SYNTHESIS OF A NEW 1,4-DIHYDROPYRIDINE CONTAINING THE IMIDAZO[1,5-A]PYRIDINE NUCLEUS

The synthesis of the new dihydropyridine diethyl 1,4-dihydro-4-(imidazo[1,5-a]pyridin-8-yl)-2,6-dimethyl-pyridine-3,5-dicarboxylate (1) is described. After many attempts to prepare the key intermediate aldehyde 2a by different approaches, this compound has been obtained in good yields from methyl 2-cyano-3-pyridinecarboxylate (10). A three-step procedure involving reduction to the amine, formylation with concomitant cyclization and reduction of the ester group was used.