Potassium Hydroxide → 2,3-Dibromo-benzo[b]thiophen-6-ol

HRID 732817Notes

Reaction equation

HRID 732817 reaction equation
[Br:1][C:2]1[S:6][C:5]2[CH:7]=[C:8]([O:11]C(=O)C(C)(C)C)[CH:9]=[CH:10][C:4]=2[C:3]=1[Br:18].[OH-].[K+]>C(O)C>[Br:1][C:2]1[S:6][C:5]2[CH:7]=[C:8]([OH:11])[CH:9]=[CH:10][C:4]=2[C:3]=1[Br:18]

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 690743452,2-Dimethyl-propionic acid 2,3-dibromo-benzo[b]thiophen-6-yl ester

Product 1

HCID 690721602,3-Dibromo-benzo[b]thiophen-6-olYield 101%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Dissolve 2,2-dimethyl-propionic acid 2,3-dibromo-benzo[b]thiophen-6-yl ester (32 g, 82 mmol) in ethanol (725 mL), add 50% aqueous solution of potassium hydroxide (39 mL, 328 mmol) and heat to reflux for 4 hours. Concentrate in vacuo to ½ volume, partition between ethyl acetate (500 mL) and saturated aqueous ammonium chloride (500 mL), separate layers, wash organic with saturated aqueous ammonium chloride (2×500 mL), and brine (300 mL). Dry with sodium sulfate, filter, and concentrate in vacuo to give 25.5 g of 2,3-dibromo-benzo[b]thiophen-6-ol (100%).

Workup

  1. temperatureheat
  2. temperatureto reflux for 4 hours
  3. concentrationConcentrate in vacuo
  4. custompartition between ethyl acetate (500 mL) and saturated aqueous ammonium chloride (500 mL)
  5. customseparate layers
  6. washwash organic with saturated aqueous ammonium chloride (2×500 mL), and brine (300 mL)
  7. dry with materialDry with sodium sulfate
  8. filtrationfilter
  9. concentrationconcentrate in vacuo

Sources & evidence

ORD record
ord-7abb6580cd1e4411abe5e929db464960
Source dataset
uspto-grants-2009_09
Patent number
US07585977B2

Reaction notes

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