نتایج جستجو برای: chiral pyrrolidines
تعداد نتایج: 37647 فیلتر نتایج به سال:
1,3-dipolar cycloaddition reaction of 1 mol or 2 mol of dibenzalaceton with 1 mol of non-stabilized azomethinylides generated in situ by decarboxylative condensation of isatin and proline or sarcosine give the novel new spiro-oxindolo(pyrrolizidines/ pyrrolidines) instead of bis-spirooxindolo( pyrrolizidines/ pyrrolidines).
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...
Recent syntheses of azetidines, pyrrolidines, piperidines and azepines through cycloaddition or sigmatropic rearrangements of vinylaziridines are described. Applications to natural product synthesis and mechanistic investigations are also summarized.
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 efficient aziridine ring expansion cascade of cinnamylaziridine has been developed. N-Bromosuccinimide was used as the promoter. The resulting functionalized pyrrolidines are the fundamental units of many useful molecules.
Substituted tetrahydrofuran and pyrrolidine moieties are displayed in a wide range of interesting biologically active molecules. The Pd-catalyzed carboetherification or carboamination of γ-hydroxy- and γ-aminoalkenes is a powerful tool for the construction of these heterocycles, as it is convergent and can allow access to a variety of analogs from a single γ-hydroxy- or γ-aminoalkene starting m...
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 ...
The development of multicomponent reactions (MCRs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. A comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...
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