Boron tribromide → 5-(4-Hydroxy-2-methyl-phenyl)-4-methyl-thiophene-2-carboxylic acid methyl ester

HRID 250226Notes

Reaction equation

HRID 250226 reaction equation
[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]([C:11]2[CH:16]=[CH:15][C:14]([O:17]C)=[CH:13][C:12]=2[CH3:19])=[C:8]([CH3:10])[CH:9]=1)=[O:4].B(Br)(Br)Br>ClCCl>[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]([C:11]2[CH:16]=[CH:15][C:14]([OH:17])=[CH:13][C:12]=2[CH3:19])=[C:8]([CH3:10])[CH:9]=1)=[O:4]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 667042235-(4-Methoxy-2-methyl-phenyl)-4-methyl-thiophene-2-carboxylic acid methyl ester

Product 1

HCID 667041595-(4-Hydroxy-2-methyl-phenyl)-4-methyl-thiophene-2-carboxylic acid methyl esterYield 82%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a solution of 5-(4-methoxy-2-methyl-phenyl)-4-methyl-thiophene-2-carboxylic acid methyl ester (540 mg, 2 mmol) in dichloromethane (30 mL) at 0° C. is added BBr3 in dichloromethane (1N, 5.0 mL). The mixture is stirred at ambient temperature overnight. The reaction is quenched by addition of methanol and is evaporated. The residue is purified by column chromatography (0-20% EtOAc in hexanes) to give 5-(4-hydroxy-2-methyl-phenyl)-4-methyl-thiophene-2-carboxylic acid methyl ester (420 mg, 82%). 1H NMR (CDCl3): δ 7.62 (s, 1H), 7.10 (d, 1H, J=7.9 Hz), 6.76 (s, 1H), 6.70 (d, 1H, J=7.9 Hz), 4.79 (bs, 1H), 3.88 (s, 3H), 2.15 (s, 3H), 2.02 (s, 3H).

Workup

  1. customThe reaction is quenched by addition of methanol
  2. customis evaporated
  3. customThe residue is purified by column chromatography (0-20% EtOAc in hexanes)

Sources & evidence

ORD record
ord-8f83a8bf69d241879bff40742d0cc220
Source dataset
uspto-grants-2011_01
Patent number
US07863302B2

Reaction notes

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