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New Chiral (new + chiral)

Distribution by Scientific Domains
Chemistry100%

Terms modified by New Chiral

  • new chiral auxiliary
    		•
  • new chiral ligand
    		•

    Selected Abstracts

    Synthesis and Evaluation of a Broad Range of New Chiral (Aminoalkyl)phosphane Ligands for Asymmetric Hydrogen-Transfer Reduction of Prochiral Ketones

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2003
    Matthieu Léautey
    Abstract Twenty new chiral (aminoalkyl)phosphane ligands have been prepared from four enantiomerically pure advanced chiral compounds. We describe their use for asymmetric hydrogen-transfer reduction of three prochiral ketones. Enantioselectivities up to 90% were obtained. We investigated the influence on the enantioselectivity of each part of these new (aminoalkyl)phosphane ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    ChemInform Abstract: A Facile Synthesis of New Chiral [1 + 1] Macrocyclic Schiff Bases.

    CHEMINFORM, Issue 15 2008
    Paulsamy Suresh
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    New Chiral 1,3-Diphosphine Ligands for Rh-Catalyzed Enantioselective Hydrogenation: A Search for Electronic Effects.

    CHEMINFORM, Issue 17 2006
    Natalia V. Dubrovina
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

    ChemInform Abstract: New Chiral 1,4-Aminoalcohols Derived from (+)-Camphor and (-)-Fenchone for the Enantioselective Addition of Diethylzinc to Aldehyde.

    CHEMINFORM, Issue 12 2001
    Naoto Hanyu
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    Ethene Polymerization Behavior of MAO-Activated Dichloridotitanium Complexes Bearing Bi- and Tetradentate Salicylaldimine Derivatives

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2010
    Antti Pärssinen
    Abstract New chiral bridged tetradentate (N2O2)TiIVCl2 -type complexes bearing dimethylbiphenyl (1-Ti,3-Ti) and previously published binaphthyl-bridged (4-Ti) complex were synthesized with high yields. This was achieved by treating the corresponding Schiff-base ligand (H2L) precursors with Ti(NMe2)4, followed by conversion of these diamido complexes to LTiCl2 derivatives by the addition of excess of Me3SiCl. A series of unbridged titanium complexes 5-Ti,8-Ti with similar substituents at the phenoxy group were studied and their polymerization properties, after methylaluminoxane (MAO) activation, compared with the above bridged complexes. It was found that the catalysts bearing chiral tetradentate biaryl-bridged salicylaldimine ligands produce multimodal polyethylene (PE) with low activity [below 10 kgPE/(molTi,h,bar)] while their unbridged analogues provide activities that are 10,1000 times greater under similar reaction conditions. The reasons for this dramatic difference in polymerization activities are discussed based on the stabilities of the different cationic species configurations. [source]

    Synthesis and Evaluation of a Broad Range of New Chiral (Aminoalkyl)phosphane Ligands for Asymmetric Hydrogen-Transfer Reduction of Prochiral Ketones

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2003
    Matthieu Léautey
    Abstract Twenty new chiral (aminoalkyl)phosphane ligands have been prepared from four enantiomerically pure advanced chiral compounds. We describe their use for asymmetric hydrogen-transfer reduction of three prochiral ketones. Enantioselectivities up to 90% were obtained. We investigated the influence on the enantioselectivity of each part of these new (aminoalkyl)phosphane ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Synthesis and anti-HIV activity of new chiral 1,2,4-triazoles and 1,3,4-thiadiazoles

    HETEROATOM CHEMISTRY, Issue 3 2007
    Tashfeen Akhtar
    5-substituted 4-(4-chlorophenyl)-4H-1,2,4-triazol-3-thiones 3 and 2-substituted 5-(4-chlorophenylamino)-1,3,4-thiadiazoles 4 were prepared from the intermediate thiosemicarbazides 2 under basic and acidic conditions, respectively. The thiosemicarbazides, in turn, were prepared by the reaction of hydrazides 1 with 4-chlorophenylisothiocyanate in MeOH. Some of the new synthesized compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. All the compounds were inactive except 3f, which showed an EC50 value of 23.9 ,g/mL and 9.9 ,g/mL against HIV-1 and HIV-2 with a therapeutic index of 3 and 7, respectively. It means that compound 3f was cytotoxic to MT-4 cells at CC50 of 72.7 ,g/mL in both strains. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:316,322, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20282 [source]

    Solution 1H and 13C NMR of new chiral 1,4-oxazepinium heterocycles and their intermediates from the reaction of 2,4-pentanedione with ,- L -amino acids and (R)-(,)-2-phenylglycinol

    MAGNETIC RESONANCE IN CHEMISTRY, Issue 12 2003
    M. Concepción Lozada
    Abstract The reaction of 2,4-pentanedione (1) with (R)-(,)-2-phenylglycine methyl ester (2), (R)-(,)-2-phenylglycinol (3) and the proteinogenic amino acids (2S,3R)-(,)-2-amino-3-hydroxybutyric acid (L -threonine) (4) and (R)-(,)-2-amino-3-mercaptopropionic acid (L -cysteine) (5) methyl esters was investigated. The corresponding enamines 6, 7 and 8 were isolated and characterized spectroscopically whereas 9, which is unstable, was transformed in situ into 13. Treatment of 7, 8 and 9 with boron trifluoride etherate afforded the new [1,4]oxazepines 10, 11 and [1,4]thiazepine (12) as their BF3O, salts. The structures of the enamines and their corresponding seven-membered heterocycles were assessed by 1D and 2D NMR spectroscopy. Variable-temperature experiments revealed different molecular mobility behavior among these heterocycles. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    3-Substituted BINOL Schiff bases and their reductive products for catalytic asymmetric addition of diethylzinc to aldehydes

    CHIRALITY, Issue 7 2008
    Bing Liu
    Abstract Three new chiral 3-substituted BINOL Schiff bases and their reductive 3-arylaminomethyl BINOL products have been synthesized and used for the asymmetric addition reaction of diethylzinc to aldehydes in the presence of titanium tetraisopropoxide. The reaction provided optically active secondary alcohols in high yield (86,100%) and good enantioselectivity (up to 92% ee). Chirality, 2008. © 2008 Wiley-Liss, Inc. [source]