- Synthesis and characterization of sterically and electrostatically shielded pyrrolidine nitroxide radicals
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Two new pyrrolidine nitroxide radicals, cis/trans-2,5-bis(carboxymethyl)-2,5-diethylpyrrolidine 1-oxyl and 2-(carboxymethyl)-2,5,5-triethylpyrrolidine 1-oxyl, for potential applications as spin probes and labels are reported. Carboxymethyl and ethyl groups have been introduced in the α-positions of the nitroxide group in order to improve the stability of the radicals through steric and electrostatic shielding. The compounds were structurally characterized by X-ray crystallography and EPR spectroscopy. An ascorbic acid reduction assay proves that the newly synthesized radicals exhibit higher reductive stability than the well-known and commercially available nitroxide radicals 3-carboxy-PROXYL and 4-carboxy-TEMPO.
- Lampp, Lisa,Morgenstern, Uwe,Merzweiler, Kurt,Imming, Peter,Seidel, Rüdiger W.
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Read Online
- Synthesis of β-nitro ketones from geminal bromonitroalkanes and silyl enol ethers by visible light photoredox catalysis
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Various β-nitro ketones, including those bearing a β-tertiary carbon, were prepared from geminal bromonitroalkanes and trimethylsilyl enol ethers of a broad range of ketones by visible light photoredox catalysis, which were then easily converted into β-amino ketones, 1,3-amino alcohols, α,β-unsaturated ketones, β-cyano ketones and γ-nitro ketones.
- Cao, Haoying,Ma, Shanshan,Feng, Yanhong,Guo, Yawen,Jiao, Peng
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supporting information
p. 1780 - 1783
(2022/02/17)
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- Crystallization Does It All: An Alternative Strategy for Stereoselective Aza-Henry Reaction
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An efficient and experimentally straightforward method for the stereoselective synthesis of a variety of β-nitro-α-amino carboxylic acids via aza-Henry (nitro-Mannich) reaction of aldimines is disclosed, yielding either anti- or a rarely reported syn-configuration. The reaction operates directly on free glyoxylic acid and generates imine species in situ. Crystallization-controlled diastereoselectivity enables isolation of the target compounds in high enantio- and diastereomeric purities by a simple filtration.
- Mar?eková, Michaela,Ger?a, Peter,?oral, Michal,Moncol, Ján,Berke?, Du?an,Kolarovi?, Andrej,Jakubec, Pavol
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supporting information
p. 4580 - 4584
(2019/06/17)
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- Green synthesis method for preparing nitroalkanes by oxime oxidation
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The invention belongs to the field of organic chemical industries, and provides a green synthesis method for preparing nitroalkanes by oxime oxidation. At the temperature of 55 to 120 DEG C and under the pressure of 0 to 1.0 MPa, oxime, a solvent and hydrogen peroxide are reacted for 20 to 200min in the presence of certain amounts of nanoporous skeleton metal hybrid catalysts and cocatalysts, a reaction liquid is subjected to membrane separation, the catalysts can be repeatedly used for more than 7 times, and distilled to obtain nitroalkane products, the purity of the products is not less than 99%, and the yield of the products is not less than 95%. Furthermore, the green synthesis method for preparing nitroalkanes by the oxime oxidation disclosed by the invention is a green synthesis method of nitroalkanes, and suitable for large-scale industrialized production.
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Paragraph 0031; 0032
(2017/08/29)
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- Silver(I)-Promoted ipso-Nitration of Carboxylic Acids by Nitronium Tetrafluoroborate
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A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.
- Natarajan, Palani,Chaudhary, Renu,Venugopalan, Paloth
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p. 10498 - 10504
(2015/11/18)
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- Aggregation behaviour of peptide-polymer conjugates containing linear peptide backbones and multiple polymer side chains prepared by nitroxide-mediated radical polymerization
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A series of peptides with an alternating sequence of alkoxyamine conjugated lysine and glycine residues were synthesized by classical solution phase peptide coupling. The resulting peptides containing up to eight alkoxyamine moieties were used as initiato
- Moeller, Michael,Hentschel, Carsten,Chi, Lifeng,Studer, Armido
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supporting information; experimental part
p. 2403 - 2412
(2011/05/14)
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- NITRATED HYDROCARBONS, DERIVATIVES, AND PROCESSES FOR THEIR MANUFACTURE
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Provided is a process for the formation of nitrated compounds by the nitration of hydrocarbon compounds with dilute nitric acid. Also provided are processes for preparing industrially useful downstream derivatives of the nitrated compounds, as well as novel nitrated compounds and derivatives, and methods of using the derivatives in various applications.
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Page/Page column 30-31; 33
(2009/12/02)
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- Formation of Organic Nitro-compounds in Flowing H2O2+NO2+N2+Organic Vapour Systems. Part 3.-Effects of O2 Addition on H2O2+NO2+N2+Alkane Systems
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The effects of oxygen on the product distribution from the surface-initiated reactions in flowing mixtures of H2O2, NO2, N2 and RH, where RH=ethane, propane, n-butane and n-pentane, at 298 K have been studied.In the absence of O2, the principal products are the corresponding nitroalkane, alkyl nitrite and alkyl nitrate.In the presence of sufficiently large concentrations of O2, the predominant product is the alkyl nitrate and the only other products of significance, in some cases, are the corresponding carbonyl compounds.The variation of the product yields with / gives values for the rate-constant ratios k8/(k3+k4) for reaction at both primary and secondary radical sites:.Possible mechanisms by which the products are formed are discussed.
- Baulch, Donald L.,Campbell, Ian M.,Chappel, Jonathan M.
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p. 617 - 628
(2007/10/02)
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- Novel indolyl alkyl amines, method of producing same, and their use as anorectic agents
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Indolyl alkyl amines of the following formula: SPC1 And their salts with organic or inorganic acids. In this formula I, A and A1 denote identical or different alkyl radicals which both together have a total of 3-8 C-atoms. R1 denotes hydrogen, a lower alkyl radical having up to 4 C-atoms or a possibly substituted benzyl or benzoyl radical. R2 and R3 may be the same or different and denote hydrogen, a halogen (more particularly chlorine, bromine or fluorine) or (possibly halogenated) lower alkyl radicals or (possibly etherified) hydroxy radicals. R4 denotes hydrogen, a lower alkyl radical, an acyl group or a (possibly substituted) benzyl radical or the cyano-ethyl group. The compounds are useful as anoretics (appetite inhibitors) and can be made by various disclosed methods.
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