboxylateHCID 25134Boron tribromide

Product 1

HCID 90677Ethyl 5-hydroxy-1H-indole-2-carboxylateYield 48.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Boron tribromide (64.58 g) was added dropwise to a stirred solution of ethyl 5-methoxyindole-2-carboxylate (20 g) in dichloromethane (1000 ml) at −78° C. under an atmosphere of argon. The reaction was allowed to warm to room temperature and stirred for a further 2 hours. The reaction was poured into ice/saturated aqueous sodium hydrogen carbonate solution with stirring and extracted with ethyl acetate. Combined organic extracts were washed with saturated aqueous sodium hydrogen carbonate solution, water, aqueous saturated sodium chloride solution and dried. The solution was concentrated in vacuo and the residue was purified by column chromatography using 0-60% diethyl ether: iso-hexane as eluent to yield product as a white solid (9.02 g, 48%). NMR: δ 1.31) (t, 3H), 4.29 (q, 2H), 6.79 (dd, 1H), 6.90 (dd. 1H), 7.22 (d, 1H), 8.84 (s, 1H), 11.52 (brs, 1H); m/z 206 (M+H+).

Workup

  1. additionThe reaction was poured into ice/saturated aqueous sodium hydrogen carbonate solution
  2. stirringwith stirring
  3. extractionextracted with ethyl acetate
  4. washCombined organic extracts were washed with saturated aqueous sodium hydrogen carbonate solution, water, aqueous saturated sodium chloride solution
  5. customdried
  6. concentrationThe solution was concentrated in vacuo
  7. customthe residue was purified by column chromatography

Sources & evidence

ORD record
ord-9d3f90b361804a7595a9da7dbe982da8
Source dataset
uspto-grants-2004_05
Patent number
US06737435B1

Reaction notes

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