Quantitative NMR-Derived
Interproton Distances Combined
with Quantum Mechanical Calculations of <sup>13</sup>C Chemical Shifts
in the Stereochemical Determination of Conicasterol F, a Nuclear Receptor
Ligand from <i>Theonella swinhoei</i>
- Publication date
- Publisher
Abstract
Here we report the first application of combined accurate
ROE-distance
analysis with DFT calculations of NMR chemical shifts to achieve the
relative configuration assignment of a marine natural product, conicasterol
F, a new polyhydroxylated steroid isolated from the marine sponge <i>Theonella swinhoei</i>. We demonstrate the substantial advantages
of this combined approach as a tool for structural studies of natural
products, providing a powerful alternative to, or information to underpin,
total synthesis when more classical NMR data analysis fails to provide
unequivocal results. In this paper, we also describe the isolation
and structure elucidation of conicasterol F and its 24-ethyl derivative,
theonellasterol I, and their pharmacological evaluation as human nuclear
receptor modulators