An efficient dipeptide-catalyzed direct asymmetric aldol reaction of equimolar reactants in solid media.

abstract：:The synthesis of the eight stereoisomers of muscarine has been efficiently accomplished by utilizing the two enantiomers of lactic esters as starting material. The synthetic strategy is based on a SnCl4-catalyzed addition of allyltrimethylsilane to O-protected lactic aldehydes followed by an iodocyclization process. A...

journal_title：Chirality

authors： De Amici M,Dallanoce C,De Micheli C,Grana E,Dondi G,Ladinsky H,Schiavi G,Zonta F

更新日期：1992-01-01 00:00:00

abstract：:Enantiomers of chiral aliphatic hydrocarbons are generally difficult to separate because they lack functional groups to be derivatized in order to generate diastereomers. The systematic and quantitative separation of a series of branched hydrocarbon enantiomers using a chiral cyclodextrin stationary phase and a cryost...

journal_title：Chirality

authors： Meierhenrich UJ,Nguyen MJ,Barbier B,Brack A,Thiemann WH

更新日期：2003-01-01 00:00:00

abstract：:A calculation of the circular dichroism (CD) spectra of carbonmonoxy- and deoxy-myoglobin is carried out in relation to a time-resolved CD experiment. This calculation allows us to assign a dominant role to the proximal histidine in the definition of the electronic normal modes and to interpret the transient CD struct...

journal_title：Chirality

authors： Dartigalongue T,Hache F

更新日期：2006-05-05 00:00:00

abstract：:Vibrational circular dichroism (VCD) spectra of (+)-alpha-pinene solutions in carbon tetrachloride have been measured in the range of volume fractions 5-100% (v/v) in the mid-infrared region. The concentration dependence measured was statistically analyzed with the aim of obtaining a reliable correlation between the V...

journal_title：Chirality

authors： Urbanova M,Setnicka V V,Volka K

更新日期：2000-05-01 00:00:00

abstract：:The chiral squaramide catalysts (8-15) were synthesized, and their catalytic efficiency in the enantioselective conjugate addition of pyrazolones to nitroalkenes was described. This protocol provides excellent chemical yields (up to 93%) of chiral 5-methyl-4-(2-nitro-1-arylethyl)pyrazol-3-ol derivatives with high enan...

journal_title：Chirality

authors： Aydin AE,Culha S

更新日期：2021-01-11 00:00:00

abstract：:The chiral fungicide furametpyr is widely used in the rice field to control rice sheath blight; however, furametpyr enantiomers are treated as just one compound in traditional achiral analysis, which gives only partial information. An effective chiral analytical method was developed for the resolution and determinatio...

journal_title：Chirality

authors： Dong F,Chen X,Xu J,Liu X,Chen Z,Li Y,Zhang H,Zheng Y

更新日期：2013-12-01 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：:We report a method to determine the absolute configuration of alpha-amino acids by exciton coupled circular dichroism (ECCD). Naturally occurring amino acids were successfully derivatized with 2-bromomethylquinoline. Complexation of these conformationally flexible ligands with Cu(II) salts yielded defined propeller-li...

journal_title：Chirality

authors： Holmes AE,Zahn S,Canary JW

更新日期：2002-06-01 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：: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：:Synthesis and catalyst performance of 2,3- (types and ) and 2,8-disubstituted (type ) thiourea bifunctional organocatalysts was attempted. The synthesis of catalyst of type has, so far, not been realized, while catalysts of type , i.e., the 2,3-exo- and the 2-endo-3-exo-thiourea catalysts, were prepared in six steps s...

journal_title：Chirality

authors： Ričko S,Golobič A,Svete J,Stanovnik B,Grošelj U

更新日期：2015-01-01 00:00:00

abstract：:An enantioseparation of the antipsychotic drug butaclamol in human plasma by high-performance liquid chromatography (HPLC) with solid phase extraction is presented. The separation was achieved on the vancomycin macrocyclic antibiotic chiral stationary phase (CSP) Chirobiotic V with a polar ionic mobile phase (PIM) con...

journal_title：Chirality

authors： Aboul-Enein HY,Hefnawy MM

更新日期：2004-03-01 00:00:00

abstract：:Numbers of resolving factors were investigated to improve resolution of venlafaxine 1. An effective resolving agent, O,O'-di-p-toluoyl-(R, R)-tartaric acid 2, was screened using similar method of 'Dutch resolution' from tartaric acid derivatives. The resolution efficiency was up to 88.4%, when the ratio of rac-1 and 2...

journal_title：Chirality

authors： Liu ZJ,Liu H,Chen XW,Lin M,Hu Y,Tuo X,Yuan ZY,Sun XX

更新日期：2018-03-01 00:00:00

abstract：:C2 -symmetric N,N-bis(phosphinomethyl)amines were prepared by the thermal reaction of aromatic aldehydes with ammonia and hypophosphorus acid as previously described. Both enantiomers of C2 -symmetric N,N-bis(phosphinomethyl)amine were obtained in a high enantiomeric purity through the diastereomeric salt formation wi...

journal_title：Chirality

authors： Kaboudin B,Faghihi MR,Kazemi F,Yokomatsu T

更新日期：2015-01-01 00:00:00

abstract：:This study focused on the chiral characteristics of methamphetamine seizures in Shanghai for inferring the synthetic pathways of drugs. Capillary electrophoresis coupled to time-of-flight mass spectrometry was used for simultaneous chiral separation of amphetamine-type stimulants and ephedrine, including S(+)-amphetam...

journal_title：Chirality

authors： Cui X,Liang C,Gong F,Wang R,Ni C,Wu Y,Chen G,Zhang Y

更新日期：2018-09-01 00:00:00

abstract：:3alpha,12alpha-dihydroxy-5beta-cholan-24-oic acid (deoxycholic acid DCA) is able to discriminate between the R- and S-enantiomers of camphorquinone and endo-(+)-3-bromocamphor and select only the S-enantiomers from a racemic mixture. DCA forms novel well ordered 1:1 adducts with (1S)-(+)-camphorquinone and (1S)-endo-(...

journal_title：Chirality

authors： Tahir MI,Rees NH,Heyes SJ,Cowley AR,Prout K

更新日期：2008-07-01 00:00:00

abstract：:The present work firstly described the enantioseparation and determination of flumequine enantiomers in milk, yogurt, chicken, beef, egg, and honey samples by chiral liquid chromatography-tandem mass spectrometry. The enantioseparation was performed under reversed-phase conditions on a Chiralpak IC column at 20°C. The...

journal_title：Chirality

authors： Li S,Liu B,Xue M,Yu J,Guo X

更新日期：2019-11-01 00:00:00

abstract：:A simple, green, and direct three-component condensation of acetophenone, aromatic aldehydes with 3-oxo-N-phenylbutanamide (acetoacetanilide) to generate some novel (1S,6R)/(1R,6S)-2-oxo-N,4,6-triarylcyclohex-3-enecarboxamide derivatives was carried out over K2 CO3 (10 mol%) with high efficiency in water/ethanol as gr...

journal_title：Chirality

authors： Mousavi SR

更新日期：2016-11-01 00:00:00

abstract：:The use of stereodynamic probes is becoming one of the leading strategies for the fast and effective determination of enantiomeric excess. Recently, we reported a series of novel molecular architectures based on a modified tris(2-pyridylmethyl)amine complex (TPMA), which are able to amplify the electronic CD, in the c...

journal_title：Chirality

authors： Carmo Dos Santos NA,Badetti E,Licini G,Abbate S,Longhi G,Zonta C

更新日期：2018-01-01 00:00:00

abstract：:The perturbation of the racemic equilibrium of luminescent D3 terbium(III) complexes with chelidamic acid (CDA), a hydroxylated derivative of 2,6-pyridine-dicarboxylic acid (DPA), by added chiral biomolecules such as L-amino acids has been studied using circularly polarized luminescence and 13C NMR spectroscopy. It is...

journal_title：Chirality

authors： Moussa A,Pham C,Bommireddy S,Muller G

更新日期：2009-05-01 00:00:00

abstract：:A chiral alkylglucoside surfactant, namely n-octyl-beta-D-maltopyranoside (OM), was evaluated in the enantiomeric separation of phenoxy acid herbicides. The enantiomeric resolution of the phenoxy acid herbicides could be manipulated readily by adjusting the surfactant concentration, ionic strength, pH, the percent org...

journal_title：Chirality

authors： Mechref Y,el Rassi Z

更新日期：1996-01-01 00:00:00

abstract：:The prochiral anthelmintic drug albendazole was administered orally to sheep and rats. Blood samples were taken at standardized intervals during the time course of the plasma kinetics: 18 h in rats and 48 h in sheep. The enantiomeric ratio of the sulfoxide metabolite was determined by means of HPLC on a chiral station...

journal_title：Chirality

authors： Delatour P,Benoit E,Caude M,Tambute A

更新日期：1990-01-01 00:00:00

abstract：:Human carboxylesterase 1 (hCES1) is an enzyme that plays an important role in hydrolysis of pharmaceuticals in the human liver. In this study, elucidation of the chiral recognition ability of hCES1 was attempted using indomethacin esters in which various chiral alcohols were introduced. Indomethacin was condensed with...

journal_title：Chirality

authors： Takahashi M,Takani D,Haba M,Hosokawa M

更新日期：2020-01-01 00:00:00

abstract：:(3SR,4RS)-3,4-Epoxypiperidine-4-carboxylic acid (isoguvacine oxide) is a potent and specific GABAA receptor agonist. Isoguvacine oxide, originally designed as a potentially alkylating agonist, turned out to interact with the GABAA receptor in a fully reversible manner. The protected form of isoguvacine oxide, benzyl (...

journal_title：Chirality

authors： Frølund B,Jeppesen L,Krogsgaard-Larsen P,Hansen JJ

更新日期：1995-01-01 00:00:00

abstract：:The concentration sensitivity of a racemic drug (chlorpheniramine maleate) in chiral capillary electrophoresis with electrospray ionization – mass spectrometric detection was improved ~500-fold via stacking. Enantiomeric separation was achieved through the use of a neutral chiral pseudostationary phase (2-hydroxpropyl...

journal_title：Chirality

authors： Wuethrich A,Haddad PR,Quirino JP

更新日期：2014-11-01 00:00:00

abstract：:This work reports confirmation of the experimental assignment of the absolute-handedness chirality of single-walled carbon nanotubes (SWNTs). This was achieved by applying the scanning tunneling microscopy (STM) imaging technique to a supramolecular composite consisting of a metalized porphyrin derivative (nickel-5,15...

journal_title：Chirality

authors： Abd El-Mageed AIA,Ogawa T

更新日期：2020-03-01 00:00:00

abstract：:We introduce a method to detect the activity of ion channels and pores with circular dichroism (CD) spectroscopy. G-quartets obtained by potassium templated self-assembly of 5'-guanosine monophosphate (GMP) are used as CD probes, the bee-toxin melittin as representative pore and gramicidin A as representative ion chan...

journal_title：Chirality

authors： Hennig A,Matile S

更新日期：2008-09-01 00:00:00

abstract：:The special relationship between France and the polarization of light from the beginning of the 19th century until the present day is reviewed in the lives and works of Étienne Louis Malus, François Arago, Jean-Baptiste Biot, Augustin Fresnel, Louis Pasteur, Frédéric Wallerant, Aimé Cotton, Francis Perrin, and Alain A...

journal_title：Chirality

authors： Kahr B

更新日期：2018-04-01 00:00:00

abstract：:The adsorption of heptahelicene, a helically shaped polyaromatic hydrocarbon (C(30)H(18)), on a Cu(111) surface was studied by means of thermal desorption mass spectrometry (TDMS) and low energy electron diffraction (LEED) at temperatures between 130-1,000 K under ultrahigh vacuum (UHV) conditions. The molecule in the...

journal_title：Chirality

authors： Ernst KH,Kuster Y,Fasel R,Müller M,Ellerbeck U

更新日期：2001-01-01 00:00:00

abstract：:Here, we report the general strategies by which NMR spectroscopy can be used to determine the enantiopurity and absolute configuration of chalcogen containing secondary alcohols, including the evaluation of the use of chiral solvating and chiral derivatizing agents. The BINOL/DMAP ternary complex demonstrated a simple...

journal_title：Chirality

authors： Marques NBG,Jacob RG,Perin G,Lenardão EJ,Alves D,Silva MS

更新日期：2019-01-01 00:00:00