نتایج جستجو برای: chiral forms

تعداد نتایج: 305620  

Journal: :Soft matter 2016
Kinga Roszak Monika Piasecka Andrzej Katrusiak Karol Kacprzak

10,11-Didehydroquinine is a simple, low molecular weight supergelator which forms, in nonpolar media, stable chiral organogels composed of unique double-helix nano-sized fibers. A novel gelation mechanism involves a hydrogen bonding network formed by an acidic alkyne proton of the Cinchona gelator and the carbonyl group of ethyl acetate used as a solvent.

Journal: :Chemical communications 2010
Alexander A Bredikhin Zemfira A Bredikhina Flyura S Akhatova Aidar T Gubaidullin

p-Tolyl glycerol ether not belonging to any of the known gelator families forms stable transparent gels in hydrocarbon media showing very good quantitative characteristics of gelling abilities, which are, in turn, strongly dependent on the chiral characteristics of the gelator. The crystal packing differences between the rac- and scal-substances could be the reason for such behaviour.

1996
J. Grandy

We present a refined calculation of the η ′ mass using staggered fermions and Wuppertal smeared operators to suppress excited state contributions. We use quenched and dynamical configurations of size 16 3 × 32, with N f = 0, N f = 2 and N f = 4, and compare our results with the expected theoretical forms from quenched, partially quenched, and unquenched chiral perturbation theory.

Journal: :Chemical communications 2009
Chui-Shan Tsang Ho-Lun Yeung Wing-Tak Wong Hoi-Lun Kwong

Reaction of a pinene-based pyridylthioamide with 1,4-dibromo-2,3-butanedione in refluxing methanol yielded a new chiral pyridylthiazole ligand L which forms a dinuclear double-stranded helicate with Cu(i) ions; this helicate has opposite helical chirality when compared with its quaterpyridine analogue.

Journal: :Organic & biomolecular chemistry 2011
Reji Thomas Nobuyuki Tamaoki

The transfer and dynamic fixation of chirality in cyclic azobenzenes using R-(+)-1-phenylethylalcohol (R-PEA) and S-(-)-1-phenylethylalcohol (S-PEA) as solvents or additives are investigated. The cyclic azobenzenes used in this study carry a 1,5-dioxynaphthalene moiety as rotating unit, connected to the photoisomerizing (E-Z) azobenzene unit with spacers of varying lengths. With suitable length...

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: :iranian journal of chemistry and chemical engineering (ijcce) 2015
shaoxiang wu qi wang yao-feng wang pran gopal karmaker fu-xue chen

trifluoromethylated organic compounds, especially chiral quaternary alcohols bearing trifluoromethyl group are of important intermediates in drugs, agrochemicals and etc.an efficient epoxidation of β-cf3-β,β-disubstituted unsaturated ketones (6) has been developed with environmental benign hydrogen peroxide as the oxidant and f5-substituted chiral quaternary ammonium salt (1g or 5) derived from...

Ali Reza Badiei Ghodsi Mohammadi Ziarani R. Chenevert

(-)-Gephyrotoxin-223 was formally synthesized from chiral synthon 1 which has been chemoenzymatically synthesized  in the presence  of Candida Antartica lipase.        

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: :international journal of bio-inorganic hybrid nanomaterials 0

one-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. in this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...

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