In the search of new compounds with antineoplastic activity, we have analysed the effect of several structural modifications on the nucleus 6-benzo [b] thiophenesulphonamide 1, 1- dioxide on its cytotoxic activity on tumour cells. Lipophilic substituents on the sulphonamide group significantly increased the cytoxic activity measured using a panel of human tumour cell lines. Only slight variations on cytotoxicity were obtained when the sulphonamide ...