An α-4(20)-epoxy-5α-hydroxytaxinine B 1, when treated with diethylaluminum chloride, underwent reactions involving intramolecular substitution along with deacetylation or addition leading to new rings. Two novel 1-d...An α-4(20)-epoxy-5α-hydroxytaxinine B 1, when treated with diethylaluminum chloride, underwent reactions involving intramolecular substitution along with deacetylation or addition leading to new rings. Two novel 1-deoxy compounds 2 and 3 were isolated and fully characterized.展开更多
A new taxane diterpenoid with a rearranged 5/7/6-membered ring system was isolated from the seeds of the Chinese pew, Taxus yunnanensis. Its structure was established as 9 alpha-acetoxy-5 alpha-cinnamoy]-11(15 --> ...A new taxane diterpenoid with a rearranged 5/7/6-membered ring system was isolated from the seeds of the Chinese pew, Taxus yunnanensis. Its structure was established as 9 alpha-acetoxy-5 alpha-cinnamoy]-11(15 --> 1)-abeotaxa-4(20), 11-diene-10 beta, 13 alpha, 15-triol on the basis of spectroscopic analysis. Its relative stereochemistry is proposed from the results of a NOESY experment.展开更多
New D-seco-taxoids were synthesized from 1-deoxybaccatinⅥand their structures were confirmed by 1H NMR,13C NMR, ESIMS and X-ray crystallography.The key step of the synthesis involved the opening of the oxetane ring u...New D-seco-taxoids were synthesized from 1-deoxybaccatinⅥand their structures were confirmed by 1H NMR,13C NMR, ESIMS and X-ray crystallography.The key step of the synthesis involved the opening of the oxetane ring under acid and basic conditions in order to obtain new multidrug resistance（MDR） reversal agents and new synthetic precursors of paclitaxel analogues.展开更多
Microbial trdrisformation of taxoids was inveStigared: taxoid 2 was transformed into 1β and 14β hydroxylated derivahves 3 and 4, unnatural taxoid 6 was transformed into 1β-hydroxy derivative 7 and 11(15-1) abeotaxa...Microbial trdrisformation of taxoids was inveStigared: taxoid 2 was transformed into 1β and 14β hydroxylated derivahves 3 and 4, unnatural taxoid 6 was transformed into 1β-hydroxy derivative 7 and 11(15-1) abeotaxane 8. Taxoids with an oxetane ring, 11-13 were synthesized from 1 via chemical reachons.展开更多
Some natural products, such as traditional Chinese medicines（TCMs）, contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and con...Some natural products, such as traditional Chinese medicines（TCMs）, contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and convenient assay for screening antimicrotubule compounds in which in vitro microdialysis/high-performance liquid chromatography （HPLC） is used to monitor the binding of the compounds extracted from TCM Taxus cuspidata Siebold ＆ Zucc（Taxus） to microtubules is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubules by biological fingerprinting analysis, and they were identified as the taxoids of taxol, baccatin III, 10-deacetylbaccatin Ⅲ（10-DAB）, cephalomannine and 7-epi-10-deacetyltaxol （7-epi-10-DAT） based on the comparison of their high-performance liquid chromatographic/mass spectrometric and UV spectra with those of the standard samples, both assembly-promoting and disassembly-inhibiting characteristics of those compounds were evaluated. It was observed that baccatin Ⅲ and 10-DAB bound to microtubules and the binding degrees were influenced by GTP. Competitive binding behavior of taxol with other four taxoids to microtubules was also investigated.展开更多
Three novel bicyclic taxane diterpenoids with the rare 6/12-membered rings wereisolated from the need ies of Taxus chinensis var. mairei. The structures were established with the help of 1D and 2D NMR spectral analysis.
Taxayuntin I, a new 11I (15→1)abeotaxane. was isolated from the leaves and stems ofTaxes yunnanensis. Its structure was elucidated on the basis of spectroscopic data.
A new taxoid, 2-deacetyl-2a, 14b-dihydroxybaccatin IV (1), was isolated from the leaves and branches of Taxus chinensis together with the known compound baccatin IV (2). The structure of the new compound was elucidat...A new taxoid, 2-deacetyl-2a, 14b-dihydroxybaccatin IV (1), was isolated from the leaves and branches of Taxus chinensis together with the known compound baccatin IV (2). The structure of the new compound was elucidated by spectroscopic techniques. The detailed 13C NMR assignments of baccatin IV are reported for the first time.展开更多
Compound 2 with 14β-hydroxyl group was successfully converted into its epimerized α-counterpart via oxidation - reduction.The elimination product (6) was auto-oxidized to epoxide 8,even in the solid state
-An oxetane ring can be constructed from 5 α-acyloxy-Δ4(20) -taxoids with osmylation as the first step in the usual manner. The innovation reported here is the use of an intramolecularly available acyl group for the...-An oxetane ring can be constructed from 5 α-acyloxy-Δ4(20) -taxoids with osmylation as the first step in the usual manner. The innovation reported here is the use of an intramolecularly available acyl group for the protection of 20-OH by an unexpected 5-to 20-migration under slightly basic conditions.展开更多
1-Hydroxyl acetylation of 10-deacetylbaccatin Ⅲ was achieved by removing the neighboring bulky 2-benzoyl group and oxidizing 2-hydroxyl group to a ketone function, but attempted reductive cleavage of 1-acetoxy gave r...1-Hydroxyl acetylation of 10-deacetylbaccatin Ⅲ was achieved by removing the neighboring bulky 2-benzoyl group and oxidizing 2-hydroxyl group to a ketone function, but attempted reductive cleavage of 1-acetoxy gave rearranged products under different conditions with or without proton source.展开更多
A new taxoid taxa-4(20), 11-diene-2α, 5β, 10β, 14β-tetraol-2α, 14β-diacetate (sinenxan H) (1) was obtained by biotransformation of taxa-4(20), 11-diene-2α, 5α, 10β, 14β-tetraol-2α, 5α, 10β, 14β-tetraacet...A new taxoid taxa-4(20), 11-diene-2α, 5β, 10β, 14β-tetraol-2α, 14β-diacetate (sinenxan H) (1) was obtained by biotransformation of taxa-4(20), 11-diene-2α, 5α, 10β, 14β-tetraol-2α, 5α, 10β, 14β-tetraacetate (2) with a fungus isolated from Taxus yunnanensis. Its structure was determined based on spectral data展开更多
A new taxane diterpenoid, named 7-deacetoxy taxinine J, together with ten knowncompounds were isolated from the needles of Taxus × media Hickiii. The structures of allcompounds were elucidated and identified by s...A new taxane diterpenoid, named 7-deacetoxy taxinine J, together with ten knowncompounds were isolated from the needles of Taxus × media Hickiii. The structures of allcompounds were elucidated and identified by spectroscopic methods. T'he structure of 7-deacetoxytaxinine J was further confirmed by X-ray crystallographic analysis. The structure of the knowncompound, taxinine E, was also revised.展开更多
A new taxoid with 5/716 taxane skeleton, named taxamedin A (1) was isolated from the needles of Taxus x media Hicksii. Its structure was elucidated by spectal analysis
Two new taxane diterpenoids, 2-deacetoxy-7,9-dideacetyltaxinine J (1) and 2-deacetoxytaxinine B (3), were isolated from the barks of Taxus chinensis. Their structures were elucidated by spectroscopic methods.
We have studied the fragmentation behavior of positive and negative ions of taxoi and 6/8/6 type taxoids, the influence of different substituents on fragmentation, and the correlativity between fragmentation patterns ...We have studied the fragmentation behavior of positive and negative ions of taxoi and 6/8/6 type taxoids, the influence of different substituents on fragmentation, and the correlativity between fragmentation patterns and structure by MS/MS technique with different ionization methods such as FAB-MS, ESI-MS, ete. We have also investigated in detail the fragmentation of various molecular-related ions, such as [M+H]+, [M+Na]+ and [M-H] ions, and the formation pathways of characteristic fragment ions. It has been found that there exists some competing reaction between the loss of C-13 side chain and decomposition by loss of acetic acid. In addition, by comparing CID spectra obtained with low- and high-energy collision, it is seen that CID-MS/MS with low-energy collision is more suitable for the study of the structural analysis of small molecules and drug metabolites. The experimental results demonstrate that MS/MS spectra can reflect more effectively the slight difference of structure between the related展开更多
An oxetane ring can be constructed from 5α-acyloxy-Δ4(20)-taxoids. Hie facile intramolecular acyl migration from 5- to 20-position under slightly basic conditions enabled the construction of the oxetane ring in a co...An oxetane ring can be constructed from 5α-acyloxy-Δ4(20)-taxoids. Hie facile intramolecular acyl migration from 5- to 20-position under slightly basic conditions enabled the construction of the oxetane ring in a convenient short cut, whereas the acyl migration from 2- to 20-position left the 2-hydroxyl accessible to a later benzoylation. An unexpected five-mem-bered 4-O, 20- O sulfite ring was formed in the attempted construction of the oxetane ring with 5α-triflate as a leaving group. After the construction of the oxetane ring, treatment with strong base LiHMDS and acetyl chloride gave the expected 4-O-acetate while treatment with acetic anhydride and DMAP gave a 4-O-acetoacetate.展开更多
基金Giant-in-Aid for scientific reserch from the Ministry of Education, Science and Culture of JapanJSPS fellowship to DL Q. Che
文摘An α-4(20)-epoxy-5α-hydroxytaxinine B 1, when treated with diethylaluminum chloride, underwent reactions involving intramolecular substitution along with deacetylation or addition leading to new rings. Two novel 1-deoxy compounds 2 and 3 were isolated and fully characterized.
基金described here comes from the Ministry of Education, Scienceports, and Culture of japan through a grant-in-aid for scientifi
文摘A new taxane diterpenoid with a rearranged 5/7/6-membered ring system was isolated from the seeds of the Chinese pew, Taxus yunnanensis. Its structure was established as 9 alpha-acetoxy-5 alpha-cinnamoy]-11(15 --> 1)-abeotaxa-4(20), 11-diene-10 beta, 13 alpha, 15-triol on the basis of spectroscopic analysis. Its relative stereochemistry is proposed from the results of a NOESY experment.
基金the National Natural Science Foundation of China(No.30672506)Leading Academic Discipline Project of Shanghai Municipal Education Commission(No.J50102)
文摘New D-seco-taxoids were synthesized from 1-deoxybaccatinⅥand their structures were confirmed by 1H NMR,13C NMR, ESIMS and X-ray crystallography.The key step of the synthesis involved the opening of the oxetane ring under acid and basic conditions in order to obtain new multidrug resistance（MDR） reversal agents and new synthetic precursors of paclitaxel analogues.
文摘Microbial trdrisformation of taxoids was inveStigared: taxoid 2 was transformed into 1β and 14β hydroxylated derivahves 3 and 4, unnatural taxoid 6 was transformed into 1β-hydroxy derivative 7 and 11(15-1) abeotaxane 8. Taxoids with an oxetane ring, 11-13 were synthesized from 1 via chemical reachons.
基金the National Natural Science Foundation of China(No.90709021)Knowledge Innovation Program of Chi-nese Academy of Sciences(No.KJCX2.YW.HO9)
文摘Some natural products, such as traditional Chinese medicines（TCMs）, contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and convenient assay for screening antimicrotubule compounds in which in vitro microdialysis/high-performance liquid chromatography （HPLC） is used to monitor the binding of the compounds extracted from TCM Taxus cuspidata Siebold ＆ Zucc（Taxus） to microtubules is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubules by biological fingerprinting analysis, and they were identified as the taxoids of taxol, baccatin III, 10-deacetylbaccatin Ⅲ（10-DAB）, cephalomannine and 7-epi-10-deacetyltaxol （7-epi-10-DAT） based on the comparison of their high-performance liquid chromatographic/mass spectrometric and UV spectra with those of the standard samples, both assembly-promoting and disassembly-inhibiting characteristics of those compounds were evaluated. It was observed that baccatin Ⅲ and 10-DAB bound to microtubules and the binding degrees were influenced by GTP. Competitive binding behavior of taxol with other four taxoids to microtubules was also investigated.
文摘Three novel bicyclic taxane diterpenoids with the rare 6/12-membered rings wereisolated from the need ies of Taxus chinensis var. mairei. The structures were established with the help of 1D and 2D NMR spectral analysis.
文摘Taxayuntin I, a new 11I (15→1)abeotaxane. was isolated from the leaves and stems ofTaxes yunnanensis. Its structure was elucidated on the basis of spectroscopic data.
文摘A new taxoid, 2-deacetyl-2a, 14b-dihydroxybaccatin IV (1), was isolated from the leaves and branches of Taxus chinensis together with the known compound baccatin IV (2). The structure of the new compound was elucidated by spectroscopic techniques. The detailed 13C NMR assignments of baccatin IV are reported for the first time.
文摘Compound 2 with 14β-hydroxyl group was successfully converted into its epimerized α-counterpart via oxidation - reduction.The elimination product (6) was auto-oxidized to epoxide 8,even in the solid state
文摘-An oxetane ring can be constructed from 5 α-acyloxy-Δ4(20) -taxoids with osmylation as the first step in the usual manner. The innovation reported here is the use of an intramolecularly available acyl group for the protection of 20-OH by an unexpected 5-to 20-migration under slightly basic conditions.
文摘1-Hydroxyl acetylation of 10-deacetylbaccatin Ⅲ was achieved by removing the neighboring bulky 2-benzoyl group and oxidizing 2-hydroxyl group to a ketone function, but attempted reductive cleavage of 1-acetoxy gave rearranged products under different conditions with or without proton source.
文摘A new taxoid taxa-4(20), 11-diene-2α, 5β, 10β, 14β-tetraol-2α, 14β-diacetate (sinenxan H) (1) was obtained by biotransformation of taxa-4(20), 11-diene-2α, 5α, 10β, 14β-tetraol-2α, 5α, 10β, 14β-tetraacetate (2) with a fungus isolated from Taxus yunnanensis. Its structure was determined based on spectral data
文摘A new taxane diterpenoid, named 7-deacetoxy taxinine J, together with ten knowncompounds were isolated from the needles of Taxus × media Hickiii. The structures of allcompounds were elucidated and identified by spectroscopic methods. T'he structure of 7-deacetoxytaxinine J was further confirmed by X-ray crystallographic analysis. The structure of the knowncompound, taxinine E, was also revised.
文摘A new taxoid with 5/716 taxane skeleton, named taxamedin A (1) was isolated from the needles of Taxus x media Hicksii. Its structure was elucidated by spectal analysis
文摘Two new taxane diterpenoids, 2-deacetoxy-7,9-dideacetyltaxinine J (1) and 2-deacetoxytaxinine B (3), were isolated from the barks of Taxus chinensis. Their structures were elucidated by spectroscopic methods.
文摘We have studied the fragmentation behavior of positive and negative ions of taxoi and 6/8/6 type taxoids, the influence of different substituents on fragmentation, and the correlativity between fragmentation patterns and structure by MS/MS technique with different ionization methods such as FAB-MS, ESI-MS, ete. We have also investigated in detail the fragmentation of various molecular-related ions, such as [M+H]+, [M+Na]+ and [M-H] ions, and the formation pathways of characteristic fragment ions. It has been found that there exists some competing reaction between the loss of C-13 side chain and decomposition by loss of acetic acid. In addition, by comparing CID spectra obtained with low- and high-energy collision, it is seen that CID-MS/MS with low-energy collision is more suitable for the study of the structural analysis of small molecules and drug metabolites. The experimental results demonstrate that MS/MS spectra can reflect more effectively the slight difference of structure between the related
基金Project supported by Chinese Academy of Medical Science Researeh Grant and Taisho Pharmaceutical Co. Ltd.
文摘An oxetane ring can be constructed from 5α-acyloxy-Δ4(20)-taxoids. Hie facile intramolecular acyl migration from 5- to 20-position under slightly basic conditions enabled the construction of the oxetane ring in a convenient short cut, whereas the acyl migration from 2- to 20-position left the 2-hydroxyl accessible to a later benzoylation. An unexpected five-mem-bered 4-O, 20- O sulfite ring was formed in the attempted construction of the oxetane ring with 5α-triflate as a leaving group. After the construction of the oxetane ring, treatment with strong base LiHMDS and acetyl chloride gave the expected 4-O-acetate while treatment with acetic anhydride and DMAP gave a 4-O-acetoacetate.
