Synthesis of 6-(4-methanesulphonamidophenyl)-substituted dihydropyridazinone/ phthalazinone derivatives as potent anti-inflammatory and analgesic agents

New 6-(4-methanesulphonamidophenyl)-substituted dihydropyridazinones and their phthalazinone analogues have been synthesized and evaluated for anti-inflammatory and analgesic activities using carrageenan induced paw edema and acetic acid induced writhing models, respectively. Most of the newly synthesized compounds displayed potent anti-inflammatory activity without ulcerogenic side effects. Both pyridazinone as well as phthalazinone analogues displayed moderate analgesic activity at 40 mg/kg. In general, all pyridazinone derivatives showed activity better than their phthalazinone counterparts.