- Late Stage Functionalization of Secondary Amines via a Cobalt-Catalyzed Electrophilic Amination of Organozinc Reagents
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A general preparation of polyfunctional hydroxylamine benzoates from the corresponding secondary amines is reported. This convenient synthesis allows the setup of a late-stage functionalization of various secondary amines, including pharmaceuticals and peptidic derivatives. Thus, a cross-coupling of hydroxylamine benzoates with various alkyl-, aryl-, and heteroaryl-zinc chlorides in the presence of 5 mol % CoCl2 (25 °C, 2 h) provides a range of polyfunctional tertiary amines. This method was used to prepare penfluridol and gepirone.
- Gra?l, Simon,Chen, Yi-Hung,Hamze, Clémence,Tüllmann, Carl Phillip,Knochel, Paul
-
supporting information
p. 494 - 497
(2019/01/14)
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- Enantioselective Synthesis of 4-Aminotetrahydroquinolines via 1,2-Reductive Dearomatization of Quinolines and Copper(I) Hydride-Catalyzed Asymmetric Hydroamination
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A 1,2-reductive dearomatization of quinolines and copper(II) acetate monohydrate/(R,R)-Ph-BPE/P(p-tolyl)3-catalyzed enantioselective hydroamination sequence was developed, affording diverse 4-amino-1,2,3,4-tetrahydroquinolines with high levels of enantioselectivity in either a stepwise or one-pot fashion. Pleasingly, internal cis-cyclic alkenes, which are challenging substrates in copper hydride-catalyzed enantioselective hydroamination reactions, were transformed efficiently under mild conditions.
- Xu-Xu, Qing-Feng,Zhang, Xiao,You, Shu-Li
-
supporting information
p. 5357 - 5362
(2019/09/06)
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- Copper-Catalyzed Ring Opening of Benzofurans and an Enantioselective Hydroamination Cascade
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A copper(II) acetate/(R)-DTBM-SEGPHOS-catalyzed ring opening of benzofurans and enantioselective hydroamination cascade with dimethoxymethylsilane (DMMS) and hydroxylamine esters is described. Starting from readily available substituted benzofurans, a series of chiral N,N-dibenzylaminophenols, which are of high interest in pharmaceutical chemistry, were obtained with excellent enantioselectivities (up to 66 % yield, 94 % ee).
- Xu-Xu, Qing-Feng,Liu, Qiang-Qiang,Zhang, Xiao,You, Shu-Li
-
supporting information
p. 15204 - 15208
(2018/10/24)
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- Synthesis and characterization of N-methyl and N-benzyl cinnamohydroxamic acids
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N-methyl and N-benzyl cinnamohydroxamic acid was prepared by coupling reaction between N-methyl hydroxylamine and N-benzyl hydroxylamine with cinnamoyl chloride. The compounds were structurally characterized with 1H NMR, IR and elemental analysis.
- Rajput, Surendra K.,Patel, Anita,Bapat, Kishor N.
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p. 885 - 887
(2017/02/10)
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- Selective Oxidation of Secondary Amines to N,N-Disubstituted Hydroxylamines by Choline Peroxydisulfate
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N,N-Disubstituted hydroxylamines were prepared directly from secondary amines by a reliable method using an oxidizing task-specific ionic liquid, choline peroxydisulfate. The operational simplicity, high selectivity, and green reaction conditions, make this method efficient and practical.
- Banan, Alireza,Valizadeh, Hassan,Heydari, Akbar,Moghimi, Abolghasem
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p. 2315 - 2319
(2017/10/06)
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- The Reactivity of Difluorocarbene with Hydroxylamines: Synthesis of Carbamoyl Fluorides
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Carbamoyl fluorides are formed in reactions of hydroxylamines with difluorocarbene generated from sodium bromodifluoroacetate as readily available and non-toxic carbene precursor. The process shows a high functional group tolerance, and the reaction path has been rationalized by computational calculations. (Figure presented.) .
- Baars, Hannah,Engel, Julien,Mertens, Lucas,Meister, Daniela,Bolm, Carsten
-
supporting information
p. 2293 - 2299
(2016/07/29)
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- Synthesis of N,N,O-Trisubstituted Hydroxylamines by Stepwise Reduction and Substitution of O-Acyl N,N-Disubstituted Hydroxylamines
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Diverse N,N,O-trisubstituted hydroxylamines, an under-represented group in compound collections, are readily prepared by partial reduction of N-acyloxy secondary amines with diisobutylaluminum hydride followed by acetylation and reduction of the so-formed O-acyl-N,N-disubstituted hydroxylamines with triethylsilane and boron trifluoride etherate. Use of carbon nucleophiles in the last step, including allyltributylstannane, silyl enol ethers, and 2-methylfuran, gives N,N,O-trisubstituted hydroxylamines with branching α- to the O-substituent. N,N-Disubstiuted hydroxylamines are conveniently prepared by reaction of secondary amines with dibenzoyl peroxide followed by diisobutylaluminum hydride reduction.
- Dhanju, Sandeep,Crich, David
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p. 1820 - 1823
(2016/05/19)
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- O-trifluoromethylation of N,N-disubstituted hydroxylamines with hypervalent iodine reagents
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A mild trifluoromethylation reaction of N,N-disubstituted hydroxylamines that is tolerant towards a variety of functional groups, including nitriles, alcohols, ketones, esters, amides, imides, and nitrogen heterocycles, is reported. The key feature of this reaction is the activation of the CF 3 reagent with either trimethylsilyl triflate or LiClO4 and partial or full deprotonation of the substrate with tetramethylguanidine or lithium diisopropylamide. Products were obtained in up to 80 % yield. Preliminary mechanistic studies suggested that the reaction follows a radical pathway in which the deprotonated hydroxylamine and a Lewis or Bronsted acid activated CF3 reagent engages in a single-electron-transfer step to generate a pair of radicals that recombine to afford the desired product. The trifluoromethylation procedure was successfully used in the modification of secondary nitrogen groups of pharmaceutically relevant targets (Fluoxetine and Mefloquine), which afforded new derivatives containing a novel N-trifluoromethoxy moiety. Copyright
- Matousek, Vaclav,Pietrasiak, Ewa,Sigrist, Lukas,Czarniecki, Barbara,Togni, Antonio
-
supporting information
p. 3087 - 3092
(2014/06/09)
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- Methyltrioxorhenium-catalysed oxidation of secondary amines to nitrones in ionic liquids
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Nitrones serve as starting materials for the synthesis of many heterocycles. Oxidation of secondary amines using hydrogen peroxide and the catalytic amount of methyltrioxorhenium in ionic liquids is a useful method for the preparation of nitrones. Ultrasonic irradiation and ionic liquids have a positive influence on the reaction. The nitrones required were isolated in good yields. Corresponding hydroxylamines, which can be easily oxidised to nitrones, often accompanied the main products. Methyltrioxorhenium in ionic liquids was re-used in several reaction cycles without any deteriorating effect on the course of the reaction.
- Meciarova, Maria,Mojzesova, Melinda,Sebesta, Radovan
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p. 51 - 58,8
(2020/08/20)
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- Highly diastereoselective anti-dihydroxylation of 3-N,N- dibenzylaminocyclohex-1-ene N-oxide
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Oxidation of 3-N,N-dibenzylaminocyclohex-1-ene N-oxide in the presence of Cl3CCO2H proceeds with high levels of anti- diastereoselectivity (97% de), with no competing side reactions, allowing access to 1,2-anti-2,3-anti-3-aminocycloh
- Aciro, Caroline,Davies, Stephen G.,Kurosawa, Wataru,Roberts, Paul M.,Russell, Angela J.,Thomson, James E.
-
supporting information; experimental part
p. 1333 - 1336
(2009/09/27)
-
- Metal-free artificial nucleases based on simple oxime and hydroxylamine scaffolds
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Hydrolysis of DNA is of increasing importance in biotechnology and medicine. In this Letter, we present the DNA-cleavage potential of metal-free hydroxylamines and oximes as new members of nucleic acid cleavage agents.
- Fernandes, Luciano,Fischer, Franciele L.,Ribeiro, Carolina W.,Silveira, Gustavo P.,Sa, Marcus M.,Nome, Faruk,Terenzi, Hernan
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supporting information; experimental part
p. 4499 - 4502
(2009/04/08)
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- C3-symmetric titanium(IV) triphenolate amino complexes for a fast and effective oxidation of secondary amines to nitrones with hydrogen peroxide
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The efficient catalytic oxidation of secondary amines to nitrones using hydrogen peroxide as primary oxidant is described. The titanium(IV) complex 2 bearing a C3-symmetrical triphenolate amino ligand has proved to be an air- and water-tolerant complex that efficiently catalyzes secondary amine oxidations at 60°C without previous activation [catalyst loading as low as 0.01%, yields up to 99%, turnover numbers (TONs) up to 8000 and turnover frequencies (TOFs) up to 11000 h-1).
- Zonta, Cristiano,Cazzola, Elisa,Mba, Miriam,Licini, Giulia
-
scheme or table
p. 2503 - 2506
(2009/09/07)
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- Solid-phase synthesis of hydroxypiperazine derivatives using phenethylamine linker by oxidation-Cope elimination
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A general method is reported for the parallel solid-phase synthesis of hydroxypiperazine derivatives based on the oxidation-Cope elimination of polymer-bound phenethylamine linker with m-CPBA. The key intermediate of phenethylamine N-oxide resins was separable on solid-phase for subsequent β-elimination, from which the desired hydroxypiperazine products could be obtained in high purities and yields without any significant contamination at 90°C for 2 h. The utility of the methodology for solid-phase synthesis of general hydroxylamines was also investigated using the same linker. The progress of reactions could be monitored on polymer bound intermediates by ATR-FTIR spectroscopy on single bead. The desired products were obtained in good six-step overall yields upon cleavage from the resins and were characterized by LC/MS, 1H NMR, and 13C NMR spectroscopy.
- Seo, Jin-Soo,Kim, Hye-Won,Cheol, Min Yoon,Deok, Chan Ha,Gong, Young-Dae
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p. 9305 - 9311
(2007/10/03)
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- Ti(IV)-based catalytic membranes for efficient and selective oxidation of secondary amines
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The incorporation of homogenous Ti(IV)/trialkanolamine catalyst in polymeric membranes provided new polymeric catalytic Ti(IV)-based membranes, stable and efficient as heterogeneous catalysts for chemoselective oxidations of secondary amines to nitrones by alkyl hydroperoxides. Polyvinylidene fluoride (PVDF)-based catalytic membranes gave the best results affording products in short reaction times, high yields and selectivity using as little as 1% of catalyst, comparable with the performances of the corresponding homogeneous system. PVDFa€"Ti membrane could be recycled up to five runs with no loss of activity.
- Buonomenna, Maria Giovanna,Drioli, Enrico,Nugent, William A.,Prins, Leonard J.,Scrimin, Paolo,Licini, Giulia
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p. 7515 - 7518
(2007/10/03)
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- BF3-promoted hydrostannation of N-heteroatom-substituted imines for the reduction of C=N bond
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Hydrostannation of N-heteroatom-substituted imines such as oxime ethers, hydrazones, oximes, nitrones, and N-sulfonyl imines using a combination of Bu3SnH and BF3·OEt2 has been systematically studied. Not only aromatic aldimines but also kitimines and aliphatic imines were reduced to give the corresponding amines.
- Ueda, Masafumi,Miyabe, Hideto,Namba, Megumi,Nakabayashi, Toshiki,Naito, Takeaki
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p. 4369 - 4371
(2007/10/03)
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- Mechanism of the 10-methylacridinium ion-sensitized photooxidation of N,N-dibenzylhydroxylamine and its derivatives in acetonitrile
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The 10-methylacridinium ion (MA+)-sensitized photooxidation of substituted N,N-dibenzylhydroxylamines (1) in acetonitrile occurred mainly by a superoxide ion mechanism to give N-benzylidenebenzylamine N-oxides (2) and hydrogen peroxide quantitatively. Analysis of substituent effects on the limiting quantum yield for formation of 2 showed that back electron transfer (ET) from the 10-methylacridinyl radical (MA.) to the radical cation 1+. proceeds in the Marcus 'normal region'. In addition, this back ET was found to take place in preference to one-electron reduction of O2 by MA..
- Ohba, Yasuhiro,Kubo, Kanji,Igarashi, Tetsutaro,Sakurai, Tadamitsu
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p. 491 - 493
(2007/10/03)
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- Imine-forming radical elimination reactions of O-(1-naphthoyl)-N,N- bis(p-substituted benzyl)hydroxylamines activated by triplet benzophenone
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It was shown that despite the occurrence of a diffusion-limited triplet energy transfer between the title hydroxylamine 1 and benzophenone, triplet 1 decomposed inefficiently giving p-substituted N-(p-substituted benzylidene)benzylamine 2 and 1-naphthoic acid (3) as unimolecular radical elimination products. The logarithm of the k(r)/k(d) ratio (where k(r) is the rate constant for homolytic cleavage of the N-O bond in triplet 1 and k(d) is that for its deactivation) used as a measure of the triplet-state reactivities of 1, showed a negligible dependence on the substituent constant. This finding was explained in terms of a very small contribution of the ionic structure to the transition state for the N-O bond homolysis.
- Andoh, Fumihiko,Kubo, Kanji,Sakurai, Tadamitsu
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p. 2537 - 2542
(2007/10/03)
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- Methyltrioxorhenium-Catalyzed Oxidation of Secondary and Primary Amines with Hydrogen Peroxide
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The methyltrioxorhenium-catalyzed oxidation of secondary amines and primary amines with hydrogen peroxide has been carried out. The oxidation of secondary amines afforded nitrones in good-to-excellent yield. Benzylamines were selectively oxidized to oximes, while general primary alkylamines possessing the α-C -H bond gave mixtures of oximes, nitroso dimers, and azoxy compounds.
- Yamazaki, Shigekazu
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p. 877 - 883
(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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- Oxidation of organonitrogen compounds by the methyltrioxorhenium-hydrogen peroxide system
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Methyltrioxorhenium catalyzes the reaction of hydrogen peroxide with organonitrogen compounds. The reactions are facile and high yield at room temperature of below. The observed chemistry is similar to that previously described by us using dimethyldioxirane as the oxidant.
- Murray, Robert W.,Iyanar, Kaliappan,Chen, Jianxin,Wearing, James T.
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p. 805 - 808
(2007/10/03)
-
- Action d'un Tetrafluoroborate d'Oxaziridinium sur les Amines et les Imines
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The Oxaziridinium salt 1 derived from dihydroisoquinolin is an oxygen transfer reagent to primary amines leading to nitrosoderivatives (if R = Alkyl) or nitro compounds (if R = Aryl), to tertiary amines leading to N-oxides, and to secondary amines and imines leading to the corresponding nitrone.
- Hanquet, Gilles,Lusinchi, Xavier
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p. 12185 - 12200
(2007/10/02)
-
- Dioxiranes. 20. Preparation and properties of some new dioxiranes
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The in situ method for producing dioxiranes has been modified to permit the isolation in ketone solution of some nonvolatile dioxiranes. The dioxiranes have been characterized spectroscopically and, in some cases, by chemical reactions.
- Murray, Robert W.,Singh, Megh,Jeyaraman, Ramasubbu
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p. 1346 - 1351
(2007/10/02)
-
- The Chemistry of N-Substituted Benzotriazoles. Part 14. Novel Routes to Secondary and Tertiary Amines and to N,N-Disubstituted Hydroxylamines
-
Tertiary amines of types R4R3CHNR1R2 (2), (R2CH2)2NR1 (10) and 11, or (R2CH2)3N (12), secondary amines of type (R2CH2)2NH (8), and N,N-disubstituted hydroxylamines of type (R2CH2)2NOH (9), are prepared in high yield by the action of Grignard reagents or sodium borohydride on easily available N,N-dialkyl-N-amines (1) or tris(benzotriazolylmethyl)amine (7), on bis(benzotriazolylmethyl)amines (3), (5), and (6), and on N,N-bis(benzotriazolylmethyl)hydroxylamine (4), respectively.
- Katritzky, Alan R.,Yannakopoulou, Konstantina,Lue, Ping,Rasala, Danuta,Urogdi, Laszlo
-
p. 225 - 233
(2007/10/02)
-
- A HIGH YIELD ONE STEP SYNTHESIS OF HYDROXYLAMINES
-
Oxidation of secondary amines with dimethyldioxirane gives hydroxylamines in a simple, one step and high yield process.
- Murray, Robert W.,Singh, Megh
-
p. 3509 - 3522
(2007/10/02)
-
- Oxidation of Amines with 2-Sulfonyloxaziridines (Davis' Reagents)
-
2-(Phenylsulfonyl)-3-aryloxaziridines (Davis' Reagents) react rapidly with amines that are more basic than pyridine to give products that are dependent upon the structure of the amine.Tertiary aliphatic amines are oxidized to the corresponding N-oxides in high yields, while secondary aliphatic amines give the N,N-disubstituted hydroxylamines and corresponding nitrones in variable, stoichiometrically dependent ratios.Primary aliphatic amines give 10-35percent yields of nitroso compounds and 50-65percent yields of N-arylideneamines formed by the transimination reaction of the amine with the N-arylidenebenzenesulfonamide generated following oxygen transfer from the 2-(phenylsulfonyl)-3-aryloxaziridine.
- Zajac, Walter W.,Walters, Thomas R.,Darcy, Michael G.
-
p. 5856 - 5860
(2007/10/02)
-
- ALKYLATION OF AMINOHYDROXY ANION, DISSOCIATED SPECIES OF HYDROXYLAMINE
-
Aminohydroxy anion (3), dissociated species of hydroxylamine, was demontrated to be nucleophilic on oxygen atom from INDO calculation, and to give directly O-alkylhydroxylamines.
- Kashima, Choji,Yoshiwara, Nobutoshi,Omote, Yoshimori
-
p. 2955 - 2956
(2007/10/02)
-
- REARRANGEMENTS OF N-SUBSTITUTED HYDROXYLAMINES - POTENTIAL GENERATORS OF NITRENIUM IONS
-
The transformations of N-substituted hydroxylamines into Schiff bases by the action of phosphorus pentachloride, which have only been observed previously in the aromatic series (the so-called Stieglitz rearrangement), also occur among aliphatic monosubstituted and N,N-disubstituted hydroxylamines and their salts.The Schiff bases which form can be regarded as the product from stabilization of the intermediate nitrenium ions RNH+ and R2N+, but it is not possible to confirm the participation of the latter in reactions by interaction with the solvent.
- Stolyarov, B. V.,Krylov, A. I.
-
p. 1523 - 1528
(2007/10/02)
-