Ethyl methyl 1,4-dihydro-4-(3-nitrophenyl)-2, 6-bis(1-piperidylmethyl)pyridine-3,5-dicarboxylate.

In the title compound, C(28)H(38)N(4)O(6), the 4-aryl substituent occupies a pseudo-axial position approximately orthogonal to the plane of the dihydropyridine ring [88.1 (3) degrees ]. The dihydropyridine ring adopts a flattened boat conformation. The H atom on the pyridine N atom is involved in a bifurcated intramolecular hydrogen bond, the acceptors being the N atoms of the two piperidylmethyl groups [N.N 2.629 (4) and 2.695 (4) A].

Synthesis, structural studies and pharmacological activity of novel bicyclic compounds derived from 3,4-dihydropyridones: 4-aryl-7,7-dimethyl-2,5-dioxo-1,2,3,4,5,6,7,8-octahydroquinolines.

The purpose of this research is to characterize the possible vascular selectivity of a series of novel bicyclic compounds derived from 3,4-dihydropyridones. We describe the synthesis, structural study by X-ray analysis and quantum chemical calculations at semiempirical (AMI) and ab initio (HF/321G) levels and pharmacological activity of these 4-aryl-7,7-dimethyl-2,5-dioxo-1,2,3,4,5,6,7,8-octahydroquinolines. In addition, the more favoured conformation for compounds 4a-c in solution was determined from the calculated and experimental proton coupling constants. We report the first computational study on the structure of octahydroquinolines. The results of ab initio (HF/3-21G) and semiempirical molecular orbital calculations (AMI) are compared with the data obtained by X-ray crystallographic study for 4a.