2-Amino-1,4-dihydropyridines bearing a carbonyl function in the 5-position and being optionally substituted by lower alkyl or phenyl in the 6-position, and the corresponding 2-amino1,4,5,6,7,8-hexahydro-5-oxoquinolines, which derivatives are further substituted by a carbonyl group in the 3-position and optionally substituted in the 4-position by lower alkyl, phenyl, substituted phenyl or a heterocyclic group are antihypertensive agents and coronary vessel dilators. The compounds, of which 2amino-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5dicarboxylic acid 3,5-diethyl ester is a representative embodiment, are prepared through condensation of an ylideneacetoacetic acid ester and an amidine.