Five new labdane diterpenes from Amphiachyris amoena

Five new labdane diterpenes, amoenolide A 19-aldehyde [2], and amoenolides B [3], C [4], D [5], and J [6] were isolated from the above-ground parts of Amphiachyris amoena, and their structures determined by spectral methods, in particular high-field nmr, and selective chemical studies. Amoenolide J [6] had its carbon skeleton established by the INADEQUATE 13C-13C connectivity nmr experiment.