Title
Four new compounds from Ligularia virgaurea: isolation of eremophilane and noreremophilane sesquiterpenoids and the absolute configuration of 2α-hydroxyeremophil-11-en-9-one by CD spectrum and DFT calculation
Author
Yoshinori Saito, Mizuho Taniguchi, Teppei Komiyama, Ayumi Ohsaki, Yasuko Okamoto, Xun Gongc, Chiaki Kurodad, Motoo Tori
Year
2013
Journal
Tetrahedron
Abstract
Four new compounds, rearranged noreremophilan-8,6-olide, rearranged dinoreremophilanone, epoxy γ-lactone, and 2α-hydroxyermophil-11-en-9-one, along with eremophilenolides related to ligularol and other known terpenoids, were isolated from Ligularia virgaurea (ligularol type) collected from the northern Sichuan Province of China. Three of the new compounds had degraded and unique structures. The absolute configuration of 2α-hydroxyermophil-11-en-9-one was determined on the basis of density functional theory calculation. The back octant rule cannot be applied to this compound because of the contribution of the hydroxy group to the front octant.
Instrument
J-725
Keywords
Circular dichroism, Absolute configuration,