InfrastructureInfrakstrukturhttp://hdl.handle.net/10033/68572024-02-08T19:58:18Z2024-02-08T19:58:18ZStereoselective Synthesis of a Protected Side Chain of Meliponamycin A.Andler, OliverKazmaier, Ulihttp://hdl.handle.net/10033/6231742022-04-26T02:07:07Z2023-03-28T00:00:00ZStereoselective Synthesis of a Protected Side Chain of Meliponamycin A.
Andler, Oliver; Kazmaier, Uli
The Matteson homologation was found to be a versatile tool for the construction of the linear polyketide side chain of meliponamycin and related compounds in only four steps. The ester dienolate version of this reaction allowed the introduction of the unsaturated ester moiety in a highly stereoselective fashion. Boronate oxidation/deoxygenation and Sharpless dihydroxylation are additional key steps in the stereoselective construction of this highly functionalized tetrahydropyran ring system, which is characteristic of this substance class
The Matteson homologation was found to be a versatile tool for the construction of the linear polyketide side chain of meliponamycin and related compounds in only four steps. The ester dienolate version of this reaction allowed the introduction of the unsaturated ester moiety in a highly stereoselective fashion. Boronate oxidation/deoxygenation and Sharpless dihydroxylation are additional key steps in the stereoselective construction of this highly functionalized tetrahydropyran ring system, which is characteristic of this substance class
2023-03-28T00:00:00Z1-Acyl-3-O-[β-glucopyranosyl-(1″→6′)-β-glucopyranosyl]-glycerols and Cordycedipeptides B and C, New Metabolites from Bacillus pumilusWang, HongpengDrawert, FrederikeSteinert, MichaelSchulz, StefanLaatsch, Hartmuthttp://hdl.handle.net/10033/6221192020-02-06T02:09:32Z2016-09-01T00:00:00Z1-Acyl-3-O-[β-glucopyranosyl-(1″→6′)-β-glucopyranosyl]-glycerols and Cordycedipeptides B and C, New Metabolites from Bacillus pumilus
Wang, Hongpeng; Drawert, Frederike; Steinert, Michael; Schulz, Stefan; Laatsch, Hartmut
Four 1-monoacyl-3-O-[β-glucopyranosyl-(1→6)-β-glucopyranosyl]-glycerols (1) and four 1,2-diacyl-3-O-[β-glucopyranosyl-(1→6)-β-glucopyranosyl]-glycerols (2a) with acyl residues consisting of 1:1 mixtures of 1-iso-pentadecanoyl- and 1-anteiso-pentadecanoyl residues and the respective heptadecanoic acid isomers s as main components, have been characterized in the extracts of Bacillus pumilus strain DKS1. Twenty-seven further metabolites, among them the diketopiperazines cordycedipeptide A (3), B (4), and C (5), were obtained. All compounds were elucidated by NMR and MS techniques and fully characterized and tested for antimicrobial activity against Legionella pneumophila.
2016-09-01T00:00:00ZCyathane Diterpenes from Cultures of the Bird's Nest Fungus Cyathus hookeri and Their Neurotrophic and Anti-neuroinflammatory Activities.Tang, DanXu, Yuan-ZhenWang, Wei-WeiYang, ZhiLiu, BoStadler, MarcLiu, Ling-LiGao, Jin-Minghttp://hdl.handle.net/10033/6218942019-11-20T09:37:50Z2019-06-18T00:00:00ZCyathane Diterpenes from Cultures of the Bird's Nest Fungus Cyathus hookeri and Their Neurotrophic and Anti-neuroinflammatory Activities.
Tang, Dan; Xu, Yuan-Zhen; Wang, Wei-Wei; Yang, Zhi; Liu, Bo; Stadler, Marc; Liu, Ling-Li; Gao, Jin-Ming
Six new cyathane diterpenoids, cyahookerins A-F (1-6), as well as nine known analogues (7-15), were isolated from the liquid culture of the basidiomycete Cyathus hookeri. Their structures were elucidated on the basis of extensive spectroscopic analyses (1D and 2D NMR, HRESIMS, and ECD), and the absolute configurations of compounds 1 and 4 were determined by single-crystal X-ray crystallography. Compounds 1 and 2 represent the first unusual cyathane acetals featuring a dioxolane ring. Compounds 1-6 displayed differential nerve growth factor-induced neurite outgrowth-promoting activity in PC-12 cells at concentrations of 10 μM. In addition, cyahookerin B (2), cyathin E (9), cyathin B2 (12), and cyathin Q (13) showed significant nitric oxide production inhibition in Lipopolysaccharide (LPS)-activated BV-2 microglial cells with IC50 values of 12.0, 6.9, 10.9, and 9.1 μM, respectively. Similar binding modes of the four compounds were indicated by molecular-docking studies, and structure-activity relationships are discussed.
2019-06-18T00:00:00ZQuantification of Stable Isotope Traces Close to Natural Enrichment in Human Plasma Metabolites Using Gas Chromatography-Mass Spectrometry.Krämer, LisaJäger, ChristianTrezzi, Jean-PierreJacobs, Doris MHiller, Karstenhttp://hdl.handle.net/10033/6213462019-08-30T11:34:22Z2018-02-14T00:00:00ZQuantification of Stable Isotope Traces Close to Natural Enrichment in Human Plasma Metabolites Using Gas Chromatography-Mass Spectrometry.
Krämer, Lisa; Jäger, Christian; Trezzi, Jean-Pierre; Jacobs, Doris M; Hiller, Karsten
Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker13C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak13C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS). The limit of quantification was increased by optimizing (1) the metabolite extraction from plasma, (2) the GC-MS measurement, and (3) most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of13C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of13C-labeled bread and quantified13C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine). Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated.
2018-02-14T00:00:00Z