New Eremophilenolides from Senecio dianthus

From the aerial parts of Senecio dianthus , four new eremophilenolides ( 1 – 4 , resp.) and one new eremophilenolide alkaloid ( 5 ), of the relatively uncommon eremophilenoid‐type sesquiterpenoid lactones, were isolated together with three known sesquiterpenoid lactones, 10 β ‐hydroxyeremophil‐7(11)‐en‐12,8 α ‐olide ( 6 ), 8 β ,10 β ‐dihydroxyeremophil‐7(11)‐en‐12,8 α ‐olide ( 7 ), and 10 α ‐hydroxy‐1‐oxoeremophila‐7(11),8(9)‐dien‐12,8‐olide ( 8 ). On the basis of IR, MS, and NMR data, particularly 2D‐NMR analyses, the structures of the new compounds were established as: 2 β ‐(angeloyloxy)‐10 β ‐hydroxyeremophil‐7(11)‐en‐12,8 α ‐olide ( 1 ), 6 β ‐(angeloyloxy)‐10 β ‐hydroxyeremophil‐7(11)‐en‐12,8 α ‐olide ( 2 ), 2 β ‐(angeloyloxy)‐8 β ,10 β ‐dihydroxyeremophil‐7(11)‐en‐12,8 α ‐olide ( 3 ), 2 β ‐(angeloyloxy)‐8 α ‐hydroxyeremophila‐7(11),9(10)‐dien‐12,8 β ‐olide ( 4 ), and 8 β ‐amino‐10 β ‐hydroxyeremophil‐7(11)‐en‐12,8 α ‐olide ( 5 ). In addition, the relative configuration of 1 was corroborated by X‐ray diffraction analysis.