Synthesis of 4-(1,4-diaryl-2H-cyclopent[d]pyridazin-2-yl) benzenesulfonamides

The condensation of cyclopentadienyl-derived γ-diketones and arylhydrazines was utilized to synthesize 4-(1,4-diphenyl-2H-cyclopent[d]- pyridazin-2-yl)benzenesulfonamide and 4-(1,4-di-(4-methylphenyl)-2H-cyclopent[d]pyridazin-2-yl)benzenesulfonamide in better than 80% yield. The crystal structures of the precursor hydroxyfulvene, {(5Z)-5-[hydroxy(4-methylphenyl)- methylene]cyclopenta-1,3-dien-1-yl}(4-methylphenyl)methanone, and the derived pyridazine 4-(1,4-diphenyl-2H-cyclopent[d]pyridazin-2-yl)benzenesulfonamide, were also obtained.