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<正>非天然手性氨基酸是已经上市的和正在研发的手性药物、手性农药和手性食品添加剂的关键中间体[1-2].随着相关产业的发展,非天然手性氨基酸的市场需求与日俱增.非天然手性氨基酸不能像天然L-氨基酸一样采用发酵法生产,主要制备方法包括化学法和生物法.化学法包括化学不对称合成法和化学拆分法.化学不对称合成法采用价格昂贵的手性源、手性助剂或手性金属催化剂.化学拆分法采用手性酸为拆分剂,经历与消旋氨基酸成盐、解 相似文献
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介绍了近十几年来兴起的分子设计中的手性元方法。通过与合成子方法的对比突出了它的优越性,并说明了手性元方法的应用在天然活性物质立体合成中的重要意义。 相似文献
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天然手性源在光学活性菊酸合成中的应用 总被引:1,自引:0,他引:1
概述了用天然手性源制取光学活性菊酸的近期进展.讨论了利用天然手性试剂、酶以及微生物等对外消旋菊酸进行拆分,以天然氨基酸等作为手性诱导试剂进行不对称合成以及利用萜、碳水化合物、酒石酸等分子中天然存在的立体结构进行骨架改造和选择性合成. 相似文献
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连续全碳季碳手性中心是活性天然产物中常见且具有合成挑战性的结构单元.本文首先介绍了本研究组在含连续全碳季碳手性中心天然产物的全合成研究进展;随后对含多个(≥3)连续全碳季碳手性中心天然产物的合成策略进行分类;最后以Waihoensene和Crinipellins家族天然产物的全合成研究为例,结合其他课题组报道的全合成研究,对比分析相关合成方法学及合成策略的优势和不足. 相似文献
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手性螺环配体的合成及其在不对称催化反应中的应用研究进展 总被引:2,自引:0,他引:2
手性螺环配体的合成及其在不对称催化反应中的应用是不对称合成和催化研究中重要的研究领域之一, 一些手性螺环配体被合成出来并成功地应用于不对称催化反应中. 综述了近十年来手性螺环配体的合成及在不对称催化反应中的应用研究进展. 相似文献
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Natural fragrances from lemon verbena (Aloysia triphylla) were studied by headspace solid phase microextraction (HS-SPME) techniques followed by gas chromatography-mass spectrometry (GC-MS), with six different fibre coatings being tested to evaluate the extraction efficiencies of several selected compounds. A total of 14 compounds were identified in the fragrances of lemon verbena. Geranial and neral were detected as major components and alpha-pinene, beta-pinene, beta-caryophyllene, and curcumene as minor components. Enantiomeric analysis of chiral compounds from lemon verbena was carried out on a chiral column. alpha-Pinene, limonene, and camphor in the fragrances emitted from lemon verbena were found in the (+), (-), and (-) forms, respectively. 相似文献
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D. Gautam 《Tetrahedron letters》2009,50(15):1693-2091
A Chiron approach for the synthesis of (+)-secosyrin 1 from d-mannitol has been described. The key steps are a stereoselective Wittig reaction and an intramolecular Michael addition on the disubstituted butenolide, leading to a highly stereoselective formation of the tertiary chiral centre of (+)-secosyrin 1. 相似文献
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Natural products have been synthesized for billions of years in animals, plants, and microorganisms. As a rule they occur enantiomerically pure. Their chiral character corroborates their use in metabolism or as biologically active agents. Natural products may be insufficient in quality or quantity. They have recently begun to become accessible, either unchanged or modified, by biological synthesis; here, too, they are obtained enantiomerically pure. In the last twenty years chemical synthesis has become a major concern of organic chemists. Their target compounds are primarily enantiomerically pure natural products or biologically active variants thereof. 相似文献
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The physiologically active groups such as purine and pyrimidine bases are introduced to the asymmetric ynthesis. The optically pure compounds bearing purine and pyrimidine bases (5a—5e) were prepared via the asymetric Michael addition reaction of purines and pyrimidines as Michael donators with the chiral source 5-(R)-[(1R, 2S, 5R)-menthyloxy]-2(5H)-furanone (3a), which was prepared from the natural chiral auxiliary (-)-menthol. The synthetic method was studied in detail and the new compounds were identified on the basis of their analytical data and spectroscopic data, such as [α]_D~(20), IR, UV, ~1H NMR, ~(13)C NMR and MS. The absolute configuration of 5a was established by X-ray crystallography. The results provided an efficient synthetic route to chiral purines and pyrimidine analogues, and offered chiral sources for further research on the physiologically active compounds of chiral nucleotides. 相似文献
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Lan He 《Tetrahedron》2005,61(35):8505-8511
This paper described an efficient synthetic strategy for chiral acyclic nucleoside analogues containing both the phenoxy components of some bioactive natural compounds and a heterocyclic base. The phenoxy components with adenine moiety were incorporated into the chiral acyclic nucleoside analogues through two key synthetic tactics. Chiron 5-(R)-menthyloxy-2(5H)-furanone 5 was obtained in good yield from the cheap starting material furfural via a valuable synthetic route. The asymmetric Michael addition of 5 with adenine and the subsequent reduction reaction afforded the key chiral intermediate, 2-(R)-(9′-adeninyl)-1,4-butanediol 8. The absolute configuration of 8 was established by X-ray crystallography. The intermolecular dehydration reaction between 2-(9′-adeninyl)-1,4-butanediol 8 and phenoxy components 9 on treatment with diethyl azodicarboxylate and triphenylphosphine was carried out to give the chiral acyclic nucleoside analogues 1a-1e. The regioselectivity of the reaction was established by NMR methods, especially through 13C NMR shifts and NOE effect observed in the target molecule 1c, as well as by HMBC/HMQC experiments. The target compounds were tested for inhibition of cytopathogenicity against different cancer cells and exhibited potential anticancer activity. 相似文献
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Natural compounds can exist in different forms, where molecules possessing chirality play an essential role in living organisms. Currently, one of the most important tasks of modern analytical chemistry is the enantioseparation of chiral compounds, in particular, the enantiomers of compounds having biological and/or pharmaceutical activity. Whether the task is to analyze environmental or food samples or to develop an assay for drug control, well-reproducible, highly sensitive, stereoselective, and robust methods are required. High-performance liquid chromatography best meets these conditions. Nevertheless, in many cases, gas chromatography, supercritical fluid chromatography, or capillary electrophoresis can also offer a suitable solution. Amino acids, proteins, cyclodextrins, derivatized polysaccharides, macrocyclic glycopeptides, and ion exchangers can serve as efficient selectors in liquid chromatography, and they are quite frequently applied and reviewed. Crown ethers and cyclofructans possessing similar structural characteristics and selectivity in the enantiodiscrimination of different amine compounds are discussed less frequently. This review collects information on enantioseparations achieved recently with the use of chiral stationary phases based on crown ethers or cyclofructans, focusing on liquid chromatographic applications. 相似文献
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Three chiral compounds were successfully separated in a short time with two enantiomer separation models on packed-capillary
electrochromatography (CEC). (i) 75 μm I.D. capillaries were packed with 5 μm β-cyclodextrin (βCD) chiral stationary phase
(CSP). Effects of voltage, pH and concentration of organic modifier on electroosmotic flow (EOF) and chiral separations were
investigated systematically. Enantiomers of a neutral compound (benzoin) and a neutral drug (mephenytoin) were separated within
a short time with high efficiency. Efficiency of 32 000 theoretical plates per meter and resolution (R8) of 1.42 were achieved for enantiomers of benzoin using a βCD packed column with 6.2crn packed length. Efficiency of 45 000
theoretical plates per meter andR8 of 3.40 were obtained for enantiomers of mephenytoin. Especially, the enantiomer separation of mephenytion was performed
in just 3.4 min with R8 of 2.60. (ii) 75 μm I.D. capillary was packed with octadecylsilica particles (ODs). Chiral separation of a basic drug, propranolol,
was studied with chiral agent, via addition of the dimethyl-β-cyclodextrin (DM β-CD) directly into the mobile phase on this
column. Baseline separation and efficiency of 81 000 theoretical plates per meter were achieved for propranolol.
Project supported by the Natural Science Foundation of Liaoning Province, China, the National Natural Science Foundation of
China (Grant No.29875030), and the Excellent Young Scientist Award from the National Natural Science Foundation of China.
(Grant No.29725512). 相似文献
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Zeng BB Wu Y Jiang S Yu Q Yao ZJ Liu ZH Li HY Li Y Chen XG Wu YL 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(1):282-290
A class of structurally simplified analogues of the naturally occurring annonaceous acetogenins were developed, amongst which some non-THF analogues showed remarkable cytotoxicities against tumor cell lines, as well as good selectivity between human tumor cells and normal cells. The synthetic routes were significantly shortened because of the removal of the chiral centers bearing the THF rings on the natural templates. This simplification also provides access to the parallel synthesis of these mimics by a combinatorial strategy. The remaining stereogenic centers at the positions alpha to the ethereal links were introduced by the Chiron approach from the easily accessible chiral building blocks 6a and/or 6b, made in turn from L-ascorbic acid or D-mannitol, while the one in the butenolide segment was taken from L-lactate. All four diastereomeric non-THF analogues 2a-2d showed remarkable activity against the HCT-8 cell line, and better differentiation was found when testing against the HT-29 cell line. It was also discovered that both the butenolide and ethylene glycol subunits play essential roles in the cytotoxicities against tumor cell lines, while the 10-substituted hydroxy group and the absolute configuration of methyl group at the butenolide moiety are less important for their activity. 相似文献
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Seiji Kurihara Teppei Yoshioka Tomonari Ogata Alam Md Zahangir Takamasa Nonaka 《Liquid crystals》2003,30(10):1219-1223
We have synthesized azobenzene-based molecules containing either one or two chiral groups. A cholesteric phase can be induced by adding the chiral azobenzene compounds to a host nematic liquid crystal. We investigated the effects of the trans - cis photoisomerization of the chiral azobenzene compounds on the properties of the cholesteric phase, such as the helical pitch length. This can be increased or decreased by the photoisomerization of the chiral azobenzene compounds. We discuss the photochemically driven change in the helical pitch of the cholesteric phase with respect to structural effects involving the chiral groups. 相似文献
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Seiji Kurihara Teppei Yoshioka Tomonari Ogata Alam Md Zahangir Takamasa Nonaka 《Liquid crystals》2013,40(10):1219-1223
We have synthesized azobenzene-based molecules containing either one or two chiral groups. A cholesteric phase can be induced by adding the chiral azobenzene compounds to a host nematic liquid crystal. We investigated the effects of the trans-cis photoisomerization of the chiral azobenzene compounds on the properties of the cholesteric phase, such as the helical pitch length. This can be increased or decreased by the photoisomerization of the chiral azobenzene compounds. We discuss the photochemically driven change in the helical pitch of the cholesteric phase with respect to structural effects involving the chiral groups. 相似文献