Novel 4-substituted-2(1H)-phthalazinone derivatives: synthesis, molecular modeling study and their effects on α-receptors.

Novel 4-(4-bromophenyl)phthalazine derivatives connected via an alkyl spacer to amine or N-substituted piperazine were designed and synthesized as promising α-adrenoceptor antagonists. The structures of the phthalazine derivatives were established using elemental and spectral analyses. Twelve of the tested compounds displayed significant α-blocking activity. Molecular modeling studies were performed to rationalize the biological results. Among the tested compounds, 7j displayed the best-fitting score and the highest in vitro activity.