Sodium Hydroxide → 2-Thiophenecarboxylic acid, 4-bromo-3-methoxy-

HRID 507347Notes

Reaction equation

HRID 507347 reaction equation
C[O:2][C:3]([C:5]1[S:6][CH:7]=[C:8]([Br:12])[C:9]=1[O:10][CH3:11])=[O:4].[OH-].[Na+]>O1CCCC1>[Br:12][C:8]1[C:9]([O:10][CH3:11])=[C:5]([C:3]([OH:4])=[O:2])[S:6][CH:7]=1

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 2736824Methyl 4-bromo-3-methoxythiophene-2-carboxylate

Product 1

HCID 5422672-Thiophenecarboxylic acid, 4-bromo-3-methoxy-Yield 90%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

The product from Step A above (22.5 g, 84.36 mmol) was dissolved in 60 mL of tetrahydrofuran and added with 125 mL of a 1.0 M NaOH aqueous solution. The mixture was stirred at room temperature for 4 d, then washed with ether (60 mL×2), acidified to pH ˜2 using a 1.0 M HCl aqueous solution. Solids were precipitated out after acidification, and collected by filtration. The solid was dissolved in methylene chloride-ethyl acetate (˜4:1, v/v). The organic solution was washed with H2O and brine, dried with Na2SO4, and concentrated in vacuo to a light yellow solid, further dried on height vacuum, yielding 17.95 g of 4-bromo-3-methoxy-2-thiophene carboxylic acid (90%, MH+=237.0).

Workup

  1. washwashed with ether (60 mL×2)
  2. customSolids were precipitated out after acidification
  3. filtrationcollected by filtration
  4. dissolutionThe solid was dissolved in methylene chloride-ethyl acetate (˜4:1, v/v)
  5. washThe organic solution was washed with H2O and brine
  6. dry with materialdried with Na2SO4
  7. concentrationconcentrated in vacuo to a light yellow solid
  8. customfurther dried on height vacuum

Sources & evidence

ORD record
ord-dc9515ace12f42f99dcfe4956070c045
Source dataset
uspto-grants-2010_08
Patent number
US07786149B2

Reaction notes

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