title: New taxanes from the needles of Taxus canadensis.
abstract: Ten new taxanes were isolated from the methanol extract of the needles of the Canadian yew, Taxus canadensis. On the basis of their spectral analysis, their structures were established as 9alpha-hydroxy-2alpha,7alpha,10beta-triacetoxy-5alpha-cinnamoyloxy-3,11-cyclotaxa-4(20)-en-13-one (1), 9alpha,10beta-diacetoxy-5alpha-cinnamoyloxy-3,11-cyclotaxa-4(20)-en-13-one (2), 9alpha,20-dihydroxy-2alpha,10beta,13alpha-triacetoxytaxa-4(5),11(12)-diene (3), 2alpha,9alpha,10beta-triacetoxy-20-cinnamoyloxy-11,12-epoxytaxa-4-en-13-one (4), 9alpha-hydroxy-2alpha,10beta,13alpha-triacetoxy-5alpha-(3'-methylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene (5), 2alpha,10beta-diacetoxy-5alpha,9alpha-dihydroxytaxa-4(20),11-dien-13-one (6), 2alpha,9alpha-diacetoxy-5alpha,10beta-dihydroxytaxa-4(20),11-dien-13-one (7), 5alpha,9alpha-dihydroxy-2alpha,10beta,13alpha-triacetoxytaxa-4(20),11-diene (8), 5alpha,10beta-dihydroxy-2alpha,9alpha,13alpha-triacetoxytaxa-4(20),11-diene (9), and 7beta,11beta-dihydroxy-2alpha,9alpha,10beta,13-tetraacetoxy-5alpha-cinnamoyloxytaxa-4(20),12-diene (10). Taxane 1 is the first example of a 3,11-cyclotaxane with a 7-epi-alpha-oxygenated group. Taxane 4 is the first taxane with a C-11,12-epoxide ring as well as a C-4(5)-endo-double bond. Taxanes with a 12(13) double bond as in 10 instead of the usual 11(12) double bond have been found so far only in the needles, stem, and seeds of the Japanese yew.
authors.affiliation: INRS-Institut Armand-Frappier-Santé Humaine, Université du Québec, 531 Boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
authors.forename: Qing-Wen
authors.initials: QW
authors.lastname: Shi
authors.forename: Françoise
authors.initials: F
authors.lastname: Sauriol
authors.forename: Orval
authors.initials: O
authors.lastname: Mamer
authors.forename: Lolita O
authors.initials: LO
authors.lastname: Zamir
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry / Q000302:isolation & purification*; D002170:Canada; D002851:Chromatography, High Pressure Liquid; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010946:Plants, Medicinal / Q000737:chemistry*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D043823:Taxoids; D020946:Taxus / Q000737:chemistry*
chemical_list: D001952:Bridged-Ring Compounds; D043823:Taxoids; C080625:taxane