The N-substituted benzenesulphonamide of claim 1, which has the general formula ##STR82## in which n is 2 or 3,R1 and R2 is methyl or ethyl, R4 is a hydrogen atom or an NH2 group. 3. 2-Methoxy-4-amino-5-chloro-N-(3-diethylaminopropyl) benzenesulphonamide of the formula ##STR83##