Pyrido[2,3-d]pyrimidin-4(3H)-one derivatives and 1,2,3,4-tetrahydro- pyrido[2,3-d]pyrimidine derivatives: synthesis and in vitro study of their activity against platelet aggregation.

Some new derivatives of pyrido[2,3-d]pyrimidin-4(3H)-one A and 1,2,3,4-tetrahydro-pyrido[2,3-d]pyrimidines B were prepared. The study of their in vitro antiaggregating activity showed that the compounds A possessed an inhibitory potency when aggregation was induced with ADP. Their reduction to derivatives of 1,2,3,4-tetrahydro-pyrido[2,3-d]pyrimidine B led to a new series of molecules possessing a greater antiaggregating power. When compared to that of acetylsalicylic acid under the same conditions, this activity was weaker with collagen, the same with arachidonic acid-induced aggregation, but greater when aggregation was induced by ADP. However, they inhibited serotonin release only slightly. Compared to ginkgolide they remained weaker with PAF-induced aggregation.