A5075887497- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Crystallography and molecular interactions
- Chemical Synthesis and Analysis
- Asymmetric Synthesis and Catalysis
- Synthesis and Properties of Aromatic Compounds
- Fluorine in Organic Chemistry
- Porphyrin and Phthalocyanine Chemistry
- Organic Chemistry Cycloaddition Reactions
- Chemical Reaction Mechanisms
- Synthetic Organic Chemistry Methods
- Molecular spectroscopy and chirality
- Coordination Chemistry and Organometallics
- Supramolecular Chemistry and Complexes
- Molecular Junctions and Nanostructures
- Carbohydrate Chemistry and Synthesis
- Photochromic and Fluorescence Chemistry
- RNA and protein synthesis mechanisms
- Synthesis and Catalytic Reactions
- Computational Drug Discovery Methods
- Synthesis of heterocyclic compounds
- Analytical Chemistry and Chromatography
- DNA and Nucleic Acid Chemistry
- Synthesis and Biological Evaluation
- Asymmetric Hydrogenation and Catalysis
RheinMain University of Applied Sciences
2019-2023
ETH Zurich
2009-2018
Uppsala University
2017
École Polytechnique Fédérale de Lausanne
1978-2014
University of Münster
2013
Institut de Chimie de Strasbourg
2011-2012
Université de Strasbourg
2011-2012
Philips (Finland)
2004-2011
Philips (Germany)
2004-2011
Lehigh University
2011
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOn the validity of Wallach's rule: on density and stability racemic crystals compared with their chiral counterpartsCarolyn Pratt Brock, W. Bernd Schweizer, Jack D. DunitzCite this: J. Am. Chem. Soc. 1991, 113, 26, 9811–9820Publication Date (Print):December 1, 1991Publication History Published online1 May 2002Published inissue 1 December 1991https://pubs.acs.org/doi/10.1021/ja00026a015https://doi.org/10.1021/ja00026a015research-articleACS...
A collaborative workshop was held in May 1999 at the Cambridge Crystallographic Data Centre to test how well currently available methods of crystal structure prediction perform when given only atomic connectivity for an organic compound. blind conducted on a selection four compounds and wide range methodologies representing, principal computer programs were used. There 11 participants who allowed propose most three structures each No program gave consistently reliable results. However, seven...
We report on the organization and outcome of fourth blind test crystal structure prediction, an international collaborative project organized to evaluate present state in computational methods predicting structures small organic molecules. There were 14 research groups which took part, using a variety generate rank most likely for four target systems: three single-component 1:1 cocrystal. Participants challenged predict systems, given only their molecular diagrams, while recently determined...
Following the interest generated by two previous blind tests of crystal structure prediction (CSP1999 and CSP2001), a third such collaborative project (CSP2004) was hosted Cambridge Crystallographic Data Centre. A range methodologies used in searching for ranking likelihood predicted structures is represented amongst 18 participating research groups, although most are based on global minimization lattice energy. Initially participants were given molecular diagrams three molecules asked to...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAlkylation of amino acids without loss the optical activity: preparation .alpha.-substituted proline derivatives. A case self-reproduction chiralityDieter Seebach, Michael Boes, Reto Naef, and W. Bernd SchweizerCite this: J. Am. Chem. Soc. 1983, 105, 16, 5390–5398Publication Date (Print):August 1, 1983Publication History Published online1 May 2002Published inissue 1 August...
Abstract We report the synthesis and physical study of a series 1,1‐dicyano‐4‐[4‐(diethylamino)phenyl]buta‐1,3‐dienes in which number position additional CN substituents along 1,1‐dicyanobuta‐1,3‐dienyl fragment is systematically varied. While X‐ray analysis provided unambiguous information about molecular geometries crystal, UV/Vis electrochemical measurements, by cyclic voltammetry (CV) rotating disk (RDV), revealed that introduction cyano groups C2‐ C4‐positions most affected optical...
The first collaborative workshop on crystal structure prediction (CSP1999) has been followed by a second (CSP2001) held at the Cambridge Crystallographic Data Centre. 17 participants were given only chemical diagram for three organic molecules and invited to test their programs within range of named common space groups. Several different computer used, using methodology wherein molecular model is used construct theoretical structures in groups, usually based minimum calculated lattice...
Abstract Average bond distances and angles in carboxylic esters with different substitution patterns have been derived by analyzing data from many crystal structures retrieved the Cambridge Structural Database (CSD). Conformation‐al preferences attachment of substituents are found.
Wormholes through chemical space: Spirocyclic oxetanes are described as analogues of morpholine and also topological siblings their carbonyl counterparts. They particularly promising in terms both physicochemical properties the ease with which they can be grafted onto molecular structures. The data collected highlight hydrophilic sister a gem-dimethyl unit group's lipophilic brother. We were intrigued by apparent analogy between van 't Hoff description R2CO,1 close correspondence these two...
The presence of potentially persistent and bioactive human metabolites in surface waters gives rise to concern; yet little is known date about the environmental fate these compounds. This work investigates direct photolysis antibiotic sulfamethoxazole (SMX). In particular, we determined kinetics products, as well their concentrations lake water. SMX, N-acetyl sulfamethoxazole, β-D-glucuronide, 4-nitroso 4-nitro were irradiated under various light sources pH conditions. All investigated...
A combination of a chemical double-mutant cycle and linear free energy relationship has demonstrated that weak attractive interaction (−0.8 to −1.5 kJ mol−1) exists between an organic fluorine substituent the face amide functional group (see picture). This study supports recent results have suggested such attraction may be operative in enzyme–inhibitor interactions. Supporting information for this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z460781_s.pdf...
Abstract Reaction of 2‐phenylacetaldehyde with the Me 3 Si ether diphenyl‐prolinol, removal H 2 O, gives a crystalline enamine ( 1 ). The HBF 4 salts MePh diphenyl‐prolinol and 2‐( tert ‐butyl)‐3‐methyl‐ 5‐benzyl‐2,2,3‐trimethyl‐1,3‐imidazolidin‐4‐one react cinnamaldehyde to give iminium 2, , . Single crystals two salts, were subjected X‐ray structure analysis Figs. 1, 6 ), 2D‐NMR spectrum third salt was recorded Fig. 7 crystal NMR structures confirm commonly accepted, general types reactive...
Medical investigations targeting a quantitative analysis of the position emission tomography (PET) images require incorporation additional knowledge about photon attenuation distribution in patient. Today, energy range adapted maps derived from computer (CT) scans are used to effectively compensate for image quality degrading effects, such as and scatter. Replacing CT by magnetic resonance (MR) is considered next evolutionary step field hybrid imaging systems. However, unlike CT, MR does not...
Abstract The structures of the crystalline lithium enolates derived from 3, 3‐dimethyl‐2‐butanone and cyclopentanone have been determined by X‐ray analysis. Both are tetrameric aggregates based on a Li 4 O ‐cube, each + ‐ion being additionally bonded to O‐atom tetrahydrofuran solvent molecule.
Abstract Structures of the reactive intermediates (enamines and iminium ions) organocatalysis with diarylprolinol derivatives have been determined. To this end, methyl silyl ethers, 1 , aldehydes, PhCH 2 CHO, t BuCH PhCH=CHCHO, are condensed to corresponding enamines, A 3 ( Scheme ), cinnamoylidene salts, B 4 ). These isolated fully characterized by melting/decomposition points, [ α ] D elemental analysis, IR NMR spectroscopy, high‐resolution mass spectrometry (HR‐MS). Salts BF PF 6 SbF...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructures of three lithium ester enolates by x-ray diffraction: derivation reaction path for cleavage into ketene and alcoholateDieter Seebach, Rene Amstutz, Thomas Laube, W. Bernd Schweizer, J. D. DunitzCite this: Am. Chem. Soc. 1985, 107, 19, 5403–5409Publication Date (Print):September 1, 1985Publication History Published online1 May 2002Published inissue 1 September...
The gauche effect that is induced upon reversible formation of an iminium ion (see structure: green F, blue N) provides a powerful method for the preorganization transient intermediates are central to secondary amine catalyzed processes. This phenomenon has been exploited in design novel organocatalyst and showcased stereoselective epoxidation alpha,beta-unsaturated aldehydes.
Just a pinch of catalyst: 0.05 mol % novel planar chiral ferrocenyl–imidazoline palladacycle catalyst (FIP) is sufficient to catalyze highly efficient aza-Claisen rearrangement N-para-methoxyphenyl trifluoroacetimidates and thereby provide access protected primary allylic amines with unprecedentedly high enantioselectivities (see scheme). Supporting information for this article available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z601731_s.pdf or from author. Please note:...
A series of donor-acceptor chromophores was prepared in which the spacer separating 4-dimethylanilino (DMA) donor and C(CN)(2) acceptor moieties is systematically varied. All new push-pull systems, except 4 b, are thermally stable molecules. In a, DMA rings directly attached to central spacer, whereas b additional acetylene inserted. X-ray crystal structures were obtained for seven new, intensely colored target compounds. sterically forced out mean plane residual pi system, entire conjugated...
Asymmetric Michael‐Additions Practically Completely Diastereo‐ and Enantloselective Alkylations of the Enamine from Cyclohexanone Prolinyl Methyl Ether by ω‐Nitrostyrenes to Give u 2‐(1′‐Aryl‐2′‐nitroethyl)cyclohexanones When enamine (S) ‐ N ‐(1′cyclohexenyl)‐2‐methoxymethyl‐pyrrolidine is added 2‐aryl‐l‐nitroethylenes, only one four possible enantiomerically pure diastereomers formed. Hydrolysis crude primary products furnishes α‐alkylated cyclohexanones > 90% e. ( 3 , Scheme ). Their (2...
Abstract We describe the synthesis of 2′‐deoxy‐3′,5′‐ethano‐ D ‐ribonucleosides 1 – 8 (= (5′,8′‐dihydroxy‐2′‐oxabicyclo‐[3.3.0]oct‐3′‐yl)purines or ‐pyrimidines) nucleobases adenine, thymine, cytosine, and guanine. They differ from natural 2′‐deoxyribonucleosides only by an additional ethylene bridge between centers C(3′) C(5′). The configuration at these (3 S ,5′ R ) was chosen as to match geometry a repeating nucleoside unit in duplex DNA close possible. These nucleosides were designed...
Finding the right balance: An indole-extended molecular torsion balance has geometry for measuring a truly orthogonal noncovalent interaction between CF bond dipole and an amide carbonyl group (see picture, green F, red O, blue N). Employing double-mutant cycle approach, negative free enthalpies were determined. Thus dipolar interactions can be new tool stabilizing protein–ligand complexes assembling supramolecular architectures.