Synthesis and pharmacological evaluation of 2,5-cycloamino-5H-[1]benzopyrano[4,3-d]pyrimidines endowed with in vitro antiplatelet activity

A series of new 2,5-cycloamino-5H-[1]benzopyrano[4,3-d]pyrimidines 3a–i have been synthesized and tested in vivo for the anti-inflammatory/analgesic/antipyretic effects and in vitro to evaluate the antiplatelet activity on guinea-pig platelet-rich plasma aggregated by collagen, adenosine-5′-diphosphate (ADP) and arachidonic acid (AA). Title compounds were ineffective in vivo; however, the pyrrolidino derivatives 3a and 3c exhibited an antiplatelet activity against all the aggregants differing from that of acetylsalicylic acid (ASA) while the 5-morpholino derivatives 3g–i showed the most potent ASA-like antiplatelet activity.