Complete assignments of H-1 and C-13 NMR spectral data for three sesquiterpenoids from Inula helenium

摘要

The complete assignments of all the H-1 and C-13 NMR signals of three sesquiterpene lactones, 4-oxo-5(6),11-eudesmadiene-8,12-olide (1), 4-oxo-11-eudesmaene-8,12-olide (2) and (11 (10)E)-5 beta-Hydroxygermacra-1 (10),4(15),11-trien-8,12-olide (3), were carried out by various 2D NMR experiments. Compounds 1-3 were isolated from the roots of Inula helenium for the first time. Among them, 1 was identified as a new nor-sesquiterpene lactone, and 2 was isolated from a natural source for the first time. The C-13-NMR data of compound 3 was also reported for the first time. Copyright (C) 2008 John Wiley & Sons, Ltd.