CHEMICAL STUDIES OF TAXUS YUNN ANENSIS IV:ISOLATION AND STRUCTURE ELUCIDATION OF TWO NEW TAXANE DITERPENOIDS

On the continuing study for discovering antitumor agents from the stem bark of Taxus Yunnanensis,seven taxane diterpenoids were isolated. Five of them are known compounds ,their structures were elucidated,on the basis of MS,¹HNMR,¹H-^lH COSY,¹³CNMR,¹³C-¹H COSY and ¹³C-H COLOC analyses,as 7-epi-10-deacetyl taxol(Ⅰ),7-epi-10-deacetyl cephalomannine(Ⅱ),10- deacetvl taxol(Ⅲ),10-deacetyl cephalomannine(Ⅳ),10-deacetyl baccatin Ⅲ(Ⅶ).The structures of two the unknown compounds , named as yunnanxol(Ⅴ)and yannanxamine(Ⅵ),were elucidated as 13(2′,3′- dihydroxy-3′-phenyl)-propionyl baccatin Ⅲ and 9-deoxo-9α-hydroxy taxol respec- tively.