- Strain-Release Driven Cycloadditions for Rapid Construction of Functionalized Pyridines and Amino Alcohols
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This paper describes the development of a new variant of stereoselective strain-release driven reactions (formal homo [3 + 2] dipolar cycloadditions) which utilize housane (1) to construct functionalized amino alcohols and pyridine-substituted cyclopentanes in two to three steps from simple and easily available building blocks (nitrones and pyridine N-oxides respectively).
- Clementson, Sebastian,Radaelli, Alessio,Fjelbye, Kasper,Tanner, David,Jessing, Mikkel
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supporting information
p. 4763 - 4766
(2019/06/24)
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- Gold Supported on Silica Catalyzes the Aerobic Oxidation of N,N-Disubstituted Hydroxylamines to Nitrones
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A new method for the preparation of nitrones through the aerobic oxidation of the corresponding N,N-disubstituted hydroxylamines has been developed by exploring a new catalytic reactivity of gold supported on silica. The oxidation occurs under very mild c
- D'Adamio, Giampiero,Parmeggiani, Camilla,Goti, Andrea,Cardona, Francesca
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supporting information
p. 6541 - 6546
(2015/10/19)
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- Molybdenum oxide/bipyridine hybrid material {[MoO3(bipy)] [MoO3(H2O)]}n as catalyst for the oxidation of secondary amines to nitrones
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The inorganic-organic hybrid material {[MoO3(bipy)][MoO 3(H2O)]}n (bipy = 2,2′-bipyridine) can be used as a water-tolerant catalyst for the oxidation of secondary amines under mild conditions using either urea hydrogen peroxide (UHP) or tert-butylhydroperoxide (TBHP) as the oxidant. Under optimized reaction conditions (2 mol % catalyst, 3-4 equiv TBHP, CH2Cl2 as the solvent, 40 °C), the corresponding nitrones were obtained with different efficiency depending on the nature of the cyclic or acyclic amine used.
- Abrantes, Marta,Gonalves, Isabel S.,Pillinger, Martyn,Vurchio, Carolina,Cordero, Franca M.,Brandi, Alberto
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experimental part
p. 7079 - 7082
(2012/01/30)
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- Process for the preparation of amine oxides
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The present invention provides a process for the preparation of amine oxide by reacting a tertiary or a secondary amine with hydrogen peroxide as an oxidant in the presence of a recyclable heterogeneous catalyst comprising a layered double hydroxide exchanged with an anion in the presence of an additive selected from the group consisting of benzonitrile, propionitrile, isoburyronitrile, benzamide and isobutyramide.
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Page/Page column 8
(2008/06/13)
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- Two new methodologies for the deoxygenation and reduction of nitrones based on the use of lithium and DTBB (cat.)
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A variety of nitrones undergo deoxygenation when treated with an excess of lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) (10 mol%) in THF at room temperature to give the corresponding imines. The Li/DTBB system, when combined with nickel(II) chloride dihydrate allows the reduction of a series of nitrones to secondary amines. The use of the deuterium oxide-containing nickel(II) salt transforms the starting nitrones to deuterated secondary amines.
- Radivoy,Alonso,Yus
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p. 427 - 430
(2007/10/03)
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- Synthesis of nitrones by methyltrioxorhenium catalyzed direct oxidation of secondary amines
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Oxidation of secondary amines catalyzed by methyltrioxorhenium (MTO) with H2O2 or urea-hydrogen peroxide complex (UHP) at room temperature gives the corresponding nitrones in good yields.
- Goti, Andrea,Nannelli, Luca
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p. 6025 - 6028
(2007/10/03)
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- Synthesis of nitrones using the methyltrioxorhenium/hydrogen peroxide system
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Secondary amines are oxidized by the methyltrioxorhenium/hydrogen peroxide system to the corresponding nitrones in excellent yield. The results provide a further example of the parallel between the chemistry of this metal system and that of the dioxiranes.
- Murray, Robert W.,Iyanar, Kaliappan,Chen, Jianxin,Wearing, James T.
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p. 8099 - 8102
(2007/10/03)
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- Oxidation of secondary amines to nitrones using urea-hydrogen peroxide complex (UHP) and metal catalysts
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Secondary amines can be readily oxidized to the corresponding nitrones using urea-hydrogen peroxide complex (UHP) and metal catalysts in methanol at room temperature. Sodium tungstate is the most effective catalyst in several runs and common protecting groups are tolerated in these conditions.
- Marcantoni, Enrico,Petrini, Marino,Polimanti, Olga
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p. 3561 - 3562
(2007/10/02)
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- Synthesis and Cycloaddition of 6-Substituted-3,4,5,6-tetrahydropyridine 1-oxides
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A study of the regiochemical behaviour of the peracid induced ring opening of several hexahydro-2H-isoxazolopyridines (4), leading mainly to ketonitrones (6), has been carried out.Mercury(II) oxide oxidation of unsymmetrical N-hydroxypiperidines (1
- Ali, Sk. Asrof
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p. 301 - 317
(2007/10/02)
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- Highly efficient and mild synthesis of nitrones by catalytic oxidation of hydroxylamines with tetra-n-propylammonium perruthenate
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Oxidation of N,N-disubstituted hydroxylamines by N-methylmorpholine N- oxide (NMO) and catalytic amounts of tetra-n-propylammonium perruthenate (TPAP) at room temperature occurs very rapidly to give the corresponding nitrones, which can be trapped by dipo
- Goti, Andrea,De Sarlo, Francesco,Romani, Michela
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p. 6571 - 6574
(2007/10/02)
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- Angiotensin II receptor blocking 2,3,6 substituted quinazolinones
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This disclosure describes novel 2, 3, 6 substituted quinazolinones having the formula: STR1 wherein X, R, and R 6 are described in the specification which have activity as angiotensin II (AII) antagonists.
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- Angiotensin II receptor blocking 2, 3, 6 substituted quinazolinones
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This disclosure describes novel 2,3,6, substituted quinazolinones of the formula: STR1 wherein R 1, R 6 and X are described in the specification which have activity as angiotensin II (AII) antagonistis.
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- Mercury(II) oxide oxidation of 2-substituted-N-hydroxypiperidine: A solution to the regiochemical problem
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Mercury(II) oxide oxidation of N-hydroxypiperidines having tertiary alcohol group at the β position of the C(2) side chain gave aldonitrones in a highly regioselective manner.
- Asrof Ali
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p. 5325 - 5326
(2007/10/02)
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- Tungstate-Catalyzed Oxidation of Secondary Amines to Nitrones. α-Substitution of Secondary Amines via Nitrones
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The sodium tungstate catalyzed oxidation of secondary amines with hydrogen peroxide gives the corresponding nitrones.Acyclic and cyclic nitrones can be obtained from secondary amines in a single step in good to escellent yields.The oxidation of secondary amines in the presence of alkenes gives isoxazolidines by 1,3-dipolar cycloaddition of nitrones.Introduction of a substituent at the α-position of secondary amines can be performed upon oxidation of secondary amines and subsequent treatment with various nucleophiles.
- Murahashi, Shun-Ichi,Mitsui, Hitoshi,Shiota, Tatsuki,Tsuda, Tomoyasu,Watanabe, Shoji
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p. 1736 - 1744
(2007/10/02)
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- Nitrone Cycloadditions: Synthesis of (+/-)-Andrachamine
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The usefulness of the cycloaddition of alkenes to 2-alkyl-2,3,4,5-tetrahydropyridine oxides for the preparation of trans-2,6-dialkylpiperidines is confirmed by a stereoselective synthesis of (+/-)-andrachamine.Peroxy acid oxidation of 9-oxa-1-azabicyclononanes does not lead regioselectively to the corresponding 2-alkyl-2,3,4,5-tetrahydropyridine oxide, as had previously been claimed.
- Carruthers, William,Coggins, Peter,Weston, John B.
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p. 2323 - 2327
(2007/10/02)
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- SELENIUM DIOXIDE CATALYZED OXIDATION OF SECONDARY AMINES WITH HYDROGEN PEROXIDE. SIMPLE SYNTHESIS OF NITRONES FROM SECONDARY AMINES
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Oxidation of secondary amines with hydrogen peroxide in the presence of selenium dioxide catalyst at room temperature gives nitrones, which are versatile synthetic intermediates, highly efficiently.
- Murahashi, Shun-Ichi,Shiota, Tatsuki
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p. 2383 - 2386
(2007/10/02)
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- Synthesis of nitrone from secondary amine
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A nitrone is synthesized from a secondary amine by reacting a compound represented by the following general formula STR1 wherein R1 and R2 mean individually a hydrogen atom or an alkyl or aryl group and R3 denotes an alkyl or aryl group with a peroxide in the presence of a catalyst selected from the group consisting of tungsten compounds, molybdenum compounds, vanadium compounds, titanium compounds, palladium compounds, rhodium compounds, ruthenium compounds and nickel compounds. This process provides the nitrone by one-step oxidation of the secondary amine.
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- Tungstate Catalysed Oxidation of Secondary Amines with Hydrogen Peroxide. A Novel Transformation of Secondary Amines into Nitrones
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The sodium tungstate catalysed oxidation of secondary amines with hydrogen peroxide gives the corresponding nitrones, which are versatile synthetic intermediates and spin trapping reagents, in a single step.
- Mitsui, Hitoshi,Zenki, Sei-ichi,Shiota, Tatsuki,Murahashi, Shun-Ichi
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p. 874 - 875
(2007/10/02)
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- Synthesis and Thermolysis of O-Alkyl-N-vinylhydroxylamine Derivatives
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Oxoiminium salts 11 a-e and 13 a-e have been prepared from the ο-chloroketones 9 a-e by oximation via the cyclic oxime ethers 10 a-e and the cyclic imine oxides 12 a-e, followed by alkylation with "Meerwein salt".The deprotonation reaction of 11 a-e and 13 a-e yields, via the regioselectively prepared intermediates 14 a-e and 17 a-e, the α, β-unsaturated imines 15 a-e and the cyclic imines 18 a-e, respectively.
- Shatzmiller, Shimon,Shalom, Eytan
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p. 897 - 905
(2007/10/02)
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