Taxoids from the needles of the Canadian yew.

Systematic characterization of the taxoids in the needles of Taxus canadensis led to the discovery of seven taxanes along with three known congeners. Their structures were rigorously established by spectroscopic methods as 15-benzoyl-10-deacetyl-2-debenzoyl-10-dehydro-abeo-baccat in III; 15-benzoyl-2-debenzoyl-7, 9-dideacetyl-abeo-baccatin VI; N-acetyl-N-debenzoyltaxol; 7,9,13-trideacetylbaccatin VI; 10-deacetyl-10-glycolylbaccatin IV; 1 beta-hydroxy-10-deacetyl-10-glycolylbaccatin I; and 7-deacetyltaxuspine L. These taxanes, specific to the Canadian yew, were co-isolated with taxacustin, taxagifine and 2-deacetyl-7,10-diacetyl-5-deaminoacyl taxine A previously found in Taxus cuspidata, baccata, and yunnanensis, respectively.