1,2-fused pyrimidines. VI. Substituted 2-amino-4H-pyrido[1,2-a]pyrimidin-4-ones with antiplatelet activity

Abstract

The N-substituted 2-amino-4H-pyrido[1,2-a]pyrimidin-4-ones 2 d,g-i,l-p,r,s and derivatives 4,5 b,6 a,b, 7 a,b were prepared. Both these novel compounds (except the insoluble 7a) and compounds 2 a-c,e,f,j,k,q, 5a, previously prepared by us, were tested in vitro for their inhibitory activity on human platelet aggregation induced by ADP, collagen, or A23187. On the whole, the compounds tested proved to be more active towards collagen than towards ADP and A23187. The 2-(4-methyl-1-piperazinyl)derivative 2 g was the most active compound both towards ADP and collagen, whereas the 2-(diethylamino)derivative 2 b proved to be the most active one towards A23187.