Phenylpiperazinylalkylamino substituted pyridazinones as potent alpha(1) adrenoceptor antagonists.

QSAR models have been used for designing a series of compounds characterized by a N-phenylpiperazinylalkylamino moiety linked to substituted pyridazinones, which have been synthesized. Measurements of the binding affinities of the new compounds toward the α1a-, α1b-, and α1d-AR cloned subtypes as well as the 5-HT1A receptor have been done validating, at least in part, the estimations of the theoretical models. This study provides insight into the structure activity relationships of the α1-ARs ligands and their α1-AR/5-HT1A selectivity.