Evaluation of the enantiomeric composition of amino acids in tobacco.

abstract：:E-6087 is a nonsteroidal anti-inflammatory compound that selectively inhibits cyclooxygenase-2. Because E-6087 has a chiral center, this compound is a racemic mixture of two stereoisomers, (+)-(R)-E-6087 (E-6231) and (-)-(S)-E-6087 (E-6232). A normal-phase liquid-chromatographic method for the enantioselective determi...

journal_title：Chirality

authors： Salgado L,Encina G,Farran R,Puig S,Martínez L

更新日期：2004-05-15 00:00:00

abstract：:About 30% of a chemically diverse set of compounds were found to separate on four polysaccharide chiral stationary phases using polar organic mobile phases. No structural features appeared to correlate to successful separations. Titrations between normal and polar organic mobile phases suggested that separation mechan...

journal_title：Chirality

authors： Lynam KG,Stringham RW

更新日期：2006-01-01 00:00:00

abstract：:The application of the Cartesian coordinate tensor transfer (CCT) technique for simulations of the IR absorption and vibrational circular dichroism (VCD) spectra of relatively large nucleic acid fragments is demonstrated on several case studies. The approach is based on direct ab initio calculations of atomic tensors,...

journal_title：Chirality

authors： Andrushchenko V,Bouř P

更新日期：2010-01-01 00:00:00

abstract：:A series of representative optically active derivatives of 4-hydroxy-5-alkylcyclopent-2-en-1-one were prepared from the respective 2-furyl methyl carbinols via the Piancatelli rearrangement followed by the enzymatic kinetic resolution of racemates. Applicability of chiroptical methods (experimental and calculated elec...

journal_title：Chirality

authors： Frelek J,Karchier M,Madej D,Michalak K,Różański P,Wicha J

更新日期：2014-06-01 00:00:00

abstract：:The macrocyclic glycopeptide, ristocetin A, was covalently bonded to a silica gel support and evaluated as a liquid chromatographic (LC) chiral stationary phase (CSP). Over 230 racemates were resolved in either the reversed-phase mode, the normal-phase mode, or the polar-organic mode. The retention behavior and select...

journal_title：Chirality

authors： Ekborg-Ott KH,Liu Y,Armstrong DW

更新日期：1998-01-01 00:00:00

abstract：:Antimalarial drugs have shown potential in suppressing the role of glycosaminoglycans (GAGs) in the pathology of prion protein conformational disorders (e.g. "Mad Cow" disease) by competing for sites of electrostatic interaction. In this study, circular dichroism (CD) and UV/Visible (UV/Vis) absorption spectroscopy te...

journal_title：Chirality

authors： Stanley FE,Warner AM,McWilliams KM,Stalcup AM

更新日期：2011-01-01 00:00:00

abstract：:Asymmetric molecular and supramolecular systems are characterized by: i. the circular dicroism in the angular distribution of valence photoelectrons emitted from randomly oriented chiral molecules by their interaction with circularly polarized VUV light; ii. the different stability and reactivity of diastereomeric agg...

journal_title：Chirality

authors： Giardini A,Paladini A,Catone D,Piccirillo S,Rondino F,Satta M,Filippi A,Speranza M,Turchini S,Zema N

更新日期：2006-08-01 00:00:00

abstract：:Vibrational circular dichroism spectra (VCD) in the mid-IR region and electronic circular dichroism (ECD) spectra for three carnitine derivatives in the form of hydrochloride salts were recorded in deuterated methanol solutions. Density Functional Theory calculations help one to understand the significance of the obse...

journal_title：Chirality

authors： Mazzeo G,Abbate S,Longhi G,Castiglioni E,Villani C

更新日期：2015-12-01 00:00:00

abstract：:Environmental enantioselectivity information is important to fate assessment of chiral contaminants. Warfarin, a rodenticide and prescription medicine, is a chiral chemical but used in racemic form. Little is known about its enantioselective behavior in the environment. In this study, enantioselective degradation of w...

journal_title：Chirality

authors： Lao W,Gan J

更新日期：2012-01-01 00:00:00

abstract：:Trigonostemons G and H, two novel dimeric dinorditerpenoids, were isolated from the stem barks of Trigonostemon chinensis. Their planar structures and relative configurations were established by extensive analysis of spectroscopic data. Trigonostemons G and H possess a homodimeric biaryl skeleton obtained from two rea...

journal_title：Chirality

authors： Zhu Q,Tang C,Mándi A,Kurtán T,Ye Y

更新日期：2020-03-01 00:00:00

abstract：:The absolute configuration of the acyclic side chain of heptopyranosides and heptofuranosides was determined by exciton coupled CD, employing the strongly fluorescent 2-anthroate chromophore. The usage of this chromophore offers significant improvements over previous chemical and spectroscopic procedures since its int...

journal_title：Chirality

authors： Akritopoulou-Zanze I,Nakanishi K,Stepowska H,Grzeszczyk B,Zamojski A,Berova N

更新日期：1997-01-01 00:00:00

abstract：:Six secondary phosphine oxides and their tautomeric equilibria as free ligands and in the presence of an equimolar amount of the chiral dirhodium complex Rh* are described and discussed. Discrimination of enantiomers is easily possible by inspecting the (31)P NMR resonances; some (1)H and (13)C NMR resonances are usef...

journal_title：Chirality

authors： Magiera D,Szmigielska A,Pietrusiewicz KM,Duddeck H

更新日期：2004-01-01 00:00:00

abstract：:We study the chiroptical properties of one-dimensional photonic crystals supporting superchiral surface waves by introducing a simple formalism based on the Fresnel reflection matrix. We show that the proposed framework provides useful insights on the behavior of all the relevant chiroptical quantities, allowing for a...

journal_title：Chirality

authors： Pellegrini G,Finazzi M,Celebrano M,Duò L,Biagioni P

更新日期：2018-07-01 00:00:00

abstract：:Studies of xenobiotic disposition in rodents often employ experimental designs using differing routes of administration. In an effort to investigate the effects of route of administration on enantioselective disposition of xenobiotics, a chiral polychlorinated biphenyl (PCB), racemic PCB 136, was administered as a sin...

journal_title：Chirality

authors： Kania-Korwel I,Shaikh NS,Hornbuckle KC,Robertson LW,Lehmler HJ

更新日期：2007-01-01 00:00:00

abstract：:Cyclodextrins that are indiscriminately carboxymethylated at the 2-, 3-, and 6-positions are used as chiral NMR solvating agents for cationic substrates with phenyl, naphthyl, pyridyl, indoline, and indole rings. Enantiodifferentiation with the alpha-, beta-, and gamma-cyclodextrin derivatives is compared. The carboxy...

journal_title：Chirality

authors： Provencher KA,Weber MA,Randall LA,Cunningham PR,Dignam CF,Wenzel TJ

更新日期：2010-03-01 00:00:00

abstract：:Analogs of the opioid peptide [D-Ala8]dynorphin A-(1-11)NH2 containing optically pure (R)- and (S)-2-aminotetralin-2-carboxylic acid (Atc) in position 4 were synthesized and evaluated for opioid receptor affinity. These peptides are the first reported dynorphin A analogs containing a conformationally constrained amino...

journal_title：Chirality

authors： Aldrich JV,Zheng QI,Murray TF

更新日期：2001-01-01 00:00:00

abstract：:The two enantiomers of N-acyl amide and N-ureide derivatives of 3-amino-5-phenyl-1,4-benzodiazepin-2-ones, which have been known to show anti-respiratory syncytial virus (RSV) activity, were resolved on seven different Pirkle-type chiral stationary phases (CSPs) with the use of 10% isopropyl alcohol in hexane as a mob...

journal_title：Chirality

authors： Park JY,Cho HS,Hyun MH

更新日期：2011-01-01 00:00:00

abstract：:Weinreb amide 3 was synthesized using isobutyl chloroformate, carbonyldiimidazole, or ethylcarbodiimide as the coupling agent in the reaction of Boc-phenylalanine with O,N-dimethylhydroxylamine hydrochloride. An optically active oil was isolated along with an optically inactive solid irrespective of the type of coupli...

journal_title：Chirality

authors： Zheng X,Donkor IO,Miller DD,Ross CR 2nd

更新日期：2000-01-01 00:00:00

abstract：:Hornet silks adopt a variety of morphology such as fibers, sponge, films, and gels depending on the preparation methods. We have studied the conformation change of hornet silk proteins (Vespa mandarina) as regenerated films, using chiroptical spectrophotometer universal chiroptical spectrophotometer 1, which can measu...

journal_title：Chirality

authors： Kuroda R,Kameda T

更新日期：2018-05-01 00:00:00

abstract：:The opening of ortho-substituted phenyl oxiranes by borohydrides is described both in aqueous and solid phases. Some remarkable differences in the regioselectivity and inversion of enantioselectivity of oxirane ring-opening are reported. The results obtained are compared with previous studies and have allowed some fac...

journal_title：Chirality

authors： Doussot J,Guy A,Siaugue JM,Ferroud C,Guieres AF

更新日期：1999-01-01 00:00:00

abstract：:A method is described for the HPLC analysis of oxamniquine enantiomers in liver fraction incubates, using a second-generation alpha 1-acid glycoprotein-based column (Chiral-AGP). Oxamniquine is extracted from the incubation media by liquid-liquid extraction, using diethyl ether. The dried residue is redissolved in elu...

journal_title：Chirality

authors： Noctor TA,Fell AF,Kaye B

更新日期：1990-01-01 00:00:00

abstract：:The hydrolysis and acyl migration of biosynthetic S-naproxen-beta-l-O-acyl glucuronide (I) and R-naproxen-beta-l-O-acyl glucuronide (II) was followed by HPLC. Nine first-order kinetic rate constants for the hydrolysis and acyl migration between the beta-l-O-acyl glucuronide, its alpha/beta-2, alpha/beta-3-, alpha/beta...

journal_title：Chirality

authors： Mortensen RW,Sidelmann UG,Tjørnelund J,Hansen SH

更新日期：2002-05-05 00:00:00

abstract：:The separation methods of the enantiomers of two β-blockers and tryptophan were studied using capillary electrochromatography with heparin covalently as well as non-covalently, bonded onto the capillary inner wall as stationary phase and electrokinetic chromatography with heparin as pseudostationary phase. In the case...

journal_title：Chirality

authors： Liu Y,Sombra LL,Stege PW

更新日期：2018-06-25 00:00:00

abstract：:Treatment of benzoate, formate, or trifluoroacetate esters with silyldibromomethyllithiums provides alkyl silyl mixed acetals via the 1,3-rearrangement of a silyl group from carbon to oxygen. A high level of asymmetric induction onto the acetal carbon is observed when chiral alkyl esters are employed. The stereochemic...

journal_title：Chirality

authors： Shinokubo H,Kondo J,Inoue A,Oshima K

更新日期：2003-01-01 00:00:00

abstract：:Polymorphonuclear neutrophils (PMNs) are short-lived leukocytes that die by apoptosis. Although PMNs are crucial in the defense against infection, they have been implicated in the pathogenesis of tissue injury observed in inflammatory diseases. The induction or prevention of PMN apoptosis is currently discussed as a k...

journal_title：Chirality

authors： Zielińska-Przyjemska M,Główka FK,Klaczyńska J

更新日期：2008-02-01 00:00:00

abstract：:Compared to simulated moving bed (SMB) chromatography, fractional crystallization is a simple and economical method for enantioseparation. Therefore, the coupling of SMB chromatography and fractional crystallization is suggested for enantioseparation of racemic compounds. In this work, a nonsteroidal antiinflammatory ...

journal_title：Chirality

authors： Hong Lu Y,Bun Ching C

更新日期：2004-10-01 00:00:00

abstract：:The application of helical poly[(S)-3-vinyl-2,2'-dihydroxy-1, 1'-binaphthyl] (L*) in the asymmetric borane reduction of prochiral ketones was studied. The results showed that L* had excellent catalytic activity as well as enantioselectivity, giving up to 96% yield and up to 99% enantiomeric excess (ee) of the correspo...

journal_title：Chirality

authors： Qin G,Chen Y,Yang L,Yang N,Yang Z

更新日期：2015-07-01 00:00:00

abstract：:The modern use of preparative chromatography in pharmaceutical development is illustrated by the case of a recent preclinical candidate from these laboratories. The synthesis of the candidate employed a coupling of two enantiopure intermediates, each of which could be resolved using preparative chiral chromatography. ...

journal_title：Chirality

authors： Leonard WR Jr,Henderson DW,Miller RA,Spencer GA,Sudah OS,Biba M,Welch CJ

更新日期：2007-09-01 00:00:00

abstract：:In the past years, enantioanalysis became very important for clinical analysis; biomarkers/substances of biomedical importance with chiral structure should be analyzed and their presence correlated with the specific disorder. Therefore, we developed a method for the assay of l- and d-glucose, based on molecular recogn...

journal_title：Chirality

authors： Stefan-van Staden RI,Mitrofan G

更新日期：2018-05-01 00:00:00

abstract：:Stereoselective high-performance liquid chromatographic separations of eight sterically constrained cyclic β-amino acid enantiomer pairs were carried out using the newly developed Cinchona alkaloid-based zwitterionic chiral stationary phases Chiralpak ZWIX(+) and ZWIX(-). The effects of the mobile phase composition, t...

journal_title：Chirality

authors： Ilisz I,Gecse Z,Lajkó G,Forró E,Fülöp F,Lindner W,Péter A

更新日期：2015-09-01 00:00:00