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

Three series of new 2-[(4-substituted piperazin-1-yl) methyliquinazolin-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-I were designed and synthesized as promising alpha(1)-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 alpha(1)-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 alpha(1)-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. (C) 2010 Elsevier Masson SAS. All rights reserved.