Hexachloroethane → 5-Chlorothieno[2,3-d][1,2,3]thiadiazole-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

79 ml (201.6 mmol) of n-butyllithium (1.6M in hexane) are added at -30° C., under nitrogen, to a solution of 20.4 g (201.6 mmol) of diusopropylamine in 200 ml of tetrahydrofuran (THF). After 20 minutes' stirring at -20° C., the LDA solution so prepared is added dropwise at -90° C., under nitrogen, by means of a capillary, to a suspension of 15.0 g (80.6 mmol) of thieno[2,3-d]1,2,3-thiadiazole-6-carboxylic acid in 150 ml of THF. After 90 minutes' stirring at -50° C., a solution of 42.0 g (177.2 mmol) of hexachloroethane in 70 ml of THF is added at -90° C. and the reaction mixture is heated to room temperature within a period of 2 hours. Then the reaction mixture is poured onto 2 litres of water, the aqueous phase is extracted with diethyl ether and acidified with concentrated hydrochloric acid, and the product is isolated by filtration. There are obtained 17.55 g of light-brown solid having a melting point of 255°-265° C. (decomposition).

Provenance & Evidence