New sulfamoylphenethylamines, potent alpha 1-adrenoceptor antagonists.

The (+)-isomer of amosulalol, a combined alpha- and beta-adrenoceptor antagonist, was one log unit order more potent and less potent than the (-)-isomer in blocking alpha 1- and beta 1-adrenoceptors, respectively, in anaesthetized rats. Nine newly synthesized desoxy compounds derived from amosulalol and its analogues were found to possess potent alpha 1-adrenoceptor blocking activity and to be practically devoid of beta 1-adrenoceptor blocking activity. Among the desoxy derivatives, YM-12617 was more potent than prazosin in blocking alpha 1-adrenoceptors in anaesthetized rats and in reducing blood pressure, total peripheral resistance and left ventricular work in anaesthetized dogs.