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 beta-hydroxyeremophil-7(11)-en-12,8 alpha-olide (6), 8 beta,10 beta-dihydroxyeremophil-7(11)-en-12,8 alpha-olide (7), and 10 alpha-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 beta-(angeloyloxy)-10 beta-hydroxyeremophil-7(11)-en-12,8 alpha-olide (1), 6 beta-(angeloyloxy)-10 beta-hydroxyeremophil-7(11)-en-12,8 alpha-olide (2), 2 beta-(angeloyloxy)-8 beta,10 beta-dihydroxyeremophil-7(11)-en-12,8 alpha-olide (3), 2 beta-(angeloyloxy)-8 alpha-hydroxyeremophila-7(11),9(10)-dien-12,8 beta-olide (4), and 8 beta-amino-10 beta-hydroxyeremophil-7(11)-en-12,8 alpha-olide (5). In addition, the relative configuration of 1 was corroborated by X-ray diffraction analysis.