Taxoids from the needles of the Canadian yew

Systematic characterization of the taxoids in the needles of Taxus canadens is 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-baccatin 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-hydr oxy-10-deacetyI-10-glycolylbaccatin I; and 7-deacetyltaxuspine L. These tax anes, specific to the Canadian yew, were co-isolated with taxacustin, taxag ifine and 2-deacetyl-7-7,10-diacetyl-5-deaminoacyl taxine A previously foun d in Taxus cuspidata, baccata, and yunnanensis, respectively. (C) 2000 Else vier Science Ltd. All rights reserved.