共查询到20条相似文献,搜索用时 78 毫秒
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头孢噻吩手性对映体高效毛细管电泳分离 总被引:3,自引:0,他引:3
1 引 言头孢噻吩为第二代头孢菌素 ,对革兰氏阴性菌有较强的抗菌作用 ,且具有高度抗 β 内酰胺酶性质 ,可用于治疗敏感菌所致的尿路感染、呼吸道感染、腹膜炎、败血症、心内膜炎、皮肤和软组织感染等。但有胃肠道反应、白细胞减少、转氨酶升高、氮质血症和肾功能减退等副作用。目前国内使用的头孢噻吩对映体为含有两种对映异构体的外消旋体的混合物。对于头孢噻吩手性对映体高效毛细管电泳手性分离未见文献报道。因此 ,研究它们的手性分离不仅为此类手性药物提供了一种新的手性分离分析方法 ,而且对了解它们的药理作用、药效以及在临床… 相似文献
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反式取代的γ 丁内酯是重要的有机合成中间体[1],已有多种合成路线见诸报道[2~ 4 ].这些方法各有特色 ,但也存在原料难以得到、合成路线冗长、反应条件苛刻、立体选择性不高、总产率低等不足 .我们以巴豆酸甲酯 ( 1)为原料 ,经 5步反应立体选择性地合成了 (± ) 反 科涅克内酯 ( 5 ) .反应式如下 : 岛津IR 44 0型红外光谱测定仪 ,KBr压片 .VarianEA 3 60L型核磁共振仪 ,CDCl3为溶剂 ,TMS为内标 .KyKy QP 10 0 0A型气相色 质联用仪 ,电离方式为EI ,电子能量 70eV .VarianSP 3 40 0型色谱仪 ,固… 相似文献
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对映体选择性化学传感器的研究是化学传感器研究领域新的重要课题。本文作为作者关于这一课题研究报道的开篇,综述了具有手性识别功能的对映体选择性化学传感器和作为其敏感材料的手性识别载体的研究概况,概述了其发展方面及有关问题,收引参考文献67篇。 相似文献
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将光电化学方法与原位分子印迹技术相结合,通过使用手性布洛芬的对映体S-布洛芬(S-ibuprofen)和R-布洛芬(R-ibuprofen)为模板分子,在原位生长的单晶二氧化钛(TiO_2)纳米棒表面构筑S-ibuprofen和R-ibuprofen分子印迹位点,制备出能够对S-ibuprofen和R-ibuprofen选择性识别和催化氧化的印迹电极。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和拉曼光谱(Raman)对电极的形貌、结构和组成进行表征,通过电化学阻抗对电极表面的电子传递阻力进行研究,以制备得到的印迹电极为工作电极通过光电化学方法对其印迹位点的光电识别选择性和光电降解选择性进行测试。制备得到的TiO_2为单晶纳米棒阵列,印迹位点成功构筑在TiO_2纳米棒表面且具有很好的择形吸附能力。本工作首次实现了手性医药布洛芬对映体在人工光电催化剂表面的选择性识别和选择性氧化降解。 相似文献
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The employment of enantioselective transition‐metal‐catalyzed transformations as key steps in asymmetric natural product syntheses have attracted considerable attention in recent years owing to their versatile synthetic utilities, mild conditions and high efficiency in chirality generation. The chiral catalysts or supporting ligands are believed to be crucial for the requisite reactivity and enantioselectivity. Therefore, the rational design of chiral ligands is at the heart of developing new asymmetric transition‐metal catalyzed reactions and provides an avenue to the asymmetric synthesis of natural products. Our group has been engaged in the development of transition‐metal‐catalyzed enantioselective cross‐coupling, cyclization and other related reactions and the application of these methodologies to natural product syntheses. In this account, we summarized our recent synthetic efforts towards the efficient total syntheses of several different types of natural products including terpenes, alkaloids and polyketides facilitated by the design of a series of versatile P‐chiral phosphorous ligands. 相似文献
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Dr. Costyl N. Njiojob Prof. Joseph J. Bozell Prof. Brian K. Long Dr. Thomas Elder Dr. Rebecca E. Key Dr. William T. Hartwig 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(35):12506-12517
We describe an efficient five‐step, enantioselective synthesis of (R,R)‐ and (S,S)‐lignin dimer models possessing a β‐O‐4 linkage, by using the Evans chiral aldol reaction as a key step. Mitsunobu inversion of the (R,R)‐ or (S,S)‐isomers generates the corresponding (R,S)‐ and (S,R)‐diastereomers. We further extend this approach to the enantioselective synthesis of a lignin trimer model. These lignin models are synthesized with excellent ee (>99 %) and high overall yields. The lignin dimer models can be scaled up to provide multigram quantities that are not attainable by using previous methodologies. These lignin models will be useful in degradation studies probing the selectivity of enzymatic, microbial, and chemical processes that deconstruct lignin. 相似文献
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An Efficient Enantioselective Synthesis of Natural Gingerols,the Active Principles of Ginger 下载免费PDF全文
A. Ramesh Reddy Sachin B. Wadavrao J. S. Yadav A. Venkat Narsaiah 《Helvetica chimica acta》2015,98(7):1009-1017
A straightforward synthesis of (S)‐gingerols 1 – 3 has been described. The requisite stereogenic center in the target molecules was introduced by Sharpless asymmetric dihydroxylation using a chiral complex, AD‐mix β. This route is simple and efficient to prepare the products in very good yields. 相似文献
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综述了手性辅剂樟脑磺内酰胺在不对称共轭加成反应、不对称Diels-Alder反应、不对称1,3-偶极环加成反应、不对称羰基化合物的a-烷基化反应、不对称羟醛缩合反应及胺化反应中的应用研究进展. 相似文献
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Brønsted Acid Catalyzed Addition of Enamides to ortho‐Quinone Methide Imines—An Efficient and Highly Enantioselective Synthesis of Chiral Tetrahydroacridines 下载免费PDF全文
M. Sc. Martin Kretzschmar M. Sc. Tomáš Hodík Prof. Dr. Christoph Schneider 《Angewandte Chemie (International ed. in English)》2016,55(33):9788-9792
The direct and highly enantioselective synthesis of tetrahydroacridines was achieved through the phosphoric acid catalyzed addition of enamides to in situ generated ortho‐quinone methide imines and subsequent elimination. This novel one‐step process constitutes a very efficient, elegant, and selective synthetic approach to valuable N‐heterocycles with a 1,4‐dihydroquinoline motif. By subsequent highly diastereoselective hydrogenation and N‐deprotection the reaction products were easily converted into free hexahydroacridines with a total of three new stereogenic centers. 相似文献
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Dr. Shiqing Xu Akimichi Oda Dr. Thomas Bobinski Dr. Haijun Li Yohei Matsueda Prof. Dr. Ei‐ichi Negishi 《Angewandte Chemie (International ed. in English)》2015,54(32):9319-9322
A new strategy for highly concise, convergent, and enantioselective access to polydeoxypropionates has been developed. ZACA‐Pd‐catalyzed vinylation was used to prepare smaller deoxypropionate fragments, and then two key sequential Cu‐catalyzed stereocontrolled sp3–sp3 cross‐coupling reactions allowed convergent assembly of smaller building blocks to build‐up long polydeoxypropionate chains with excellent stereoselectivity. We employed this strategy for the synthesis of phthioceranic acid, a key constituent of the cell‐wall lipid of Mycobacterium tuberculosis, in just 8 longest linear steps with full stereocontrol. 相似文献
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Xueyang Wang Jianan Wang Fengbo Ma Qinghua Bian Min Wang Jiangchun Zhong 《Molecules (Basel, Switzerland)》2022,27(20)
Tetropium fuscum is a harmful forest pest and attacks spruces. The contact sex pheromone of this pest, (S)-11-methyl-heptacosane, and its enantiomer were synthesized via Evans’ chiral auxiliaries. The key steps of this approach included acylation of carboxylic acid, diastereoselective methylation of oxazolidinone amide, and Wittig coupling of the aldehyde with chiral phosphonium salt. The synthetic pheromones would have potential utility in the control of this pest. 相似文献
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含氟有机化合物, 特别是手性氟化物在医药、农药及功能性材料等相关领域的作用备受注目. 尽管在分子中有立体选择性地引入一个氟原子一直是有机化学家面临的一个挑战性问题, 近年来在化学家们的不断努力下, 对映选择性氟化反应研究取得重要进展. 高光学活性的手性氟化物可通过手性亲电氟化试剂诱导的立体选择性氟化反应, 基于底物的手性氟化反应以及手性催化剂诱导的不对称催化氟化反应等来制备. 特别是, 手性金属配合物和有机催化剂诱导的不对称催化氟化反应被广泛应用于各类手性氟化物的合成, 已成为不对称氟化反应研究的热点. 全面介绍对映选择性亲电氟化反应研究概况和最新进展, 讨论各种不对称氟化反应的特点及应用范围. 相似文献