Boron tribromide → Methyl 5-hydroxybenzo[b]thiophene-2-carboxylate

HRID 493178Notes

Reaction equation

HRID 493178 reaction equation
[CH3:1][O:2][C:3]([C:5]1[S:9][C:8]2[CH:10]=[CH:11][C:12]([O:14]C)=[CH:13][C:7]=2[CH:6]=1)=[O:4].B(Br)(Br)Br>C(Cl)Cl>[CH3:1][O:2][C:3]([C:5]1[S:9][C:8]2[CH:10]=[CH:11][C:12]([OH:14])=[CH:13][C:7]=2[CH:6]=1)=[O:4]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 23261726Methyl 5-methoxybenzo[b]thiophene-2-carboxylate

Product 1

HCID 13662999Methyl 5-hydroxybenzo[b]thiophene-2-carboxylateYield 77.8%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
0 °C

Procedure

The above prepared 5-methoxy-benzo[b]thiophene-2-carboxylic acid methyl ester (0.199 g, 0.895 mmol) was dissolved in 6 mL of CH2Cl2, cooled to 0° C., and treated with BBr3 (1.79 mL of 1M solution in CH2Cl2, 2 eq.). After 2 additional h at 0° C., the reaction mixture was carefully poured onto crashed ice, twofold extracted with AcOEt, washed with water, dried over sodium sulfate, and evaporated to dryness. Flash chromatography (SiO2, hexane/AcOEt=7/3) yielded 0.145 g of the title compound as off-white solid.

Workup

  1. additionAfter 2 additional h at 0° C., the reaction mixture was carefully poured
  2. extractiontwofold extracted with AcOEt
  3. washwashed with water
  4. dry with materialdried over sodium sulfate
  5. customevaporated to dryness

Sources & evidence

ORD record
ord-3d30292e24f04efa8fb228637cb91172
Source dataset
uspto-grants-2009_05
Patent number
US07534788B2

Reaction notes

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