手性化合物研究进展

手性对映体的生物学活性、毒性、代谢和药物素质完全不同。本文从手性基本概念出发，综述了手性药物、手性农药和手性中间体的研究现状和应用前景。     

除草剂中的手性化合物

最近开发的除草剂的分子结构及其作用原理各式各样,而手性则是一种重要的普遍现象,它是这些除草剂分子的固有特性之一,对映选择性及对映特殊反应对于化合物活性与代谢作用是十分重要的问题,因为手性除草剂会引起植物的不同生理特性。本文讨论了重要的手性除草剂及不同反应、对映体选择性作用的相似性、手性与活性的相关性、对映体的代谢作用以及在禾本科植物分类中的不同手性反应。     

手性化合物的萃取拆分研究

分析了目前外消旋体拆分方法 ,对萃取拆分法作了分析总结。至少存在三种萃取拆分体系 ,即 :亲和萃取拆分体系 ,配位萃取拆分体系和形成非对映体立体异构体萃取拆分体系。膜技术用于萃取拆分过程有助于实现萃取拆分分离。萃取拆分技术适用性强、便于连续拆分有望成为外消旋体拆分分离操作的先进技术。     

手性化合物对映体拆分方法概述

回顾了对映体的研究历史，综述了手性化合物对映体的拆分方法，展望了该领域未来的发展前景。     

手性化合物的非目标对映体转化

介绍了通过构型反转和外消旋化反应对手性醇类、氨基醇类和氨基酸类化合物的非目标对映体进行转化的最新研究进展。构型反转能够直接得到所需要的对映体,效率高,但其应用局限性较大;而催化外消旋化反应的应用范围更加广泛,尤其是将金属配合物与酶联用的动态动力学拆分法使消旋率达到了100%,并最终直接得到所需构型的对映体,应是今后研究的重点,同时固定床连续外消旋化的方法也具有良好的应用前景。     

双相（O/W）识别手性萃取分离多巴对映体研究

为了研究多巴在D（L）-2酒石酸异丁酯1,2二氯乙烷有机相和羟丙基-β-环糊精水相萃取体系中的分配行为;运用双相（O/W）识别手性萃取,考察酒石酸构型和浓度、羟丙基-β-环糊精浓度、水相pH值等因素对萃取性能的影响。羟丙基-β-环糊精对S-多巴对映体的识别能力大于对R-多巴对映体的识别能力,而L-酒石酸异丁酯的识别能力刚好相反;在羟丙基-β-环糊精和L-酒石酸异丁酯萃取体系中,多巴外消旋体一次萃取分离后R和S对映体的分配系数（kR和kS）分别为8.92和5.34,分离因子α达1.67;同时pH值和萃取剂浓度对手性分离能力有显著的影响。双相（O/W）识别手性萃取具有较强的手性分离能力,它对外消旋体化合物的制备性分离有着十分重要的意义。     

手性药物与手性药物的分离分析技术

概述了手性药物在医药领域的重要性,综述了近年来各种色谱分析分离技术在手性药物分离中的应用及进展,其中包括气相色谱法、液相色谱法、毛细管电泳和超临界色谱法等。     

氟西汀的手性拆分研究进展

氟西汀(Fluoxetine)作为一种选择性5-HT再摄取抑制剂(SSRI)型的抗抑郁药,被广泛应用于治疗抑郁症,在临床上多以外消旋体给药,然而因其药物分子中存有一个手性碳原子,作为一种手性药物,氟西汀不同的对映体在药理作用方面也存在相应的差别,因此关于氟西汀异构体的外消旋拆分具有一定的意义。本文综合国内外研究成果,对氟西汀拆分技术进行了较系统的综述。     

手性化合物研究、开发的意义及探讨

1、手性化合物的广泛应用一个物体若于自身镜象不能叠合,就叫做具有手性。在立体化学中,不能与镜象叠合的分子就叫做手性分子,它是能使平面偏振光发生偏转的光学活性物质。凡是手性分子,必有互为镜象的构型。互为镜象的两种构型的异构体叫做对映体,他们的熔点、沸点、相对密度、折光率、在一般溶剂中的溶解度,以及光谱图等物理性质都相同,但由于他们对偏振光的作用不同,因而他们的旋光能力相同,但方向相反。对映体的存在是自然界中的一种普遍现象,对映现象在有机化学、药物化学以及生物化学等领域大为常见,手性是自然界的本质属性之一,等量…     

组氨酸对映体的环糊精超分子体系手性识别研究

采用β－环糊精超分子体系对映体利用荧光分析法进行手性识别作了研究。阐明了β－环糊精对不同氨基酸对映体的手性包络作用。     

Chiral resolution of differently substituted racemic acetyl‐1‐phenyl ethanol using lipase from Bacillus subtilis

In the present investigation a Lipase producing strain, Bacillus subtilis (MTCC‐121) was grown on various media containing different sources of carbon, nitrogen and other nutrients. The best media found for the production of lipase was M2 media containing 0.4% peptone, 0.2% beef extract and 1% NaCl. Lipase produced from this culture was used for the kinetic resolution of racemic acetyl‐1‐phenyl ethanol and its derivatives, which are important as chiral auxiliaries and intermediates in the synthesis of natural products, pharmaceuticals and agrochemicals. The lipase resolved these substrates after 48 h with enantiomeric excess of 90–98% and conversion 40–48%. Copyright © 2010 Society of Chemical Industry     

Sensing and Biosensing with Semiconductor Quantum Dots

Due to an internal error, the following article was added after the original publication of the special issue on Nanochemistry (11-12/2012). Semiconductor quantum dots (QDs) exhibit unique photophysical properties, turning these nanomaterials into ideal components for the development of optical or optoelectronic sensors and biosensors. Various methods and mechanisms of using QDs for sensing have been implemented, including the probing of recognition events by the luminescence of the QDs, their application in fluorescence resonance energy transfer (FRET), electron transfer (ET), chemiluminescence resonance energy transfer (CRET), and photoelectrochemical generation of photocurrents. These different mechanisms are exemplified by discussing the QD-based sensing of low-molecular-weight substrates, chiroselective sensing of amino acids, probing of the catalytic activities of enzymes (casein kinase, tyrosinase, NAD⁺-dependent enzymes), and analysis of DNA and of aptamer-substrate complexes. Specifically, the amplified QD-based sensing of DNA using exonuclease III as target regeneration biocatalyst and the multiplexed detection of DNAs using differently sized QDs are discussed. Also, the implementation of the CRET process for the multiplexed analysis of DNA using differently sized QDs is addressed. Finally, the use of semiconductor QDs for the photoelectrochemical detection of DNA, aptamer-substrate complexes and enzyme activities are discussed. Specifically, the use of QDs for photoelectrochemical sensors, using the CRET process as internal excitation light source, is described. The future applications of the various QD-based sensors as analytical devices and as nanotools that probe intracellular processes are discussed.     

生物催化制备手性化合物技术进展

综述了单一对映体手性化合物的制备方法和生物催化制备手性化合物的研究进展。已经工业化应用的生物催化技术有水解酶催化和不对称生物催化氧化,可生产的产品包括(S)-氰醇、(S)-1-苯乙胺和6-羟基烟酸等。对生物催化制备手性化合物工业应用中存在的一些问题进行了讨论。     

手性表面活性剂在手性合成、识别及拆分中的应用

当今社会对单一对映体的需求越来越大,由于手性表面活性剂具有区域选择性、手性催化能力及手性识别能力,因而在手性合成、手性识别及手性拆分中的应用也越来越受封重视。文章综述了近年来手性表面活性剂在不对称催化、乎性识剐及手性拆分中的应用。     

手性氨基烷基酚的合成及其绝对构型的确定

合成了新型催化剂（1S，2R）-1-[[（1R）-1-（2-羟基-5-甲基苯基）乙基]氨基}-2-茚满醇，其结构通过IR、1H NMR和元素分析得到证实。绝对构型通过对其单晶的x-射线衍射结果分析，确定了新化合物的绝对构型为（S，R，R）。     

生物催化羰基不对称还原合成手性醇的研究及应用进展

综述了国内外利用生物催化羰基的不对称还原合成手性醇的研究情况。介绍了生物催化各类潜手性羰基化合物不对称还原的原理、菌种的筛选,以及生物催化不对称还原各类羰基化合物的实例。     

Differential Interactions of Chiral Nanocapsules with DNA

(1) Background: Chiral nanoparticular systems have recently emerged as a compelling platform for investigating stereospecific behavior at the nanoscopic level. We describe chiroselective supramolecular interactions that occur between DNA oligonucleotides and chiral polyurea nanocapsules. (2) Methods: We employ interfacial polyaddition reactions between toluene 2,4-diisocyanate and lysine enantiomers that occur in volatile oil-in-water nanoemulsions to synthesize hollow, solvent-free capsules with average sizes of approximately 300 nm and neutral surface potential. (3) Results: The resultant nanocapsules exhibit chiroptical activity and interact differentially with single stranded DNA oligonucleotides despite the lack of surface charge and, thus, the absence of significant electrostatic interactions. Preferential binding of DNA on d-polyurea nanocapsules compared to their l-counterparts is demonstrated by a fourfold increase in capsule size, a 50% higher rise in the absolute value of negative zeta potential (ζ-potential), and a three times lower free DNA concentration after equilibration with the excess of DNA. (4) Conclusions: We infer that the chirality of the novel polymeric nanocapsules affects their supramolecular interactions with DNA, possibly through modification of the surface morphology. These interactions can be exploited when developing carriers for gene therapy and theranostics. The resultant constructs are expected to be highly biocompatible due to their neutral potential and biodegradability of polyurea shells.     

Ultra-trace Analysis of Enantiomeric Impurities in Proteinogenic N-Fmoc-Amino-acid Samples on Cinchona Alkaloid-based Chiral Stationary Phases

The enantiomeric purity of N_α-Fmoc-protected amino acids is crucial from the viewpoint of peptide synthesis; therefore, a sensitive high-performance liquid chromatographic protocol was developed for the identification and quantification of enantiomeric impurities of commercially available N_α-Fmoc-protected amino acids on Cinchona alkaloid quinine- and quinidine-based weak anion exchanger-type chiral stationary phases. In the course of the evaluation of the chiral chromatographic method, the effect of the mobile phase composition, nature, and concentration of different additives were optimized. The specific phenomenon that quinine- and quinidine-based chiral stationary phases behave as pseudo-enantiomers permits that the sequence of elution of the enantiomers might be reversed by simple column switching. This is quite advantageous as regards the separation of the minor component in the presence of the major one. The method developed permits detection of less than 0.01 % enantiomeric impurity in the presence of the major enantiomer.     

Recognition-mediated assembly of quantum dot polymer conjugates with controlled morphology

We have demonstrated a polymer mediated "bricks and mortar" method for the self-assembly of quantum dots (QDs). This strategy allows QDs to self-assemble into structured aggregates using complementary three-point hydrogen bonding. The resulting nanocomposites have distinct morphologies and inter-particle distances based on the ratio between QDs and polymer. Time resolved photoluminescence measurements showed that the optical properties of the QDs were retained after self-assembly.