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

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence