نتایج جستجو برای: chiral center
تعداد نتایج: 319485 فیلتر نتایج به سال:
Strong coupling dynamics of Yang–Mills theories with chiral fermion content remained largely elusive despite much effort over the years. In this work, we propose a dynamical framework in which we can address non-perturbative properties of chiral, non-supersymmetric gauge theories, in particular, chiral quiver theories on S1×R3. Double-trace deformations are used to stabilize the center-symmetri...
PURPOSE Indapamide is probably the most frequently prescribed diuretic drug, generally being used for the treatment of hypertension. It contains a chiral center in its molecule; is marketed as a racemic mixture; but there are rather few studies regarding the pharmacokinetic and the pharmacological effect differences of the two enantiomers. Our aim was the development of a simple, rapid and prec...
The introduction of a chlorine atom to a carbon center in an enantioselective manner via conventional C-Cl bond formation is difficult. Here we report a new approach to this class of tertiary alkyl chlorides with high optical purities. Instead of forming a new C-Cl bond, our approach involves carbene-catalyzed desymmetrization of 2-chloro-1,3-diols as the key step to set up the chiral carbon ce...
Chiral supramolecular boron Lewis acid catalysts were developed with the use of chiral 3-phosphoryl-BINOLs, 2-cyanophenylboronic acids, and tris(pentafluorophenyl)borane based on CN···B and PO···B coordination bonds. In particular, coordinated tris(pentafluorophenyl)boranes can increase the Lewis acidity of the active center based on the Lewis acidassisted Lewis acid catalyst system. A possible...
Recently, it has been found that room-temperature ionic liquids can be used as stable, unusual selectivity stationary phases. They show "dual nature" properties, in that they separate nonpolar compounds as if they are nonpolar stationary phases and separate polar compounds as if they are polar stationary phases. Extending ionic liquids to the realm of chiral separations can be done in two ways:...
Here we show experimental evidence for the spontaneous chiral resolution of icosahedral [12Pro+H]+ cluster ion. Molecular simulations reveal that the icosahedron consists of 12 equally spaced prolines where the rigid pyrrolidine ring of each monomer is sticking out of the closed cage. The tightly packed chiral cage traps a single proton in the center cavity. On the other hand, racemic [12Pro+H]...
(-)-gephyrotoxin-223 was formally synthesized from chiral synthon 1 which has been chemoenzymatically synthesized in the presence of candida antartica lipase.
In this paper we examine theoretically the chiral discrimination of molecules with a single chiral center. We propose a definition of the chiral discrimination parameter A in terms of the difference between the second virial coefficient of pure enantiomers and their racemic mixture. This parameter enters in the equation of state of racemic mixtures and will determine their phase diagrams. We ca...
Strecker reaction is one of the simplest multicomponent reactions. It used for synthesis of chiral α-amino nitriles. This reaction was carried out in the presence of catalytic amount of layered double hydroxides (LDHs). In this study, simple and practical method for the synthesis of this class of catalysts is provided. The results shown that LDH is the good heterogen catalyst for synthesis of c...
The high performance liquid chromatography (HPLC) enantioseparation of four β-blocking agents metoprolol, bisoprolol, propranolol and atenolol was performed on amylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phase using n-hexane-ethanol-diethylamine (DEA) as the mobile phase and related chiral recognition mechanisms were discussed. Enantiomeric separation of the fourβ-blockers was ...
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