Two New Taxanes from the Needles and Branches Bark of Taxus cuspidata

Abstract

Two new taxanes were isolated from the MeOH extract of the needles and branches bark of the Japanese yew, Taxus cuspidata. The structures were established as (2alpha,5alpha,7beta,9alpha,10beta,13alpha)-5,10,13,20-tetraacetoxytax-11-ene-2,7,9-triol (1) and (2alpha,5alpha,9alpha,10beta)-2,9,10-triacetoxy-5-[(beta-D-glucopyranosyl)oxy]-3,11-cyclotax-11-en-13-one (2) on the basis of in-depth 1D- and 2D-NMR analyses. Compound 2 is the first example of a transannular taxane glycoside isolated from a natural source.

A Novel Taxane 13-Glucoside and Other Taxanes from the Leaves ofTaxus cuspidata

“…Compound 2 was isolated as a gummy solid, [α] D 22 : + 73 (c 0.05, MeOH), and its molecular formula was established as C 26 H 36 O 10 (HR-FAB-MS: m/z = 551.2263 [M + K] + , Δ = + 0.4 mmu). The 1 Hand 13 C-NMR spectral data (l "Table 2) almost coincided with the known taxane 5α,10β,13α,20-tetraacetoxytax-11-ene-2α,7β,9αtriol, which was isolated by us from the bark of T. cuspidata[13], except for the chemical shift values of the 20 position (Δδ H = − 0.59 and − 0.49 ppm, Δδ C = − 1.8 ppm) and one missing acetyl group. This information together with analysis of 2D NMR spectral data revealed that the structure of 2 was 5α,10β,13α-triacetoxytax-11-ene-2α,7β,9α,20-tetraol.The following equipment and materials were used: optical rotation, Jasco DIP-370; NMR, Bruker Avance-500; HR-FAB-MS, Vacuum Generators ZAB-HS; preparative HPLC, Waters Delta Prep 3000, UV 2487, Partisil 10 ODS-2 MAG-20 (9.4 × 250 mm); TLC, EM Science silica gel 60 F 254 ; column chromatography, EM Science silica gel 60 (230-400 mesh).…”

“…T. cuspidata is one of the most extensively investigated yews, and more than 120 taxanes have been isolated from it [1][2][3][4][5][6]. As a continuation of our research on plants from the Taxus genus, we reinvestigated the leaves of T. cuspidata collected at Sendai, Japan [7][8][9][10][11][12][13][14][15], and isolated three new taxanes (l " Fig. 1 [10,11,16]).…”

Three New Taxanes with the 10-Alkoxy Group from the Heartwood ofTaxus cuspidata

“…Therefore the signal at H 1.84 (1H, d, J ¼ 2:4 Hz) was attributed to H-1. Continuing this spin system, the signals at H 5.02 (1H, dd, J ¼ 9:5, 5.0 Hz), 2.75 (1H, dd, J ¼ 9: 5 Note tions with C-3 and C-20. 7) The chemical shift of H-5 implied that a free hydroxy group was connected to C-5.…”

Chemical Studies on Taxus cuspidata

“…Irradiation of the corresponding 13-oxotax-11-enes led to the bonding between C(3) and C(11); however, only a mixture of isomers was obtained ((Z)-and (E)-configured side-chains) [92], and the 3,11-bridge rendered the structure less flexible. Taxinine K (27) and taxinine L (28) are the first two 3,11-cyclotaxanes from T. cuspidata [40], while taxuspine H (30) is the sole 3,11-cyclotaxane with an alkaloid side chain at C(5) [36], and 34 is the first 3,11-cyclotaxane with a glycoside at C(5) [38] (see Fig. 3).…”