نتایج جستجو برای: chiral

تعداد نتایج: 37423  

2017
Ting Chen Shu-Ying Li Dong Wang Li-Jun Wan

Noncovalently introducing stereogenic information is a promising approach to embed chirality in achiral molecular systems. However, the interplay of the noncovalently introduced chirality with the intrinsic chirality of molecules or molecular aggregations has rarely been addressed. We report a competitive chiral expression of the noncovalent interaction-mediated chirality induction and the intr...

Journal: :Dalton transactions 2014
Yizhan Wang Lei Shi Yang Yang Bao Li Lixin Wu

To explore the principle of chiral induction in inorganic clusters, chiral organic cations with two stereocenters, R- and S-BPEA, are used to encapsulate a series of polyoxometalates (POMs) bearing different structures and transition absorption bands in aqueous solution, constructing a series of chiral supramolecular complexes. Due to the induction of chiral organic cations, POMs possessing bot...

2012
Mireia Oromí-Farrús Mercè Torres Ramon Canela

The use of iodine as a catalyst and either acetic or trifluoroacetic acid as a derivatizing reagent for determining the enantiomeric composition of acyclic and cyclic aliphatic chiral alcohols was investigated. Optimal conditions were selected according to the molar ratio of alcohol to acid, the reaction time, and the reaction temperature. Afterwards, chiral stability of chiral carbons was stud...

2006
Svjetlana Fajfer

We consider chiral loop corrections to the effective couplings which describe the strong interactions of two heavy mesons of even or odd parities and a light pseudoscalar meson, within a framework which combines heavy quark effective theory and chiral perturbation theory. The strong couplings are extracted from the experimental results for the decay widths, after including chiral corrections. W...

Journal: :Molecules 2004
Sharon T Marino Danuta Stachurska-Buczek Daniel A Huggins Beata M Krywult Craig S Sheehan Thao Nguyen Neil Choi Jack G Parsons Peter G Griffiths Ian W James Andrew M Bray Jonathan M White Rustum S Boyce

In the past decade there has been a significant growth in the sales of pharmaceutical drugs worldwide, but more importantly there has been a dramatic growth in the sales of single enantiomer drugs. The pharmaceutical industry has a rising demand for chiral intermediates and research reagents because of the continuing imperative to improve drug efficacy. This in turn impacts on researchers invol...

2009
Tomás Andrade Donald Marolf

At the classical level, chiral gravity may be constructed as a consistent truncation of a larger theory called log gravity by requiring that left-moving charges vanish. In turn, log gravity is the limit of topologically massive gravity (TMG) at a special value of the coupling (the chiral point). We study the situation at the level of linearized quantum fields, focussing on a unitary quantizatio...

2006
Isabel Hubard Egon Schulte Asia Ivić Weiss

This paper presents a technique for constructing new chiral or regular polyhedra (or maps) from self-dual abstract chiral polytopes of rank 4. From improperly self-dual chiral polytopes we derive “Petrie-Coxeter-type” polyhedra (abstract chiral analogues of the classical Petrie-Coxeter polyhedra) and investigate their groups of automorphisms.

1994
Mannque Rho

The role of chiral symmetry in nuclear physics is summarized. The topics treated are the chiral bag model for nucleon structure resulting from large N c QCD, the pion cloud in chiral perturbation theory for low-energy electroweak nuclear response functions, " swelled hadrons " in nuclear matter, chiral symmetry restoration and pseudo-Goldstone meson condensation in nuclear medium.

Journal: :Chemical & pharmaceutical bulletin 2001
M Toriyama A N Tokutake K Koga

Based on the solution structures of chiral bidentate lithium amides ((R)-3a,b) having a phenyl group on the chiral carbon, chiral bidentate amines ((R)-5a,b-8a,b and (S)-9a,b) having a bulkier group instead of a phenyl group on the chiral carbon were designed and synthesized.

Journal: :Organic letters 2009
Mukund P Sibi Keisuke Kawashima Levi M Stanley

A rare example of the application of a catalytic, enantioselective Diels-Alder cycloaddition to affect a kinetic resolution has been developed. Chiral pyrazolidinones are resolved with high selectivity through a process that utilizes a relay of stereochemical information from a permanent chiral center to a fluxional chiral center to enhance the inherent selectivity of the chiral Lewis acid cata...

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