Chlorosulfonic acid → 7-Methyl-9-oxothioxanthene-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

The 2-(p-tolylthio)benzene-1,4-dicarboxylic acid is transferred slowly to a flask, containing 100 ml of chlorosulfonic acid. The temperature is maintained between the 5 and 10° C. with an ice-bath. At the end of the addition, the solution is left to rest for maturation and after 1 hour is poured in water and ice. The precipitate is filtered, washed with water and dried in a vacuum oven obtaining 19.69 g (yield: 96.7%) of 7-methyl-9-oxo-thioxanthene-3-carboxylic acid as a yellow solid. Melting point>250° C.

Provenance & Evidence