Substituted N-aminomethylene sulfonamide compounds (I) and their salts are new. Substituted N-aminomethylene sulfonamide compounds of formula (I) and their salts are new. R1 : H, halo or CF 3 R2 : H, amino, (di)1-3C alkylamino or 1-3C alkoxy R3 : 1-10C alkyl, 2-10C alkenyl, (hetero)aryl or heterocyclyl (all optionally substituted by T) T : (hetero)aryl, heterocyclyl, (hetero)aryl-(1-6C-alkyl)-, heterocyclyl-(1-6C alkyl)-, -O-aryl, F, Cl, Br, -CF 3, -OCF 3, -NO 2, -CN, -C(O)R7, OH, 1-6C alkyl or 1-3C alkoxy (where (hetero)aryl and heterocyclyl rings are optionally substituted by F, Cl, Br, oxo, -CF 3, -OCF 3, -NO 2, -CN, OH, 1-3C alkyl or monosubstituted 1-3C alkoxy) R4, R5 : H or 1-10C alkyl (optionally substituted by T) or NR4R5 : heterocyclyl (optionally substituted by T1) T1 : halo, 1-6C alkyl, 1-6C alkoxy, phenyl, oxo, amino, (di)1-3C alkylamino, -OCF 3, -CF 3 or OH R6 : 1-10C alkyl, 2-10C alkenyl or aryl-(1-6C-alkyl) (all optionally substituted by T1), H or -SO 2(1-3C alkyl) or R6+R3, X+R6 : heterocyclyl (optionally substituted by T) R7 : 1-3C alkoxy, -O-phenyl, 1-3C alkyl, amino, (di)1-3C alkylamino or phenyl (where phenyl is optionally substituted by F, Cl, Br, -CF 3, -OCF 3, -NO 2, -CN, OH, 1-3C alkyl or monosubstituted 1-3C alkoxy) A : SO 2, CO or CH 2 X : NR6 or O where R1 and R2 are not simultaneously hydrogen, heteroaryl is 5-10 membered, aromatic, mono- or bicyclic heterocycle, containing heteroatom(s) of N, O or S, aryl is 5-10-membered, aromatic, mono- or bicycle, and heterocyclyl is 5-10 membered, non-aromatic, mono- or bicyclic heterocycle containing N, O and/or S and provided that when R2 is H and R1 is halo, then A-XR3 is not -C(O)-O-CH 2-CH 2-NH 2 (i), -C(O)-NH-CH 2-CH=CH 2 (ii), -C(O)-NHCH 2-CH 2-Z (iii) (where Z is halo, OH, trialkylammonium, mesylate or tosylate), -C(O)-O-(1-6C-alkyl) (iv), -C(O)-NH-benzimidazolyl (v) or -C(O)-NH-(1,2,3,4-tetrahydroisochinolinyl) (vi), where in (i) and (iii) -CH 2-CH 2 fragment exhibits 1-4C alkyl of R1-R4, wh
