NMR SPECTRAL-ANALYSIS AND MOLECULAR-DYNAMICS STUDY OF 3-QUINUCLIDINOLAND 3-QUINUCLIDINYL BENZILATE

Proton chemical shifts and coupling constants of 3-quinuclidinol and 3 -quinuclidinyl benzilate were determined by computer analysis. The rel atively broad lines of the quinuclidine protons have their origin in n umerous non-resolved transitions arising from the extensively coupled spin system of 12 nuclei. The signs of the long-range coupling constan ts were determined by COSY-45 and E.COSY. Vicinal coupling constants w ere converted into proton-proton torsion angles by applying the Altona -Haasnoot equation. Some geometrical ambiguities were revealed, which were studied by molecular dynamics calculations and simulated annealin g. The torsion angles and the results from molecular dynamics calculat ions indicated significant flexibility of the quinuclidine part. For t he sake of completeness the carbon chemical shifts of both compounds a re presented. (C) John Wiley & Sons, Ltd.