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Wyniki wyszukiwania dla: CHIRAL DETERMINATION
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Common methods for the chiral determination of amphetamine and related compounds II: Capillary electrophoresis and nuclear magnetic resonance
PublikacjaAmphetamine group and related ring-substituted substances are generally synthetic compounds, belonging to one of the most heavily abused drug groups in recent years. Some compounds in this class also originate from plants. Analysis of the enantiomers of AM-type compounds and metabolites is extremely important for a number of scientific disciplines. From studies of biological activity or mechanisms through determination of precursor...
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Common methods for the chiral determination of amphetamine and related compounds I. Gas, liquid and thin-layer chromatography
PublikacjaThis article reviews the most common, useful methods for the chiral determination of amphetamine (AM) and AM-deriveddesigner drugs in different of matrix, including blood, hair, urine, medicaments or standard solutions, taking into considerationarticles published in the past 15 years. We consider chromatographic methods (e.g., gas, liquid, high-performance liquid, and thinlayer). We describe several types of chiral derivatization...
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Monosaccharides as Potential Chiral Probes for the Determination of the Absolute Configuration of Secondary Alcohols
PublikacjaHerein, a new method for the elucidation of the absolute configuration of chiral secondary alcohols is proposed. This method is an alternative for a widely used approach reported by Mosher and Dale and similar methods that are based on the 1H NMR shift (δ) changes of protons that are attached to the substituents of the oxymethine carbon atom. The presented method is not based on tracking the chemical shift changes and utilizes...
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Detection, identification and determination of chiral pharmaceutical residues in wastewater: Problems and challenges
PublikacjaChiral pharmaceuticals (CPs) are widely used in different areas of human life, thus they are frequentlydetected in different ecosystems. However, before CPs reach the environment, wastewater is subjected todifferent treatment processes in order to remove them. Nevertheless, such processes may affect thechirality of CPs, thus it is very important to monitor CP levels during the wastewater treatment.This review addresses the present...
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Enantioselective Extraction System Containing Binary Chiral Selectors and Chromatographic Enantioseparation Method for Determination of the Absolute Configuration of Enantiomers of Cyclopentolate
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Chiral analysis of chloro intermediates of methylamphetamine by one-dimensional and multidementional NMR and GC/MS
PublikacjaImpurity profiling and classification of abused drugs using chiral analytical techniques is of particular interest and importance because of the additional information obtained fromthis approach. When these methods are applied to the synthesis of illicitly used substances, they can supply valuable information about the conditions/chemicals used in the synthesis. We have applied GC and NMR methods to the study of intermediates found...
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Kagome Lattice Promotes Chiral Spin Fluctuations
PublikacjaDynamical spin fluctuations in magnets can be endowed with a slight bent toward left- or right-handed chirality by Dzyaloshinskii-Moriya interactions. However, little is known about the crucial role of lattice geometry on these chiral spin fluctuations and on fluctuation-related transport anomalies driven by the quantum-mechanical (Berry) phase of conduction electrons. Via thermoelectric Nernst effect and electric Hall effect experiments,...
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Bypassing the stereoselectivity issue: transformations of Kinugasa adducts from chiral alkynes and non-chiral acyclic nitrones
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Pharmaceutical and forensic drug applications of chiral supercritical fluid chromatography
PublikacjaTHE SUPERCRITICAL FLUID IS AN EXCELLENT CHOICE AS THE CHROMATOGRAPHIC MOBILE PHASE BECAUSE IT ALLOWS RAPID SEPARATION WITH HIGH EFFICIENCY AND APPLICATIONS INVOLVING ENANTIORESOLUTION ARE COMMON. SUPERCRITICAL FLUID CHROMATOGRAPHY (SFC) IS INCREASINGLY USED FOR ANALYTICAL, SEMI-PREPARATIVE AND PREPARATIVE PURIFICATION OF CHIRAL COMPOUNDS, INCLUDING PRODUCTION OF ENANTIOMERS THAT ARE MAINLY ENCOUNTERED DURING DRUG DEVELOPMENT. SFC...
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Application of molecularly imprinted polymers in analytical chiral separations and analysis
PublikacjaOver the last two decades the process of development and application of a new types of molecular imprinted polymer (MIP) sorbents in the field of analytical chemistry have been widely described in the literature. One of the new trends in analytical chemistry practice is the use of new types of MIP sorbents as specific sorption materials constituting the stationary phase in advanced separation techniques. The following review paper...
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Analysis of the vibrational spectra of chiral liquid crystalline thioesters
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Chiral-based optical and electrochemical biosensors: Synthesis, classification, mechanisms, nanostructures, and applications
PublikacjaThis review seeks to collect, summarize, classify and discuss the latest advances in chiral-based optical biosensors. Starting from the identification of chiral molecules, photoluminescence, and electrochemical sensors, applications of chiral structures in biosensing molecules are reviewed. Then, biosensors working on the basis of chirality are classified, followed by summarizing the outcomes of research works on design, synthesis,...
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Magnetic properties of α-KCoPO4 compound with a chiral polar crystal structure
PublikacjaWe have obtained polycrystalline samples of a metastable α variant of KCoPO4 by low temperature (350–400 °C) solid state metathesis reaction of potassium oxalate and ammonium cobalt orthophosphate. The material crystallizes in a polar chiral structure (sg. P63, no. 173). Measurements of magnetic properties reveal antiferromagnetic interactions and no ordering observed down to T = 1.9 K, well below the Weiss temperature |Θcw| =...
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Chiral Schiff base complexes as an effective catalyst in Diels-Alder reaction
PublikacjaDiels Alder reaction is a very important tool in carbon-carbon bond formation. It is a cycloaddition between a conjugated diene and a second compound called dienophile. Where one or more heteroatoms are present in the diene and/or dienophile framework, the cycloaddition is called hetero-Diels-Alder reaction (HDA). The asymmetric Diels-Alder reaction is among the most powerful available methodologies for that construction of optically...
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Exploiting isohexide scaffolds for the preparation of chiral ionic liquids tweezers
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Chiral phonons in the honeycomb sublattice of layered CoSn-like compounds
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The influence of the position of a chiral substituent on undecathiophene chain. A DFT study
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Chiral gas chromatography as a tool for investigation into illicitly manufactured methamphetamine
PublikacjaW pracy przedstawiono zastosowanie gazowej chromatografii chiralnej do rozdzielania związków ubocznych powstających w trakcie syntezy metylamfetaminy. Opisano rozdzielanie enancjomerów efedryny, pseudoefedryny, chlorowanych związków posrednich i metylamfetaminy stosując do derywatyzacji bezwodniki fluorowanych kwasów. Jako fazę chiralną zastosowano CHIRALDEX B-DM. Do rozdzielenia enancjomerów pseudoefedryny oraz chlorowanych produktów...
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Combined reversible switching of ECD and quenching of CPL with chiral fluorescent macrocycles
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Chiral crystals from porphyrinoids possessing a very low racemization barrier
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Chiral Diketopyrrolopyrrole-Helicene Polymer With Efficient Red Circularly Polarized Luminescence
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Molecular self-assembly and optical activity of chiral thionooxalamic acid esters
PublikacjaZsyntezowano kilka optycznie czynnych estrów dietylowych kwasu bis(tiooksamowego). Związki te, z powodu ich zdolności do tworzenia ze sobą komplementarnych cyklicznych wiązań wodorowych, są potencjalnie użytecznym materiałem budulcowym większych układów supramolekularnych. Odpowiednie układy modelowe otrzymano z optycznie czynnych 1,2-diamin, które poddano acylowaniu chlorooksooctanem etylu, a następnie otrzymane półprodukty tionowano...
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Riboflavin binding protein—Chiral stationary phase: Investigation of retention mechanism
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Helicity Discrimination in Diaryl Dichalcogenides Generateded by Inclusion Complexation with Chiral Hosts
PublikacjaNiektóre z molekuł pozbawione centrum stereogenicznego mogą przyjmować chiralną konformację na skutek wewnętrznej rotacji wzdłuż odpowiedniego wiązania. Do grupy tej należą badane przez nas diarylodichalogenki; diarylodisiarczki, diarylodiselenki i diaryloditellurki. Niska bariera rotacji wokół wiązania chalogen-chalogen skutkuje szybką racemizacją molekuł tych związków w roztworze i uniemożliwia badanie czynności optycznej. Wykazaliśmy,...
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Application of chiral chromatography for enantiomeric separation of currently used pesticides from various chemical groups
PublikacjaChiral pesticides account for more than 25 % of currently used pesticides and this ratio is still increasing. According to the number of chiral centers in the structure, a pesticide may consist of two or multiple enantiomers or stereoisomers. Studies into the stereoselective behaviour of pesticides started in the early 1990s and most research efforts focused on understanding the environmental fate and effects of these pesticides....
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Application of the 2-deoxyglucose scaffold as a new chiral probe for elucidation of the absolute configuration of secondary alcohols
PublikacjaHerein, we present the application of 2-deoxy-D-glucose derivatives as chiral probes for elucidation of the absolute configuration of chiral secondary alcohols. The probes are attached to the studied molecules via glycosylation reaction and the resulting products are examined by a set of standard 2D NMR experiments. The absolute configuration of an oxymethine carbon atom binding the probe is established on a basis of a set of diagnostic...
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Helicene Monomers and Dimers: Chiral Chromophores Featuring Strong Circularly Polarized Luminescence
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Enantioselective sensing of (S)-Thalidomide in blood plasma with a chiral naphthalene diimide derivative
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TaRh 2 B 2 and NbRh 2 B 2 : Superconductors with a chiral noncentrosymmetric crystal structure
PublikacjaIt is a fundamental truth in solid compounds that the physical properties follow the symmetry of the crystal structure. Nowhere is the effect of symmetry more pronounced than in the electronic and magnetic properties of materials—even the projection of the bulk crystal symmetry onto different crystal faces is known to have a substantial impact on the surface electronic states. The effect of bulk crystal symmetry on the properties...
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An approach to new chiral bicyclic imines and amines via Horner–Wadsworth–Emmons reaction
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Chiral Molecular Cages Based on Cyclotriveratrylene and Sucrose Units Connected with p ‐Phenylene Linkers
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Aqueous Biphasic Systems Using Chiral Ionic Liquids for the Enantioseparation of Mandelic Acid Enantiomers
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Chiral and achiral crystals, charge-assisted hydrogen-bond patterns and self-organization of selected solid diaminium thiosulfates
PublikacjaAbstract A series of diaminium thiosulfates, derivatives of diamines: NH2CH2CH(CH3)NH2 (1) and NH2(CH2)nNH2, n = 3-6 (2-5 respectively)and thiosulfuric acid were prepared and their structures determined by crystal X-ray diffraction analysis. Compounds 1, 2 and 4 turned out to be hydrates. The crystal structure of 1,2-proylenediaminium thiosulfate is chiral and exhibits spontaneous resolution. Crystals for both enantiomers...
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Application of the 2-deoxyglucose scaffold as a new chiral probe for elucidation of the absolute configuration of secondary alcohols
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Trinuclear Complexes Derived from R/S Schiff Bases – Chiral Single‐Molecule Magnets
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Trinuclear Complexes Derived from R/S Schiff Bases – Chiral Single‐Molecule Magnets
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Circular Dichroism Imaging: Mapping the Local Supramolecular Order in Thin Films of Chiral Functional Polymers
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New chiral discotics with helical organization of the mesophase—liquid crystalline derivatives of dibenzotetraaza[14]annulene
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Planar chiral dianthranilide and dithiodianthranilide molecules: optical resolution, chiroptical spectra, and molecular self-assembly.
PublikacjaChiralny planarnie diantranilid został rozdzielony na enancjomery przy użyciu chlorku (-)-(1S,4R)-kamfanoilu. Konfigurację absolutną (S)-enancjomeru ustalono na podstawie analizy rentgenograficznej monokryształu jego N,N'-dikamfoilopochodnej. Natomiast rozdział ditiodiantranilidu na enancjomery przeprowadzono poprzez tworzenie związków inkluzyjnych z (R,R)-1,2-diaminocykloheksanem. Otrzymanemu w ten sposób enancjomerowi przypisano...
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Analysis of chiral pharmaceutical residues in influent and effluent samples at racemic and enantiomeric level using liquid chromatography-tandem mass spectrometry
PublikacjaIn this work, two different chromatographic methods for seasonal monitoring of pharmaceutical residue in wastewater samples were developed. In the case of enantiomeric separation of selected compounds, LC-MS technique combining with vancomycin based chiral stationary phase was used. The performance of chiral analysis enabled to monitor the pharmaceutical contamination at the enantiomeric level. The d-SPE procedure was developed...
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Electronic circular dichroism imaging (CDi) maps local aggregation modes in thin films of chiral oligothiophenes
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Copper(I) halide cluster-based coordination polymers modulated by chiral ditopic dithiodianthranilide ligands: synthesis, crystal structure and photoluminescence
PublikacjaReaction of copper(I) halides with chiral dithiodianthranilidesmdtaandbdtaafforded polymeric complexeswhere polynuclear CuX clusters were linked together by ditopic bridging ligands into 1D chains or 2D layerstructures. In the case of racemic ligands double stranded chain polymers were formed where the Cu4X4(X = I or Br) cores are connected by enantiomeric pairs of the ditopic ligands. In contrast, a homochiralmdtaligand created...
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Chiral Pyrazolo[4,3-e][1,2,4]triazine Sulfonamides—Their Biological Activity, Lipophilicity, Protein Affinity, and Metabolic Transformations
PublikacjaReferring to our previous laboratory results related to the tyrosinase and urease inhibition by pyrazolo[4,3-e][1,2,4]triazine sulfonamides, we examined here in silico the mechanism of action at the molecular level of the investigated pyrazolotriazine sulfonamides by the molecular docking method. The studied compounds being evaluated for their cytotoxic effect against cancer cell lines (MCF-7, K-562) and for recombinant Abl and...
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Broad-Range Spectral Analysis for Chiral Metal Coordination Compounds: (Chiro)optical Superspectrum of Cobalt(II) Complexes
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Syntheses, structures, and chiroptical and magnetic properties of chiral clusters built from Schiff bases: a novel [MnIIMnIII6NaI2] core
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Abuse or contamination? Ratio determination of clenbuterol enantiomers to distinguish between doping use and meat contamination
PublikacjaClenbuterol has been detected in urine of several athletes during routine doping control in the past years. Athletes claimed that the clenbuterol was ingested by eating contaminated meat. Providing analytical prove for this claim is difficult. clenbuterol consists of two enantiomers, R(-) and S(+)-clenbuterol. Currently available human and veterinary preparations were found to consist of a racemic mixture of both enantiomers. When...
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Effects of Surface Energy and Surface Residual Stresses on Vibro-Thermal Analysis of Chiral, Zigzag, and Armchair Types of SWCNTs Using Refined Beam Theory
PublikacjaIn this article, vibration characteristics of three different types of Single-Walled Carbon Nanotubes (SWCNTs) such as armchair, chiral, and zigzag carbon nanotubes have been investigated considering the effects of surface energy and surface residual stresses. The nanotubes are embedded in the elastic substrate of the Winkler type and are also exposed to low and high-temperature environments. A new refined beam theory namely, one-variable...
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Achiral and Chiral Transition Metal Complexes with Modularly Designed Tridentate PNP Pincer-Type Ligands Based on N-Heterocyclic Diamines
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Helicity discrimination in N,N'-dibenzoyl-1,2,3,4,7,8,9,10-octahydro-1,10-phenanthrolines and their thiono- and selenocarbonyl analogues by inclusion complexation with chiral diols
PublikacjaX-ray crystallographic analysis of the title compounds revealed that they assume a folded helical con- formation of an approximate C2 symmetry in the solid state. Dithioamide, diselenoamide and monoselenoamide were resolved to enantiomers by inclusion crystallization with optically active diols (TADDOLs). The absolute configuration of the guest molecules in the complexes was assigned as P. The optical activity of the resolved compounds...
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Molecular geometry and optical activity of helically chiral N-nitrosamines derived from 1,2,3,4-tetrahydro- and 1,2,3,4,7,8,9,10-octahydro-1,10-phenanthroline
PublikacjaX-ray crystallographic analysis of the title N-nitrosamines revealed that they assume helical conformations in the solid state. Nitrosamines 1b and 2b were resolved by inclusion crystallization with optically active diols (TADDOLs). The absolute configuration of the guest molecules in the complexes 1b·3b and 2b·3b was assigned as M. The optical activity of the resolved compounds is manifested by their solid state CD spectra, which...