p-Toluenesulfonic acid → Methyl 4-acetoxythiophene-3-carboxylate

HRID 236804

Reaction equation

HRID 236804 reaction equation
[O:1]=[C:2]1[CH2:6][S:5][CH2:4][CH:3]1[C:7]([O:9][CH3:10])=[O:8].C([CH2:14][C:15]([O-])=[O:16])(C)=C.C1(C)C=CC(S(O)(=O)=O)=CC=1>>[CH3:10][O:9][C:7]([C:3]1[C:2]([O:1][C:15](=[O:16])[CH3:14])=[CH:6][S:5][CH:4]=1)=[O:8]

Participants

4

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 984243-Thiophenecarboxylic acid, tetrahydro-4-oxo-, methyl esterHCID 18355900Isopropenylacetate

Product 1

HCID 12520003Methyl 4-acetoxythiophene-3-carboxylate

Conditions

Temperature
-25 °C

Procedure

A 320 g. portion of methyl tetrahydro-4-oxo-3-thiophenecarboxylate [Hromatka et al., Monat. Chemie, 104, 1520 (1973)] is dissolved in 650 ml. of isopropenylacetate, 2.0 g. of p-toluenesulfonic acid is added and the mixture is refluxed overnight. The mixture is concentrated, dissolved in 750 ml. of methylene chloride, cooled to -25° C. and 160 ml. of sulfuryl chloride is added over a one hour period. The methylene chloride is distilled off giving 4-acetoxy-3-thiophenecarboxylic acid methyl ester.

Workup

  1. temperaturethe mixture is refluxed overnight
  2. concentrationThe mixture is concentrated
  3. dissolutiondissolved in 750 ml
  4. additionof sulfuryl chloride is added over a one hour period
  5. distillationThe methylene chloride is distilled off

Sources & evidence

ORD record
ord-5a2eb643307f43f39a15f4f1ab268324
Source dataset
uspto-grants-1979_06
Patent number
US04157444

Linked notes

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