Dimethyl Sulfate → Methyl 4-hydroxythiophene-2-carboxylate

HRID 868211Notes

Reaction equation

HRID 868211 reaction equation
[OH:1][C:2]1[CH:3]=[C:4]([C:7]([OH:9])=[O:8])[S:5][CH:6]=1.[C:10](=O)(O)[O-].[Na+].COS(OC)(=O)=O>CC(=O)CC>[OH:1][C:2]1[CH:3]=[C:4]([C:7]([O:9][CH3:10])=[O:8])[S:5][CH:6]=1

Participants

5

Reactant 3

HCID 6497Dimethyl SulfateHCID 516892Sodium BicarbonateHCID 132779074-Hydroxythiophene-2-carboxylic acid

Product 1

HCID 13277908Methyl 4-hydroxythiophene-2-carboxylate

Reagents, catalysts & solvents 1

HCID 6569Methyl Ethyl KetoneSolvent

Procedure

50.0 g (0.347 mol) of 4-hydroxy-2-thiophenecarboxylic acid and 58.3 g (0.694 mol) of sodium bicarbonate are heated at the boiling point in 900 ml of absolute 2-butanone under nitrogen, and 43.7 g (0.347 mol) of dimethylsulfate are added dropwise in the course of 20 minutes. The mixture is heated under reflux for a further 2.5 hours. It is then evaporated in vacuo and the residue is partitioned between saturated sodium bicarbonate solution and ether. The aqueous phase is extracted five more times with 80 ml of ether each time. The combined organic phases are dried over sodium sulfate/active charcoal, filtered and evaporated.

Workup

  1. temperatureThe mixture is heated
  2. temperatureunder reflux for a further 2.5 hours
  3. customIt is then evaporated in vacuo
  4. customthe residue is partitioned between saturated sodium bicarbonate solution and ether
  5. extractionThe aqueous phase is extracted five more times with 80 ml of ether each time
  6. dry with materialThe combined organic phases are dried over sodium sulfate/active charcoal
  7. filtrationfiltered
  8. customevaporated

Sources & evidence

ORD record
ord-45a6de1835734273ac33a7171cf215f4
Source dataset
uspto-grants-1988_10
Patent number
US04778803

Reaction notes

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