- Facile Synthesis of 7-epi-Taxane and Its Derivatives and Preliminary Evaluation of Anticancer Activity
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7-epi-Taxane has been achieved efficiently in gram scale from natural taxane via inversion of the 7-hydroxyl group simply using Ag2O as catalyst and DMF as solvent. The catalyst could be quantitatively recovered by filtration without loss of catalytic activity. This condition is also applicable to the direct epimerization of taxane derivatives (e.g., docetaxel and paclitaxel) to 7-epi-taxane derivatives (e.g., 7-epi-docetaxel and 7-epi-paclitaxel). Furthermore, 33 ester derivatives of 7-epi-taxane with different amino acid moieties at the position of C-13 were successfully synthesized via esterification without protecting C-7-OH. Bioassay results revealed that compounds 13 and 18 have good selectivity against prostatic cancer cell line DU145, with IC50value as low as 15.9 nmol/L for 18.
- Li, Zhao,Feng, Jia,Zou, Kun,Yang, Zhuo,Zhang, Yong,Xu, Zhijian,Li, Bo,Shi, Jiye,Li, Yiming,Zhu, Weiliang,Chen, Kaixian
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- An effective method to produce 7-epitaxol from taxol in HCO3–
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It is known that 7-epitaxol has much stronger cytotoxicity than taxol does. However, the content of 7-epitaxol in yew is much less than taxol, which makes it more costly to obtain. We describe here a method to effectively convert taxol to 7-epitaxol. The
- Hao, Xiaoran,Liu, Yanjie,Ma, Xiaoyu,Zhou, Mengkai,Zhu, Xudong
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- Paclitaxel stability in solution
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Research in this laboratory has focused on the cytokinetic effect of taxanes on nonmammalian systems. Taxanes are a class of natural products that includes the well-known anticancer compound, paclitaxel (Taxol). Our methodology for the study of fungal growth in liquid medium amended with paclitaxel included membrane solid phase extraction (SPE) of the fungal broth. This was followed by elution of paclitaxel from the SPE membrane using methanol. The methanolic solution was evaporated under relatively mild conditions, namely 41-43°C and approximately 85 kPag. Analysis of the concentrated solution indicated that it contained a considerable quantity of 7-epi-taxol and smaller quantities of 7-epi-10-deacetyltaxol, 10-deacetyltaxol, and baccatin III, in addition to paclitaxel, even in those cases where the medium had not been inoculated with fungus. Obviously, fungal metabolism could not account for these observations. Although epimerization in solution at carbon 7 in the C ring of the taxane core has been observed and reported previously, no detailed study of the solution kinetics of paclitaxel degradation, including epimerization, is available. We report here our investigation of the stability of paclitaxel in several solvent systems at various temperatures and pressures. The investigations indicate that the apparent activation energy barrier (Ea) for paclitaxel degradation is highly dependent on experimental conditions. These stability studies emphasize the need to demonstrate explicitly that all taxane degradation, including epimerization, observed during in vitro studies is not an artifact of the analytical methodology employed.
- MacEachern-Keith,Butterfield, L. J. Wagner,Mattina, M. J. Incorvia
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- Trifluoroacetic acid-mediated cleavage of a triethylsilyl protecting group: Application in the final step of the semisynthetic route to paclitaxel (Taxol)
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The final step of the semisynthetic route to paclitaxel involves cleavage of the triethylsilyl (TES) protecting group from the C-7 hydroxyl group. Paclitaxel is an extremely complex molecule, and standard deprotection conditions led to formation of several impurities. Trifluoroacetic acid in aqueous acetic acid was found to be very effective in the cleavage of the TES group without compromising the quality of the product.
- Singh, Ambarish K.,Weaver, Raymond E.,Powers, Gerald L.,Rosso, Victor W.,Wei, Chenkou,Lust, David A.,Kotnis, Atul S.,Comezoglu, F. Taha,Liu, Mark,Bembenek, Kenneth S.,Phan, Bich D.,Vanyo, Dale J.,Davies, Merrill L.,Mathew, Rachel,Palaniswamy, Venkatapuram A.,Li, Wen-Sen,Gadamsetti, Kumar,Spagnuolo, Ciro J.,Winter, William J.
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- Method of generating 7-epipaclitaxel by converting hydrocarbonate into taxol
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The invention relates to a method of generating 7-epipaclitaxel by converting hydrocarbonate into taxol. The method comprises the steps of dissolving hydrocarbonate in sterile water, adding the same volume of the sterile water into an acetonitrile solutio
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Paragraph 0019-0047
(2019/07/04)
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- Method for preparing 7-epi-taxane compounds
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The invention relates to a method for preparing 7-epi-taxane compounds from 7-beta-hydroxy taxane compounds. The method comprises the step of converting 7-beta-hydroxy taxane compounds into 7-epi-taxane compounds in the solvent S under the existence of a
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Paragraph 0078-0080
(2017/03/14)
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- Biological degradation of taxol by action of cultured cells on 7-acetyltaxol-2″-yl glucoside
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Biodegradation pathways of taxol in cultured cells of Synechocystis sp. PCC 6803, Synechococcus sp. PCC 7942, Marchantia polymorpha, Nicotiana tabacum, and Glycine max were investigated using a water-soluble taxol derivative, 7-ace-tyltaxol-2″-yl glucoside, as the substrate. Although cyanobacteria, Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7942, and a lower plant, M. polymorpha, catalyzed the epimerization at 7-position of taxol skeleton, no epimerization occurred with higher plants, N. tabacum and G. max. On the other hand, Synechocystis sp. PCC 6803, Synechococcus sp. PCC 7942, M. polymorpha, and N. tabacum catalyzed hydrolysis at 13-position of taxol to give baccatin III and 10-deacetyl baccatin III. Both cyanobacteria cells also deacetylated 7-epi-baccatin III at its 10-position. M. polymorpha and G. max deacetylated at 10-position of taxol. Copyright
- Shimoda, Kei,Mikuni, Katsuhiko,Nakajima, Kiyoshi,Hamada, Hatsuyuki,Hamada, Hiroki
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p. 362 - 363
(2008/09/20)
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- NEW METHODS FOR THE PREPARATION OF TAXANES USING CHIRAL AUXILIARIES
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The present invention relates to a stereoselective synthesis of novel β-lactam dimers as useful precursors for the preparation of paclitaxel, docetaxel, and analogues thereof. More particularly, the new β-lactams are prepared from readily available and enantiomerically pure chiral auxiliaries. The β-lactams are then reacted with a suitably protected taxane to produce diastereomerically enriched side chain-bearing taxanes. Finally, the chiral auxiliary is cleaved and protecting groups are removed to provide the desired taxane.
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Page/Page column 42-43
(2008/06/13)
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- Paclitaxel delivery systems: The use of amino acid linkers in the conjugation of paclitaxel with carboxymethyldextran to create prodrugs
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Paclitaxel was bound via its hydroxyl group to carboxymethyldextran (CMDex, 150 kDa) by means of an amino acid linker; the linker was introduced into the 2′- or 7-hydroxyl group of the paclitaxel through an ester bond. These conjugates - CMDex-2′-paclitax
- Sugahara, Shu-Ichi,Kajiki, Masahiro,Kuriyama, Hiroshi,Kobayashi, To-Ru
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p. 632 - 641
(2007/10/03)
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- Process for selective derivatization of taxanes
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A process is described for converting the C(7) hydroxy group of a 10-acyloxy-7-hydroxytaxane to an acetal or ketal, the process comprising treating the 10-acyloxy-7-hydroxytaxane with a ketalizing agent in the presence of an acid catalyst to form a C(7) ketalized taxane of the formula or wherein either X31 or X32 represents the 10-acyloxy-7-hydroxytaxane moiety and the other of X31 and X32 as well as X33 and X34 are independently hydrocarbyl, substituted hydrocarbyl or heteroaryl moieties. Taxanes having a ketalized C(7) hydroxy group are also described.
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- Synthesis and evaluation of some 10-mono- and 2',10-diesters of 10- deacetylpaclitaxel
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10-Deacetylpaclitaxel, isolated from the bark of Taxus brevifolia, was converted into paclitaxel in one composite step (trimethylsilylation, acetylation, and desilylation) and in an overall yield of 80-85%. A series of 10-monoesters of 10-deacetylpaclitaxel are prepared by protection of the 2'- and 7-hydroxyls with a chloroacetyl group, acylation, and deprotection. Depending on the reaction conditions, the 10-monoesters, either exclusively or accompanied by the 2',10-diesters, are formed. The mono- and diesters were evaluated using the L-1210 cell culture assay. The 10-monoesters were comparable to paclitaxel and more active than the corresponding 2',10- diesters. The 10-[(4-methoxyphenyl)acetyl], 10-(2-nitrobenzoyl), and 10- (phenylacetyl) esters were found to be somewhat more active than paclitaxel.
- Rao,Bhakuni,Johnson,Oruganti
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p. 3411 - 3414
(2007/10/02)
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- A facile synthesis of 7,10-dideoxy taxol and 7-epi-10-deoxy taxol
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7,10-Dideoxy taxol 2 was prepared from baccatin III in 4 steps via the Barton deoxygenation reaction. Similarly, 7-epi-10-deoxy taxol 3 was prepared in one step from 7-epi taxol in high yield. The key reaction was the tributyltin hydride-mediated directed reduction of the C10 acetate.
- Chen,Wei,Vyas,Doyle,Farina
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p. 6845 - 6848
(2007/10/02)
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- New and efficient approaches to the semisynthesis of taxol and its C-13 side chain analogs by means of β-lactam synthon method
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Highly efficient chiral ester enolate-imine condensation giving 3-hydroxy-4-aryl-β-lactams with excellent enantiomeric purity is successfully applied to the asymmetric synthesis of the enantiomerically pure taxol C-13 side chain, N-benzoyl-(2R,3S)-3-phenyl-isoserine and its analogs. (3R,4S)-N-benzoyl-3-(1-ethoxyethoxy)-4-phenyl-2-azetidinone readily derived from the 3-hydroxy-4-phenyl-β-lactam is coupled with protected baccatin IIIs, followed by deprotection to give optically pure taxol and 10-deacetyl-7,10-bis(Troc)-taxol in good yields. Fully assigned 1H, 13C, and 2D (COSY and HETCOR) NMR spectra of taxol thus synthesized are shown and discussed.
- Ojima, Iwao,Habus, Ivan,Zhao, Mangzhu,Zucco, Martine,Park, Young Hoon,Sun, Chung Ming,Brigaud, Thierry
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p. 6985 - 7012
(2007/10/02)
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