Solid-state circular dichroism and hydrogen bonding, part 2: the case of hypothemycin re-investigated.


:The impact of crystalline forces on the solid-state circular dichroism (CD) spectrum of hypothemycin (), a biologically active molecule extracted from natural sources, has been analyzed by means of time-dependent density functional theory CD calculations. Input structures were extracted from the X-ray geometry of and consisted in the isolated molecule, its cluster with five water molecules, and 20 different dimers (plus water molecules) representative of all the closest neighbors found in the crystal. The effects of solid-state intermolecular hydrogen bonds and through-space exciton couplings in determining the solid-state CD spectrum of hypothemycin were evaluated and compared.






Pescitelli G




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2012-09-01 00:00:00












  • Separation and determination of tetracycline hydrochloride in real water samples using binary small molecule alcohol-salt aqueous two-phase system coupled with high-performance liquid chromatography.

    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...


    pub_type: 杂志文章


    authors: Guo DG,Ni L,Wang L,Shao L

    更新日期:2019-09-01 00:00:00

  • Determination of enantiomeric excess of ethyl 3,5-dihydroxy-6-benzyloxy hexanoate by chiral reverse phase high performance liquid chromatography.

    abstract::A simple and reliable chiral HPLC method was developed for the determination of enantiomeric excess of a chiral dihydroxy intermediate for the chemoenzymatic synthesis of side chain of statin drugs. After evaluating different columns and conditions, the four stereoisomers of ethyl 3,5-dihydroxy-6-benzyloxy hexanoate w...


    pub_type: 杂志文章


    authors: Liu JH,Yu BY,Chen YJ

    更新日期:2008-01-01 00:00:00

  • Enantioselective degradation of warfarin in soils.

    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...


    pub_type: 杂志文章


    authors: Lao W,Gan J

    更新日期:2012-01-01 00:00:00

  • Enantioselective determination of isradipine in human serum using chiral stationary phase liquid chromatography and gas chromatography with nitrogen selective detection.

    abstract::rac-Isradipine is a dihydropyridine type calcium antagonist. Its calcium entry blocking effect is due primarily to the (+)-(S)-enantiomer. This study describes a sensitive enantioselective method for the determination of isradipine in human serum. Following alkaline extraction into hexane, the enantiomers of isradipin...


    pub_type: 杂志文章


    authors: Rask HS,Angelo HR,Christensen HR

    更新日期:1998-01-01 00:00:00

  • Derivatization, complexation, and absolute configurational assignment of chiral primary amines: application of exciton-coupled circular dichroism.

    abstract::We report here a sensitive method for the determination of the absolute configurations of primary amines using exciton-coupled circular dichroism (ECCD). The method works on a microgram scale by derivatization of chiral amines with quinoline chromophores. Complexation of the chiral ligands with metal ion fixes the geo...


    pub_type: 杂志文章


    authors: Zhang J,Holmes AE,Sharma A,Brooks NR,Rarig RS,Zubieta J,Canary JW

    更新日期:2003-02-01 00:00:00

  • Direct asymmetric Michael addition of thioether-based aryl sulfanyl-propan-2-one to nitroalkenes catalyzed by a chiral amine-thiourea bifunctional organocatalyst.

    abstract::Although the organocatalytic direct asymmetric Michael reactions of carbonyl compounds to nitroalkenes have been investigated intensely, the Michael reaction of the thioether-based donors remains a rather undeveloped field. This work concerns the asymmetric Michael addition of aryl sulfanyl-propan-2-one to nitroalkene...


    pub_type: 杂志文章


    authors: Jiang X,Zhang B,Zhang Y,Lin L,Yan W,Wang R

    更新日期:2010-07-01 00:00:00

  • Enantioselective and diastereoselective Michael addition of ketone/aldehyde to trans-nitroolefins catalyzed by a novel chiral pyrrolidine-thiourea.

    abstract::The direct Michael addition reaction of cyclohexanone/aliphatic aldehydes with nitroolefins, catalyzed by a novel chiral pyrrolidine-thiourea catalyst 1a, is described. The desired 1,4-adducts were obtained in moderate yields with enantioselectivities up to 99% ee and dr up to 99:1 of the syn product. ...


    pub_type: 杂志文章


    authors: Shen Z,Zhang Y,Jiao C,Li B,Ding J,Zhang Y

    更新日期:2007-05-05 00:00:00

  • Nonhanded chirality in octahedral metal complexes.

    abstract::Chiral molecules can either be handed (i.e., "shoes") or nonhanded ("potatoes"). The only chiral ligand partition for tetrahedral metal complexes (or for a tetrahedral carbon atom such as that found in amino acids and other chiral biological molecules) is the fully unsymmetrical degree 6 partition (1(4)), which leads ...


    pub_type: 杂志文章


    authors: King RB

    更新日期:2001-08-01 00:00:00

  • Unexpected difference in enantioselective retention on cellulase (CHB I) silica stationary phase caused by exchange of potassium for sodium ion in the mobile phase.

    abstract::An increase in both retention and enantioselectivity for some beta-blocking agents was observed when exchanging potassium to sodium ion in the buffer used as mobile phase. A large effect of ionic strength on retention was observed, while the enantioselectivity was constant. ...


    pub_type: 杂志文章


    authors: Hedeland M,Jönsson S,Isaksson R,Pettersson C

    更新日期:1998-01-01 00:00:00

  • Pharmacologic implications of alpha-adrenoreceptor interactive parameters for epinephrine enantiomers in the rat vas deferens.

    abstract::After alkylation of a fraction of the total alpha-adrenoreceptors by phenoxybenzamine in rat vas deferens, the dissociation constants of (-)- and (+)-epinephrine in functional studies were 7 X 10(-7) M and 2 X 10(-5) M, respectively. In the adrenoreceptor-containing tissue fraction, when 3H-labeled WB4101 was used as ...


    pub_type: 杂志文章


    authors: Rice PJ,Miller DD,Sokoloski TD,Patil PN

    更新日期:1989-01-01 00:00:00

  • Secondary phosphine oxides: tautomerism and chiral recognition monitored by multinuclear NMR spectroscopy of their Rh2[(R)-MTPA]4 adducts.

    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...


    pub_type: 杂志文章


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

    更新日期:2004-01-01 00:00:00

  • Chirality as an inherent general property of matter.

    abstract::A statement has been formulated that chirality is an indispensable inherent property of all material objects, at one level of organization of matter or another. The translation of chirality from one level of material objects to another deserves our attention. The parity violation of weak interactions can be discussed ...


    pub_type: 杂志文章


    authors: Davankov V

    更新日期:2006-08-01 00:00:00

  • Nonlinear chiral interactions in resolutions with benzylamine derivatives.

    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. ...


    pub_type: 杂志文章


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

    更新日期:2007-01-01 00:00:00

  • Stereoselective sulfation of terbutaline by the rat liver cytosol: evaluation of experimental approaches.

    abstract::Little is known about the stereochemistry of sulfation of chiral phenolic drugs. In this study we examined several in vitro approaches to this question, using (+)-, (-)-, or (+/-)-terbutaline as the substrate and the rat liver cytosol as the phenolsulfotransferase enzyme source. The cosubstrate PAPS was either generat...


    pub_type: 杂志文章


    authors: Walle UK,Walle T

    更新日期:1989-01-01 00:00:00

  • Highly enantioselective asymmetric autocatalysis of 2-alkenyl- and 2-vinyl-5-pyrimidyl alkanols with significant amplification of enantiomeric excess.

    abstract::2-Alkenyl- and 2-vinyl-5-pyrimidyl alkanols are highly enantioselective asymmetric autocatalysts with significant amplification of enantiomeric excess in the enantioselective addition of diisopropylzinc to 2-alkenyl- and 2-vinylpyrimidine-5-carbaldehydes. Consecutive asymmetric autocatalysis starting from 7% ee increa...


    pub_type: 杂志文章


    authors: Sato I,Yanagi T,Soai K

    更新日期:2002-02-01 00:00:00

  • Enantioselective electrochemical oxidation of enol acetates using a chiral supporting electrolyte.

    abstract::Anodic oxidation of 1-acetoxy-3,4-dihydronaphthalene (1) and alpha-acetoxy-beta-alkylstyrenes (3) at -78 degrees C in a mixed solvent of acetonitrile (CH(3)CN), tetrahydrofuran (THF), and acetic acid (AcOH) containing (S)-tetraethylammonium camphorsulfonate as a chiral supporting electrolyte brought about enantioselec...


    pub_type: 杂志文章


    authors: Maekawa H,Itoh K,Goda S,Nishiguchi I

    更新日期:2003-01-01 00:00:00

  • Comparative study on kynurenic acid production in the rat striatum by tryptophan enantiomers: an in vivo microdialysis study.

    abstract::Kynurenic acid (KYNA), an endogenous antagonist of N-methyl-D-aspartate and α(7) nicotinic acetylcholine receptors, is one of the L-tryptophan (Trp) metabolites. To compare the level of KYNA produced in the striatum of rats after independent administration of L-Trp and D-Trp, rats were intraperitoneally administered L...


    pub_type: 杂志文章


    authors: Ishii K,Iizuka H,Ogaya T,Song Z,Fukushima T

    更新日期:2011-01-01 00:00:00

  • Noncovalent immobilization of ionic-tagged box-Cu(OAc)2 complex and its application in asymmetric Henry reaction.

    abstract::Immobilized Cu(OAc)(2)-bis(oxazolines) via hydrogen bonding by SBA-15 was applied to asymmetric Henry reaction, and good enantioselectivities were obtained (up to 83% ee) between 2-methoxybenzaldehyde and CH(3)NO(2) in isopropyl alcohol (iPrOH). The catalyst could be reused seven times without any obvious loss in enan...


    pub_type: 杂志文章


    authors: Li ZH,Zhou ZM,Hao XY,Zhang J,Dong X,Liu YQ

    更新日期:2012-12-01 00:00:00

  • Dynorphin A analogs containing a conformationally constrained phenylalanine derivative in position 4: reversal of preferred stereochemistry for opioid receptor affinity and discrimination of kappa vs. delta receptors.

    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...


    pub_type: 杂志文章


    authors: Aldrich JV,Zheng QI,Murray TF

    更新日期:2001-01-01 00:00:00

  • Stereochemical study of tolperisone, a muscle relaxant agent, by circular dichroism and ultraviolet spectroscopy.

    abstract::The stereochemistry of tolperisone, a chiral aryl-alkyl basic ketone was investigated by means of circular dichroism (CD) and ultraviolet (UV) spectroscopy. The unusually high optical activity of tolperisone hydrochloride in the n-->pi* region is interpreted by the presence of a chiral conformer in solution. For stere...


    pub_type: 杂志文章


    authors: Zsila F,Hollósi M,Gergely A

    更新日期:2000-11-01 00:00:00

  • Highly diastereoselective addition of silyldihalomethyllithiums to chiral alkyl esters.

    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...


    pub_type: 杂志文章


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

    更新日期:2003-01-01 00:00:00

  • Surface-enhanced chiroptical spectroscopy with superchiral surface waves.

    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...


    pub_type: 杂志文章


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

    更新日期:2018-07-01 00:00:00

  • Asymmetric Diels-Alder reaction involving chiral benzimidazoles as organocatalysts.

    abstract::(S)-(-)-2-(α-hydroxyethyl)-benzimidazole and (S)-(+)-2-(α-hydroxybenzyl)-benzimidazole work as chiral Brønsted bases (BBs) in Diels-Alder reaction between anthrone and maleimides under mild reaction condition. These chiral BBs cause asymmetric induction. ...


    pub_type: 杂志文章


    authors: Mirgane NA,Karnik AV

    更新日期:2011-05-01 00:00:00

  • Enantioselective separation of 1,4-disubstituted piperazine derivatives on two cellulose chiralcel OD and OJ and one amylose chiralpak AD chiral selectors

    abstract::A series of 1,4-disubstituted piperazine derivatives with hypnotic activity were examined on three polysaccharide-based chiral stationary phases, namely, Chiracel OD, Chiracel OJ and Chiralpak AD. It was possible to resolve all the compounds on all the phases examined (1.13


    pub_type: 杂志文章


    authors: Chilmonczyk Z,Ksycinska H,Mazgajska M,Aboul-Enein HY

    更新日期:1999-01-01 00:00:00

  • Highly enantiomeric reduction of acetophenone and its derivatives by locally isolated Rhodotorula glutinis.

    abstract::Ninety isolates of microorganisms belonging to different taxonomical groups (30 bacteria, 20 yeast, and 40 fungi) were previously isolated from various samples. These isolates were screened as reducing agents for acetophenone 1a to phenylethanol 2a. It was found that the isolate EBK-10 was the most effective biocataly...


    pub_type: 杂志文章


    authors: Zilbeyaz K,Kurbanoglu EB

    更新日期:2010-10-01 00:00:00

  • Enantiopurity determination of the enantiomers of the triple reuptake inhibitor indatraline.

    abstract::The present study describes the development of two approaches for the determination of the enantiopurity of both enantiomers of indatraline. Initially, a method was developed using different chiral solvating agents (CSAs) for diastereomeric discrimination regarding signal separation in (1)H nuclear magnetic resonance ...


    pub_type: 杂志文章


    authors: Grimm SH,Allmendinger L,Höfner G,Wanner KT

    更新日期:2013-12-01 00:00:00

  • Unexpected rearrangement of enantiomerically pure 3-aminoquinuclidine as a simple way of preparing diastereomeric octahydropyrrolo[2,3-c]pyridine derivatives.

    abstract::Reaction of (S)- or (R)-3-aminoquinuclidine with 2-chloropyrimidine or 2-bromopyrimidine led to an unexpected formation of both cis- and trans-octahydropyrrolo [2,3]pyridine derivatives. A single-step synthesis of two of the four stereoisomers of these octahydropyrrolo[2,3]pyridine derivatives provides a convenient wa...


    pub_type: 杂志文章


    authors: Goljer I,Molinari A,He Y,Nogle L,Sun W,Campbell B,McConnell O

    更新日期:2009-07-01 00:00:00

  • Improvement of enantioselective syntheses and chiral high resolution gas chromatographic analyses of (+)-2-allyl-2-carboethoxy-cyclopentanol.

    abstract::The improvement of the biocatalytic reduction of 2-allyl-carboethoxy-cyclopentanone (2) to the corresponding cyclopentanol derivative (+)-(1R,2R)-(1) was accomplished employing baker's yeast in organic media. This chiral cyclopentanol derivative (1), analyzed by high resolution gas chromatography performed over beta-c...


    pub_type: 杂志文章


    authors: Fraga CA,Barreiro EJ,da Silva EF,dos Santos AR,KV Ramos MdaC,de Aquino Neto FR

    更新日期:1997-01-01 00:00:00

  • Isothermal titration calorimetry for chiral chemistry.

    abstract::One of the most powerful techniques that are currently available to measure thermodynamic parameters such as enthalpy (ΔH), Gibbs free energy (ΔG), entropy changes (ΔS), and binding affinity in chemical reactions is isothermal titration calorimetry (ITC). Recent advances in instrumentation have facilitated the develop...


    pub_type: 杂志文章,评审


    authors: Werber L,Mastai Y

    更新日期:2018-05-01 00:00:00

  • Comparison of mid-infrared Fourier transform vibrational circular dichroism measurements with single and dual polarization modulations.

    abstract::Fourier transform infrared vibrational circular dichroism (FTIR-VCD) measurements have gone through major advances in the last decade. A major thrust in these advances was to find ways that can minimize the VCD spectral artifacts and obtain the VCD signals at enhanced signal quality. However, all these advances are no...


    pub_type: 杂志文章


    authors: Polavarapu PL,Shanmugam G

    更新日期:2011-10-01 00:00:00