One chloro-furoeremophilanoid and two new natural dimers from Ligularia atroviolacea

Three new compounds, including one chloro-furoeremophilanoid (1), one eremophiladiolide (2), a rare dimer of nor-furoeremophilanoid, ligulatrovine A (3), and a known furoeremophilanolide (4), were isolated from Ligularia atroviolacea. The structures of compounds 1–4 were elucidated by spectroscopic methods including 1D and 2D NMR experiments as well as X-ray diffraction study.