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Chiral separation

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https://www.readbyqxmd.com/read/28635154/chiral-responsive-liquid-quantum-dots
#1
Jin Zhang, Junkai Ma, Fangdan Shi, Demei Tian, Haibing Li
How to convert the weak chiral-interaction into the macroscopic properties of materials remains a huge challenge. Here, this study develops highly fluorescent, selectively chiral-responsive liquid quantum dots (liquid QDs) based on the hydrophobic interaction between the chiral chains and the oleic acid-stabilized QDs, which have been designated as (S)-1810-QDs. The fluorescence spectrum and liquidity of thermal control demonstrate the fluorescence properties and the fluidic behavior of (S)-1810-QDs in the solvent-free state...
June 21, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28631515/one-pair-of-new-cyclopentaisochromenone-enantiomer-from-alternaria-sp-tnxy-p-1-and-their-cytotoxic-activity
#2
Xiao-Jie Lu, Shao-Fei Chen, Xiang-Wei Xu, Dan Zhao, Hai-Feng Wang, Jiao Bai, Hui-Ming Hua, Gang Chen, Yue-Hu Pei
One pair of new cyclopentaisochromenone derivatives, (+)-(S)-6-hydroxy-1,8-dimethoxy-3a-methyl-3,3a-dihydrocyclopenta[c]isochromene-2,5-dione (1a) and (-)-(R)-6-hydroxy-1,8-dimethoxy-3a-methyl-3,3a-dihydrocyclopenta[c]isochromene-2,5-dione (1b), together with seven known analog 2‒8, were isolated from a rice solid culture of the endophytic fungus Alternaria sp. TNXY-P-1, obtained from fresh leaf of Arisaema heterophyllum. Their structures were elucidated on the basis of detailed 1D, 2D NMR, and HRESIMS analysis...
June 20, 2017: Journal of Asian Natural Products Research
https://www.readbyqxmd.com/read/28628334/chiral-indolylarylsulfone-non-nucleoside-reverse-transcriptase-inhibitors-as-new-potent-and-broad-spectrum-anti-hiv-1-agents
#3
Valeria Famiglini, Giuseppe La Regina, Antonio Coluccia, Domiziana Masci, Andrea Brancale, Roger Badia, Eva Riveira Muñoz, Jose A Este, Emmanuele Crespan, Alessandro Brambilla, Giovanni Maga, Myriam Catalano, Cristina Limatola, Francesca Romana Romana Formica, Roberto Cirilli, Ettore Novellino, Romano Silvestri
We designed and synthesized a series of chiral indolyarylsulfones (IASs) as new HIV-1 NNRTIs. The new IASs 8-37 showed potent inhibition of the HIV-1 WT NL4-3 strain and of the mutant K103N, Y181C, Y188L and K103N-Y181C HIV-1 strains. Six racemic mixtures, 8, 23-25, 31 and 33, were separated at semipreparative level into their pure enantiomers. The (R)-8 enantiomer bearing the chiral (α-methylbenzyl) was superior to the (S)-counterpart. IAS derivatives bearing the (S) alanine unit, (S)-23, (S,R)-25, (S)-31 and (S)-33, were remarkably more potent than the corresponding (R)-enantiomers...
June 19, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28621815/liquid-chromatographic-enantioseparation-of-limonene-based-carbocyclic-%C3%AE-amino-acids-on-zwitterionic-cinchona-alkaloid-based-chiral-stationary-phases
#4
Gyula Lajkó, Tímea Orosz, Imre Ugrai, Zsolt Szakonyi, Ferenc Fülöp, Wolfgang Lindner, Antal Péter, István Ilisz
The eight stereoisomers of limonene-based carbocyclic β-amino acids containing three chiral centers have been directly separated on chiral stationary phases containing Cinchona alkaloid-based zwitterionic selectors. The effects of bulk solvent composition of the mobile phase, the nature of base additives, counter-ion concentration, and the structure of selector on the enantiorecognition were studied. Experiments were performed at constant mobile phase composition in the temperature range 5-40°C to study the effect of temperature...
June 16, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28619591/doxycycline-as-a-new-chiral-selector-in-capillary-electrophoresis
#5
Min Gyeong Jang, Myung Duk Jang, Jung Hag Park
Doxycycline (DOX) is one of the tetracycline class of antibiotics and has not been examined for its enantioseparation abilities previously. The purpose of the present work was to evaluate DOX as a chiral selector (CS) using capillary electrophoresis (CE) in nonaqueous mode. Systematic experiments were performed to investigate the effects of concentration of CS, compositions of organic solvents and background electrolytes, applied voltage on chiral separation of a set of acidic chiral compounds. Excellent resolutions of enantiomers of acidic chiral compounds were attained in a background electrolytes composed of 50:50 acetonitrile/methanol+214mM acetic acid+ 63mM triethylamine and 38mM DOX...
June 9, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28615493/optically-ambidextrous-circularly-polarized-reflection-from-the-chiral-cuticle-of-the-scarab-beetle-chrysina-resplendens
#6
Ewan D Finlayson, Luke T McDonald, Pete Vukusic
The evolution of structural colour mechanisms in biological systems has given rise to many interesting optical effects in animals and plants. The instance of the scarab beetle Chrysina resplendens is particularly distinctive. Its exoskeleton has a bright, golden appearance and reflects both right-handed and left-handed circularly polarized light concurrently. The chiral nanostructure responsible for these properties is a helicoid, in which birefringent dielectric planes are assembled with an incremental rotation...
June 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28608589/new-chiral-stationary-phases-based-on-xanthone-derivatives-for-liquid-chromatography
#7
Carla Fernandes, Maria Elizabeth Tiritan, Sara Cravo, Ye' Zaw Phyo, Anake Kijjoa, Artur M S Silva, Quezia B Cass, Madalena M M Pinto
Six chiral derivatives of xanthones (CDXs) were covalently bonded to silica, yielding the corresponding xanthonic chiral stationary phases (XCSPs). The new XCSPs were packed into stainless-steel columns with 150 x 4.6 mm i.d. Moreover, the greening of the chromatographic analysis by reducing the internal diameter (150 x 2.1 mm i.d.) of the liquid chromatography (LC) columns was also investigated. The enantioselective capability of these phases was evaluated by LC using different chemical classes of chiral compounds, including several types of drugs...
June 13, 2017: Chirality
https://www.readbyqxmd.com/read/28608452/chiral-separation-and-modeling-of-baclofen-bupropion-and-etodolac-profens-on-amylose-reversed-phase-chiral-column
#8
Imran Ali, Mohd Suhail, Zeid A Alothman, Abdulrahman Alwarthan
Chiral resolution of baclofen, bupropion, and etodolac profens was obtained with amylose derivatized chiral reversed stationary phase (carbamate groups). The eluent used for bupropion and etodolac was MeOH-water (20:80, v/v) and for baclofen was water-methanol (95:5, v/v). The eluent run rates, finding wavelength and temperature, were 1.0 mL/min, 220 nm and 27 ± 1 °C for all the eluents. The magnitude of the retardation factors for S- and R-enantiomers of baclofen, bupropion, and etodolac were 1.37, 2...
July 2017: Chirality
https://www.readbyqxmd.com/read/28606529/controlled-synthesis-immobilization-and-chiral-recognition-of-carboxylic-acid-functionalized-cellulose-tris-3-5-dimethylphenylcarbamate
#9
Miaomiao Han, Xiaosa Jin, Han Yang, Xiao Liu, Yadong Liu, Shengxiang Ji
Traditional cellulose-based chiral stationary phases (CSPs) are prepared by physically coating cellulose derivatives onto substrates and only compatible with a very limited range of solvents as the mobile phase. Therefore, chemical immobilization of cellulose derivatives onto silica gel has been efficiently applied to improve the solvent compatibility of cellulose-based CSPs. Here we developed a novel approach to homogeneously modifying cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC). A series of carboxylic acid functionalized CDMPCs (CC-Xs) with controlled amounts and randomly distributed carboxylic acid groups was synthesized...
September 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28599860/molecularly-imprinted-nanoparticles-grafted-to-porous-silica-as-chiral-selectors-in-liquid-chromatography
#10
Raquel Gutierrez-Climente, Alberto Gomez-Caballero, Antonio Guerreiro, Deiene Garcia-Mutio, Nora Unceta, M Aránzazu Goicolea, Ramon J Barrio
The work presented here explores the grafting of molecularly imprinted nanoparticles (MIN) on silica beads for the development of new chiral stationary phases (CSP). Both solid-phase imprinting and precipitation polymerisation were tested for MIN synthesis though the latter approach was the only one that provided efficient chiral selectors. MIN particles were prepared by iniferter polymerisation initiated by UV radiation, using itaconic acid as functional monomer and ethylene dimethacrylate as cross-linker...
June 3, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28595723/stable-isotope-n-phosphoryl-amino-acids-labeling-for-quantitative-profiling-of-amine-containing-metabolites-using-liquid-chromatography-mass-spectrometry
#11
Shanshan Zhang, Jinwen Shi, Changkai Shan, Chengting Huang, Yile Wu, Rong Ding, Yuhua Xue, Wen Liu, Qiang Zhou, Yufen Zhao, Pengxiang Xu, Xiang Gao
Stable isotope chemical labeling liquid chromatography-mass spectrometry (LC-MS) is a powerful strategy for comprehensive metabolomics profiling, which can improve metabolites coverage and quantitative information for exploration of metabolic regulation in complex biological systems. In the current work, a novel stable isotope N-phosphoryl amino acids labeling strategy (SIPAL) has been successful developed for quantitative profiling of amine-containing metabolites in urine based on organic phosphorus chemistry...
July 25, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28590728/switchable-chiral-selection-of-aspartic-acids-by-dynamic-states-of-brushite
#12
Wenge Jiang, Haihua Pan, Zhisen Zhang, S Roger Qiu, J Dongun Kim, Xurong Xu, Ruikang Tang
We herein show the chiral recognition and separation of aspartic acid (Asp) enantiomers by achiral brushite due to the asymmetries of their dynamical steps in its nonequilibrium states. Growing brushite has a higher adsorption affinity to d-Asp, while l-Asp is predominant on the dissolving brushite surface. Microstructural characterization reveals that chiral selection is mainly attributed to brushite [101] steps, which exhibit two different configurations during crystal growth and dissolution, respectively, with each preferring a distinct enantiomer due to this asymmetry...
June 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28579634/dynamic-susceptibility-of-concentric-permalloy-rings-with-opposite-chirality-vortices
#13
C McKeever, F Y Ogrin, M M Aziz
The high frequency dynamic behaviour of concentric permalloy nanorings with vortex domain structures with a thickness of 20 nm, a width in the range of 100 nm-250 nm, and a separation in the range of 10 nm-600 nm is investigated by micromagnetic simulations. The aim is to explore the ferromagnetic resonance of the concentric ring structure as a function of geometric parameters of the system. The dynamic susceptibility spectrum and spatial localization of the ferromagnetic resonance mode are investigated for varying ring widths and separations...
May 28, 2017: Journal of Applied Physics
https://www.readbyqxmd.com/read/28573867/dna-carbon-nanotube-complexation-affinity-and-photoluminescence-modulation-are-independent
#14
Prakrit V Jena, Mohammad M Safaee, Daniel A Heller, Daniel Roxbury
Short single-stranded DNA (ssDNA) has emerged as the natural polymer of choice for noncovalently functionalizing photoluminescent single-walled carbon nanotubes. In addition, specific empirically identified DNA sequences can be used to separate single species (chiralities) of nanotubes, with an exceptionally high purity. Currently, only limited general principles exist for designing DNA-nanotube hybrids amenable to separation processes, due in part to an incomplete understanding of the fundamental interactions between a DNA sequence and a specific nanotube structure, whereas even less is known in the design of nanotube-based sensors with determined optical properties...
June 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28573160/quantification-of-2-hydroxyglutarate-enantiomers-by-liquid-chromatography-mass-spectrometry
#15
William M Oldham, Joseph Loscalzo
Two enantiomers of 2-hydroxyglutarate (2HG), L (L2HG) and D (D2HG), are metabolites of unknown function in mammalian cells that were initially associated with separate and rare inborn errors of metabolism resulting in increased urinary excretion of 2HG linked to neurological deficits in children (Chalmers et al., 1980; Duran et al., 1980; Kranendijk et al., 2012). More recently, investigators have shown that D2HG is produced by mutant isocitrate dehydrogenase enzymes associated with a variety of human malignancies, such as acute myeloid leukemia, glioblastoma multiforme, and cholangiocarcinoma (Cairns and Mak, 2013; Dang et al...
August 20, 2016: Bio-protocol
https://www.readbyqxmd.com/read/28560736/enantioseparation-of-ofloxacin-and-its-four-related-substances-with-ligand-exchange-micellar-electrokinetic-chromatography-using-copper-ii-l-isoleucine-complex-as-chiral-selector
#16
Yongjing Liu, Xiaoying Wang
A ligand-exchange micellar electrokinetic capillary electrophoresis system with copper(II)-L-isoleucine complexes as the chiral selector incorporated in micelles of sodium dodecyl sulfate (SDS) was developed for the enantioseparation of ofloxacin and its four related substances (impurities A, C, E, and F). The effects of important parameters affecting separation such as buffer pH, SDS concentration, chiral selector concentration, and organic additive were investigated in detail. Under optimum experimental conditions, enantioseparation of ofloxacin, impurities A, C, E, and F enantiomers was accomplished with resolutions of 4...
May 31, 2017: Chirality
https://www.readbyqxmd.com/read/28558906/carbamoylated-azithromycin-incorporated-zirconia-hybrid-monolith-for-enantioseparation-of-acidic-chiral-drugs-using-non-aqueous-capillary-electrochromatography
#17
Shuchi Dixit, Il Seung Lee, Jung Hag Park
Carbamoylated derivatives of two antibiotics, namely, clindamycin phosphate (CLIP) and erythromycin (ERY) were successfully employed as co-precursors, in combination of zirconium tetrabutoxide as a precursor, to prepare chiral organic-zirconia hybrid monoliths (i.e., CLIP-ZHMs and ERY-ZHMs, respectively) via a single-step in-situ sol-gel approach in our previous works. Their superiority over chiral organic-zirconia/silica monoliths, prepared by post-modification approach, in terms of better enantioresolution and enhanced stability inspired us to prepare ZHMs based on an another antibiotic, azithromycin (i...
May 23, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28553499/understanding-gas-capacity-guest-selectivity-and-diffusion-in-porous-liquids
#18
Rebecca L Greenaway, Daniel Holden, Edward G B Eden, Andrew Stephenson, Chin W Yong, Michael J Bennison, Tom Hasell, Michael E Briggs, Stuart L James, Andrew I Cooper
Porous liquids are a new class of material that could have applications in areas such as gas separation and homogeneous catalysis. Here we use a combination of measurement techniques, molecular simulations, and control experiments to advance the quantitative understanding of these liquids. In particular, we show that the cage cavities remain unoccupied in the absence of a suitable guest, and that the liquids can adsorb large quantities of gas, with gas occupancy in the cages as high as 72% and 74% for Xe and SF6, respectively...
April 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28553497/mapping-a-protein-recognition-centre-with-chiral-photoactive-ligands-an-integrated-approach-combining-photophysics-reactivity-proteomics-and-molecular-dynamics-simulation-studies
#19
Daniel Limones-Herrero, Raúl Pérez-Ruiz, Emilio Lence, Concepción González-Bello, Miguel A Miranda, M Consuelo Jiménez
A multidisciplinary strategy to obtain structural information on the intraprotein region is described here. As probe ligands, (S)- and (R)-CPFMe (the methyl esters of the chiral drug carprofen) have been selected, while bovine α1-acid glycoprotein (BAAG) has been chosen as a biological host. The procedure involves the separate irradiation of the BAAG/(S)-CPFMe and BAAG/(R)-CPFMe complexes, coupled with fluorescence spectroscopy, laser flash photolysis, proteomic analysis, docking and molecular dynamics simulations...
April 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28551128/on-line-identification-of-chiral-ofloxacin-in-milk-with-an-extraction-ionization-device-coupled-to-electrospray-mass-spectrometry
#20
Jiang Wang, Xiao-Xiao Jiang, Wei Zhao, Jun Hu, Qi-Yuan Guan, Jing-Juan Xu, Hong-Yuan Chen
The direct separation and analysis of chiral drugs in the complex matrix systems are meaningful and challenging. As the most common broad-spectrum antibiotic, levofloxacin has a strong antibacterial ability, but its enantiomer, dextrofloxacin can cause serious harm to human health. In this work, we reported a rapid on-line extraction/ionization device coupled with Electrospray Mass Spectrometry (ESI-MS) for chiral analysis of ofloxacin enantiomers in complex matrix of milk. Since ofloxacin is difficult to dissolve in water and most organic solvents, the procedure of separating ofloxacin in complex system is often complicated...
August 15, 2017: Talanta
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