SYNTHESIS AND STRUCTURE OF NEW PYRIDO[2,3-D]PYRIMIDINE DERIVATIVES WITH CALCIUM-CHANNEL ANTAGONIST ACTIVITY

Several series of pyrido[2,3-d]pyrimidine derivatives were synthesized by reaction of aryl methyleneacetoacetates with different aminopyrimi dines. The solid-state structure of the methyl 5,8-hexahydropyrido[2,3 -d]pyrimidine-6-carboxylate shows that these compounds can adopt some of the most important structural features of the 1,4-dihydropyridine c alcium channel blockers. The scope and limitations of the synthetic pr ocedure with different aminoheterocycles is presented together with th e initial evaluation of their calcium antagonistic activity by compari son with the usual reference compound nifedipine.