Scheme 1: Synthesis of 5-chloro-2-methoxy-N-(4-sulphamoylphenyl) benzamide derivatives (4a-t). Reagents and conditions: (a) aniline, triethylamine, ethylchloroformate, DCM, rt, 3 h, 94%; (b) chlorosulphonic acid, neat, rt, 12 h, 87%; (c) appropriate amine, sodium carbonate, THF/H2O (2:1), rt, 12 h, 45-93%.