Taxuspines N, O, and P, new taxoids from Japanese yew Taxus cuspidata

Novel Taxa-4(20),12-diene and 2(3→20)Abeotaxane from Needles ofTaxus canadensis

“…The locations of the acetyl groups were deduced from the HMBC correlations of carbonyl carbons with corresponding protons. The signal at C 78.2, which showed long-range correlations with H-C(9), H-C(10), Me (16) and Me (17) in the HMBC experiment, was assigned to C (11), and a hydroxy group attached to C(11) was suggested by its chemical shift value and molecular formula. The olefinic carbon at C 132.5, which showed HMBC correlations with H-C (10) and Me(18), was assigned to C(12).…”

Taxanes with C-5-amino-side chains from the needles of Taxus canadensis

“…Detailed interpretation of its 1D-and 2D-NMR including HSQC and HMBC spectra enabled us to establish the structure of taxane 1 as 2a,7b,9a,10b, 13-pentaacetoxy-11b-hydroxy-5a-(3 0 -N,N-dimethylamino-3 0 -phenyl)-propionyloxytaxa-4(20),12-diene. A literature search showed that the structure of 1 is identical with taxuspine P isolated from the stem of the Japanese yew, Taxus cuspidata (Kobayashi et al, 1996). For comparison with taxuspine P, we recorded the NMR for 1 in benzene-d6 (Table 1).…”

Chemical Studies on Taxus cuspidata

“…Taxuspine D (95) and paclitaxel induced overstabilized Taxuspines N and P (116 and 94, resp.) exhibited cytotoxicity against murine lymphoma L 1210 cells with IC 50 values of 7.8 and 2.5 mg/ml, respectively, and human epidermoid carcinoma KB cells with IC 50 values of > 10 and 2.6 mg/ml, respectively [15]. It was noted that taxuspine E (115), lacking the side chain at C(13), showed potent cytotoxicity against KB cells, since the baccatin III-type compounds with an oxetane ring but no side chain at C(13) were reported to be ca.…”

“…7-epi-10-Deacetyltaxol (135) was a sole case with a-OH group at C(7). Taxuspine N (116) is the first example of a taxane diterpene which contains a 6/8/6-ring system with a 3-(dimethylamino)-2-hydroxy-3-phenylpropanoyloxy group (Wintersteins acid) at C(13) from yew trees [15]. Compounds of 137 -139 have the same skeleton as baccatin III (126) and bear an O-linked xylosyl group at C(7).…”