1,5-Benzodiazepines. X. Dialkylamino substituted 1,5-benzodiazepine and [1,2,4]triazolo [4,3-a][1,5] benzodiazepine derivatives with inhibitory activity on PAF-induced platelet aggregation.

Novel 4-(dialkylamino) substituted (4, 5 c, 8) and 2,4-bis(dialkylamino) substituted (6) 1,5-benzodiazepine derivatives were synthesized. Both these new compounds and the substituted 4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepine-5-amines 2 a-h, recently described by us, were tested in vitro for their inhibitory activity on the PAF-induced aggregation of human platelets. Actually, bicyclic compounds 4 d, 5 c and tricyclic compounds 2 g, h showed a significant activity: in all them the dialkylamino substituent was the 4-(ethoxycarbonyl)-1-piperazinyl group. On the contrary, compounds 4 d, 5 c, 2 g,h showed practically no inhibitory activity when platelet aggregation was induced by ADP, A23187, or collagen.