New 11(15→1) Abeotaxane, 11(15→1), 11(10→9)Bisabeotaxane and 3,11-Cyclotaxanes from Taxus yunnanensis

Abstract

Chemical examination of the seeds of Chinese yew, Taxus yannanensis Cheng et L.K. Fu resulted in the isolation of an 11(15→1)abeotaxane, an 11(15→1), 11(10→9)bisabeotaxane and two 3,11-cyclotaxanes. The structures of these new taxoids were established as 13α-acetoxy-5α-cinnamoyloxy-11(15→1)abeotaxa-4(20), 11-diene-9α,10β, 15-triol (1), 20-acetoxy-2α-benzoyloxy-4α,5α,7β,9α,13α-pentahydroxy-11(15→1), 11(10→9)bisabeotax-11-eno-10, 15-lactone (2), 2α,10β-diacetoxy-5α-cinnamoyloxy-9α-hydroxy-3,11-cyclotax-4(20)-en-13-one (3) and 10β-acetoxy-2α,5α,9α-trihydroxy-3,11-cyclotax-4(20)-en-13-one (4) on the basis of spectral analyses.