The Hantzsch condensation of alkyl acetoacetates 3 with methyl 3-aminocrotonate (4) and pyridinecarboxaldehydes 5 afforded the unsymmetrical alkyl methyl 1, 4-dihydro-2, 6- dimethyl-4-(pyridinyl)-3, 5-pyridinedi~~ xylates 6, whereas condensation of 3 with 5 and ammonium hydroxide gave the symmetrical dialkyl 1, 4-dihydro-2, 6-dimethyl-4-(pyridinyl)-3, 5-pyridinedicarboxylates 7. The calcium channel antagonist activities of disubstituted 1, 4- ...
