Gaudichanolides A and B, clerodane diterpenes from Baccharis gaudichaudiana.

Two new clerodane diterpenoids, gaudichanolides A (1) and B (2), were isolated from the dried twigs of Baccharis gaudichaudiana, together with 7-oxo-16,19-dihydroxy-3,4-dehydroclerodan-15,20-diacid dilactone, spathulenol, 4,10-aromadendranediol, kobusone, trans-cosanyl ferulate, and defuscin. The structures and relative stereochemistry of 1 and 2 were elucidated by detailed 2D NMR spectroscopic experiments, and the absolute stereochemistry of 1 was determined by X-ray crystallographic analysis.