Hydrochloric Acid → 3-Chlorothiophene-2-carboxylic acid

Participants

Reaction Steps

14.5 liters of absolute carbon tetrachloride (refluxed for 1 hour with 500 g of P2O5 and then distilled) is placed in a 25 liter apparatus equipped with stirrer, dropping funnel, drainage cock and reflux condenser with gas outlet; while stirring, 2,200 g (10.05 moles) of PCl5 is added. Upon refluxing the mixture the PCl5 goes into solution (a small amount of PCl5 settles in the drainage cock). 660 g (4.18 moles) of methyl 3-hydroxythiophene-2-carboxylate (prepared as described in German Pat. No. 1,020,641) dissolved in 2 liters of absolute carbon tetrachloride is allowed to flow at a just continuous rate over a period of 4 hours into the boiling solution (vigorous evolution of HCl).

Provenance & Evidence