Asymmetric aldol reactions catalyzed by efficient and recyclable silica-supported proline-based peptides.


:A series of silica-supported proline-based peptides were synthesized and applied as catalysts for direct asymmetric intermolecular aldol reactions. Among these, a peptide with two L-proline units was found to be the most efficient one for the asymmetric aldol reactions between acetone and aromatic aldehydes. The reactions generated the corresponding products with satisfactory isolated yields (up to 97%) and enantiomeric excesses (up to 96%) in the presence of this catalyst (5 mol %). Furthermore, the silica-supported organocatalyst could be recovered and recycled by a simple filtration of the reaction solution and used for five consecutive trials without loss of its reactivity.






Yan J,Wang L




Has Abstract


2009-04-01 00:00:00












  • Synthesis of novel camphor-derived bifunctional thiourea organocatalysts.

    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...


    pub_type: 杂志文章


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

    更新日期:2015-01-01 00:00:00

  • Stereoselective Behavior of the Chiral Herbicides Diclofop-Methyl and Diclofop During the Soy Sauce Brewing Process.

    abstract::Chiral pesticides are now receiving more and more attention in the food-making process. This experiment studied the enantioselective behavior of diclofop-methyl (DM) and its main metabolite, diclofop (DC), during the soy sauce brewing process. Two kinds of commonly used strains, Aspergillus oryzae and Saccharomyces ro...


    pub_type: 杂志文章


    authors: Lu Y,Zhang D,Liao Y,Diao J,Chen X

    更新日期:2016-01-01 00:00:00

  • A stereodynamic fluorescent probe for amino acids. Circular dichroism and circularly polarized luminescence analysis.

    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...


    pub_type: 杂志文章


    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

  • Tautomerism of 4-hydroxy-2,5-dimethyl-3(2H)-furanone: evidence for its enantioselective biosynthesis.

    abstract::Chiral natural flavor compounds exhibit characteristic enantiomeric excesses due to stereoselective, enzymatically catalyzed reactions during biogenesis. Although the enzymatic formation of the strawberry key flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF; Furaneol(R)) is anticipated, the naturally occurr...


    pub_type: 杂志文章


    authors: Raab T,Hauck T,Knecht A,Schmitt U,Holzgrabe U,Schwab W

    更新日期:2003-08-01 00:00:00

  • Asymmetric allylation of α-ketoester-derived N-benzoylhydrazones promoted by chiral sulfoxides/N-oxides Lewis bases: highly enantioselective synthesis of quaternary α-substituted α-allyl-α-amino acids.

    abstract::Chiral sulfoxides/N-oxides (R)-1 and (R,R)-2 are effective chiral promoters in the enantioselective allylation of α-keto ester N-benzoylhydrazone derivatives 3a-g to generate the corresponding N-benzoylhydrazine derivatives 4a-g, with enantiomeric excesses as high as 98%. Representative hydrazine derivatives 4a-b were...


    pub_type: 杂志文章


    authors: Reyes-Rangel G,Bandala Y,García-Flores F,Juaristi E

    更新日期:2013-09-01 00:00:00

  • Improved chiral electrochemical recognition of tryptophan enantiomers based on three-dimensional molecularly imprinted overoxidized polypyrrole/MnO2 /carbon felt composites.

    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 ...


    pub_type: 杂志文章


    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

  • 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

  • Separation and aquatic toxicity of enantiomers of synthetic pyrethroid insecticides.

    abstract::Synthetic pyrethroid insecticides are chiral compounds with multiple asymmetric positions. In this study, isomers of four commonly used pyrethroids were separated at the enantiomeric level by enantioselective high-performance liquid chromatography (HPLC), and differences between enantiomers in aquatic toxicity were ch...


    pub_type: 杂志文章


    authors: Liu W,Gan JJ,Qin S

    更新日期:2005-01-01 00:00:00

  • Circular dichroism of tocopherols versus tocotrienols.

    abstract::Vitamin E is an essential nutrient of still increasing economic importance. Vitamin E derivatives include many nonracemic chiral compounds whose chirooptical characterization is scarcely described in the literature. We report the CD spectra of delta-tocopherol and its unsaturated analog delta-tocotrienol. TDDFT calcul...


    pub_type: 杂志文章


    authors: Mazzini F,Pescitelli G,Di Bari L,Netscher T,Salvadori P

    更新日期:2009-01-01 00:00:00

  • Conformational and Chiral Properties of Cyclic-tri(N-methyl-meta-benzamide) Bearing Amidino Groups.

    abstract::Cyclic triamides bearing amidino groups at the meta position of the phenyl rings were synthesized, and their conformational properties in the crystal and in solution were examined. Compound exists as a capsule-type dimer of the enantiomers with a bowl-shaped syn conformation in the crystal state. Compound exists mainl...


    pub_type: 杂志文章


    authors: Nishiyama S,Urushibara K,Masu H,Azumaya I,Kagechika H,Tanatani A

    更新日期:2015-08-01 00:00:00

  • The enantioselective enrichment, metabolism, and toxicity of fenoxaprop-ethyl and its metabolites in zebrafish.

    abstract::To investigate the impacts of the widely used chiral herbicide fenoxaprop-ethyl (FE) on aquatic organisms, the enrichment, metabolism, acute toxicity, and oxidative stress of fenoxaprop-ethyl and its main metabolites fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA...


    pub_type: 杂志文章


    authors: Xu Y,Jing X,Zhai W,Li X

    更新日期:2020-07-01 00:00:00

  • Effect of serum lipoproteins on stereoselective halofantrine metabolism by rat hepatocytes.

    abstract::Experimental hyperlipidemia has shown to decrease cytochrome P450 3A4 and 2C11 expression and to increase liver concentrations and the plasma protein binding of halofantrine (HF) enantiomers. The present study examined the effect of hyperlipidemic (HL) serum on the metabolism of HF enantiomers by primary rat hepatocyt...


    pub_type: 杂志文章


    authors: Patel JP,Hamdy DA,El-Kadi AO,Brocks DR

    更新日期:2012-07-01 00:00:00

  • Chiral doping of nematic phases and its application to the determination of absolute configuration.

    abstract::Doping nematic liquid crystals with nonracemic chiral compounds induces a twisted nematic (cholesteric) phase. The ability of solutes to twist the nematic phase may be related to the overall shape of the chiral dopant and consequently to its absolute configuration. The cholesteric induction is therefore a powerful too...


    pub_type: 杂志文章


    authors: Pieraccini S,Ferrarini A,Spada GP

    更新日期:2008-05-15 00:00:00

  • Photo-ionization spectroscopy and mass spectrometry of some molecular and supramolecular asymmetric systems in the isolated state.

    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...


    pub_type: 杂志文章


    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

  • CHIRBASE, a graphical molecular database on the separation of enantiomers by liquid-, supercritical fluid-, and gas chromatography.

    abstract::In order to cope with the increasing number of publications on the separation of enantiomers by chromatography on a chiral stationary phase, the graphical molecular database CHIRBASE was created. In the present state, the database package covers information (structural, bibliographic, and chromatographic data) on liqu...


    pub_type: 杂志文章


    authors: Koppenhoefer B,Nothdurft A,Pierrot-Sanders J,Piras P,Popescu C,Roussel C,Stiebler M,Trettin U

    更新日期:1993-01-01 00:00:00

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

    abstract::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 ...


    pub_type: 杂志文章


    authors: Pescitelli G

    更新日期:2012-09-01 00:00:00

  • The asymmetric synthesis of (R,R)-formoterol via transfer hydrogenation with polyethylene glycol bound Rh catalyst in PEG2000 and water.

    abstract::(R,R)-formoterol was synthesized in seven steps with 4-hydroxyl-3-nitro-acetophenone as the starting material. The key intermediate, the chiral secondary alcohol 4, was prepared via Rh-catalyzed asymmetric transfer hydrogenation with (S,S)-PEGBsDPEN as the ligand and sodium formate as the hydrogen donor under mild con...


    pub_type: 杂志文章


    authors: Huang L,Liu J,Shan W,Liu B,Shi A,Li X

    更新日期:2010-02-01 00:00:00

  • In vitro stereoselective degradation of carprofen glucuronide by human serum albumin. Characterization of sites and reactive amino acids.

    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...


    pub_type: 杂志文章


    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

  • Supramolecular photochirogenesis with novel cyclic tetrasaccharide: enantiodifferentiating photoisomerization of (Z)-cyclooctene with cyclic nigerosylnigerose-based sensitizers.

    abstract::Isophthalic and terephthalic acid monoesters of cyclic nigerosyl-(1→6)-nigerose (CNN), a cyclic tetrasaccharide composed of four d-glucopyranosyl residues connected by alternating α-1,3- and α-1,6-linkages, were synthesized as novel chiral supramolecular sensitizers for enantiodifferentiating photoisomerization of (Z)...


    pub_type: 杂志文章


    authors: Yang C,Liang W,Nishijima M,Fukuhara G,Mori T,Hiramatsu H,Dan-oh Y,Tsujimoto K,Inoue Y

    更新日期:2012-11-01 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

  • Two-dimensional separation of [7]helicene enantiomers on Cu(111).

    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...


    pub_type: 杂志文章


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

    更新日期:2001-01-01 00:00:00

  • Chiroptical property tuning of supramolecular assemblies in polymer matrices.

    abstract::Chiroptical materials have received much attention in diverse fields for applications such as displays, sensors, smart memory devices, and catalysis. Here, we develop a simple fabrication method for polymer films with tunable chiroptical properties using small amounts of self-assembling fluorescent dye as an additive....


    pub_type: 杂志文章


    authors: Jintoku H,Ihara H

    更新日期:2020-05-01 00:00:00

  • N,N-dimethylcarbamyl derivatives of oxazepam.

    abstract::Three N,N-dimethylcarbamyl derivatives of oxazepam (1-(N,N-dimethylcarbamyl)oxazepam, 3-O-(N,N-dimethylcarbamyl)oxazepam, and 1,3-O-bis(N,N-dimethylcarbamyl) oxazepam) and a 3-O-acyl-1-(N,N-dimethylcarbamyl)-oxazepam were synthesized from either oxazepam or demoxepam. Enantiomeric pairs of these derivatives and of cam...


    pub_type: 杂志文章


    authors: Yang SK,Lu XL

    更新日期:1991-01-01 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

  • (R,R)-N,N'-dimethylcyclohexyl-1,2-diazaseleno-phospholidine as a chiral derivatizing agent for the evaluation of chiral alcohols.

    abstract::Previously, a diazaphospholidine has been synthesized and evaluated as a chiral derivatizing reagent for the determination of the optical purity of chiral alcohols via 31P NMR spectroscopy (Alexakis et al., J. Org. Chem. 57:1224-1237, 1992). Our laboratory is interested in the advantageous and practical applications o...


    pub_type: 杂志文章


    authors: House KL,O'Connor MJ,Silks LA 3rd,Dunlap RB,Odom JD

    更新日期:1994-01-01 00:00:00

  • Asymmetric catalytic ene-cyclization approach to 2-fluoro-19-nor-1,25-dihydroxyvitamin D(3) A-ring analog with significant transactivation activity.

    abstract::1alpha,25-Dihydroxyvitamin D(3) (1alpha,25(OH)2D3) has been shown to modulate not only proliferation and differentiation, but also apoptosis in malignant cells, indicating that it could be useful for the treatment of cancer and psoriasis. However, little information has been available on the binding conformation of th...


    pub_type: 杂志文章


    authors: Mikami K,Ohba S,Ohmura H,Kubodera N,Nakagawa K,Okano T

    更新日期:2001-07-01 00:00:00

  • Measurements of concentration dependence and enantiomeric purity of terpene solutions as a test of a new commercial VCD spectrometer

    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...


    pub_type: 杂志文章


    authors: Urbanova M,Setnicka V V,Volka K

    更新日期:2000-05-01 00:00:00

  • Structure-retention relationship for enantioseparation of selected fluoroquinolones.

    abstract::Fluoroquinolones are popular class of antibiotics with distinct chemical functionality. Most of them are ampholytes with one chiral center. Stereogeneic center is located either in the side ring of Gatifloxacin (GFLX) or in the quinolone core of Ofloxacin (OFLX). These two amphoteric fluoroquinolones have terminal ami...


    pub_type: 杂志文章


    authors: Hassan RM,Yehia AM,Saleh OA,El-Azzouny AA,Aboul-Enein HY

    更新日期:2018-06-01 00:00:00

  • Structural Basis and Mechanism of Chiral Benzedrine Molecules Interacting With Third Dopamine Receptor.

    abstract::In order to investigate the chiral benzedrine molecules corresponding to their different characteristics in biochemical systems, we studied their interaction with D3 R using the docking method, molecular dynamic simulation, and quantum chemistry. The obtained results indicate that the active residues for R-benzedrine ...


    pub_type: 杂志文章


    authors: Wang M,Xie W,Li A,Xu S

    更新日期:2016-10-01 00:00:00

  • Stereoselective intramolecular cyclization to 4-(hydroxymethyl)-3-(1H-indolyl)oxazolidin-2-ones.

    abstract::A simple high-yield three-steps route to optically active 4-hydroxymethyl-3-(1H-indolyl)oxazolidin-2-ones from (S)-glycidol is described. The key intermediates (R)-oxiran-2-ylmethyl 1H-indol-4/-5-ylcarbamates are obtained in high yields from (S)-glycidol. These are readily transformed to oxazolidin-2-ones, very intere...


    pub_type: 杂志文章


    authors: Chiummiento L,Funicello M,Tramutola F

    更新日期:2012-04-01 00:00:00