Five novel taxanes from taxus canadensis
Five novel taxanes (1-5) have been isolated from the needles of Taxus canadensis, and their structures were elucidated on the basis of spectroscopic data. Two of these taxanes have structural features seldom found in yews, with a C-12, C-13 double bond and a hydroxymethylene at C-4. In addition, the 2D structures generated by molecular modeling of taxanes 1 and 2, differing mostly in the location of the double bond in ring A, were compared. The different conformation of ring A derived from the C-12, C-13 double bond is particularly interesting because it implies that if a Taxol (paclitaxel) side chain were attached to C-13 it would have a different orientation from that in paclitaxel.
Zamir
LO
Universite du Quebec, INRS-Institut Armand-Frappier-Sante Humaine, 531 Boulevard des Prairies, Laval, Quebec, Canada, H7N 4Z3, Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada, H3A 2K6, and.
Zhang
J
Wu
J
Sauriol
F
Mamer
O