an efficient one-pot three-component procedure for the synthesis of new chiral spiro-oxindolopyrrolizidines with highly regio-, diastereo-, and enantioselective from 1,3-dipolar cycloaddition of azomethine ylides and optically pure active cinamoyl oxazolidinone are described. the process occurs at room temperature in aqueous ethanol as green solvent and in the absence of any bidentate chelating...

in recent years there has been considerable interest in the synthesis and separation of enantiomers of organic compounds especially because of their importance in the biochemistry and pharmaceutical industry. high-performance liquid chromatography is a very useful method for the direct separation of enantiomers. however, about 30−40 years ago, commercially available chiral stationary phases wer...

In recent years there has been considerable interest in the synthesis and separation of enantiomers of organic compounds especially because of their importance in the biochemistry and pharmaceutical industry. High-performance liquid Chromatography is a very useful method for the direct separation of enantiomers. However, about 30−40 years ago, commercially available chiral stationary phases wer...

one of the problems encountered in ce separations of basic compounds is the adsorption of analytes onto the negatively charged capillary wall which could lead to poor repeatability of migration time and peak area. additionally, separation of enantiomers of chiral of basic drugs is commonly carried out in low ph buffer which contributes to strong ionic interaction of the cationic drug ions with ...

We report the most sensitive direct search for pair production of fourth-generation bottomlike chiral quarks (b') each decaying promptly to tW. We search for an excess of events with an electron or muon, at least five jets (one identified as due to a b or c quark), and an imbalance of transverse momentum by using data from pp collisions collected by the CDF II detector at Fermilab with an integ...

It has been known for some time that the Boltzmann weights of the chiral Potts model can be parametrized in terms of hyperelliptic functions, but as yet no such parametrization has been applied to the partition and correlation functions. Here we show that for N = 3 the function S(t p) that occurs in the recent calculation of the order parameters can be expressed quite simply in terms of such a ...

A hexafullereno-diporphyrinoid was obtained in a sequence of cycloaddition steps using porphyrins programmed for [4+2]-cycloaddition reactions and C(60)-fullerene.

carbon nanotubes (cnts) are specific structures with valuable characteristics. in general, the structure of each nanotube is defined by a unique chiral vector. in this paper, different structures of short single-walled cnts are simulated and their mechanical properties are determined using finite element method. for this aim, a simple algorithm is presented which is able to model the geometry o...

One of the problems encountered in CE separations of basic compounds is the adsorption of analytes onto the negatively charged capillary wall which could lead to poor repeatability of migration time and peak area. Additionally, separation of enantiomers of chiral of basic drugs is commonly carried out in low pH buffer which contributes to strong ionic interaction of the cationic drug ions with ...

An important property of electromagnetic fields, which arises from the interaction between fields and chiral molecules, is called optical chirality. By enhancing this field property, while maintaining constant input power, we are able to increase absorption of circularly polarized light by chiral molecules of a certain handedness. This enhancement is achieved through the use of achiral plasmoni...