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Showing 1 to 20 of 25 for “"nitrones"”.
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Diastereoselectivity of Organometallic Additions to Nitrones
Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs
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Alpha-Oxygenation by Acylation-Rearrangement of Nitrones
The acylation-rearrangement of N-alkylnitrones with acid chlorides and triethylamine affords a new method for the (alpha)-oxygenation of aldehydes and cyclic ketones via (alpha)-acyloxy imines. The reaction apparently proceeds by initial acylation of the nitrone oxygen, proton removal, and …
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Cyclic nitrones: oxidation studies and the synthesis of a heterocyclic nitrone
… IR and p.m.r. spectra. Part 2: Cyclic aldonitrones and some related cyclic hydroxylamines have been shown to undergo oxidation by ferric chloride to cyclic hydroxamic acids. For example, the 2-unsubstituted 1-pyrroline 1-oxides gave l-hydroxy-2-pyrrolidones , and 1-piperideine 1-oxide gave …
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Synthèse de Nouvelles Nitrones du Type Pyrroline-N-Oxyde et leur Utilisation en Spin-Trapping
… étude a été de synthétiser et tester plusieurs nitrones pour mieux cerner les effets électroniques et stériques du groupement phosphoré. Nous avons préparé et testé trois nouvelles nitrones, le 2-diéthoxyphosphorylméthyl-2-méthyl- 3,4-dihydro-2H-pyrrole-1-oxyde (ESP), le …
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Scope and stereochemistry of carbon-carbon bond formation via addition of carbon nucleophiles to nitrones
… and silyl ketene acetals to acyclic and cyclic nitrones have been studied. A 4:1 selectivity favoring axial addition was observed in the reactions of cis-3,5-dimethyl-2,3,4,5-tetrahydropyridine N-oxide with both methyl and phenyl Grignard reagents and the silyl ketene acetal of t-butyl acetate. …
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Aliphatic Nitroxyl Radicals as Antifatigue Agents for Rubbers
… nitroxyl radicals. On the other hand N-alkyl aldonitrones containing semi-hindered phenolic antioxidant functions were good antifatigue agents. Optimum activity was achieved when they were premilled with the rubber for two minutes on an open two-roll mill prior to the compounding operations. …
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Acyclic Imidate and Thiomidate Normal-Oxides: Nitrones of Esters and Thioesters (alpha-Alkoxynitrones, Alpha-Alkylthionitrones, Normal - Alkylthiohydroxamic Acids, X-Ray)
… with aliphatic orthoesters. The (alpha)-alkoxynitrones and their hydrochlorides were characterized by ('1)H NMR spectroscopy and, in one case, by reaction with ammonia and aniline. In addition, a series of N,S-dialkylthioimidate N-oxides hydroiodides was synthesized by S-alkylation of …
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THE PHOTOISOMERIZATION OF 2-PHENYL-3H-INDOL-3-ONE N-OXIDE (2- PHENYLISATOGEN) TO 2-PHENYL-4H-3,1-BENZOXAZIN-4-ONE
The use of nitrones is an important synthetic tool for the organic chemist. An unusual reaction of these nitrones is a photochemical ring expansion under proper conditions that allows the nitrone oxygen to migrate past a carbon atom in a ring and insert itself into a ring that is expanded by the …
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The Design and Synthesis of Novel Chiral Z-Nitrones with Applications Towards the Syntheses of Enantiomerically Pure 4-Hydroxy Amino Acids
… via 1,3-dipolar cycloadditions of novel Z-nitrones and substituted olefins. Three achiral nitrones were synthesized in pursuit of a conformationally stable yet reactive Z-nitrone. The carboisopropoxynitrone was determined to be the best synthon in cycloadditions that favored a Z-nitrone …
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Tandem Cycloaddition Chemistry: Part I. Synthesis and Crystallographic Analysis of 1-Azafenestranes. Part II. Synthesis and Reactivity of N-Vinyl Nitrones
… reaction. A general synthesis of N-vinyl nitrones through selenoxide elimination was developed. Beginning from nitroalkenes, conjugate addition of benzeneselenol provides 2-nitro selenides which can be reduced to the corresponding hydroxylamines and combined with benzaldehyde to provide …
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A study of mechanochemical reactions of spin traps in hydrocarbon polymers
… (>NOH, >NOR) formed from nitroso compounds and nitrones in EPR and PP during spin trapping techniques have been examined. The nitroxyl yield and polymer bound nitroxyl percentage formed from these spin traps were found to be strongly dependent on the nature of spin trap and radical generator, …
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ΜΕΛΕΤΗ ΑΝΤΙΔΡΑΣΕΩΝ ΔΙΑΡΥΛΟΙΩΔΩΝΙΑΚΩΝ ΚΑΙ ΦΑΙΝΥΛΟ(Β-ΑΡΥΛΟΑΙΘΙΝΥΛΟ) ΙΩΔΩΝΙΑΚΩΝ ΑΛΑΤΩΝ
… (ARYLETHYNYL) IODONIUM SALTS REACT ALSO WITH NITRONES BUT THE RESULTING PHENYL (SUBSTITUTED ISOXAZOLINYL) IODONIUM SALTS WITH ONE EXCEPTION ARE DIFFICULT TO ISOLATE BECAUSE OF READY HYDROLYSIS.
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Synthesis of functionalised sulfonamides
… a [3+2] cycloaddition with a variety of N-methyl-nitrones, providing access to the corresponding 4C-substituted isoxazolidine in a regio- and diastereoselective manner. Aminolysis of the resultant PFP sulfonate ester then provides functionalised sulfonamides of potential biological utility. In …
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The Behaviour of Substituted Diaryl Nitroxyl Radicals and their Derivatives as Antifatigue Agents for Rubbers
… of the diaryl nitroxyl radicals. Diaryl nitrones were also shown to produce the corresponding nitroxyl radical during processing, although their antifatigue activity was low. However inclusion of a semi-hindered phenolic moiety in the molecule markedly improved activity...
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Interfacial Nitrone 1,3-Dipolar Cycloadditions for Modification of Monolayer Protected Gold Nanoparticles
… cycloaddition reaction with a series of nitrones under ambient and high-pressure conditions. Expanding the scope of this reaction to the investigation in synthesizing a nitrone modified-MPN and examine its ability to undergo the 1,3-dipolar cycloaddition reaction with a series of …
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Isoxazole Linked siRNA Cholesterol Conjugates by Catalyst Free Nitrile Oxide/Alkyne Cycloadditions
… value of dipolar cycloaddition chemistry of nitrones and nitrile oxides with alkene and alkyne dipolarophiles Chapter 2 presents the somewhat disappointing findings on the cycloaddition reactions of maleimides. Reactions with “simple” maleimides suffered from poor yield and/or poor …
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