Dimethyl Sulfate → Methyl 4-hydroxythiophene-2-carboxylate

Participants

Reaction Steps

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.

Provenance & Evidence