Studies on Agents with Vasodilator and β-Blocking Activities. I

A series of novel pyridazinone derivatives (II) having a phenoxypropanolamine moiety was synthesized. Their hypotensive and β-blocking activities were evaluated after intravenous administration of the compounds to anesthetized rats. Among them, the 5-chloro-2-cyanophenoxy derivative (29) showed the promising dual activities and was selected for further studies.