نتایج جستجو برای: chiral forms

تعداد نتایج: 305620  

2003
Mukesh C. Gohel

Introduction Chiral molecules exist in a pair of stereoisomers (enantiomers). If a plane of polarized light is passed through a sample of each enantiomer, one will rotate the light to the left (levorotatory or (-)-enantiomer or R-form),and the other will rotate the light to the right (dextrorotatory or (+)-enantiomer or Sform). Rotation of light will not be observed if the light is passed throu...

Journal: :Journal of High Energy Physics 2022

A bstract In our previous article Phys. Rev. Lett. 127 (2021) 271601, we announced a novel ‘democratic’ Lagrangian formulation of general nonlinear electrodynamics in four dimensions that features electric and magnetic potentials on equal footing. Here, give an expanded more detailed account this new formalism, then proceed to push it significantly further by building the corresponding theories...

2002
Kazuo Fujikawa Masato Ishibashi Hiroshi Suzuki

If one uses a general class of Ginsparg-Wilson operators, it is known that CP symmetry is spoiled in chiral gauge theory for a finite lattice spacing and the Majorana fermion is not defined in the presence of chiral symmetric Yukawa couplings. We summarize these properties in the form of a theorem for the general GinspargWilson relation. The Ginsparg-Wilson relation[1] provides a convenient fra...

A new chromatographic procedure was proposed for the separation of propranolol (PRN) enantiomers based upon enantioselective chiral ligand-exchange chromatography. The separation was carried out on a short C8 column leading to considerably short separation time. L-alanine and Cu2+ were applied as chiral selector and central bivalent complexing ion, respectively. It was found that the kind of co...

Chiral pyrrolidines and pyrrolizidines with spirooxindole ring systems are the central skeletons for numerous alkaloids and pharmacologically important compounds. Gelesmine, pseudotabersonine, formosanine, isoformosanine, morroniside and mitraphylline are some of the alkaloids containing spirooxindole ring systems. Derivatives of spirooxindole find very wide biological applications as anti micr...

Khosrow Jadidi Mohammad Javad Taghizadeh,

An efficient one-pot three-component procedure for the synthesis of new chiral spiro oxindolopyrrolidines/pyrrolizidines with highly regio- and diastereo-enantio, selective from 1,3-dipolar cycloaddition of azomethine ylides and chiral menthol-drived trans-cinnamic are described. The mechanism of the reaction is discussed on basis of the assignment of the absolute configuration of one of the cy...

Journal: :iranian chemical communication 2014
mohammad javad taghizadeh khosrow jadidi

an efficient one-pot three-component procedure for the synthesis of new chiral spiro oxindolopyrrolidines/pyrrolizidines with highly regio- and diastereo-enantio, selective from 1,3-dipolar cycloaddition of azomethine ylides and chiral menthol-drived trans-cinnamic are described. the mechanism of the reaction is discussed on basis of the assignment of the absolute configuration of one of the cy...

Journal: :Journal of the American Chemical Society 2004
Gonglu Tian Yujie Lu Bruce M Novak

The helix-sense selective polymerization of achiral monomers by homochiral catalysts was investigated. Polymerization of chiral carbodiimides (N-(R)-2,6-(dimethylheptyl)-N'-phenylcarbodiimide) by achiral catalysts yields polymers that undergo mutorotation at elevated temperatures, thus illustrating that these chains are formed under kinetic rather than thermodynamic control. Building on this ob...

2008
Klaus Fabricius Barry M. McCoy

We derive sets of functional equations for the eight vertex model by exploiting an analogy with the functional equations of the chiral Potts model. From these equations we show that the fusion matrices have special reductions at certain roots of unity. We explicitly exhibit these reductions for the 3,4 and 5 order fusion matrices and compare our formulation with the algebra of Sklyanin.

2006
Olivier Piva

The photodeconjugation of conjugated esters and lactones in the presence of small amounts of chiral catalysts is enantioselective. The enantiomeric excess is very sensitive to the conditions of the reaction. When chiral amino alcohols are used as chiral catalysts a synergism is observed between the effect of the amino and hydroxyl groups on the optical purity of the deconjugated molecules. The ...

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