Hydrochloric Acid → 1,2,3-Benzothiadiazole-7-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

100 g (0.51 mol) of 7-methoxycarbonylbenzo-1,2,3-thiadiazole are suspended in 1000 ml of water, and then 310 ml of 2N sodium hydroxide solution and 5 ml of dioxane are added. The reaction mixture is heated to 40° C., is stirred for 4 hours at that temperature and is then cooled to 10° C. A further 1000 ml of water are added and the batch is neutralised with 310 ml of 2N hydrochloric acid. The resulting precipitate is isolated by filtration, lightly dried in a current of air and then dissolved in tetrahydrofuran and the solution is dried over magnesium sulfate, filtered and concentrated. The crystals are suspended in hexane, isolated by filtration and dried.

Provenance & Evidence