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Chiral Ionic Liquids (chiral + ionic_liquid)
Selected AbstractsPolymer-Immobilized Pyrrolidine-Based Chiral Ionic Liquids as Recyclable Organocatalysts for Asymmetric Michael Additions to Nitrostyrenes under Solvent-Free Reaction ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2008Pinhua Li Abstract A polymer immobilized pyrrolidine-based chiral ionic liquid 5a was synthesized and was found to be a highly efficient catalyst for the Michael additions of ketones and aldehydes to nitrostyrenes, which afforded the corresponding adducts in good yields (up to 97,%), excellent enantioselectivities (up to >99,% ee) and high diastereoselectivities (up to >99:1 dr) under solvent-free reaction conditions. In addition, the catalyst 5a could be reused at least eight times without a significant loss of its catalytic activity and stereoselectivity.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis of Novel Chiral Ionic Liquids and Their Phase Behavior in Mixtures with Smectic and Nematic Liquid CrystalsHELVETICA CHIMICA ACTA, Issue 11 2004Martin Tosoni Alkylation of 1-alkyl-1H -imidazoles 2a,f with citronellyl bromide 1b opens access to chiral 1H -imidazolium bromides 3a,f (Scheme,1). A similar strategy yielded the chiral pyridinium ionic liquid 6 (Scheme,2). Dialkylation of 1H -imidazole (7) gave the C2 -symmetric 1,3-dicitronellyl-1H -imidazolium bromide (8) (Scheme,3). Differential scanning calorimetry and optical polarizing microscopy revealed smectic mesophases for 1-citronellyl-3-tetradecy-1H -limidazolium bromide (3e) and 1-citronellylpyridinium bromide (6) (Table). In binary mixtures with smectic and nematic liquid crystals 9 and 10, 1-citronellyl-3-methyl-1H -imidazolium bromide (3a) behaved differently. Increasing quantities of 3a cause a decrease of the smectic-phase width for the mixture 3a/9 (Fig.,3), whereas the phase width of the nematic phase for 3a/10 remained nearly constant (Fig.,4). [source] ChemInform Abstract: Preparation and Structure of Optically Active Imidazolium Tetrafluoroborates; in Search of New Chiral Ionic Liquids.CHEMINFORM, Issue 44 2009G. Mloston 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] Synthesis of Novel Chiral Ionic Liquids and Their Phase Behavior in Mixtures with Smectic and Nematic Liquid Crystals.CHEMINFORM, Issue 14 2005Martin Tosoni No abstract is available for this article. [source] Functionalized Chiral Ionic Liquids: A New Type of Asymmetric Organocatalysts and Nonclassical Chiral LigandsCHEMISTRY - AN ASIAN JOURNAL, Issue 8 2009Sanzhong Luo Prof. Abstract By judiciously anchoring functional groups onto chiral ionic liquids, functionalized chiral ionic liquids (FCILs) are emerging as a new type of asymmetric organocatalysts and nonclassical chiral ligands. This Focus Review highlights the applications of FCILs from the viewpoint of asymmetric catalysis. We focus mainly on the de,novo designed and synthesized FCILs which likely still maintain the typical ionic liquids properties, and in a few cases relevant ionic liquid immobilized chiral catalysts are briefly discussed. [source] Combined use of chiral ionic liquid and cyclodextrin for MEKC: Part I. Simultaneous enantioseparation of anionic profensELECTROPHORESIS, Issue 16 2009Bin Wang Abstract The enantiomers of five profen drugs were simultaneously separated by MEKC with the combined use of 2,3,6-tri- O -methyl-,-cyclodextrin and chiral cationic ionic liquid, N -undecenoxy-carbonyl- L -leucinol bromide, which formed micelles in aqueous buffers. Enantioseparations of these profen drugs were optimized by varying the chain length and concentration of the IL surfactant using a standard recipe containing 35,mM 2,3,6-tri- O -methyl-,-cyclodextrin, 5,mM sodium acetate at pH 5.0. The batch-to-batch reproducibility of N -undecenoxy-carbonyl- L -leucinol bromide was tested and found to have no significant impact in terms of enantiomeric resolution, efficiency, and migration time. Finally, this method was successfully applied for the quantitative determination of ibuprofen in pharmaceutical tablets. [source] Combined use of chiral ionic liquid and CD for MEKC: Part II.ELECTROPHORESIS, Issue 16 2009Determination of binding constants Abstract A competitive inhibition mechanism is proposed to investigate the interactions among 2,3,6-tri- O -methyl-,-CD (TM-,-CD), cationic ionic liquid type surfactants, N -undecenoxy-carbonyl- L -leucinol bromide (L -UCLB) and profens using affinity CE. The apparent binding constant of TM-,-CD to L -UCLB was estimated by nonlinear and linear plotting methods. The binding constants of one representative profen (e.g. fenoprofen) to TM-,-CD and L -UCLB were estimated by a secondary plotting approach. The R - and S -fenoprofens have different binding constant values, resulting in the enantioseparation due to the synergistic effect of the two chiral selectors, TM-,-CD and L -UCLB. [source] Polymer-Immobilized Pyrrolidine-Based Chiral Ionic Liquids as Recyclable Organocatalysts for Asymmetric Michael Additions to Nitrostyrenes under Solvent-Free Reaction ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2008Pinhua Li Abstract A polymer immobilized pyrrolidine-based chiral ionic liquid 5a was synthesized and was found to be a highly efficient catalyst for the Michael additions of ketones and aldehydes to nitrostyrenes, which afforded the corresponding adducts in good yields (up to 97,%), excellent enantioselectivities (up to >99,% ee) and high diastereoselectivities (up to >99:1 dr) under solvent-free reaction conditions. In addition, the catalyst 5a could be reused at least eight times without a significant loss of its catalytic activity and stereoselectivity.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Radical polymerization in a chiral ionic liquid: Atom transfer radical polymerization of acrylatesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2005Tadeusz Biedro Abstract No Abstracts. [source] Functionalized Chiral Ionic Liquids: A New Type of Asymmetric Organocatalysts and Nonclassical Chiral LigandsCHEMISTRY - AN ASIAN JOURNAL, Issue 8 2009Sanzhong Luo Prof. Abstract By judiciously anchoring functional groups onto chiral ionic liquids, functionalized chiral ionic liquids (FCILs) are emerging as a new type of asymmetric organocatalysts and nonclassical chiral ligands. This Focus Review highlights the applications of FCILs from the viewpoint of asymmetric catalysis. We focus mainly on the de,novo designed and synthesized FCILs which likely still maintain the typical ionic liquids properties, and in a few cases relevant ionic liquid immobilized chiral catalysts are briefly discussed. [source] Synthesis and characterization of novel chiral ionic liquids and investigation of their enantiomeric recognition propertiesCHIRALITY, Issue 2 2008David K. Bwambok Abstract We report the synthesis and characterization of amino acid ester based chiral ionic liquids, derived from L - and D -alanine tert butyl ester chloride. The synthesis was accomplished via an anion metathesis reaction between commercially available L - and D -alanine tert butyl ester chloride using a variety of counterions such as lithium bis (trifluoromethane) sulfonimide, silver nitrate, silver lactate, and silver tetrafluoroborate. Both enantiomeric forms were obtained as confirmed by bands of opposite sign in the circular dichroism spectra. The L - and D -alanine tert butyl ester bis (trifluoromethane) sulfonimide were obtained as liquids at room temperature and intriguingly exhibited the highest thermal stability (up to 263°C). In addition, the ionic liquids demonstrated enantiomeric recognition ability as evidenced by splitting of racemic Mosher's sodium salt signal using a liquid state 19F nuclear magnetic resonance (NMR) and fluorescence spectroscopy. The L - and D -alanine tert butyl ester chloride resulted in solid salts with nitrate, lactate, and tetrafluoroborate anions. This illustrates the previously observed tunability of ionic liquid synthesis, resulting in ionic liquids of varying properties as a function of varying the anion. Chirality, 2008. © 2007 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||