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.
ACIDITY FUNCTIONS OF AQUEOUS SOLUTIONS OF STRONG ACIDS
CONTENTS I. Acidity scale for aqueous solutions of strong acids 803 II. Indicators for measuring acidity functions 805 III. Values of H0 for aqueous solutions of strong acids and oleum 807 IV. Accuracy of measurements of H0 812 V. Physical significance of the concept of "acidity of the medium" 813 VI. Relation between the acidity of the medium and the thermodynamic activity of water 814
Configurational and conformational analysis : Axial-axial and axial-equatorial coupling constants in six-membered ring compounds
Abstract Axial-axial and axial-equatorial coupling constants (J aa and J ae ) have been obtained directly from the NMR spectra of simple AB systems in a number of cis - and trans -l-(substituted)-2-arylcyclohexanes-3,3,6,6-d 4 measured in several solvents. Variations in J aa and J ae have been observed with various substituents. No simple correlation is found between electronegativity of substituents and substituent effects on coupling constants. A review of J aa and J ae in six-membered ring compounds is given.