Thionyl Chloride → 5-Chlorothiophene-2-carbonyl Chloride

Participants

Reaction Conditions

Reaction Steps

53.6 g of 5-chlorothiophene-2-carboxylic acid (commercially available) are suspended in 344 g of toluene and heated to 80° C. At this temperature, 47.2 g of thionyl chloride are added dropwise over a period of 20 minutes, then the mixture is stirred at from 75 to 80° C. for 30 minutes and then at reflux temperature for two hours until completion of gas evolution. After cooling, the reaction mixture is concentrated to a volume of approx. 200 ml at from 30 to 35° C. and a pressure of from 40 to 48 mbar. The thus obtained solution of the acid chloride in toluene is reacted directly in the next stage.

Provenance & Evidence