Showing papers in "Chirality in 2005"

TL;DR: The synthesis of chiral ionic liquids and their use is reviewed, showing this is an area of research that is poised for rapid development and expansion.

TL;DR: This review article focuses on some of the recent developments in the rapidly growing field of lipase-catalyzed kinetic resolution of racemates as a versatile method for the separation of enantiomers.

TL;DR: In contrast to conventional natural optical activity phenomena, which depend linearly on the electric field strength of the optical field, the authors discuss how optical processes that are nonlinear (quadratic, cubic, and quartic) functions of the electromagnetic field strength may probe optically active centers and chiral vibrations.

TL;DR: The reliability of the TDDFT/GIAO methodology in determining ACs of molecules with small specific rotations of 65 conformationally rigid chiral molecules whose experimental [alpha]D values are small (<100 is examined.

TL;DR: It is suggested that significant enantioselectivity occurs for pyrethroids in aquatic toxicity, and such enantiomeric differences must be considered when evaluating ecological effects of pyrethroid insecticides.

TL;DR: Application of on-line polarimetry in combination with measurements of an on- line density meter proved the general applicability of this method in order to monitor directly the resolution progress, to recognize the region of "safe" resolution, and to gain information about the crystallization kinetics.

TL;DR: It was concluded that [BMIM]PF6 could be applied to substitute the conventional organic solvent (isooctane) in the esterification of ibuprofen.

TL;DR: The combined use of catalytic amounts of a commercially available chiral [SalenAlCl] complex and pyridine allowed the Friedel-Crafts alkylation reaction of indoles with aromatic nitro-olefins to be carried out in good yields and enantioselectivity.

TL;DR: The theory and practice of enantioselective capillary chromatography employing metal coordination compounds and modified cyclodextrins as chiral stationary phases are treated and a unified approach involving all contemporary chromatographic methods and a single enantiOSElective column is described.

TL;DR: 3-butylphthalide (S)-(-)-2, a fragrance component of essential oil of celery, has been synthesized in an enantiopure form, and its absolute configuration was unambiguously determined.

TL;DR: Sertraline represented Pfizer's first product with stereocenters not derived from natural sources, as was the case with azithromycin and beta-lactam products, and the successful outcome employed continuous chromatography.

TL;DR: A rationale which correlates the preferred handedness of the PNA-PNA Duplexes to the directionality of the binding to complementary DNA duplexes has been devised according to structural data and considering the "retro-inverso" concept widely used for peptides.

TL;DR: The results stress the importance to investigate enantiomer elution order during the development of enantioselective methods and when chromatographic conditions are optimized.

TL;DR: The chiral recognition in host-guest interactions might contribute to this enantiomer separation of amino compounds in view of the correlation between the enantiomers selectivity observed in chromatography and the complexion in solution.

TL;DR: The bioequivalencies of D,L-theanine and its enantiomers were found to be quite different from one another, Consequently, the efficacy of commercial theanine products containing D-the-anine, L-theAnine, or D, l-thea-Theanine may bequite different.

TL;DR: An historical retrospective is presented relative to the development of practical processes for the syntheses of three major drugs: methyldopa, imipenem, and efavirenz.

TL;DR: A review on the use of bile acids as hosts for molecular recognition and enantioresolution is presented and the salient aspects of the enclathration process, including X-ray diffraction results, are discussed.

TL;DR: beta-Cyclodextrin-immobilized (4S)-phenoxy-(S)-proline was prepared conveniently and proved to be an efficient catalyst for direct asymmetric aldol reactions, and the catalyst could be recycled four times without loss of enantioselectivity.

TL;DR: The SR model is used to provide an insight into the chiral recognition process from a substrate's perspective that is intuitive and simple, furnishing a rigorous stereochemical basis for explaining stereoselectivity characteristics of many biological systems.

TL;DR: The chiral recognition mechanism of a cinchona alkaloid-based chiral stationary phase (CSP) showing high enantiomer discrimination potential for 2-methoxy-2-(1-naphthyl)propionic acid (MalphaNP acid) was investigated and conformational states of the free and complexed form of the selector were found.

TL;DR: The enantiodiscriminating potential of the weak anion exchange-type quinine-based chiral stationary phases (CSPs) for direct enantiomer separation of racemic 2-methoxy-2-(1-naphthyl)propionic acid (selectand, SA) was studied and a tentative molecular recognition model was proposed.

TL;DR: The rapid disappearance of the (S)-enantiomer from the plasma was thought to be due to the rapid metabolism of the (+/-)-4-cyanoanilino)-5,6-dihydro-7-hydroxy-7H-cyclopenta[d]pyrimidine by different drug-metabolizing enzymes, depending on species.

TL;DR: Enantiomeric discrimination of chiral secondary alcohols was performed by both reversed-phase HPLC and 1H-NMR after labeling with a chiral fluorescent derivatization reagent, 2-(2,3-anthracenedicarboximide)cyclohexanecarboxylic acid.

TL;DR: Results indicate substantial stereoselectivity in the kinetics of hexaconazole enantiomers in rabbits and suggest that this fungicide is a potent triazole fungicide with high stereo- and/or enantioselective properties.

TL;DR: A user-friendly, one-pot procedure was developed to access racemic as well as enantiomerically enriched cyclopropanes and an enantiomers separation was achieved using gas chromatography on the chiral stationary phase Chirasil-beta-dex.

TL;DR: The presence of low-intensity long-wavelength electronic transitions having large rotational strengths in the electronic spectra of 3e and 3f can be accounted for by the symmetry properties of the trichromophoric macrocycles.

TL;DR: The use of BF(4) as counter ion in HKR reactions was also investigated and it was found that the catalyst could be recycled several times without loss in performance.

TL;DR: Separation and detection of chiral pharmaceuticals using HPLC with circular dichroism detection using CD, UV, and optical rotation (OR) detection.

TL;DR: This study establishes a sound method for future preparation and absolute structure determination of compounds belonging to the same class of compounds, i.e., hydroxy, methoxy, methylthionyl, and methylsulfonyl PCBs in different biota.

TL;DR: The straightforward synthesis of a series of enantiomerically pure pyridine- and quinoline-N-oxides and their use as new organocatalysts for the enantioselective allylation of aromatic aldehydes with allyl(trichloro)silane is reported.