Dimethyl Sulfate → 3-Methoxythiophene-2-carboxylic acid

HRID 1982484Notes

Reaction equation

HRID 1982484 reaction equation
C[O:2][C:3]([C:5]1[S:6][CH:7]=[CH:8][C:9]=1[OH:10])=[O:4].[C:11](=O)([O-])[O-].[K+].[K+].COS(OC)(=O)=O>CC(C)=O>[CH3:11][O:10][C:9]1[CH:8]=[CH:7][S:6][C:5]=1[C:3]([OH:2])=[O:4]

Participants

5

Reactant 3

HCID 6497Dimethyl SulfateHCID 11430Potassium CarbonateHCID 5811273-Hydroxy-thiophene-2-carboxylic acid methyl ester

Product 1

HCID 14834753-Methoxythiophene-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

48.5 g (0.31 mmoles) of 3-hydroxy-2-thiophene carboxylic acid methyl ester (IV: R3 =H) are dissolved in 400 ml of acetone, 84.7 g (0.61 moles) of potassium carbonate, 77.3 g (0.61 moles) of dimethylsulfate are added, and the mixture is refluxed with stirring for 1 hour. The salt mass is aspirated, washed several times with acetone and the combined filtrate is concentrated in vacuo. 750 ml of aqueous 2N sodium hydroxide are added and boiled. The reaction solution is cooled, washed with ether and acidified with concentrated HCl. The precipitating colorless crystals are aspirated and recrystallized from ethanol. Yield: 43.1 g (89%), m.p. 184°-185° C.

Workup

  1. temperaturethe mixture is refluxed
  2. washwashed several times with acetone
  3. concentrationthe combined filtrate is concentrated in vacuo
  4. addition750 ml of aqueous 2N sodium hydroxide are added
  5. temperatureThe reaction solution is cooled
  6. washwashed with ether
  7. customrecrystallized from ethanol

Sources & evidence

ORD record
ord-400ce99a66924c8a977fb6e79890229f
Source dataset
uspto-grants-1986_06
Patent number
US04596830

Reaction notes

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