Pyrazole-Embedded Pyridazine and Phthalazinedione Hybrids: Synthesis, Characterization and Anti-Inflammatory Potential

The synthesis of heterocycles incorporating bridgehead nitrogen, particularly pyridazine and phthalazinedione derivatives, has garnered significant interest due to their wide-ranging applications in various pharmacological fields. Recognizing the importance of eco-friendly protocols, this work reports a novel green synthetic route for the preparation of pyridazine and phthalazinedione derivatives featuring a pyrazole moiety. In this synthetic route, a one-pot multi-component reaction was performed using 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (1), various substituted aldehydes (2), hydrazine hydrate (3) and different anhydrides (4–6). The synthesized compounds were characterized and screened for their anti-inflammatory activity. Most of the compounds showed good anti-inflammatory activity.