The antitumour activity of a series of benzothiophenes

Abstract The monofunctional halogenoalkylamine and 5-HT antagonist 3-(N-)β-chloroethyl-N-ethyl aminomethyl) benzothiophene HCl, was tested against experimental tumours. It proved to have high antitumour activity but was also very toxic. Only one compound, 5-bromo-3-(N-β-chloroethyl-N-ethyl aminomethyl) benzothiophene HCl, of a series of analogues had greater antitumour action combined with acceptable toxicity. The extent of the antitumour activity was surprising in view of the general acceptance that alkylating agents require at least two functional side chains for effective antitumour activity.