2-Amino-N-methylbenzenesulfonamide is obtained by treating 2-nitrobenzenesulfonyl chloride with methylamine and subsequent reduction. Used as a dye component. The amides of 2-aminobenzenesulfonic acid can be treated with aldehydes or orthoformic acid esters to give 1,2,4-benzothiadiazine 1,1-dioxides or their dihydro compounds; these substances have been proposed as diuretics.