Three novel bicyclic 3,8-secotaxane diterpenoids from the needles of the Chinese yew, Taxus chinensis var. mairei

Three novel (1-3) and five known bicyclic 3,8-secotaxane diterpenoids were isolated from the needles of the Chinese yew, Taxus chinensis var, mairei. The structures of the new compounds were established, respectively, as (3E, 7E)-2 alpha,10 beta,13 alpha-triacetoxy-5 alpha,20-dihydroxy-3,8-11-trien-9 -one (1), (3E,7E)-2 alpha, 10 beta-diacetoxy-5 alpha,13 alpha,20-trihydroxy -3,8-secotaxa-3,7,11-trien-9-one (2), and (3E,8E)-7 beta,9,10 beta,13 alpha ,20-pentaacetoxy-3,8-secotaxa-3,8,11-triene-2 alpha,5 alpha-diol (2-deacety ltaxachitriene A) (3), on the basis of spectral analysis. The other five bi cyclic taxane diterpenoids were determined as canadensene, 6-deacetyltaxach itriene B, taxachitriene B, taxuspine U, and taxuspine X by comparison of t heir physical properties and spectral data with those previously reported.