Differentiation between 3,4- and 4,15-Epoxyeudesmanolides by Electrospray Ionization Tandem Mass Spectrometry

Scheme 1

Structure-fragmentation relationships of protonated epoxyeudesmanolide-type sesquiterpene lactones 1 and 2. The diagnostic product ions for compound 1 (3,4-epoxyeudesmanolide) are shown within boxes.