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 ...