Synthesis and pharmacological evaluation of 5,6-dihydrobenzo[f] cinnolin-2(3H)ones analogues of antihypertensive and antiaggregating benzo[h]cinnolinones.

Two new dihydrobenzo[f]cinnolin-2(3H)ones (4a,b) have been synthesized and tested for their hypotensive, antihypertensive and antiaggregating activities in comparison with the lead 8-acetylamino-4,4a,5,6-tetrahydrobenzo[h]cinnolin-3(2H)-one 1. In vivo tests indicated that 4a,b displayed hypotensive and antihypertensive properties weaker than the model compound. On the contrary both compounds were more potent than 1 in inhibiting collagen-induced platelet aggregation.