New 11(15→1)abeotaxane, 11(15→1),11(10→9)bisabeotaxane and 3,11-cyclotaxanes from Taxus yunnanensis

Chemical examination of the seeds of Chinese yew, Taxus yunnanensis 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, 9β, 13β - 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.