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

HRID 1610926Notes

Reaction equation

HRID 1610926 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.C(=O)([O-])O.[Na+]>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

5

Reactant 3

HCID 20926Ethyl 5-methoxyindole-2-carboxylateHCID 25134Boron tribromideHCID 516892Sodium Bicarbonate

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/s 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: 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/
  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-75c1cea0c94449f9b990b1a088825811
Source dataset
uspto-grants-2006_01
Patent number
US06984657B1

Reaction notes

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