Boron tribromide → Methyl 4-hydroxy-1H-indole-2-carboxylate

HRID 1595461Notes

Reaction equation

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

Participants

Conditions

Temperature: -78 °C

Procedure

Boron tribromide (73.1 ml, 1.0 M solution in DCM) was added dropwise to a solution of methyl 4-methoxyindole-2-carboxylate (5 g) in DCM (200 ml) cooled to −78° C. under argon. The reaction was allowed to warm to room temperature then partitioned between dichloromethane and saturated aqueous sodium hydrogen carbonate solution. Combined organic extracts were dried (MgSO4) and concentrated in vacuo and the residue purified by column chromatography using isohexane-50% ethyl acetate as eluent to give the end product as a yellow solid (2.98 g, 64%); NMR δ (CD3SOCD3) 3.82 (s, 3H), 6.36 (d, 1H), 6.85 (d, 1H), 7.02 (t, 1H), 7.17 (d, 1H), 9.66 (s, 1H), 11.72 (bs, 1H); M/z (+) 192 (MH+).

Workup

temperatureto warm to room temperature
customthen partitioned between dichloromethane and saturated aqueous sodium hydrogen carbonate solution
dry with materialCombined organic extracts were dried (MgSO4)
concentrationconcentrated in vacuo
customthe residue purified by column chromatography

Sources & evidence

ORD record: ord-f948bad5b89e4d4588605c05fc505ff3
Source dataset: uspto-grants-2001_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06288103B1

Reaction notes

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