N,N-disubstituted 4-amino-(6-methoxy)-3-phenyl-2H-naphtho [1,2-b]pyran-2-ones with antiarrhythmic, platelet antiaggregating and local anesthetic activities.

The synthesis of title compounds (VI) by 1,4-cycloaddition of phenylchloroketene to N,N-disubstituted (E)-2-aminomethylene-3,4-dihydro-(6-methoxy)-1(2H)naphthalenones, followed by dehydrochlorination with DBN and dehydrogenation with Pd/C of the resulting cycloadducts, is described. Some compounds (VI) showed antiarrhythmic activity in rats higher or like that of quinidine and platelet antiaggregating activity in vitro like that of acetylsalycilic acid, as well as moderate infiltration anesthesia in mice and weak hypotensive, bradicardic and antiinflammatory activities in rats.