نتایج جستجو برای: diastereoisomers

تعداد نتایج: 351  

Journal: :Pharmacological reports : PR 2010
Tadeusz Librowski Andrzej Moniczewski

Oxidants play a significant role in causing oxidative stress, which underlies the pathogenesis of inflammation and rheumatoid arthritis. The processes associated with inflammatory responses are complex and often involve reactive oxygen species. There are many mediators that initiate and amplify the inflammatory response such as histamine, serotonin and metabolic products of arachidonic acid (th...

Journal: :Environmental Health Perspectives 1999
E A Pigman J R Lott Q Fernando J Blanchard

The purpose of this study was to examine the mechanisms of lead (Pb) uptake by human intestinal cells and to compare the intestinal transport and relative lead-chelating ability of two diastereoisomeric forms (i.e., meso and racemic) of 2, 3-dimercaptosuccinic acid (DMSA). The model used was the human adenocarcinoma (Caco-2) cell monolayer. The Caco-2 cells were cultured in flasks for examinati...

2015
Hartmut Jahns Martina Roos Jochen Imig Fabienne Baumann Yuluan Wang Ryan Gilmour Jonathan Hall

An established means of improving the pharmacokinetics properties of oligoribonucleotides (ORNs) is to exchange their phosphodiester linkages for phosphorothioates (PSs). However, this strategy has not been pursued for small interfering RNAs (siRNAs), possibly because of sporadic reports that PS siRNAs show reduced inhibitory activity. The PS group is chiral at phosphorous (Rp/Sp centres), and ...

2005
DEANNA M. D’ALESSANDRO PETER C. JUNK F. RICHARD KEENE

Thermochromism and anion-dependence studies on the intervalence charge transfer (IVCT) properties of the diastereoisomers of [{Ru(bpy)2}2(m-BL)] 51 {BL 5 dpb0, dpq0, and dpb: dpb0 5 dipyrido(2,3-a;30,20-c)benzophenazine; dpq0 5 dipyrido(2,3-a;30,20-c)phenazine; dpb 5 2,3bis(2-pyridyl)-1,4-benzoquinoxaline} are reported. IVCT thermochromism studies revealed that the level of delocalisation may d...

Journal: :Journal of the American Chemical Society 2004
Hua Jiang Christel Dolain Jean-Michel Léger Heinz Gornitzka Ivan Huc

The introduction of an R asymmetric center in an aromatic oligoamide that adopts stable helical conformations leads to a significant shift of the equilibrium between the right-handed and left-handed helices in solution: the R-P and R-M helices are diastereoisomers. However, these two species were found to cocrystallize in 1:1 proportions. Thus the chiral induction observed in solution is switch...

Journal: :Chemical communications 2015
Lewis S Aitken Lisa E Hammond Rajkumar Sundaram Kenneth Shankland Geoffrey D Brown Alexander J A Cobb

An organocatalytic asymmetric synthesis of a novel, highly functionalised cyclopropane system furnished with versatile substituents and containing a quaternary centre is described. The process utilises a new bifunctional catalyst based on the cinchona alkaloid framework and the products made using this catalyst were obtained as single diastereoisomers, with very high enantioselectivities (up to...

2005
Jonathan W. Slater Deanna M. D’Alessandro F. Richard Keene Peter J. Steel

The dinuclear bis(2,2’-bipyridine)ruthenium complex of 4,5-di(2-pyridyl)imidazolate has been prepared and separated into its (meso and rac) diastereoisomers. The 2-phenyl substituted analogue forms the meso isomer selectively. All three complexes have been characterised by H NMR and X-ray crystallography. Electrochemical measurements and spectroelectrochemistry of the mixedvalence states reveal...

2014
Xiang-Xi Yi Yong Chen Wen-Pei Xie Ming-Ben Xu Yin-Ning Chen Cheng-Hai Gao Ri-Ming Huang

Four new jacaranone analogs, marinoids F-I (1-4), were isolated from the fruits of a Beibu Gulf mangrove Avicennia marina. The structures were elucidated based on analysis of spectroscopic data. Marinoids F and G are shown to be diastereoisomers of chlorocornoside, a new halogen containing marine secondary metabolite. The antioxidant activity of the isolates was evaluated using a cellular antio...

Journal: :Organic & biomolecular chemistry 2012
Rakesh Jaiswal Michael H Dickman Nikolai Kuhnert

We report on a diastereoselective synthesis of six derivatives of caffeoyl- and feruloyl-muco-quinic acids. All the muco-quinic acid derivatives were obtained in excellent yield in five steps starting from quinic acid, caffeic acid and ferulic acid. Allyl ether protection of trans-hydroxy cinnamic acids was here introduced to chlorogenic acids synthesis. We show that muco-quinic acid derivative...

Journal: :The Journal of organic chemistry 2006
Daniel K Whelligan Carsten Bolm

Syntheses of three regioisomers of aromatic-substituted phosphinyl-oxazolinyl-[2.2]paracyclophanes, pseudo-geminal, pseudo-ortho, and ortho, have been carried out or, in the latter two cases, newly developed. It has, therefore, been demonstrated that all aromatic-substituted isomers relevant for use as chelating ligands for asymmetric catalysis are accessible. These P,N-ligands, along with thei...

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