Phytochemical Study of Senecio volckmannii Assisted by CASE-3D with Residual Dipolar Couplings and Isotropic 1H/13C NMR Chemical Shifts

Nine new eremophilanolides, with seven known sesquiterpenoids, and 4-hydroxyacetophenone were isolated from the aerial parts of Senecio volckmannii var. volckmannii. The structures of these compounds were fully characterized using a combination of spectroscopic techniques including multinuclear and multidimensional NMR and mass spectrometry. The recently published Computer Assisted 3D Structure Elucidation (CASE-3D) protocol was applied in the configurational and conformational analysis of many of these eremophilanolides on the basis of Residual Dipolar Couplings (RDCs) and/or DFT predicted 1H/13C chemical shifts.