Spatial structure and conformational state of dilupinine esters of dibasic acids
Conclusions1. The conformational states of dilupinine esters of dibasic acids and their protonated forms, and also their dimethiodides, have been studied by PMR spectroscopy.2. It has been shown that the nature of the conformational transformations of the trans-quinolizidine system of lupinine and of the dilupinine esters of dicarboxylic acids depends fundamentally on the acidity of the medium, the activity of water, the strength of intramolecular bonds, and the concentration of bases.
Zur konfiguration und konstellation isomerer 1-hydroxychinolizidin-derivate
Zusammenfassung Die Konfigurationen der isomeren 1-Hydroxy-7-methyl-chinolizidine und der isomeren 1-Methyl-1-hydroxy-7-methyl-chinolizidine werden aufgrund der NMR-Spektren zugeordnet. Untersuchungen an den protonisierten Verbindungen und den Methojodiden zeigen, dass vorwiegend die polaren Eigenschaften der Substituenten neben der Raumerfullung fur die eingenommene Konformation verantwortlich sind.
Nuclear magnetic resonance spectra of veratrum alkaloids
Abstract An intercomparison of the NMR data for the methyl protons in a series of thirty-seven alkaloids of the Veratrum group provides additional support for previous proposals regarding the β-configuration of the C-27 methyl group in all of these compounds and the cis A/B ring fusion in the sabine derivatives. Furthermore, the variations of the chemical shift for the C-21 methyl protons strongly suggest that the conformation of the D-ring is changed upon formation of the D- ortho acetate grouping.