3,4-dimethoxythiophene-2,5-dicarboxylic acid → 3,4-Ethylenedioxythiophene

HRID 1270689Notes

Reaction equation

HRID 1270689 reaction equation
[CH3:1][O:2][C:3]1[C:7]([O:8][CH3:9])=[C:6](C(O)=O)[S:5][C:4]=1C(O)=O>[Cu].CS(C)=O>[CH2:1]1[CH2:9][O:8][C:7]2[C:3](=[CH:4][S:5][CH:6]=2)[O:2]1

Participants

4

Reactant 1

HCID 28015383,4-dimethoxythiophene-2,5-dicarboxylic acid

Product 1

HCID 44218643,4-EthylenedioxythiopheneYield 89.4%

Reagents, catalysts & solvents 2

HCID 23978CopperCatalystHCID 679Dimethyl SulfoxideSolvent

Procedure

3,4-Dimethoxy-2,5-thiophenedicarboxylic acid (232 g) and copper powder (23 g) were added to DMSO (650 g) at room temperature. The reaction mixture was stirred under oxygen atmosphere for 30 minutes at room temperature and then heated at 120° C. for 7 hours. The reaction mixture was then poured into ice water (500 mL), and the crude product was extracted with ethyl acetate. After drying over anhydrous sodium sulfate, the solvent was removed by evaporation. The residue was vacuum-distilled at 50 mmHg to give 127 g of 3,4-ethylenedioxythiophene in high purity (96% or higher). The purity was confirmed by gas chromatographic analysis. The chemical structure was confirmed by mass analysis and 1H-NMR.

Workup

  1. temperatureheated at 120° C. for 7 hours
  2. extractionthe crude product was extracted with ethyl acetate
  3. dry with materialAfter drying over anhydrous sodium sulfate
  4. customthe solvent was removed by evaporation
  5. distillationThe residue was vacuum-distilled at 50 mmHg

Sources & evidence

ORD record
ord-717dcbb5bbea44d692fb30bed7797cc7
Source dataset
uspto-grants-2007_04
Patent number
US07202369B2

Reaction notes

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