Molecular and crystal structures and chemical properties of 2,6-dim ethyl-4-phenyl-3,5-diethoxycarbonyl-1, 4-dihydropyridine

Abstract

The molecular and crystal structures of 2,6-dimethyl-4-phenyl-3,5-diethoxycarbonyl-1,4-dihydropyridine were determined by x-ray diffraction analysis. The following crystallographic data were obtained: a=9.754(2), b = 7.401(1), c=24.384(5) Å, β=92.61(2)°, Z=4, d_calc= 1.24 g-cm⁻³, space group P2₁/c. The structure was decoded from 1531 reflections, the intensities of which were measured with a P2₁ automatic diffractometer and refined by the method of least squares within the total matrix anisotropic approximation to R=0.061. The dihydropyridine ring has a boat conformation. Packing of the molecules in the crystal is realized at the van der Waals distances and is stabilized by an N₁- H ... O₁₅ hydrogen bond (2.98 Å). From the data on the geometry of the molecule, the compound is closer to aminovinylcarbonyl compounds, whereas according to the data on the conformation, it is closer to Meisenheimer compounds than to pyridine derivatives. The C=O bond length corresponds to its length in esters and acid amides, despite the exceptionally low reactivity of this group in 3,5-dicarbonyl-1,4-dihydropyridines.