SYNTHESIS AND PHARMACOLOGICAL EVALUATION OF YDRO-7,8-DISUBSTITUTED-BENZO[H]CINNOLIN-3(2H)-ONES

7,8-disubstituted-4,4a,5,6-tetrahydroben 2-4 have been synthesized and tested in comparison with the mino-4,4a,5,6-tetrahydrobenzo[h]cinnoli n-3(2H)-one 1 reported to be a potent antihypertensive and antithrombo tic agent. Binding studies on phosphodiesterase (PDE) isoenzymes showe d that the test compounds exhibited a modest affinity towards PDE III which in the case of 2, 3 was higher than that of 1. In vivo tests ind icated that compounds 2 and 4 displayed lower hypotensive activity tha n model 1 while 3 was inactive. Conversely, compounds 2-4 were as pote nt as 1 in inhibiting collagen-induced platelet aggregation.