zur Suche springenzur Navigation springenzum Inhalt springen

Publikationen - Natur- und Wirkstoffchemie

Sortieren nach: Erscheinungsjahr Typ der Publikation

Zeige Ergebnisse 1 bis 10 von 44.

Publikation

Paixão, M. W.; de Godoi, M.; Rhoden, C. R.; Westermann, B.; Wessjohann, L. A.; Lüdtke, D. S.; Braga, A. L.; The application of chiral, non-racemic N-alkylephedrine and N,N-dialkylnorephedrine as ligands for the enantioselective aryl transfer reaction to aldehydes J. Mol. Catal. A 261, 120-124, (2007) DOI: 10.1016/j.molcata.2006.07.076

The catalytic enantioselective arylation of several aldehydes using arylboronic acids as the source of transferable aryl groups is described; the reaction is found to proceed in excellent yields and high enantioselectivities (up to 96% ee) in the presence of a chiral amino alcohol derived from ephedrines and congeners.
Publikation

Ninh, P. T.; Anh, N. T. H.; Sung, T. V.; Wessjohann, L.; Studies on chemical constituents of the roots of Polygala sp.: II - Further phenylpropanoide sucrose esters Vietnam J. Chem. 45, 518-522, (2007)

0
Publikation

Nguyen, T. H. A.; The chemical constitutents of Vietnamese medicinal plant Ophiopogon Japonicus Tap chi Phan tich Hoa 9, 59-64, (2007)

0
Publikation

Namjooyan, F.; Azemi, M.; Mosaddegh, M.; Cheraghali, A.; Kobarfard, F.; Porzel, A.; Screening of some Solanaceae plants for cytotoxic activity, and isolation and structure elucidation of a new steroid from the active fraction of Physalis divarivata D. Don Planta Med. 73, P_422, (2007) DOI: 10.1055/s-2007-987202

0
Publikation

Michalik, D.; Schaks, A.; Wessjohann, L. A.; One-Step Synthesis of Natural Product-Inspired Biaryl Ether-Cyclopeptoid Macrocycles by Double Ugi Multiple-Component Reactions of Bifunctional Building Blocks Eur. J. Org. Chem. 2007, 149-157, (2007) DOI: 10.1002/ejoc.200600354

Isonitrile‐functionalized biaryl ethers can serve as key building blocks for the highly efficient one‐step production of natural product inspired‐macrocycles, with six or even twelve new bonds and rings with up to 50 members being formed in total yields of up to 51 %. Aliphatic diamine and diacid tethers give access to two different classes of N ‐substituted biaryl ether cyclopeptides, suitable for library construction. As part of a conceptual work on MiBs (m ultiple m ulticomponent m acrocyclizations/m acrocycles i ncluding b ifunctional b uilding b locks), the influence of length and type of flexible tethers on the propensity for cyclization is studied.
Publikation

Kreye, O.; Westermann, B.; Wessjohann, L.; A Stable, Convertible Isonitrile as a Formic Acid Carbanion [-COOH] Equivalent and Its Application in Multicomponent Reactions Synlett 2007, 3188-3192, (2007) DOI: 10.1055/s-2007-990912

The application of 2-(2,2-dimethoxyethyl) phenyl iso­nitrile in Ugi, Passerini, and Ugi-Smiles reactions is described. The simple transformation to highly activated indolyl amides allows functional-group conversion of the isonitrile moiety into a variety of carboxylic acid derivatives, overall acting as a neutral, nucleophilic COOH equivalent.
Publikation

Khine, M. M.; Arnold, N.; Franke, K.; Porzel, A.; Schmidt, J.; Wessjohann, L.; Phytoconstituents from the root of Streptocaulon tomentosum and their chemotaxonomical relevance for separation from S. juventas Biochem. Syst. Ecol. 35, 517-524, (2007) DOI: 10.1016/j.bse.2007.01.006

A new cardenolide, 17β-H-periplogenin-3-O-β-d-digitoxoside (1), and a new pregnane glycoside, Δ5-pregnene-3β,16α-diol-d-O-[2,4-O-diacetyl-β-digitalopyranosyl-(1 → 4)-β-d-cymaropyranoside]-16-O-[β-d-glucopyranoside] (2) were isolated from the roots of Streptocaulon tomentosum (Asclepiadaceae) together with a series of known compounds. Their chemotaxonomic significance for the separation of S. tomentosum from Streptocaulon juventas is discussed, suggesting a rather clear distinction of these species.
Publikation

Jelić, D.; Mildner, B.; Koštrun, S.; Nujić, K.; Verbanac, D.; Čulić, O.; Antolović, R.; Brandt, W.; Homology Modeling of Human Fyn Kinase Structure: Discovery of Rosmarinic Acid as a New Fyn Kinase Inhibitor and in Silico Study of Its Possible Binding Modes J. Med. Chem. 50, 1090-1100, (2007) DOI: 10.1021/jm0607202

Tyrosine phosphorylation represents a unique signaling process that controls metabolic pathways, cell activation, growth and differentiation, membrane transport, apoptosis, neural, and other functions. We present here the three-dimensional structure of Fyn tyrosine kinase, a Src-family enzyme involved in T-cell receptor signal transduction. The structure of Fyn was modeled for homology using the Sybyl-Composer suite of programs for modeling. Procheck and Prosa II programs showed the high quality of the obtained three-dimensional model. Rosmarinic acid, a secondary metabolite of herbal plants, was discovered as a new Fyn kinase inhibitor using immunochemical and in silico methods. Two possible binding modes of rosmarinic acid were evaluated here, i.e., near to or in the ATP-binding site of kinase domain of Fyn. Enzyme kinetic experiments revealed that Fyn is inhibited by a linear-mixed noncompetitive mechanism of inhibition by rosmarinic acid. This indicates that rosmarinic acid binds to the second “non-ATP” binding site of the Fyn tyrosine kinase.
Publikation

Iranshahi, M.; Shaki, F.; Mashlab, A.; Porzel, A.; Wessjohann, L. A.; Kopetdaghins A−E, Sesquiterpene Derivatives from the Aerial Parts and the Roots of Dorema kopetdaghense J. Nat. Prod. 70, 1240-1243, (2007) DOI: 10.1021/np070043u

Three new sesquiterpene derivatives, kopetdaghins A−C (1−3), one known prenylated coumarin (7), and two known steroid glucosides, sitosterol 3-O-glucoside and stigmasterol 3-O-glucoside, were isolated from the aerial parts of Dorema kopetdaghense. In addition, two new sesquiterpene derivatives, kopetdaghin D (4) and kopetdaghin E (5), together with kopetdaghins A−C and one known sesquiterpene coumarin (6), were isolated from the roots of the plant. The structures of these compounds were elucidated by various 1D and 2D NMR techniques as well as high-resolution positive-ion ESIMS.
Publikation

Hinneburg, A.; Egert, B.; Porzel, A.; Duplicate detection of 2D-NMR Spectra J. Integr. Bioinformatics 4, 64-80, (2007) DOI: 10.1515/jib-2007-53

2D-Nuclear magnetic resonance (NMR) spectra are used in the (structural) analysis of small molecules. In contrast to 1D-NMR spectra, 2D-NMR spectra correlate the chemical shifts of 1H and 13C at the same time. A spectrum consists of several peaks in a two--dimensional space. The most important information of a peak is the location of its center, which captures the bonding relationships of hydrogen and carbon atoms. A spectrum contains much information about the chemical structure of a product, but in most cases the structure cannot be read off in a simple and straightforward manner. Structure elucidation involves a considerable amount (manual) efforts.Using high-field NMR spectrometers, many 2D-NMR spectra can be recorded in short time. So the common situation is that a lab or company has a repository of 2D-NMR spectra, partially annotated with the structural information. For the remaining spectra the structure in unknown. In case two research labs are collaborating, the repositories will be merged and annotations shared.We reduce that problem to the task of finding duplicates in a given set of 2D-NMR spectra. Therefore, we propose a simple but robust definition of 2D-NMR duplicates, which allows for small measurement errors. We give a quadratic algorithm for the problem, which can be implemented in SQL. Further, we analyze a more abstract class of heuristics, which are based on selecting particular peaks. Such a heuristic works as a filter step on the pairs of possible duplicates and allows false positives. We compare all methods with respect to their run time. Finally we discuss the effectiveness of the duplicate definition on real data.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
IPB Mainnav Search