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Ohne Zusammenfassung 相似文献
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G. Reske G. Lagaly W. Schermann H. Bergmann W. Ried R. Hähnel H. K. Kugler Egon Matijević P. Kratochvíl 《Colloid and polymer science》1973,251(2):165-168
Ohne Zusammenfassung 相似文献
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E. Al-Momani B. D. Zlatopolskiy C. Solbach S. N. Reske H.-J. Machulla 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(3):881-886
For experimental studies by animal PET [11C]-labeled 15-(4-methylphenyl)pentadecanoic acid (MePPA) is an attractive alternative to the radioiodinated 15-(4-iodophenyl)pentadecanoic acid (IPPA) which has widely been used for imaging of fatty acid metabolism. The important physiological aspect is that the iodine atom and the methyl substituent have similar steric and lipophilic properties. For preparation of [11C]MePPA, Stille cross-coupling reaction was applied since the same tin precursor as for the radiosynthesis of IPPA and readily available [11C]CH3I can be used. Unsaturated tris(dibenzylideneacetone)dipalladium(0)/tri(o-tolyl)phosphine [Pd2(dba)3/P(o-tolyl)3] was taken as the catalytic system. The reaction conditions were optimized with respect to temperature, time, solvent and amount of precursor. The best radiochemical yields of 73 ± 2.8% (decay corr.) were obtained using 0.525 mg tin precursor in DMF at 80 °C already after a reaction time of 10 min. The labeled methyl ester was hydrolyzed by 1 M NaOH/EtOH at 80 °C within 3 min to give [11C]IPPA in a RCY of 62 ± 3.0%. The radiochemical purity of the product assured by HPLC was >99% and the overall preparation time including HPLC purification and formulation was 40 min. 相似文献
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Noeen Malik Boris D. Zlatopolskiy Christoph Solbach Wolfgang Voelter Sven N. Reske Hans-Jürgen Machulla 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(2):563-569
In this work, we tested the applicability of several methyl substituted benzyl groups as an alternative to the methyl group
for the protection of the hydroxyl groups in the nucleophilic aromatic radiofluorination. As a model synthesis, the no-carrier-added
(n.c.a.) preparation of 2-[18F]fluoro-3-hydroxy-6-methylpyridine from O-protected 3-hydroxy-6-methyl-2-nitropyridine was chosen. Conditions for acidolytic
and hydrogenolytic cleavage of heteroaryl esters were studied. Among various protecting groups tested, 4-methylbenzyl and
2,4-dimethylbenzyl groups proved to be the best by resulting in about 70% yields of [18F]-labelled product after hydrolysis with 32% HCl at 120 °C for 10 min. Furthermore, 4-methylbenzyl ester cleaved readily
under catalytic transfer hydrogenation condition using ammonium formate and 10% Pd/C in boiling methanol to give 2-[18F]fluoro-3-hydroxy-6-methylpyridine in radiochemical yield of 75% within a reaction time of 10 min. Conditions for the cleavage
of both 4-methylbenzyl and 2,4-dimethylbenzyl esters are well suited for the implementation into an automated synthesis module. 相似文献
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Morgenroth A Urusova EA Dinger C Al-Momani E Kull T Glatting G Frauendorf H Jahn O Mottaghy FM Reske SN Zlatopolskiy BD 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(36):10144-10150
The development of prostate carcinoma is associated with alterations in fatty acid metabolism. α‐Methylacyl‐CoA racemase (AMACR) is a peroxisomal and mitochondrial enzyme that catalyses interconversion between the (S)/(R)‐isomers of a range of α‐methylacyl‐CoA thioesters. AMACR is involved in the β‐oxidation of the dietary branched‐chain fatty acids and bile acid intermediates. It is highly expressed in prostate (more than 95 %), colon (92 %), and breast cancers (44 %) but not in the respective normal or hyperplastic tissues. Thus, targeting of AMACR could be a new strategy for molecular imaging and therapy of prostate and some other cancers. Unlabeled 2‐methylenacyl‐CoA thioesters ( 12 a – c ) were designed as AMACR binding ligands. The thioesters were tested for their ability to inhibit the AMACR‐mediated epimerization of (25R)‐THC‐CoA and were found to be strong AMACR inhibitors. Radioiodinated (E)‐131I‐13‐iodo‐2‐methylentridec‐12‐enoic acid (131I‐ 7 c ) demonstrated preferential retention in AMACR‐positive prostate tumor cells (LNCaP, LNCaP C4‐2wt and DU145) compared with both AMACR‐knockout LNCaP C4‐2 AMACR‐siRNA and benign BPH1 prostate cell lines. A significant protein‐bound radioactive fraction with main bands at 47 (sum of molecular weights of AMACR plus 12 c ), 70, and 75 kDa was detected in LNCaP C4‐2 wt cells. In contrast, only negligible amounts of protein‐bound radioactivity were found in LNCaP C4‐2 AMACR‐siRNA cells. 相似文献
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Andreas?Finkelmeyer Thilo?Kellermann Daniela?Bude Thomas?Nie?en Michael?Schwenzer Klaus?Mathiak Martina?Reske 《BMC neuroscience》2010,11(1):131
Background
Due to the unique neural projections of the olfactory system, odours have the ability to directly influence affective processes. Furthermore, it has been shown that emotional states can influence various non-emotional cognitive tasks, such as memory and planning. However, the link between emotional and cognitive processes is still not fully understood. The present study used the olfactory pathway to induce a negative emotional state in humans to investigate its effect on inhibitory control performance in a standard, single-trial manual Stroop colour-word interference task. An unpleasant (H2S) and an emotionally neutral (Eugenol) odorant were presented in two separate experimental runs, both in blocks alternating with ambient air, to 25 healthy volunteers, while they performed the cognitive task. 相似文献20.