Synthesis and antinociceptive activity of 6-substituted-3-pyridazinone derivatives.

A series of 3-pyridazinones carrying morpholino, arylpiperidino and arylpiperazino moiety in the position 6 IIa-g were synthesized and evaluated for antinociceptive activity. In the modified Koster test in mice 4-(4-fluorophenyl) piperazine, IIf, was found the most active compound. All the compounds except IId were more active than aspirin in the antinociceptive activity test.