Spirobipyridopyrans and indolinospiropyridopyrans: Synthesis, X-ray crystal structure, separation of enantiomers, and barriers to thermal cleavage of the C(sp(3))-O bond.

abstract：:(+/-)-Pantoprazole ((+/-)-PAN), (+/-)-5-(difluoromethoxy)-2-[[3.4-dimethoxy-2-pyridinyl)methyl]sul finyl]- 1H-benzimidazole) is a chiral sulfoxide that is used clinically as a racemic mixture. The disposition kinetics of (+)-PAN and (-)-PAN given separately has been studied in rats. Serum levels of (+)- and (-)-PAN an...

journal_title：Chirality

authors： Masubuchi N,Yamazaki H,Tanaka M

更新日期：1998-01-01 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：:Advances in the measurement, calculation, and application of vibrational circular dichroism (VCD) for the determination of absolute configuration are described. The purpose of the review is to provide an up-to-date perspective on the capability of VCD to solve problems of absolute stereochemistry for chiral molecules ...

journal_title：Chirality

authors： Freedman TB,Cao X,Dukor RK,Nafie LA

更新日期：2003-11-01 00:00:00

abstract：:An optically active spiropyran 1 with a binaphthol moiety as a chiral source was synthesized. The colored merocyanine form of (R)-1 obtained by the UV irradiation remained in the presence of D-amino acids longer than with L-amino acids. ...

journal_title：Chirality

authors： Tsubaki K,Mukoyoshi K,Morikawa H,Kinoshita T,Fuji K

更新日期：2002-10-01 00:00:00

abstract：:A rapid and simple procedure for enantioselective preparation of 2- and 3-substituted 2,3-dihydro[1,4]dioxino[2,3-b]pyridine derivatives (A and B, respectively) is described. The enantiomeric purity of each isomer was determined by capillary electrophoresis using a dual-cyclodextrin system (S-beta-CD/beta-CD) dissolve...

journal_title：Chirality

authors： Lazar S,Soukri M,El Haddad M,Akssira M,Leger JM,Jarry C,Morin P,Guillaumet G

更新日期：2005-01-01 00:00:00

abstract：:Two new carotenoids, sapotexanthin 5,6-epoxide and sapotexanthin 5,8-epoxide, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Sapotexanthin 5,6-epoxide was also prepared by partial synthesis via epoxidation of sapotexanthin, and the (5R,6S) and (5S,6R) stereoisomers were identified by high-perf...

journal_title：Chirality

authors： Murillo E,Agócs A,Nagy V,Király SB,Kurtán T,Toribio EM,Lakey-Beitia J,Deli J

更新日期：2020-05-01 00:00:00

abstract：:Diamino carboxylic acids have recently come to the attention of scientists working in the field of early life and its development. These are the monomers of a hypothetic early form of genetic material, the so-called Peptide Nucleic Acid (PNA) (Nielson et al., Proc Natl Acad Sci USA 2000;97:3868-3871). Since all biopol...

journal_title：Chirality

authors： Bredehöft JH,Breme K,Meierhenrich UJ,Hoffmann SV,Thiemann WH

更新日期：2007-07-01 00:00:00

abstract：:A three-dimensional molecularly imprinted overoxidized polypyrrole/MnO2 /carbon felt (MIOPPy/MnO2 /CF) composites were fabricated, which results in increased active area of the surface of the molecularly imprinted polymers film and greatly improved electrochemical chiral recognition effect for tryptophan isomers. The ...

journal_title：Chirality

authors： Dong L,Liu X,Xu H,Wu D,Gao S,Zhong L,Kong Y

更新日期：2019-11-01 00:00:00

abstract：:Glutathione (GSH) conjugation of the chiral compound 2-bromo-3-phenylpropionic acid (BPP) was studied in vitro and in the rat in vivo. GSH conjugation of BPP, catalyzed by a mixture of glutathione-S-transferases (GST's) from rat liver cytosol in vitro, was stereoselective: at a substrate concentration of 250 microM, (...

journal_title：Chirality

authors： Snel CA,Mahadevan S,Polhuijs M,Mulder GJ

更新日期：1992-01-01 00:00:00

abstract：:Kinetic and equilibrium binding studies were performed on the interaction of warfarin enantiomers with human serum albumin (HSA) in the absence and presence of lorazepam acetate (LoAc) enantiomers. Binding kinetics were followed by recording changes in the fluorescence of warfarin upon binding to HSA using the stopped...

journal_title：Chirality

authors： Fitos I,Visy J,Kardos J

更新日期：2002-05-15 00:00:00

abstract：:Four racemic esters of (1R*,7aR*)-3,6,7,7a-tetrahydro-1-hydroxy-7a-methyl-1H-inden-5(2H)-one were prepared and subjected to hydrolysis with two types of hydrolases, including alcalase and three lipases. Alcalase and lipase showed opposite enantiopreference on these esters. Based on this result, we developed a gram-sca...

journal_title：Chirality

authors： Lo LC,Chou TC,Shie JJ

更新日期：2004-05-05 00:00:00

abstract：:Herein we report CD spectroscopic studies on complexes of (R,R)-dimethyl-, (R,R)-diisobutyl-, and (S,S)-di-sec-butyl-phenazino-18-crown-6 ligands (Scheme 1) with selected alkali (Na+, K+), alkaline earth (Mg2+, Ca2+), and transition-metal (Ag+, Zn2+, Ni2+, Cd2+, Pb2+) cations. The complexation was monitored in the 300...

journal_title：Chirality

authors： Szarvas S,Szalay L,Vass E,Hollósi M,Samu E,Huszthy P

更新日期：2005-06-01 00:00:00

abstract：:A new colorimetric chiral sensor material consisting of three different functional sites such as chromophore (2,4-dinitrophenylazophenol dye), binding site (crown ether), and chiral barrier (3,3'-diphenyl-1,1'-binaphthyl group) was prepared and applied to the recognition of the two enantiomers of primary amino alcohol...

journal_title：Chirality

authors： Cho EN,Li Y,Kim HJ,Hyun MH

更新日期：2011-04-01 00:00:00

abstract：:The known complex trans-RuCl2(NBD)Py2 (1, NBD is norbornadiene, Py is pyridine) reacts with either (R)-BINAP ((R)-2, 2'-bis(diphenylphosphino)-1,1'-binaphthyl), (S;S)-Chiraphos ((2S;3S-(-)-2,3-bis(diphenylphosphino)butane), (S;S)-Skewphos ((2S;4S)-(-)-2,4-bis(diphenylphosphino)pentane), (R)-(S)-Josiphos ((R)-(-)-1-[(S...

journal_title：Chirality

authors： Akotsi OM,Metera K,Reid RD,McDonald R,Bergens SH

更新日期：2000-06-01 00:00:00

abstract：:A chiral liquid chromatography/mass spectrometry (LC/MS) bioanalytical procedure has been developed for the analysis of the antimalaric agent Fenozan B07 in dog plasma. Normal-phase chromatography involving a phenylcarbamate derivative of cellulose coated on silica gel as the chiral stationary phase was used to resolv...

journal_title：Chirality

authors： Maraschiello C,Vilageliu J,Dorronsoro I,Martinez A,Floriano P,Gómez-Acebo E

更新日期：2006-05-15 00:00:00

abstract：:An environmental and sensitive sample pretreatment method was established and combined with high-performance liquid chromatography (HPLC) for the analysis of tetracycline hydrochloride (TC) in feed water and lake water. One element small molecule alcohol-salt aqueous two-phase system (ATPS) cannot effectively adjust t...

journal_title：Chirality

authors： Guo DG,Ni L,Wang L,Shao L

更新日期：2019-09-01 00:00:00

abstract：:Several biologically active compounds structurally include the enantiopure 2-substituted-1,4-benzodioxane scaffold. The straightforward racemization that affects reactions involving most of the common chemical reactives is thus a crucial issue. The developing of a completely stereo-controlled synthetic route that does...

journal_title：Chirality

authors： Straniero V,Casiraghi A,Fumagalli L,Valoti E

更新日期：2018-07-01 00:00:00

abstract：:N-formylphenylalanine was subjected to optical resolution using a chiral agent such as phenylethylamine enantiomer, (R)-phenylglycine methyl ester, (S)-N-benzyl-2-aminobutanol, alone or in a mixture with each other or in a mixture with benzylamine. ...

journal_title：Chirality

authors： Pálovics E,Fogassy E,Schindler J,Nógrádi M

更新日期：2007-01-01 00:00:00

abstract：:A summary of selected NMR studies of enantiodiscrimination phenomena regarding the use of quinine-based chiral solvating agents (CSAs) for the determination of the enantiomeric compositions in solution is reported, with explanations of their multireceptorial character offered. ...

journal_title：Chirality

authors： Uccello-Barretta G,Balzano F,Salvadori P

更新日期：2005-01-01 00:00:00

abstract：:A detailed experimental investigation of an aza-Michael reaction of aniline and chalcone is presented. A series of Cinchona alkaloid-derived organocatalysts with different functional groups were prepared and used in the aza-Michael and retro-aza-Michael reaction. There was an interesting finding that a complete revers...

journal_title：Chirality

authors： Cai YF,Li L,Luo MX,Yang KF,Lai GQ,Jiang JX,Xu LW

更新日期：2011-05-01 00:00:00

abstract：:An improved synthesis of the enantiomers of the new benzofurane-type antiarrhythmic compound 1 is described, which makes use of the enantiomerically pure mbe-lactol. Thus, acylation of the benzofurane 4 with acetic anhydride and subsequent bromination gave the bromoacetyl-derivative 6, which, after reduction with LiAl...

journal_title：Chirality

authors： Ecker G,Fleischhacker W,Helml T,Noe CR,Scasny S,Lemmens-Gruber R,Studenik C,Marei H,Heistracher P

更新日期：1994-01-01 00:00:00

abstract：:This paper reports the enantioseparation of β-hydroxy-1,2,3-triazole derivatives, which present a broad range of biological properties, by supercritical fluid chromatography (SFC) and high-performance liquid chromatography techniques (HPLC). Polysaccharide-based chiral columns (cellulose and amylose) were used to eval...

journal_title：Chirality

authors： Alvarenga N,Porto ALM,Barreiro JC

更新日期：2018-07-01 00:00:00

abstract：:Acyl glucuronides formed from carboxylic acids can undergo hydrolysis, acyl migration, and covalent binding to proteins. In buffers at physiological pH, the degradation of acylglucuronide of a chiral NSAID, carprofen, consisted mainly of acyl migration. Acidic pH reduced hydrolysis and acyl migration, thus stabilizing...

journal_title：Chirality

authors： Georges H,Presle N,Buronfosse T,Fournel-Gigleux S,Netter P,Magdalou J,Lapicque F

更新日期：2000-02-01 00:00:00

abstract：:The possibility that enantiodiscrimination of bilirubin might be involved in neuronal membrane destabilization, and therefore in bilirubin toxicity, was investigated, by circular dichroism, on model membranes composed of phospholipids. The equilibrium between bilirubin enantiomers is displaced at some extent by the in...

journal_title：Chirality

authors： Bernardini C,D'Arrigo P,Elemento G,Mancini G,Servi S,Sorrenti A

更新日期：2009-01-01 00:00:00

abstract：:This work presents results of methyl 7-oxoabiet-13(14)-en-18-oate (3) self-oxidation with air-oxygen in the presence of various bases such as triethylamine or sodium t-butoxide. While under aerobic conditions, the use of sodium t-butoxide as a base results in the formation of four isomeric alcohols, an addition of tri...

journal_title：Chirality

authors： Masnyk M,Kuśmirek D,Trzybiński D,Frelek J

更新日期：2020-04-01 00:00:00

abstract：:Chirality is often glossed over in theoretical or experimental discussions concerning the origin of life, but the ubiquity of homochiral building blocks in known biological systems demands explanation. Information theory can provide a quantitative framework for understanding the role of chirality in biology. Here I sh...

journal_title：Chirality

authors： Carroll JD

更新日期：2009-03-01 00:00:00

abstract：:Six enantiomeric pairs of TADDOL-s gathered in two series with either methyl (series A) or phenyl (series B) substituent in 2-position of the dioxolane ring were studied by vibrational circular dichroism (VCD). Experimental IR and VCD spectra associated with density functional theory (DFT) calculations showed that the...

journal_title：Chirality

authors： Uncuta C,Bartha E,Gherase D,Teodorescu F,Draghici C,Cavagnat D,Daugey N,Liotard D,Buffeteau T

更新日期：2010-01-01 00:00:00

abstract：:The R enantiomers of some of the 2-arylpropionic acid non-steroidal antiinflammatory drugs (NSAIDs) are known to undergo metabolic chiral inversion to their more pharmacologically active antipodes. This process is drug and species dependent and usually unidirectional. The S to R chiral inversion, on the other hand, is...

journal_title：Chirality

authors： Jamali F,Lovlin R,Aberg G

更新日期：1997-01-01 00:00:00

abstract：:The binding of the title benzodiazepine enantiomers and its modulation by warfarin and bilirubin were studied by chromatography on human serum albumin (HSA) immobilized on Sepharose 4B, and also by a combination of ultrafiltration and circular dichroism (UF-CD) methods. In the absence of warfarin and bilirubin the bin...

journal_title：Chirality

authors： Fitos I,Visy J,Magyar A,Kajtár J,Simonyi M

更新日期：1990-01-01 00:00:00

abstract：:Copper(II) complexes of N2-octyl-(S)-phenylalaninamide (Noc-Phe-NH2), N2-dodecyl-(S)-phenylalaninamide (Ndo-Phe-NH2), and N2-octyl-(S)-norleucinamide (Noc-NLeu-NH2), dynamically adsorbed on a reversed-phase C18 column, were able to perform the direct enantiomeric separation of unmodified amino acids, amino acid amides...

journal_title：Chirality

authors： Galaverna G,Corradini R,Dossena A,Marchelli R,Dallavalle F

更新日期：1996-01-01 00:00:00