نتایج جستجو برای: chiral center

تعداد نتایج: 319485  

Journal: :iranian journal of science and technology (sciences) 2007
a. jarrahpour

synthesis of some new monocyclic β-lactams containing a quaternary carbon center via a [2+2]cycloaddition reaction is described. the reaction of achiral diphenyl ketene with chiral aldimines derivedfrom chiral 2, 3, 4, 6-tetra-o-acetyl-β-d-galactopyranosylamine, 2, 3, 4, 6-tetra-o-acetyl-β-dglucopyranosylamine and different benzaldehydes resulted in the formation of β-lactams as singlediastereo...

In the first part of this work, correlation between optical activity and elements of magnetic susceptibility tensor (MST) for five classes of model small molecules containing a single chiral center has been studied using quantum computational techniques at DFT-B3LYP level of theory with 6-311G basis set. Several molecular properties are used to reduce the MST elements prior to the examination o...

Journal: :physical chemistry research 2014
hassan sabzyan fariba taghavi

in the first part of this work, correlation between optical activity and elements of magnetic susceptibility tensor (mst) for five classes of model small molecules containing a single chiral center has been studied using quantum computational techniques at dft-b3lyp level of theory with 6-311g basis set. several molecular properties are used to reduce the mst elements prior to the examination o...

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...

Journal: :research in pharmaceutical sciences 0
f hassanzadeh m rahmani khajouei g h hakimelahi e jafari g a khodarahmi

quinazolinones are interesting materials because of their valuable biological effects. in this study some new 2,3-disubstituted-4(3h)quinqzolinone derivatives were synthesized from anthranilic acid in six steps by introducing a new chiral center to the aliphatic side chain of the quinazolinone. in the last step, a single acylation on the hydrazine moiety afforded final compounds. the structures...

Journal: :Journal of Synthetic Organic Chemistry, Japan 2010

Journal: :international journal of bio-inorganic hybrid nanomaterials 0

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...

Journal: :Nuclear Physics B - Proceedings Supplements 2013

Journal: :journal of the iranian chemical research 0
jahanbaksh ghasemi department of chemistry, faculty of sciences, k.n. toosi university of technology, tehran, iran mahmood chamsaz department of chemistry, faculty of sciences, ferdowsi university of mashhad, iran saeid asadpour department of chemistry, faculty of sciences, ferdowsi university of mashhad, iran ali sarafraz yazdi department of chemistry, faculty of sciences, ferdowsi university of mashhad, iran

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...

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