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硫肽类抗生素是一类由微生物次级代谢产生、富含硫元素并且氨基酸残基被高度修饰的核糖体肽类天然产物. 硫肽类抗生素具有包括抗感染、抗肿瘤和免疫抑制在内的一系列十分重要的生物活性, 并且其以核糖体为靶点的作用机制与目前临床上普遍使用的抗生素均不同, 这使得硫肽类抗生素发展潜力巨大, 但是其水溶性差、生物利用度低等问题限制了它们在临床上的应用. 为了提高硫肽类抗生素的理化性质, 研究者尝试用化学半合成、组合生物合成以及前体导向突变生物合成等方法对硫肽类抗生素的结构进行修饰. 硫肽类抗生素本身具有的复杂结构为其化学半合成修饰提供了众多的可修饰位点. 近年来, 对于硫肽类抗生素的化学半合成修饰研究发展迅速. 综述了近十年通过化学半合成修饰方法获得的硫肽类抗生素类似物的研究进展. 相似文献
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O-连接β-N-乙酰葡糖胺(O-GlcNAc)糖基化是广泛存在于蛋白质丝/苏氨酸残基的翻译后修饰.这一动态、可逆单糖修饰以位点特异性方式影响底物蛋白的结构和生物学功能,参与调控几乎所有细胞生理过程和重大疾病的演进过程.随着研究深入,O-GlcNAc糖基化生物功能的系统解析需要更多特异、精准的研究工具和糖蛋白质组学研究策略.近年来,化学生物学领域开发了包括小分子糖探针、生物正交糖代谢标记物、化学酶法、特异性抗体和凝集素等多种O-GlcNAc糖基化分析工具和方法,以此为基础进一步发展了O-GlcNAc糖蛋白质组学研究策略.同时,借助高分辨质谱,大量蛋白质O-GlcNAc修饰位点得以鉴定,极大促进了位点特异性O-GlcNAc的生物功能研究.本文综述了近年来这一领域的研究进展,以期为更多化学工具的开发提供依据,为揭示O-GlcNAc糖基化在疾病演进中的功能提供新的研究思路和策略. 相似文献
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评述了修饰碳糊电极的材料组成、修饰方法与修饰功能及在分析化学、生物科学、环境化学等领域的应用,预测了修饰碳糊电极在化学生物传感器方面的发展趋势(引用文献54篇)。 相似文献
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有机磷毒剂是一类含磷(膦)酸或磷(膦)酸酯类高毒有机物及其衍生物的统称,能破坏正常神经传导,造成神经系统损伤,在军事行动和农业生产等方面的非常规使用给人类生存发展带来了严重威胁。电化学传感技术以其设备简便、灵敏度高、响应速度快等优点展现了实地传感有机磷毒剂的巨大潜力。总结了近几年有机磷毒剂的电化学传感相关研究报道,依据检测原理差异性将其分为4类:直接检测法、电化学酶法、电化学免疫法和电化学发光法。分析了各种方法的检测机理和优缺点;介绍了不同传感方法对工作电极修饰材料的要求;比较了不同电极修饰材料对方法检出限和线性范围的影响;阐述了电化学与生物技术结合检测有机磷毒剂的研究进展。电化学酶法和电化学免疫法具备选择性好和适用范围宽等优点,进而提出了纳米酶、纳米抗体和多维修饰材料结合传感检测含磷毒剂的新思路。 相似文献
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随着科学的不断发展和人类认识水平的提高,科学研究的手段必然要求高效和多能,研究的对象也日趋复杂和多样化,组合化学就是在这样的形势下发展起来的。组合化学最早被用于合成肽组合库,后来被用于药物的合成与筛选,也称组合合成,组合库和自动合成法。组合化学是一门集合成化学,组合数学和计算机辅助设计等多学科交叉形成的一门边缘学科。因此,组合化学可定义为利用组合论的思想和理论,将构建单元通过有机 /无机合成或化学法修饰,产生分子多样性的群体(库 ),并进行优化选择的科学。 组合化学从制药领域逐步发展到有机小分子 /高… 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献