نتایج جستجو برای: enantiomeric excess

تعداد نتایج: 75059  

2016
Bruno Gallinella Rosella Ferretti Leo Zanitti Isabella Sestili Antonina Mosca Roberto Cirilli

A simple analytical high-performance liquid chromatography (HPLC) method was applied for the enantiomeric excess determination of esomeprazole ((S)-OME), the enantiopure active ingredient contained in drug products, in the presence of its potential organic impurities A-E. The enantioselective separation was accomplished on the immobilized-type Chiralpak ID-3 chiral stationary phase (CSP) under ...

Journal: :Biomedical chromatography : BMC 2012
F G Sánchez A Navas Díaz E Sánchez Torreño A Aguilar I Medina Lama M Algarra

A facile approach for the enantiomeric excess determination of enantiomeric mixtures without the necessity of pure enantiomer standards is presented. Promethazine and trimeprazine commercial nonracemic mixtures were used as cases study to probe the validity of the method. Chromatographic resolutions obtained with a chiral column AGP in reverse phase mode were 1.32-1.16 (promethazine) and 1.20-0...

Journal: :Physical chemistry chemical physics : PCCP 2015
Barry K Carpenter Jeremy N Harvey David R Glowacki

Classical molecular dynamics simulations are reported for the deazetisation and ring opening of meso-2,3-difluoro-2,3-dimethyldiazocyclopropane in three solvents: CHCl3, CHFClBr and CH3CH(OH)CF3 (TFIPA). The achiral reactant leads to enantiomeric allene products, and the question addressed in the study is whether either of the chiral, enantiomerically pure solvents can induce significant enanti...

Journal: :Journal of labelled compounds & radiopharmaceuticals 2015
Fengbin Song Rhys Salter Larry E Weaner

Herein, we report a short, three-step synthesis of d-[1-(14) C]-serine (4) in high enantiomeric purity. Starting from [(14) C]-KCN and 2-(benzyloxy)acetaldehyde, Strecker reaction using (R)-1-phenylethylamine as the chiral auxiliary gave two diastereomeric aminonitriles 1 and 2 in the ratio of 4:3, which were conveniently separated and purified chromatographically. Following hydrolysis and subs...

Journal: :Organic letters 2006
Hanmin Huang Xiongcai Liu Jun Deng Min Qiu Zhuo Zheng

[Structure: see text] The enantioselective hydrogenation of beta-phthalimide acrylates provides the corresponding chiral beta2-amino acids in excellent enantiomeric excess catalyzed by Rh-monophosphorus.

Journal: :Chemical communications 2005
Robert Weihofen Axel Dahnz Olena Tverskoy Günter Helmchen

Iridium-catalysed allylic substitutions with anionic N-nucleophiles were achieved with regioselectivity of up to 49:1 and enantiomeric excess of up to 98%.

Journal: :Chemical communications 2011
Han-Seop Bea Hye-Jeong Park Sang-Hyeup Lee Hyungdon Yun

Racemic aromatic β-amino acids have been kinetically resolved into (R)-β-amino acids with high enantiomeric excess (>99%) by a novel ω-TA with ca. 50% conversion.

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 2008
Ahmad Saufi Cosima B I von Heimendahl A Wilhelm Alfermann Elisabeth Fuss

Phaleria macrocarpa (Scheff.) Boerl., a member of the Thymelaeaceae, is traditionally used in Indonesia as medicinal plant against cancer. In this context, we isolated the lignans pinoresinol, lariciresinol and matairesinol from different parts of this plant. The enantiomeric composition of these lignans was determined by chiral column analysis. Pinoresinol and lariciresinol were mixtures of bo...

2005
J. Bugla W. Szeja

We report herein the separation of enantiomers of glycerol derivatives on a cellulose-modified chiral column (Chiracel OD) in normal-phase mode. This method is suitable for monitoring the progress of the reaction and for determination of the enantiomeric purity of products. The lipase Novozyme 435-catalysed enantioselective hydrolysis of 1-O-benzyl-2,3di-O-octanoyl-rac-glycerol has been shown t...

2016
G. E. TRANTER

This paper reviews evidence for the view that biomolecular chirality was determined not by chance but by the electroweak interaction. Other influences (such as the Earth's magnetic and gravitational fields, or circularly polarized light) are either falsely chiral or else even-handed on a time and space average, leaving the weak interaction as the only consistent universal chiral influence. Elec...

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