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Alkaloid Derivatives (alkaloid + derivative)
Kinds of Alkaloid Derivatives Selected AbstractsSimple Preparation of Dimeric Cinchona Alkaloid Derivatives on Polystyrene Supports and a Highly Enantioselective Catalytic Heterogeneous Dimerization of KetenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Ravindra Abstract A convenient route for the covalent immobilization of quinidine and hydroquinidine pyridazine ethers on insoluble polystyrene supports is described, which avoids the need of chromatographic purifications at any stage. The use of the heterogeneized alkaloid derivatives in the asymmetric organocatalytic dimerization of ketenes afforded high enantioselectivity values (90,97% ee) in the course of 20 reaction cycles. [source] ChemInform Abstract: gem-Difluorination of Aminoalkynes via Highly Reactive Dicationic Species in Superacid HF,SbF5: Application to the Efficient Synthesis of Difluorinated Cinchona Alkaloid Derivatives.CHEMINFORM, Issue 33 2008Anne-Celine Cantet 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] Enantiomer discrimination of peptides by tandem mass spectrometry: influence of the peptide sequence on chiral recognitionRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2004Christoph Czerwenka The enantiomer discrimination of peptides by electrospray ionization tandem mass spectrometry is described. A cinchona alkaloid derivative, tert -butylcarbamoylquinine, is used as chiral selector. The chiral selector forms diastereomeric complexes with the peptide enantiomers in the liquid phase (methanolic solution), which are then transferred to the gas phase, where their dissociation behaviour is studied in an ion-trap mass spectrometer. Different degrees of dissociation of the diastereomeric complexes allow for the discrimination of the peptide enantiomers. The influence of the peptide sequence on enantiomer discrimination is discussed and molecular recognition information is derived by comparing the results obtained for related peptides. For dipeptides, small amino acid residues at the N-terminus and bulky side chains at the C-terminus were found to enhance chiral recognition, while for tripeptides the effects were rather irregular. Copyright © 2004 John Wiley & Sons, Ltd. [source] Simple Preparation of Dimeric Cinchona Alkaloid Derivatives on Polystyrene Supports and a Highly Enantioselective Catalytic Heterogeneous Dimerization of KetenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Ravindra Abstract A convenient route for the covalent immobilization of quinidine and hydroquinidine pyridazine ethers on insoluble polystyrene supports is described, which avoids the need of chromatographic purifications at any stage. The use of the heterogeneized alkaloid derivatives in the asymmetric organocatalytic dimerization of ketenes afforded high enantioselectivity values (90,97% ee) in the course of 20 reaction cycles. [source] Chemically Induced Cardiomyogenesis of Mouse Embryonic Stem CellsCHEMBIOCHEM, Issue 2 2010Albrecht Berkessel Prof. Dr. Abstract A transgenic murine embryonic stem (ES) cell lineage expressing enhanced green fluorescent protein (EGFP) under the control of ,-myosine heavy chain (,-MHC) promoter (p,-MHC-EGFP) was used to investigate the effects of (thio)urea and cinchona alkaloid derivatives on cardiomyogenesis. The screening of the compounds yielded cardiomyogenesis inducing substances with good (IV-5, V-4) to very good activities (II-16, IV-8), as determined by a 50 to 80,% increase in the EGFP fluorescence compared to untreated cells. Time-dependent screening approaches in which compounds were added at different developmental stages of the ES cells appeared to be of limited suitability for the identification of potential cellular targets. [source] |