Molecular modeling study and synthesis of quinazolinone-arylpiperazine derivatives as α1-adrenoreceptor antagonists

Three series of new 2-[(4-substituted piperazin-1-yl) methyl]quinazolin-4(3H)-ones 4a–c, Ethyl 6,7-dimethoxy-4-oxo-3-[2-(4-substituted piperazin-1-yl)acetamido/propanamido]-3,4-dihydroquinazoline-2-carboxylates 9a–f and their 2-methyl analogues 13a–l were designed and synthesized as promising α1-adrenoceptor antagonists. The final compounds were evaluated for their in vivo hypotensive activity in normotensive cats. The most potent hypotensive quinazolinone derivatives 4b, 9e, 13i, 13j were further tested on isolated thoracic aortic rings of male Wister rats. All the tested compounds displayed α1-blocking activity with IC50 ranging from 0.2 to 0.4 mM less than prazosin. Furthermore, in the present work, molecular modeling study using Accelrys Discovery Studio 2.1 software was performed by mapping the synthesized compounds to the α1-adrenoceptor antagonist hypothesis in order to predict their mechanism of action. Compound 13j which has the best-fitting score displayed the highest in vivo and in vitro activity among the tested compounds.

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► In the present work, certain compounds belonging to a class of arylpiperazine-quinazolinone-2-carboxylate and their 2-methyl analogues were prepared.
► Discovery Studio software was used to design the proposed compounds by applying pharmacophore model.
► Four compounds were tested for their α1-adrenoceptors antagonistic activity in vitro and revealed superior activity to prazosin.