Thionyl Chloride → 4-(Aminosulfonyl)-3-thiophenecarbonyl chloride

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Reaction Steps

A mixture of 1 g. of 4-(aminosulfonyl)-3-thiophenecarboxylic acid in 20 ml of thionyl chloride is heated under reflux for 4 hours. The mixture is cooled to room temperature and is filtered. The filtrate is evaporated in a rotary evaporator and the residue is dissolved in 270 ml. of anhydrous ether. The solution is diluted with 200 ml. of petroleum ether and the precipitate which forms is collected to give 0.4 g. of product, m.p. 140; 262°-265° C.; mass spectrum CI m/e 226 MH+.

Provenance & Evidence