Showing papers in "Chirality in 2012"

TL;DR: CD spectra of nucleic acids are reviewed, beginning with early studies on natural DNA molecules through analyses of synthetic polynucleotides to study of selected genomic fragments.

TL;DR: A comprehensive database containing structures and physical properties of notable CILs that have been synthesized during the last 6 years is compiled, which is an expansion of the previous review, which covered the literature before 2005.

TL;DR: This review emphasizes on selected examples that illustrate the potential limitations in utilizing the chiroptical spectroscopic methods, including hibiscus acid dimethylester, hibISCus acid disodium salt, tartaric acid esters, and 6,6'-dibromo-[1,1'-binaphthalene]-2,2'-diol.

TL;DR: The publication of Piutti's asparagine work prompted several eminent scientists, including Louis Pasteur and Arthur Cushny, a leading pharmacologist of the time, to remark on the importance of the discovery.

TL;DR: The absolute configuration of chaetoglobosin V(b) (1) was established by means of electronic circular dichroism (CD) spectroscopy, on the basis of the comparison between the CD spectrum of (+)-1 with that calculated with time-dependent density functional theory method for a simplified model.

TL;DR: A reliable and easy-to-perform high-performance liquid chromatography ultraviolet method for the chiral separation of a set of 24 cathinone derivatives and a correlation between the substituents of the nitrogen atom and the separation results are shown.

TL;DR: The acute toxicity and toxic effects of hexaconazole against S. obliquus were enantioselective, and such enantiomeric differences must be taken into consideration in pesticide risk assessment.

TL;DR: It has been shown that the degradation of tebuconazole was enantioselective and showed a faster degradation in cabbage, while the (-)-R-tebu Conazole dissipated faster than (+)-S-form in cucumber fruit and the test soils.

TL;DR: A glimpse is given on the origin of asymmetry from a cosmological perspective and on physical transformations that lead to an enantiomeric imbalance, leaving chemical reactions essentially aside, more plausible as sources of prebiotic chirality.

TL;DR: Fundamental aspects of determining circular dichroism (CD) in fs-laser ionization mass spectrometry (fs-LIMS) are reviewed discussing an example from the literature and new data indicating CD in non-resonant fs-L IMS of propylene oxide is presented.

TL;DR: The fluorescence and CPL spectra are observed in a wavelength range where some UV and CD activity still appears, and the observed CPL features are strongly influenced by CD.

TL;DR: Novel chitosan-supported cinchona alkaloids have been developed as heterogeneous catalysts for enantioselective Michael reaction, providing highly functionalized products with good stereoselectivity in high yields and recyclability.

TL;DR: The synthesis of planar chiral strong Brønsted acid organocatalysts derived from [2.2]paracyclophane is described and two new classes of catalysts were tested in an enantioselective Friedel-Crafts reaction and in a direct asymmetric Mannich reaction.

TL;DR: This lecture discusses how the discrete symmetries of parity P, time reversal T, and charge conjugation C may be used to characterize the properties of chiral systems and considers the nature of physical influences able to induce absolute enantioselection.

TL;DR: The amyloid fibril of bovine insulin and its renaturing intermediates were studied by using Raman optical activity (ROA), showing that the hydrated α-helix of the native insulin was converted to the parallel β-sheet structure with many turns.

TL;DR: Novel copper(II) coordination compounds with chiral macrocyclic imine ligands derived from R-/S-camphor were asymmetrically synthesized and characterized with the aid of chiroptical spectroscopies, finding the absolute configuration of the copper( II) coordination compound determined from CD was found consistent with the crystal data.

TL;DR: Assessment of the stereoselectivity of two tebuconazole enantiomers in in vitro system (rat liver microsomes) revealed that there was competitive inhibition between S- and R-form and there was a significant difference between the IC(50) of R- to S-tebuconsazole and S- to R-te BuConazole.

TL;DR: The validation of the developed method by fortification rac-indoxcarb in cabbage and soil showed good accuracy and precision and proved that enantioselective degradation of indoxacarb happened inabbage and soil.

TL;DR: The use of vibrational circular dichroism spectroscopy for the chiral recognition of the two epimers of 6-cedrol, tricyclic sesquiterpenes, which contains oxygen as the heaviest atom, is shown.

TL;DR: A simple high performance liquid chromatography method HPLC-UV for simultaneous enantiomeric determination of propranolol, metoprolol, pindolol, and atenolol in natural water samples was developed and validated, using a molecularly imprinted polymer solid-phase extraction.

TL;DR: Marked differences between diastereoisomers were seen in their experimental ionization constants and lipophilicity parameters, which are explained by molecular flexibility, configuration-dependent differences in intramolecular interactions, and accessibility of functional groups.

TL;DR: A new azaphilone derivative, named fusarone (1), has been isolated from the ethyl acetate soluble extract of the fermentation broth of an endophytic fungus, Fusarium sp.

TL;DR: It is observed that within a certain concentration range, one enantiomers of the chiral α-aminocarboxylic acid anions can increase the fluorescence intensity of the crown ethers by fivefold to sixfold, whereas the other enantiomer scarcely enhances the Fluorescence.

TL;DR: The distinct induced circular dichroism effects of the diimines obtained can be used for enantioselective sensing and enantiomeric excess determination of a wide range of substrates.

TL;DR: The chiral discrimination mechanism in the resolution of sertraline with mandelic acid was investigated by examining the weak intermolecular interactions and molecular packing difference in crystal structures of the resulting diastereomeric salts and a new one-dimensional chain-like hydrogen-bonding network and unique supramolecular packing mode are disclosed.

TL;DR: Limited enantioselectivity was found in the both soils, which was the R(+) enantiomer was preferentially degraded, suggesting warfarin degradation in the soils was mainly caused by micro-organisms.

TL;DR: From the results of liquid chromatography and computational chemistry, it is concluded that d-form is preferred and more retained with van der Waals interaction in case of interaction between N-TCPHT α-amino acid ester derivatives and Chiralcel OG and Chiracel OF.

TL;DR: In vitro antitumor activity of complexes R1 and S1 were screened against human carcinoma cell lines of different histological origin and R1 proved to show better DNA cleavage ability.

TL;DR: It was shown that quizalofop-acid degraded faster in the acidic Wuhan soil than in the alkaline Baoding soil, and the enantiomerization was fast, resulting in residues enriched with R-quizalofOP-acid whatever racemic quizal ofop-ethyl or pure enantiomers were initially applied in the soils.

TL;DR: Secoscabronine M (1) is a hemiacetal cyathane diterpenoid that was isolated from the fruiting bodies of the basidiomycete Sarcodon scabrosus Karst and possesses a novel structure with a bond cleavage between C-3 and C-4.