New naturally occurring diacetylenic spiroacetal enol ethers from Artemisia selengensis

Abstract Three new diacetylenic spiroacetal enol ethers, artemiselenols A–C ( 1 – 3 ), were isolated from whole plants of Artemisia selengensis Turcz (Compositae). The structures of all compounds were elucidated on the basis of extensive spectroscopic methods and confirmed by the X-ray crystallographic diffraction of 1 . Artemiselenol A is a new naturally occurring polyacetylene containing chlorine, and its absolute configuration was determined as 2 S , 5 S , 6 S and 7 R by its X-ray crystallographic diffraction, and those of the rest of the compounds were determined by comparison of their CD spectra. All isolates were screened and evaluated for neuroprotection and inhibition of hMAOs.