Canataxpyran A, a novel 3,8-secotaxane with a 13,17-ether bridge from needles of Taxus canadensis

Abstract

A novel 6/12-membered bicyclic taxane with a 13,17-ether bridge, named canataxpyran A, was isolated from the needles of Taxus canadensis. The structures were characterized as 7 β,9,10 β,20-tetracetoxy-13 β,17-epoxy-3,8-secotaxa-3 E,8 E,11-triene-2 α,5 α -diol (designated as canataxpyran A, 1 ). This bicyclic taxane gradually decomposed in CDCl 3 to give the corresponding enones, 10 β,20-diacetoxy-13 β,17-epoxy-4 α,5 α -dihydroxy-3,8-secotaxa-2 E,7 E,11-trien-9-one (canataxpyran B, 2 ) and 5 α,10 β,20-triacetoxy-13 β,17-epoxy-4 α -hydroxy-3,8-secotaxa-2 E,7 E,11-trien-9-one (canataxpyran C, 3 ). Compound 1 is the first example of a natural 3,8-secotaxane with 13,17-oxygen bridge. Copyright © by Walter de Gruyter.