PYRAN DERIVATIVES .19. (DIALKYLAMINO) SUBSTITUTED 1-BENZOPYRANONES AND NAPHTHOPYRANONES WITH PLATELET ANTIAGGREGATING ACTIVITY

2-(Dialkylamino)chromones 4 and 4-(1-piperazinyl)coumarins 11, as well as their angular benzo-fused derivatives 1, 2 and 12, 13, respectivel y, were synthesized and tested in vitro for their inhibitory activity on human platelet aggregation induced in platelet-rich plasma by ADP ( 5.0 mu M), collagen (10.0 mu g/ml), and A 23187 (calcimycin) (20.0 mu M). Among the dialkylamino substituents used, and the ring systems exa mined, 1-piperazinyl and 1-benzopyran or naphtho[2,1-b]pyran, respecti vely, resulted the most effective ones for antiplatelet activity, both in the chromone and coumarin fields. 7-Ethoxy-4-(1-piperazinyl)coumar in 11b showed the highest activity, and higher than those of all refer ence compounds (ASA, trifluoperazine, propranolol, and dipyridamole) t owards all platelet aggregation inducers.