A novel compound, selaginellin C (1), was isolated from Selaginella pulvinata Maxim (Hook et Grev.) as (R,S)-4-((1,2-dihydroxyethyl)-2′,4′-dihydroxy-3-((4-hydroxyphenyl)ethynyl)biphenyl-2-yl)((4-hydroxyphenyl)methylene)cyclohexa-2,5-dienone, along with two known compounds, selaginellin (2) and selaginellin A (3). The structure of the new compound was elucidated on the basis of 1D and 2D NMR as well as HR-ESI-MS spectroscopic analysis.
Macrocyclic glycosides with unique 22-membered dimeric lactone skeleton, are rare occurring natural products. There are only ten compounds reported so far. Herein we reported the isolation and characterisation of five macrocyclic glycosides from Schoenoplectus tabernaemontani, including three new compounds (Schoenopolide A-C, 1–3) and two known ones, Berchemolide (4) and Clemoarmanoside B (5). Their structures were established on the basis of extensive analysis of spectroscopic data. In addition, the anti-oxidative activity of Berchemolide (4) against H2O2-induced of renal tubular epithelial (HK-2) cells was also evaluated.
Herein, we have reported the first example of both intra- and intermolecular [2+2] cycloaddition of the electron-rich indoles and unactivated aryl alkynes promoted by the combination of Fe(NO3)3 and HNO3, which highlights efficient and selective access to several different types of functionalized cyclobutene-fused indolines from readily available starting materials with cheap catalysts and simple operations.