Synthesis of 3,3-dimethyl-6-oxopyrano[3,4-c]pyridines and their antiplatelet and vasodilatory activity

Both pyridine and pyrano derivatives have been previously shown to possess biologically relevant activity. In this study, we report the incorporation of these two scaffolds into one molecule.The designed 3,3-dimethyl-6-oxopyrano[3,4-c]pyridines were synthesized by the acylation of enamine under Stork conditions followed by condensation of formed β-diketones with 2-cyanoacetamide. The structures of these compounds were confirmed by using a wide spectrum of physico-chemical methods. Their antiplatelet, anticoagulant and vasodilatory activity together with toxicity were evaluated.A series of 6-oxopyrano[3,4-c]pyridines 3a-j was obtained. Four of these compounds were reported for the first time. None of the tested compounds demonstrated anticoagulant effect but 8-methyl derivative (3a) was a potent antiplatelet compound with IC50 numerically twice as low as the clinically used acetylsalicylic acid. A series of further mechanistic tests showed that 3a interferes with calcium signaling. The compound is also not toxic and in addition possesses vasodilatory activity as well.Compound 3a is a promising inhibitor of platelet aggregation, whose mechanism of action should be studied in detail.