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

HRID 413792Notes

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 iso-hexane-50% ethyl acetate as eluent to give the end product as a yellow solid (2.98 g, 64%); NMR d (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-4d86c6be9e2e4c869fb3a2a0d5b2fa61
Source dataset: uspto-grants-2003_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06569888B1

Reaction notes

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