Studies on Pyridazinone Derivatives. XII. Synthesis and Analgesic Activity of 2-Phenyl-3(2H)-pyridazinone Derivatives

Abstract

In order to examine analgesic activity, 6-alkoxy-4-N, N-(dialkylamino) (or morphorino)-alkylamino-2-phenyl-3 (2H)-pyridazinones (III) were synthesized. Among the compounds tested, 4-(3-dimethylaminopropylamino)-6-ethoxy-2-phenyl-3 (2H)-pyridazinone (IIIg) revealed about six-fold strong activity of that of aminopyrine in an analgesic test by the modified Haffner's method. The safety margin of IIIg as an analgesic agent was considerably higher than that of aminopyrine.