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Milan Jakubek Zdeněk Kejík Robert Kaplánek Hana Veselá David Sýkora Pavel Martásek 《Supramolecular chemistry》2018,30(3):218-226
Perimidine-based chelators 1 and 2 were prepared, and their structures were confirmed by 1H and 13C NMR, MS spectroscopy and elemental analysis. These compounds were studied as specific synthetic receptors for the recognition of transition metal ions. They exhibited high affinity and selectivity towards Cu(II) ions. The conditional binding constants, linear dynamic range and detection limit were determined by UV–vis spectroscopy. These parameters demonstrated high potential of the prepared synthetic receptors for the recognition and determination of Cu(II) ions. The minimum detectable concentrations of Cu(II) ions for the synthetic receptors 1 and 2 were 270 and 75 nM (R 2 = 0.9915 and 0.9964) in aqueous medium (water/DMSO; 99:1 (v/v)), respectively. 相似文献
113.
《合成通讯》2012,42(1):1-32
AbstractThe present study describes recent advances in the chemistry of heterocycles incorporated oxazolo[4,5-b]pyridine and oxazolo[5,4-b]pyridine skeletons. The main sections included the synthesis of the investigated compounds from readily accessible aminopyridinol derivatives or aminopyridines. The reactivity of substituents attached to ring carbon or nitrogen atoms were discussed. In addition, the synthetic and biological evaluation of the inspected oxazolopyridines were highlighted. The purpose of this review is to discuss the chemistry of the title so far. The present study will support researchers in the fields of organic and medicinal chemistry to design and develop new protocols for the construction of new biological components. 相似文献
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Dr. Cédric Boulho Dr. Harmen S. Zijlstra Alexander Hofmann Prof. Dr. Peter H. M. Budzelaar Prof. Dr. Sjoerd Harder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17450-17459
Reaction of (TBBP)AlMe ? THF with [Cp*2Zr(Me)OH] gave [(TBBP)Al(THF)?O?Zr(Me)Cp*2] (TBBP=3,3’,5,5’‐tetra‐tBu‐2,2'‐biphenolato). Reaction of [DIPPnacnacAl(Me)?O?Zr(Me)Cp2] with [PhMe2NH]+[B(C6F5)4]? gave a cationic Al/Zr complex that could be structurally characterized as its THF adduct [(DIPPnacnac)Al(Me)?O?Zr(THF)Cp2]+[B(C6F5)4]? (DIPPnacnac=HC[(Me)C=N(2,6‐iPr2?C6H3)]2). The first complex polymerizes ethene in the presence of an alkylaluminum scavenger but in the absence of methylalumoxane (MAO). The adduct cation is inactive under these conditions. Theoretical calculations show very high energy barriers (ΔG=40–47 kcal mol?1) for ethene insertion with a bridged AlOZr catalyst. This is due to an unfavorable six‐membered‐ring transition state, in which the methyl group bridges the metal and ethene with an obtuse metal‐Me‐C angle that prevents synchronized bond‐breaking and making. A more‐likely pathway is dissociation of the Al‐O‐Zr complex into an aluminate and the active polymerization catalyst [Cp*2ZrMe]+. 相似文献
115.
The HNO3‐mediated CH2 extrusion reactions of phenylacetic acid lead to one pot synthesis of unexpected commercially important product 4‐nitrobenzoic acid through the formation of 4‐nitrophenylacetic acid and 2‐nitrophenylacetic acid. 相似文献
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Dr. Alexandre Lumbroso Dr. Michael L. Cooke Prof. Dr. Bernhard Breit 《Angewandte Chemie (International ed. in English)》2013,52(7):1890-1932
Allylic alcohols represent an important and highly versatile class of chiral building blocks for organic synthesis. This Review summarizes the plethora of methods developed for the catalytic asymmetric synthesis of enantioenriched allylic alcohols. These include: dynamic kinetic resolution (DKR/DKAT), nucleophilic 1,2‐addition to carbonyl groups, allylic substitution, oxidation of C? H bonds, the addition of O nucleophiles to π systems, reduction of unsaturated carbonyl compounds, and an alternative route from enantioenriched propargylic alcohols. Furthermore, these catalytic asymmetric processes are exemplified by their applications in the syntheses of complex molecules such as natural products and potential therapeutic agents. 相似文献
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Prof. Dr. Horst Kisch 《Angewandte Chemie (International ed. in English)》2013,52(3):812-847
Preceding work on photoelectrochemistry at semiconductor single‐crystal electrodes has formed the basis for the tremendous growth in the three last decades in the field of photocatalysis at semiconductor powders. The reason for this is the unique ability of inorganic semiconductor surfaces to photocatalyze concerted reduction and oxidation reactions of a large variety of electron‐donor and ‐acceptor substrates. Whereas great attention was paid to water splitting and the exhaustive aerobic degradation of pollutants, only a small amount of research also explored synthetic aspects. After introducing the basic mechanistic principles, standard experiments for the preparation and characterization of visible light active photocatalysts as well as the investigation of reaction mechanisms are discussed. Novel atom‐economic C? C and C? N coupling reactions illustrate the relevance of semiconductor photocatalysis for organic synthesis, and demonstrate that the multidisciplinary field combines classical photochemistry with electrochemistry, solid‐state chemistry, and heterogeneous catalysis. 相似文献