The structure of laurobtusol, a new rearranged sesquiterpenoid from the Mediterranean Red Alga Laurencia obtusa

An alcohol with a new tricyclic humulane skeleton, laurobtusol, was isolated from the Mediterranean Red Alga Laurencia obtusa. The structure was established mainly by 2 D NMR methods and the relative configuration was assigned by a quantitative computer simulation of the lanthanide induced shifts in the 1H NMR spectrum and Molecular Mechanics calculation (MM2).