5-Oxo-1,4-dihydroindenopyridines: Calcium modulators with partial calcium agonistic activity

The title compounds 4a-g were prepared by Knoevenagel reactions of 1,3-indandione ( 1 ) with the aromatic aldehydes 2a-g followed by cyclizing Michael addition of the products thus obtained with methyl β-aminocrotonate ( 3 ). The structures of products 4 were characterized by spectal data. Positive inotropic activities were observed on electrically stimulated, left atria of giunea pigs and these effects could be attributed to calcium agonism. On the other hand, barium chloride-induced contractions of guinea pig ileum were inhibited in a dose-dependent manner.