- Redox-Neutral Selenium-Catalysed Isomerisation of para-Hydroxamic Acids into para-Aminophenols
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A selenium-catalysed para-hydroxylation of N-aryl-hydroxamic acids is reported. Mechanistically, the reaction comprises an N?O bond cleavage and consecutive selenium-induced [2,3]-rearrangement to deliver para-hydroxyaniline derivatives. The mechanism is studied through both 18O-crossover experiments as well as quantum chemical calculations. This redox-neutral transformation provides an unconventional synthetic approach to para-aminophenols.
- Chuang, Hsiang-Yu,Schupp, Manuel,Meyrelles, Ricardo,Maryasin, Boris,Maulide, Nuno
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p. 13778 - 13782
(2021/03/31)
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- Laccase Variants
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The present invention relates to variants of a parent laccase. The present invention also relates to polynucleotides encoding the variant laccases and to nucleic acid constructs, vectors, and host cells comprising the polynucleotides, and methods of using the variant enzymes.
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- Solid-phase extraction of plutonium(IV) an americium(III) using N-benzoylphenylhydroxylamine and its derivatives
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The recovery and separation of plutonium(IV) and americium(III) by solid-phase extraction (SPE) on alkylated silica gel S16 modified with N-benzoylphenylhydroxylamine (BPHA) and with its derivatives was studied. BPHA was modified by introducing into the p-position of the phenyl ring of electronactive substituents that differ in their hydrophobicity: CH3, Ph, Cl, F, and NO2. The SPE of plutonium(IV) and americium(III) was studied in the range of acidities from pH 8 to 1 M HNO3. The recovery and separation of these elements was shown to depend on the nature of the substituent, aqueous acidity, and the preparation of S16 to SPE experiments.
- Petrukhin,Spivakov,Morgalyuk,Malofeeva,Kuzovkina,Novikov
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experimental part
p. 1839 - 1846
(2012/01/31)
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- Photoacid generators (PAGs) based on N-acyl-N-phenylhydroxylamines for carboxylic and sulfonic acids
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Simple and efficient photoacid generators (PAGs) for carboxylic and sulfonic acids based on N-acyl-N-phenylhydroxylamines have been demonstrated. Irradiation of o-carboxylates and thermally rearranged o-arenesulfonates of N-acyl-N-phenylhydroxylamines using UV light (≥254 nm) in aqueous methanolic solution resulted in efficient generation of carboxylic and sulfonic acids, respectively. The carboxylic acid generation ability of N-acyl-N- phenylhydroxylamines was found to be dependent on their N-acyl substituents. Further, polymer bearing o-arenesulfonates of N-acyl-N-phenylhydroxylamine was synthesized and demonstrated as PAG for sulfonic acids.
- Ikbal, Mohammed,Jana, Avijit,Singh, N.D. Pradeep,Banerjee, Rakesh,Dhara, Dibakar
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scheme or table
p. 3733 - 3742
(2011/06/21)
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- N-HETEROCYCLIC CARBENE (NHC) CATALYZED SYNTHESIS OF HYDROXAMIC ACIDS
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A process for preparing hydroxamic acids is provided. The process comprises reacting an aldehyde with a nitroso compound in the presence of a N-heterocyclic carbene (NHC) catalyst.
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Page/Page column 43
(2008/12/07)
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- N-heterocyclic carbene (NHC)-catalyzed direct amidation of aldehydes with nitroso compounds
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(Chemical Equation Presented) NHC-catalyzed direct amidation of aldehydes with nitroso compounds is a powerful method for the synthesis of N-arylhydroxamic acids. A variety of aryl, alkyl, alkenyl, and heterocyclic aldehydes were found to give excellent yields of the corresponding N-arylhydroxamic acids. This chemistry was also extended to the synthesis of chiral N-arylhydroxamic acids by kinetic resolution of α-branched aldehydes, a domino amidation-redox amination reaction of acrolein, and a three-component reaction for the synthesis of N-arylaziridines.
- Fong, Tian Wong,Patra, Pranab K.,Seayad, Jayasree,Zhang, Yugen,Ying, Jackie Y.
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supporting information; experimental part
p. 2333 - 2336
(2009/05/26)
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- ANTIMICROBIAL COMPOSITION CONTAINING AN OXIDOREDUCTASE AND AN ENHANCER OF THER N-HYDROXYANILIDE-TYPE
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The present invention relates to an enzymatic composition capable of killing or inhibiting microbial cells or micro-organisms, e.g. in laundry, on hard surfaces, in water systems, on skin, on teeth or on mucous membranes. The present invention also relate
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- Substituent effects in the micellar hydrolysis of N-phenylbenzohydroxamic acid under acidic conditions
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The rates of hydrolysis of some para-substituted N-phenylbenzohydroxamic acids (X.C6H4.(C = O).N(OH)C6H5; X = H, CH3, OCH3, F, NO2) under acidic conditions with cationic, anionic and nonionic surfactants have been measured. Substituent effects upon first order rate constants in water and at the micellar surface fitted Hammett equation, based on σ, σ+, σ- parameters. Values of 'p' increase with increasing surfactant concentration. The substituent effects indicate specific micellar influences on the rates and a difference in mechanism between the bulk aqueous phase and the micellar phase. The lipophilicity and polar effects of the substituents have also been evaluated.
- Ghosh, Kallol K.,Roy, Supriya
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p. 324 - 328
(2007/10/03)
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- A convenient method for the preparation of N-aryl and N-alkyl-O-methyl hydroxylamines
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Trifluoroaceto or p-nitrobenzo-N-substituted hydroxamic acids are smoothly methylated with diazomethane and the products cleanly cleaved by hydrazine to provide the title compounds.
- Santos,Lobo,Prabhakar
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p. 3509 - 3518
(2007/10/03)
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