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Wyniki wyszukiwania dla: HETERO DIELS ALDER REACTION
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Convenient Synthesis of Functionalized Unsymmetrical Vinyl Disulfides and Their Inverse Electron-Demand Hetero-Diels-Alder Reaction
PublikacjaThe simple, convenient, and efficient methods for the preparation of unsymmetrical vinyl disulfides with additional functional groups under mild conditions with moderate to high yields were designed. The developed methods include the reaction of S-vinyl phosphorodithioate with thiotosylates or S-vinyl thiotosylate with thiols. The designed methods allow for the synthesis of unsymmetrical vinyl disulfides with additional functionalities...
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Chiral Schiff base complexes as an effective catalyst in Diels-Alder reaction
PublikacjaDiels Alder reaction is a very important tool in carbon-carbon bond formation. It is a cycloaddition between a conjugated diene and a second compound called dienophile. Where one or more heteroatoms are present in the diene and/or dienophile framework, the cycloaddition is called hetero-Diels-Alder reaction (HDA). The asymmetric Diels-Alder reaction is among the most powerful available methodologies for that construction of optically...
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An experimental and theoretical study of the hetero Diels–Alder reactions between (E)-2-aryl-1-cyano-1-nitroethenes and ethyl vinyl ether: one-step or zwitterionic, two-step mechanism?
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The Mechanism of a Retro-Diels–Alder Fragmentation of Luteolin: Theoretical Studies Supported by Electrospray Ionization Tandem Mass Spectrometry Results
PublikacjaThe mechanisms of retro-Diels–Alder fragmentation of luteolin are studied theoretically using the Density Functional Theory method (B3LYP hybrid functional) together with the 6-311++G(d,p) basis set and supported by electrospray ionization tandem mass spectrometry (ESI-MS) results. The reaction paths leading to the formation of 1,3A and 1,3B fragment ions observed as the main spectral features in the ESI-MS spectrum are described...
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New products of reaction of Lawesson's reagent with diols.
PublikacjaW artykule przedstawiono syntezę i szczegółową charakterystykę strukturalną i konformacyjną 8-, 9- i 10-członowych pierścieniowych związków heterocyklicznych o unikatowym układzie atomów O-P-S-S. W wyniku reakcji a,w-dioli z odczynnikiem Lawessona wobec zasad powstają odpowiednie sole kwasów bisditiofosfonowych, które po utlenieniu dają w/w pierścieniowe disulfidy. Kwasy bisditiofosfonowe przekształcono także w trwałe diestry S-metylowe,...
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Efficient Method for the Synthesis of Functionalized Basic Maleimides
PublikacjaA three-step procedure involving Diels-Alder condensation of maleic anhydride with furane, formation of N-substituted imide upon reaction with appropriate diamine and a final retro Diels-Alder regeneration of the maleic carbon-carbon double bond is proposed for an unequivocal synthesis of N-substituted basic maleimides. The novel method is characterized by mild reaction conditions, easy work-up, high yields and no need for additional...
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Action-reaction based synthesis of acoustic wavefield equations
PublikacjaThe analysis of acoustic fields is usually based on the well-known mathematics of second order partial differential equations called wave equations. The author explores the duality and symmetry of linear fluid mechanics and develops two distinct equations of acoustics on the basis of a causal approach to local small-scale phenomena. Wavefields that are solutions of these equations have different composition, the spherical pressure...
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Alter
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Reduction of the reaction torque of an in-line four-cylinder four-stroke engine
PublikacjaW pracy przedstawiono zarówno dokładne jak i uproszczone zależności na przebieg momentu reakcyjnego silnika, jedno i wielocylindrowego, przenoszonego na ramę pojazdu lub fundament. Wyprowadzono zależność na wartość przesunięcia wałków wyrównoważających zapewniającą całkowite wyeliminowanie wpływu sił bezwładności na przebieg momentu reakcyjnego w silnikach czterosuwowych czterocylindrowych. Wprowadzono kryteria doboru optymalnej...
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Cobalt-/Copper-Containing Perovskites in Oxygen Evolution and Reduction Reactions
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Comparison of the Efficiency of Hetero- and Homogeneous Catalysts in Cellulose Liquefaction
PublikacjaBiomass liquefaction is a well-known and extensively described process. Hydrothermal processes are well understood and can be used in the fuel industry. The use of organic solvents can result in full-fledged products for use in the synthesis of polyurethanes. The plastics industry, including polyurethanes, is targeting new, more environmentally friendly solutions. One of these is the replacement of petrochemical polyols with compounds...
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In-Reactor Polypropylene Functionalization─The Influence of Catalyst Structures and Reaction Conditions on the Catalytic Performance
PublikacjaTo unravel the relationship between silylene-bridged metallocene catalyst structures and polymerization conditions and their effect on the performance in in-reactor functionalization of polypropylene, the behaviors of rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2/MMAO, rac-Me2Si(Ind)2ZrCl2, rac-Me2Si(2-Me-4-Ph-Ind)2HfCl2, and rac-Me2Si(Ind)2HfCl2 in propylene/aluminum alkyl-passivated 10-undecen-1-ol copolymerization were compared. Kinetic analysis...
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Nitrogen-doped porous carbon embedded with cobalt nanoparticles for excellent oxygen reduction reaction
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Thermal Self-Action Effects of Acoustic Beam in a Gas with Reversible or Irreversible Chemical Reaction
PublikacjaThermal self-action of acoustic beam in a gas where an exothermic chemical reaction takes place, is studied. This kind of thermal self-action differs from that in a newtonian fluid. In dependence on the type of a chemical reaction, reversible or not, heating or cooling of a medium occurs. A beam in the case of the irreversible reaction may be unusually self-focusing. The self-action effects relating to wave beams containing shock...
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Blind prediction of homo‐ and hetero‐protein complexes: The CASP13‐CAPRI experiment
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Concentration‐Induced Hetero‐Valent Partial‐Inverse Occupation of Infrared Phosphor
PublikacjaInfrared luminescent materials have evoked much attention from chemists and material scientists. Although substantial progress is made in materials design, the luminescent mechanism remains ambiguous in the complex structures, presenting major barriers to developing novel infrared luminescent materials. Herein, this study aims to deliberate a complete discussion on infrared phosphors with concentration-induced hetero-valent partial-inverse...
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Bifunctional sulfur-silicon podands as new nucleophilic ionophores in acyl transfer reactions. Influence of monovalent cations on the reaction kinetics
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Tourism for older and disabled people
PublikacjaTourist offer for the older and disabled is getting wider. Many hotels and cities are adjusted to disabled people's needs, but there are not enough safe places for leisure, where they could be surrounded by nature. In comparison with cities - villages and small towns have very little to offer as far as tourism is concerned. This problem is noticed by small local communities that threat it as a chance for their economical development....
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Metro
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Analysis of volatile fraction of hybrid fruit pulp using Proton Transfer Reaction - Time-Of-Flight Mass Spectrometry
PublikacjaFruits and vegetables are important ingredients in human diet. Because of this, it is very important to know their exact composition and to control their quality. Based on the aroma of food products, it is possible to pre-evaluate their quality and freshness. The aim of this work was to characterize the volatile fraction of the hybrid fruit ‘sweetie’ using the modern analytical device PTR-TOFMS. Hybrid fruit samples are human-made...
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Surrogate-Assisted Design of Checkerboard Metasurface for Broadband Radar Cross-Section Reduction
PublikacjaMetasurfaces have been extensively exploited in stealth applications to reduce radar cross section (RCS). They rely on the manipulation of backward scattering of electromagnetic (EM) waves into various oblique angles. However, arbitrary control of the scattering properties poses a significant challenge as a design task. Yet it is a principal requirement for making RCS reduction possible. This article introduces a surrogate-based...
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Relation ship between electron scattering grand total and ionization totalcross section.
PublikacjaZaproponowano funkcję wiążącą całkowity przekrój czynny i jonizacyjny przekrój czynny na rozpraszanie elektronów na prostych drobinach węglowodorowych i perfluorowanych. Posługując się znalezioną relacją wyznaczono przekroje czynne dla kilku związków fluoru i wodoru.
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Badanie stabilności chemicznej prepolimerów etero-uretanowych
PublikacjaPrepolimery eterouretanowe otrzymywano na podstawie oligoeterolu (Rokopolu D2002 lub PTMG 1000) i użytego w nadmiarze 4,4-diizocyjanianodifenylometanu. Określono wpływ szybkości obrotów trzpienia wiskozymetru, temperatury, procentowej zawartości grup NCOoraz rodzaju użytego oligoeterolu na lepkość otrzymanych produktów. Oceniono stabilność omawianych prepolimerów w toku przechowywania ich w ciągu 4 tygodni (zmiana zawartości...
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N-doped mesoporous carbon nanosheets obtained by pyrolysis of a chitosan–melamine mixture for the oxygen reduction reaction in alkaline media
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Morphology and dispersion of nanostructured manganese–cobalt spinel on various carbon supports: the effect on the oxygen reduction reaction in alkaline media
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N-doped mesoporous carbon nanosheets obtained by pyrolysis of a chitosan–melamine mixture for the oxygen reduction reaction in alkaline media.
PublikacjaBy simple thermal decomposition of low-cost precursors (chitosan, melamine) in an inert atmosphere, nitrogen-doped porous carbonaceous materials were prepared. The samples pyrolyzed at 700 C are composed of mainly mesoporous nitrogen-doped carbon nanosheets and partially graphitized carbon. The nanosheets contain a disordered area due to the strain imposed by the presence of nitrogen and/or oxygen groups in their structure. Some...
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Vetera christianorum
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Punto Genero
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Risks to Older People in Road Traffic
Publikacjahe article looks at road traffic risks and main trends from the perspective of older road users (drivers, cyclists, pedestrians). With a longer time to react, poor eyesight and hearing, impaired mobility, ill health and medication, older road users are put at risk. A comprehensive and pro-active strategy is needed to deal with these risk factors and meet the safety and mobility needs...
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Nursing older people
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Working with Older People
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Liquefaction of alder wood as the source of renewable and sustainable polyols for preparation of polyurethane resins
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Liquefaction of alder wood as the source of renewable and sustainable polyols for preparation of polyurethane resins
PublikacjaLiquefaction of wood-based biomass gives different polyol properties depending on the reagents used. In this article, alder wood sawdust was liquefied with glycerol and poly(ethylene glycol) solvents. Liquefaction reactions were carried out at temperatures of 120, 150 and 170 °C. The obtained bio-polyols were analyzed in order to establish the process efficiency, hydroxyl number, acid value, viscosity and structural characteristics...
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Visible light-induced photocatalytic reaction of gold-modified titanium(IV) oxide particles: action spectrum analysis
PublikacjaAnalizy spektrum działania wykazały, ze wzbudzenie powierzchniowego plazmonu złota inicjuje utlenianie 2-propanolu w świetle widzialnym w napowietrzonej zawiesinie tlenku(IV) tytanu zmodyfikowanego zlotem. Badania przeprowadzone z użyciem światła polichromatycznego wykazały, ze szybkość reakcji foto-utleniania zależy od właściwości tlenku(IV) tytanu, takich jak rozmiar ziaren, pola powierzchni właściwej, formy krystalicznej (anataz...
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ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE
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Hetero-junction composed of poly(3,4-ethylenedioxythiophene) with poly(styrenesulphonate) and iodine doped titanium dioxide
PublikacjaPraca prezentuje nowe objętościowe heterozłacze typu p-n, gdzie domieszkowany jodem ditlenek tytanu (I-TiO2) pełni rolę elementu n, a poli(3,4-etylenodioksytiofen):poli(etylenosulfonian)(pEDOT:PSS)rolę elementu p. Heterozłącze zostało otrzymane na drodze potencjostatycznej polimeryzacji monomeru w obecnosci nanoproszku I-TiO2 zawieszonego w elektrolicie. Metoda pozwala na otrzymanie warstw hybrydowych, gdzie cząstki I-TiO2 są wbudowane...
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Synthesis of new polycyclic anthracenodione analogs with hetero- or carbocyclic ring(s) fused to the chromophore system
PublikacjaZsyntezowano serię nowych analogów antracenodionów z różnymi pierścieniami hetero- lub karbocyklicznymi sprzężonymi z układem chromoforowym. Związki te mogą stanowić nową klasę pochodnych antracenodionów o potencjalnej zdolności pokonywania oporności wielolekowej komórek nowotworowych.
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Hazardous waste dewatering and dry mass reduction through hydrophobic modification by a facile one-pot, alkali-assisted hydrothermal reaction
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The reduction of (ImH)[trans-RuIIICl4(dmso)(Im)] under physiological conditions: preferential reaction of the reduced complex with human serum albumin
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Electrochemical simulation of metabolic reduction and conjugation reactions of unsymmetrical bisacridine antitumor agents, C-2028 and C-2053
PublikacjaElectrochemistry (EC) coupled with analysis techniques such as liquid chromatography (LC) and mass spectrometry (MS) has been developed as a powerful tool for drug metabolism simulation. The application of EC in metabolic studies is particularly favourable due to the low matrix contribution compared to in vitro or in vivo biological models. In this paper, the EC(/LC)/MS system was applied to simulate phase I metabolism of the representative...
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Reaction Kinetics Mechanisms and Catalysis
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Peter Meredith
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Selectivity of Mixed Iron-Cobalt Spinels Deposited on a N,S-Doped Mesoporous Carbon Support in the Oxygen Reduction Reaction in Alkaline Media
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Analysis of volatile fraction of sweetie (Citrus maxima × Citrus paradisi) and its parent fruit using proton transfer reaction mass spectrometry
PublikacjaThe quality of the fruit is affected by several main ingredients and the aroma plays a fundamental role during the selection of fruit by consumers. In the case where several fruit have similar aromas and only one of them has specific health properties, it is very important to find the differences in the volatile organic compounds (VOCs) composition to distinguish these samples. Such situations are often found for hybrid fruit....
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Dimolybdenum Tetracarboxylates as Auxiliary Chromophores in Chiroptical Studies of vic-Diols
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POLYMER REACTION ENGINEERING
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INORGANIC REACTION MECHANISMS
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Macromolecular Reaction Engineering
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Branched Poly(l-lysine)-Derived Nitrogen-Containing Porous Carbon Flake as the Metal-Free Electrocatalyst toward Efficient Oxygen Reduction Reaction
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Treatment of Hypertension in Patients 80 Years of Age or Older
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