Chlorosulfonic acid → Ethyl 3-chlorosulfanyl-4-methoxybenzoate

Participants

Reaction Conditions

Reaction Steps

A solution of ethyl 4-methoxybenzoate (15.7 g; 87.2 mmol) in CCl4 (60 ml) was cooled to −15° C., and chlorosulfonic acid (17.5 ml; 263 mmol) was added dropwise over a period of 15 min, resulting in a temperature increase to −10° C. After the addition had ended, the reaction mixture was stirred at room temperature for 2 h and then heated at 50° C. until no more starting material could be detected by thin-layer chromatography. With ice-cooling and vigorous stirring, the reaction mixture was added to a suspension of ice (50 g) in CCl4 (100 ml). The mixture was stirred vigorously for 3 min. The organic phase was separated off and the aqueous phase was extracted with CH2Cl2 (3×100 ml). The combined organic extracts were washed with saturated NaCl solution (3×), dried over Na2SO4 and concentrated. Trituration of the oily brown residue with diethyl ether resulted in 5c precipitating as a crystalline white solid.

Provenance & Evidence