Isolation of 8 ß -hydroxy-goyazensanolide from Eremanthus argenteus and the complete and unequivocal 1H and 13C NMR data assignment for this sesquiterpene lactone

This work describes the first isolation of 8 ß-hydroxy-goyazensanolide from Eremanthus argenteus and the complete and unequivocal 1H and 13C NMR assignments for this compound. The assignments were carried out in the means of spectroscopic data from 1H NMR, 13C{1H} NMR, gCOSY, gHMQC, gHMBC and J-resolved experiments. All hydrogen homonuclear coupling constants were measured, and all hydrogen signals multiplicities were clarified. This is the first report of 13C NMR data for this sesquiterpene lactone to our knowledge.