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Mario Thevis Ines Möller Andreas Thomas Simon Beuck Grigory Rodchenkov Wolfgang Bornatsch Hans Geyer Wilhelm Schänzer 《Analytical and bioanalytical chemistry》2010,396(7):2479-2491
Since January 2009, the list of prohibited substances and methods of doping as established by the World Anti-Doping Agency
includes new therapeutics such as the peroxisome-proliferator-activated receptor (PPAR)-delta agonist GW1516, which is categorized
as a gene doping substance. GW1516 has completed phase II and IV clinical trials regarding dyslipidemia and the regulation
of the lipoprotein transport in metabolic syndrome conditions; however, its potential to also improve athletic performance
due to the upregulation of genes associated with oxidative metabolism and a modified substrate preference that shifted from
carbohydrate to lipid consumption has led to a ban of this compound in elite sport. In a recent report, two presumably mono-oxygenated
and bisoxygenated urinary metabolites of GW1516 were presented, which could serve as target analytes for doping control purposes
after full characterization. Hence, in the present study, phase I metabolism was simulated by in vitro assays employing human
liver microsomal fractions yielding the same oxygenation products, followed by chemical synthesis of the assumed structures
of the two abundant metabolic reaction products. These allowed the identification and characterization of mono-oxygenated
and bisoxygenated metabolites (sulfoxide and sulfone, respectively) as supported by high-resolution/high-accuracy mass spectrometry
with higher-energy collision-induced dissociation, tandem mass spectrometry, and nuclear magnetic resonance spectroscopy.
Since urine samples have been the preferred matrix for doping control purposes, a method to detect the new target GW1516 in
sports drug testing samples was developed in accordance to conventional screening procedures based on enzymatic hydrolysis
and liquid–liquid extraction followed by liquid chromatography, electrospray ionization, and tandem mass spectrometry. Validation
was performed for specificity, limit of detection (0.1 ng/ml), recovery (72%), intraday and interday precisions (7.7–15.1%),
and ion suppression/enhancement effects (<10%). 相似文献
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Alessandro D'Aprano Dorina Ines Donato Antonio Carrubba 《Journal of solution chemistry》1982,11(4):271-281
Conductance measurements of lithium picrate in solutions of water in n-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol and 3-methyl-1-butanol have been carried out at 25°C. Ionic association and conductance were found to change with water content and with the molecular structure of the alcohols (i.e. position of the OH group and degree of branching of the alkyl chain). These results indicate that both conductance and ion pair formation are not the consequence of the simple motion of ions in the electrical field as required by the continuum model. A more realistic approach, involving the internal structure of the solvent mixtures, has been considered. 相似文献
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Is there anything resembling a truly noncoordinating anion? Would it not be great to be able to prepare any crazy, beautiful, or simply useful cationic species that one has in mind, or has detected by mass spectroscopy? In condensed phases the target cation has to be partnered with a suitable counteranion. This is the moment when difficulties arise and many wonderful ideas end in the sink owing to coordination or decomposition of the anion. However, maybe these counteranion problems can be overcome by one of the new weakly coordinating anions (WCAs). Herein is an overview on the available candidates in the quest for the least coordinating anion and a summary of new applications, available starting materials, and general strategies to introduce a WCA into a system. Some of the unusual properties of WCA salts such as high solubility in low dielectric media, pseudo gas‐phase conditions in condensed phases, and the stabilization of weakly bound and low‐charged complexes are rationalized on thermodynamic grounds. Limits of the WCAs, that is, anion coordination and decomposition, are shown and a quantum chemical analysis of all types of WCAs is presented which allows the choice of a particular WCA to be based on quantative data from a wide range of different anions. 相似文献
38.
Vujasinović I Veljković J Mlinarić-Majerski K 《The Journal of organic chemistry》2004,69(24):8550-8553
The preparation of new tin templates, stannathianes 1-3 is described. New templates have been successfully applied to the synthesis of macrocyclic polythialactones 4-9 by cyclization of corresponding stannathianes 1-3 with pimeloyl dichloride. 相似文献
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Mancini I Guella G Sauvain M Debitus C Duigou AG Ausseil F Menou JL Pietra F 《Organic & biomolecular chemistry》2004,2(5):783-787
We report here on new 6-hydroxy-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrimidinium alkaloids, belonging to the phloeodictyne family, isolated from the haplosclerid sponge Oceanapia[=Phloeodictyon]fistulosa(Bowerbank, 1873) from New Caledonian shallow waters. Online LC-ESI-MS analysis, coupled to tandem fragmentation experiments on the crude alkaloid mixture, allowed us to clarify their flat structures, including structural isomers. At least 25 different components, of which 17 are new members with variable terminus and length chains, were characterised, besides less abundant analogues bearing a thioethylguanidine side chain. Crude mixtures and HPLC enriched fractions proved active against chloroquine-resistant Plasmodium falciparum, with IC(50) values ranging from 0.6 to 6 microM, while cytotoxicity against human A-549 cell line was low. This makes these alkaloids a good prospect as leads for novel antimalarial agents. 相似文献
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