Revised structure of brevifoliol and some baccatin VI derivatives

Abstract

Brevifoliol and some baccatin VI derivatives have been shown to have a rearranged 11 (1 5-1 )abeo-taxane skeleton and not a taxane skeleton as originally reported, making abeo-taxanes an emerging major structural type of taxoids.

Chemical Studies on Taxus cuspidata

“…After interpretation of the 2D-NMR data, its structure was revised to 11(15 ! 1)abeo-taxane and further confirmed by Xray-crystallographic analysis [89] [90]. Taxuspine Q (12) bears a rare tigloyloxy group at C(10).…”

Bioactive taxoids from the Japanese yew Taxus cuspidata

“…18 The 11(15!1)-abeotaxanes (5/7/6-membered ring system) may be biogenetically generated through a WagnerMeerwein rearrangement of ring A in a 6/8/6-membered ring system. 26 On the other hand, the -verticillene. 27 The bicyclic taxane-related compounds (6/12-membered ring system) might be derived from verticillene (Fig.…”

“…Since the new taxoids, taxuspines A-H and J-Z (1-25) and taxezopidines A-H and J-L (26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36), from the Japanese yew T. cuspidata possessed various skeletons, we wish to propose the plausible biogenesis of these taxoids. The biosynthesis of taxane skeleton (6/8/6-membered ring system) has recently been suggested to involve cyclization of geranylgeranyl diphosphate to taxa-4(5),11-diene by Croteau et al, 25 while the pathway of the 3,11-cyclotaxanes (6/5/5/6-membered ring system) has been proposed to be derived from taxanes by concerted s s 2 þ p s 2 route.…”

Taxoid from the needles of the Himalayan yew Taxus wallichiana with cytotoxic and immunomodulatory activities

“…4 In a later publication, the structures of brevifoliol and its four other derivatives were revised. 13 Bioorganic However, the structure of the taxoid of molecular weight 536 was never characterized unambiguously. Therefore, we have grown crystals of the above taxoid 1 suitable for X-ray crystallography.…”