A5016219809- Analytical Chemistry and Chromatography
- Catalytic Cross-Coupling Reactions
- Mass Spectrometry Techniques and Applications
- Ammonia Synthesis and Nitrogen Reduction
- Chemical Synthesis and Analysis
- Zeolite Catalysis and Synthesis
- Innovative Microfluidic and Catalytic Techniques Innovation
- Surface Chemistry and Catalysis
- Fluorine in Organic Chemistry
- Electron and X-Ray Spectroscopy Techniques
- Magnetic properties of thin films
- Chemical Synthesis and Reactions
- Catalytic C–H Functionalization Methods
- Surface and Thin Film Phenomena
- Organometallic Complex Synthesis and Catalysis
- Crystallization and Solubility Studies
- Analytical chemistry methods development
- Chemistry and Chemical Engineering
- Nanomaterials for catalytic reactions
- Mesoporous Materials and Catalysis
- Copper Interconnects and Reliability
- Asthma and respiratory diseases
- Helicobacter pylori-related gastroenterology studies
- Semiconductor materials and devices
- Magnetism in coordination complexes
Novartis (Switzerland)
2017-2024
Novartis Institutes for BioMedical Research
2021
University of Basel
2004-2011
University of Wuppertal
2005-2010
University of Freiburg
2002-2003
University of Manchester
2000
Pennsylvania State University
1976
The shift of paradigm in combinatorial chemistry, from large compound libraries (of mixtures) on a small scale towards defined where each is prepared an individual well, has stimulated the search for alternative separation approaches. key to rapid and efficient synthesis not only parallel arrangement reactions, but simple work-up procedures so as circumvent time-consuming laborious purification steps. During initial development stages it was believed that rational compounds could be achieved...
The enantioselectivity of chiral palladium catalysts in the kinetic resolution allylic esters can be determined by mass spectrometric monitoring allyl–Pd intermediates A and B, which are derived from pseudoenantiomeric substrates 1 a b. In contrast to conventional screening methods, based on product analysis, simultaneous catalyst mixtures homogeneous solution is possible. Combinatorial methods have become an important focus research asymmetric catalysis.1, 2 During last few years efficient...
With and now without: Perfluoro-tagged catalysts immobilized on fluorous reversed-phase silica gel can be used for Suzuki Sonogashira C–C coupling reactions (see scheme; R1=e.g., phenyl, 4-MeOC6H4, R2=e.g., 4-NO2C6H4, 4-MeCOC6H4, X=Br, I) without the need perfluorinated solvents. After reaction products were isolated by decantation Pd recovered reused. In catalytic easy handling of catalyst together with its straightforward recovery possible reuse remain an important topic. A widespread...
The use of quasi-enantiomeric substrates and ESI-MS as an analytical tool has made it possible to determine the intrinsic enantioselectivity chiral catalysts by monitoring catalytic intermediates. In this way, potential problems methods based on product analysis, which may be caused catalytically active impurities, partial dissociation a ligand–metal complex, or non-catalytic background reaction can avoided. ESI-MS-based screening is fast, reliable, operationally simple, does not require...
ADVERTISEMENT RETURN TO ISSUECommunicationNEXTCombinatorial Ligand Development Based on Mass Spectrometric Screening and a Double Mass-Labeling StrategyChristian Markert, Pirmin Rösel, Andreas PfaltzView Author Information Department of Chemistry, University Basel, St. Johanns Ring 19, CH-4056 Switzerland Cite this: J. Am. Chem. Soc. 2008, 130, 11, 3234–3235Publication Date (Web):February 20, 2008Publication History Received4 June 2007Published online20 February 2008Published inissue 1 March...
The enantioselectivity of a chiral catalyst can be determined from its racemic form by mass spectrometric screening nonequal mixture two mass-labeled quasienantiomeric substrates. presented method opens up new possibilities for evaluating structures that are not readily available in enantiomerically pure form.
ESI-MS monitoring of the title reaction has led to discovery that dinuclear allyl-bridged PdI complexes are formed reversibly in substantial amounts during catalysis (see scheme; Bz=benzoyl). The structure one such complex was determined by X-ray analysis picture; P yellow, N blue, O red, Pd dark gray). Upon consumption starting materials a new resulting from reductive CCl bond cleavage CH2Cl2 observed. Supporting information for this article is available on WWW under...
Die Entwicklung in der Kombinatorischen Chemie, weg von großen Verbindungsbibliotheken (aus Gemischen) hin zu Bibliotheken aus definierten Einzelverbindungen, die jeweils eigenen Reaktionseinheiten synthetisiert werden, hat eine intensive Suche nach alternativen Trennverfahren ausgelöst. Den Schlüssel einer schnellen und effizienten Synthese liefert zum einen parallele Reaktionsführung, andern Anwendung einfacher Aufarbeitungsverfahren, mit denen sich zeitaufwändige mühsame...
The cytosolic metalloenzyme leukotriene A
Die Enantioselektivität chiraler Palladium-Katalysatoren bei der kinetischen Racematspaltung von Allylestern kann durch massenspektrometrische Bestimmung Allyl-Pd-Intermediate A und B ermittelt werden, die aus den Pseudoenantiomeren 1 a bzw. b entstehen. Im Unterschied zu konventionellen Screeningmethoden, auf Produktanalyse beruhen, eignet sich dieses Verfahren zum Simultanscreening Katalysatormischungen in Lösung.
Leukotriene A4 Hydrolase (LTA4H) is a bifunctional zinc metalloenzyme that comprises both epoxide hydrolase and aminopeptidase activity, exerted by two overlapping catalytic sites. The function of the enzyme catalyzes biosynthesis pro-inflammatory lipid mediator leukotriene (LT) B4. Recent literature suggests LTA4H responsible for degradation tripeptide Pro-Gly-Pro (PGP) which neutrophil chemotactic activity has been postulated. It speculated design selective inhibitors spare pocket may...
Silicalite membranes have been prepared using a novel seeding method. By sonicating silicalite seed crystals in the presence of stainless steel mesh followed by controlled hydrothermal synthesis step it has shown AFM, SEM, and simple diffusion measurements that coherent are produced. The sonication anchors nanometer-sized zeolite seeds to porous support subsequent growth produces membrane grown on this layer.
Sonogashira C,C couplings in a fluorous biphasic system by application of three differently perfluoro-tagged Pd complexes are reported. All were probed the coupling four bromoarenes to alkynes. The parallel workup procedure allowed for straightforward product isolation and catalyst recovery simple extraction steps. In particular, electron-deficient proceeded with good yields be used up times.
Es geht auch ohne: Auf fluorigem Umkehrphasen-Kieselgel immobilisierte perfluormarkierte Katalysatoren können in Suzuki- und Sonogashira-C-C-Kupplungen ohne perfluorierte Lösungsmittel eingesetzt werden (siehe Schema; R1=Phenyl, 4-MeO-C6H4 u. a.; R2=4-NO2-C6H4, 4-MeCO-C6H4 X=Br, I). Die Produkte lassen sich im Anschluss an die Reaktion durch einfaches Dekantieren abtrennen, eingesetzten Pd-Katalysatoren zurückgewonnen wieder verwendet werden.
LYS006 is a novel, highly potent and selective, new-generation leukotriene A4 hydrolase (LTA4H) inhibitor in clinical development for the treatment of neutrophil-driven inflammatory diseases. We describe complex pharmacokinetic to pharmacodynamic (PD) relationship blood, plasma, skin LYS006-treated nonclinical species healthy human participants. In randomized first study, participants were exposed single ascending doses up 100 mg multiple 80 b.i.d.. showed rapid absorption, overall dose...
ESI-MS-Verfolgung der Titelreaktion ergab, dass während Katalyse zweikernige allylverbrückte PdI-Komplexe in erheblicher Menge reversibel gebildet werden (siehe Schema; Bz=Benzoyl). Die Struktur eines solchen Komplexes wurde röntgenographisch ermittelt Bild; P gelb, N blau, O rot, Pd dunkelgrau). Nach Verbrauch Reaktanten eine reduktive Spaltung C-Cl-Bindung von CH2Cl2 beobachtet, die zu einem neuen zweikernigen Komplex führte. Supporting information for this article is available on the WWW...
The design of a miniaturized sputter deposition chamber for the in situ study thin film growth processes with x rays is reported. X-ray diffraction experiments, grazing incidence x-ray reflectometry, as well fluorescence analysis are possible. Due to its compact and low weight, can be used conjunction conventional reflectometers laboratory diffractometers well, i.e., very detailed studies reactive nonreactive sputtering resulting properties construction described detail first results...
The discovery of chiral amino alcohols derived from our previously disclosed clinical LTA4H inhibitor LYS006 is described. In a biochemical assay, their optical antipodes showed similar potencies, which could be rationalized by the cocrystal structures these compounds bound to LTA4H. Despite comparable stabilities in liver microsomes, they distinct vivo PK properties. Selective O-phosphorylation (R)-enantiomers blood led clearance values above hepatic flow, whereas (S)-enantiomers were...
Abstract The combination of in situ electrical resistivity measurements and ex tapping‐mode atomic force microscopy (AFM) air was used to study the surface topography properties thin d.c. magnetron‐sputtered gold films on float glass substrates. In particular, influence deposition temperature a subsequent isochronous annealing process structure polycrystalline were analysed. results show that minimum roughness about 0.4 nm achieved for 350 K. After process, an increase lateral crystallite...
Abstract X‐ray absorption near the iron K edge (XANES) was used to investigate characteristics of temperature‐induced low‐spin‐to‐high‐spin change (SC) in metallo‐supramolecular polyelectrolyte amphiphile complexes (PAC) containing FeN 6 octahedra attached two or six amphiphilic molecules. Compared typical spin‐crossover material Fe(phen) 2 (NCS) XANES spectra PAC show fingerprint features restricted near‐edge region which mainly measures multiple scattering (MS) events. The changes profiles...
In situ X-ray reflectometry, grazing-incidence absorption spectroscopy and simultaneous electrical resistivity measurements were used to investigate the microstructure of (5.9±0.1) nm thick bismuth films quench condensed at (20±1) K onto float-glass substrates. A subsequent annealing process induces an irreversible transformation film structure from amorphous a highly disordered nanocrystalline above (42±2) K. This is accompanied by increase factor more than 2.7. Different negative...
Reflection mode grazing incidence X-ray absorption spectroscopy at the Bi L3-edge and simultaneous electrical resistivity measurements were used to investigate microstructure of quench condensed thin metal films on float-glass substrates temperatures from 20 K 300 K. While ≈ 6 nm thickness appear be amorphous after deposition K, thicker about 18 show well-known rhombohedral structure bulk Bi. During a subsequent heat treatment, transforms irreversibly into crystalline form for (42 ± 2) This...