Novel taxanes from the needles of Taxus canadensis

Nineteen taxanes were characterized for the first time in the needles of th e Canadian yew. Four of these metabolites are novel: taxinine-11, 12-oxide (1), 7-acetoxytaxuspine C (2), 5-cinnamoyltaxin B (3), and 7, 9-deacetyltax inine B (4). Compound 1 is the second 11,12-epoxy-taxane known and 7-oxygen ated-3, 11-cyclotaxane structures are unique to Taxus canadensis. In additi on, taxinine and taxinine E were found to be major taxanes in the Canadian yew. The structures of all the taxanes were rigorously established by spect roscopic methods. (C) 1999 Elsevier Science Ltd. All rights reserved.