Two New Lignans from Taxus yunnanensis

Abstract The phytochemical investigation on the ethanolic extracts of the barks of Taxus yunnanensis (Taxaceae) led to the isolation of two new neo ‐lignans, named taxuyunins A (1) and B (2), a‐long with the known diterpenolignan, brevitaxin (3). Their structures were elucidated on the basis of spectroscopic and chemical evidences. Compound 1 is a neo ‐lignan xyloside while compound 2 belongs to the rare neo ‐lignan possessing a ramified C 3 side chain.