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Metal Catalysis (metal + catalysis)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Combination of Enantioselective Metal Catalysis and Organocatalysis: Enantioselective Sequential Hydroformylation/ Aldol Reactions

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010
Serghei Chercheja
Abstract This work reports the possibility of controlling the sense of enantio- and diastereoinductions in the sequential hydroformylation and aldol reactions via the judicious combination of a chiral metal catalyst with a chiral organocatalyst. The diastereoselectivity of the reaction between styrene, syngas and acetone can be increased by using a matched pair of catalysts, [rhodium/(2S,4S)-Chiraphite]/(S)-organocatalyst and decreased, but not inverted, by using a mismatched pair of catalysts, [rhodium/(2R,4R)-Chiraphite]/(S)-organocatalyst. [source]

ChemInform Abstract: Hydrogen-Bonding Asymmetric Metal Catalysis with ,-Amino Acids: A Simple and Tunable Approach to High Enantioinduction.

CHEMINFORM, Issue 2 2010
Yingdong Lu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: A Chiral Bis-Sulfoxide Ligand in Late-Transition Metal Catalysis; Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids to Electron-Deficient Olefins.

CHEMINFORM, Issue 26 2008
Ronaldo Mariz
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Antibody response to aggregated human interferon alpha2b in wild-type and transgenic immune tolerant mice depends on type and level of aggregation

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2006
Suzanne Hermeling
Abstract The aim of this study was to determine the sensitivity of transgenic immune tolerant mice for the type and level of aggregation of recombinant human interferon alpha2b (rhIFN,2b). RhIFN,2b was aggregated by metal-catalyzed oxidation or by incubation at elevated temperature and various pHs. Native rhIFN,2b was mixed with oxidized rhIFN,2b at different ratios to obtain samples with different aggregation levels. The preparations were characterized by UV and fluorescence spectroscopy, gel permeation chromatography (GPC), dynamic light scattering (DLS), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS,PAGE) and Western blotting, and ELISA. The immunogenicity was evaluated in wild-type mice and transgenic mice immune tolerant for hIFN,2. Sera were analyzed by ELISA for the presence of rhIFN,2b-specific antibodies. The oxidized and aged preparations widely differed regarding the level and nature of aggregates. All preparations containing aggregates increased the immune response in the wild-type mice as compared to native rhIFN,2b and were able to break the tolerance of the transgenic mice. The more native-like the conformation of the aggregated proteins, the more immunogenic the preparations were in the transgenic mice. The native-like aggregates prepared via metal catalysis induced a dose-dependent loss of tolerance in the transgenic mice. In conclusion, the transgenic mouse model can be used to screen rhIFN,2b formulations for low levels of immunogenic aggregates obtained under accelerated storage conditions. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:1084,1096, 2006 [source]

Probing interactions by means of pulsed field gradient nuclear magnetic resonance spectroscopy,

MAGNETIC RESONANCE IN CHEMISTRY, Issue S1 2008
Sara Cozzolino
Abstract Molecular self-diffusion coefficients (D) of species in solution are related to size and shape and can be used for studying association phenomena. Pulsed field gradient nuclear magnetic resonance (PFG-NMR) spectroscopy has been revealed to be a powerful analytical tool for D measurement in different research fields. The present work briefly illustrates the use of PFG-NMR for assessing the existence of interactions in very different chemical systems: organic and organometallic compounds, colloidal materials and biological aggregates. The application of PFG-NMR is remarkable for understanding the role of anions in homogenous transition metal catalysis and for assessing the aggregation behaviour of biopolymers in material science. Copyright © 2008 John Wiley & Sons, Ltd. [source]