- Luminescent Ce(III) Complexes as Stoichiometric and Catalytic Photoreductants for Halogen Atom Abstraction Reactions
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Luminescent Ce(III) complexes, Ce[N(SiMe3)2]3 (1) and [(Me3Si)2NC(RN)2]Ce[N(SiMe3)2]2 (R = iPr, 1-iPr; R = Cy, 1-Cy), with C3v and C2v solution symmetries display absorptive 4f → 5d electronic transitions in the visible region. Emission bands are observed at 553, 518, and 523 nm for 1, 1-iPr, and 1-Cy with lifetimes of 24, 67, and 61 ns, respectively. Time-dependent density functional theory (TD-DFT) studies on 1 and 1-iPr revealed the 2A1 excited states corresponded to singly occupied 5dz2 orbitals. The strongly reducing metalloradical character of 1, 1-iPr, and 1-Cy in their 2A1 excited states afforded photochemical halogen atom abstraction reactions from sp3 and sp2 C-X (X = Cl, Br, I) bonds for the first time with a lanthanide cation. The dehalogenation reactions could be turned over with catalytic amounts of photosensitizers by coupling salt metathesis and reduction to the photopromoted atom abstraction reactions.
- Yin, Haolin,Carroll, Patrick J.,Anna, Jessica M.,Schelter, Eric J.
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- Peculiarities of the reaction of alkali metal bis(trimethylsilyl)amides with halobenzenes
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Lithium and sodium bis(trimethylsilyl)amides react with fluoro-, bromo-, and chlorobenzenes in THF or toluene to give a mixture of N,N-bis(trimethylsilyl)aniline and N,2-bis(trimethylsilyl)aniline. The latter compound is resulted from 1,3-shift of the trimethylsilyl group from nitrogen to ortho-carbon atom of the benzene ring. Effects of the solvent, halogen, and alkali metal nature as well as the reaction conditions on the ratio of isomers were examined. Reaction of iodobenzene with sodium bis(trimethylsilyl)amide in THF produces N,N-bis(trimethylsilyl)aniline and 2-iodo-N,N-bis(trimethylsilyl)aniline, while in toluene a mixture of three products, two indicated above and N,N-bis(trimethylsilyl)benzylamine, was obtained.
- Lis,Tsyrendorzhieva,Albanov,Gostevskii,Rakhlin
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- Preliminary communication. Primary aminomethylation of organometallic compounds via N,N-bis(trimethylsilyl)methylthiomethylamine
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The reaction of various organometallic compounds with N,N-bis(trimethylsilyl)methylthiomethylamine provides an easy way for the introduction of primary aminomethyl unit into a variety of organic substrates.
- Fiocca, Luisa,Fiorenza, Mariella,Reginato, Gianna,Ricci, Alfredo,Dembech, Pasquale,Seconi, Giancarlo
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- Selenolate Anion as an Organocatalyst: Reactions and Mechanistic Studies
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A new organocatalyst, the selenolate anion [RSe]–, generated from bench-stable and commercially available diphenyl diselenide or from phenyl benzyl selenide (10 mol%) is introduced. Benchmarking is performed in the conversion of benzylic chlorides into trans-stilbenes selectively at room temperature. Mechanistic studies support the intermediacy of the selenolate anion and of 1,2-diphenylethyl phenyl selenide. (Figure presented.).
- Trofymchuk, Oleksandra S.,Zheng, Zhipeng,Kurogi, Takashi,Mindiola, Daniel J.,Walsh, Patrick J.
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p. 1685 - 1692
(2018/03/21)
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- Quantitative Silylation Speciations of Primary Phenylalkyl Amines, Including Amphetamine and 3,4-Methylenedioxyamphetamine Prior to Their Analysis by GC/MS
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A novel, quantitative trimethylsilylation approach derivatizing 11 primary phenylalkyl amines (PPAAs), including amphetamine (A) and 3,4-methylenedioxyamphetamine (MDA), was noted. Triggering the fully derivatized ditrimethylsilyl (diTMS) species with the N-methyl-N-(trimethylsilyl)-trifluoroacetamide (MSTFA) reagent, a new principle was recognized followed by GC/MS. In the course of method optimization, the complementary impact of solvents (acetonitrile, ACN; ethyl acetate, ETAC; pyridine, PYR) and catalysts (trimethylchlorosilane, TMCS; trimethyliodosilane, TMIS) was studied: the role of solvent and catalyst proved to be equally crucial. Optimum, proportional, huge responses were obtained with the MSTFA/PYR = 2/1-9/1 (v/v) reagent applying catalysts; A and MDA needed the TMIS, while the rest of PPAAs provided the diTMS products also with TMCS. Similar to derivatives generated with hexamethyldisilazane and perfluorocarboxylic acid (HMDS and PFCA) (Molnár et al. Anal. Chem. 2015, 87, 848'852), the fully silylated PPAAs offer several advantages. Both of our methods save time and cost by allowing for direct injection of analytes into the column; this is in stark contrast with the requirement to evaporate acid anhydrides by nitrogen prior to their injection. Efficiences of the novel catalyzed trimethylsilylation (MSTFA) and our recently introduced (now, for A and MDA extended) acylation principle were contrasted. Catalyzed trimethylsilylation led to diTMS derivatives resulting in on average a 1.7 times larger response compared to the corresponding acylated species. Catalyzed trimethylsilylation of PPAAs, A, and MDA were characterized with retention, mass fragmentation, and analytical performance properties (R2, LOQ values). The practical utility of ditrimethylsilyation was shown by analyzing A in urine and mescaline (MSC) in cactus samples.
- Molnár, Borbála,Fodor, Blanka,Boldizsár, Imre,Molnár-Perl, Ibolya
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p. 10188 - 10192
(2015/11/09)
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- Efficient synthesis of 1,2,4-dithiazolidine-3,5-diones [dithiasuccinoyl- amines] from bis(chlorocarbonyl)disulfane plus bis(trimethylsilyl)amines
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The 1,2,4-dithiazolidine-3,5-dione heterocycle, also referred to as a dithiasuccinoyl (Dts)-amine, serves as a readily removable amino protecting group for building blocks used in syntheses of peptides, glycopeptides, and PNA; it is also useful as a masked isocyanate and (inversely) as a sulfurization reagent for trivalent phosphorus. Bis(chlorocarbonyl)disulfane, the two-sulfur analogue of succinyl chloride, has been envisioned as a reagent for facile single-step elaboration of the heterocycle. However, reactions of bis(chlorocarbonyl)disulfane directly with primary amines fail to yield Dts-amines for reasons that are discussed. Inspired by several precedents from the organosilicon chemistry literature that a trimethylsilyl group may serve as a "large proton," a successful, high-yield preparation of Dts-amines through reactions of bis(chlorocarbonyl)disulfane with bis(trimethylsilyl)amines has been developed. Studies aimed at elucidating mechanistic reasons for these observations are also presented. Copyright
- Barany, Michael J.,Hammer, Robert P.,Merrifield,Barany, George
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p. 508 - 509
(2007/10/03)
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- Novel method for preparing bis(trimethylsilyl) amines via treatment with trimethylsilylamines and methyl iodide
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A convenient method for the synthesis of N,N-bis(trimethylsilyl)alkylamines has been reported. N-(Trimethylsilyl)diethylamine incorporated with a stoichiometric amount of methyl iodide was effective to convert primary amines, especially aromatic amines, and their monotrimethylsilyl derivatives into the corresponding N,N-bis(trimethylsilyl)amine derivatives in high yields. In the case of N-trimethylsilyl derivatives of aliphatic primary amines, a half-amount of silylamines served as a silylation agent against another half-amount of silylamines in the presence of 0.5 equivalent of methyl iodide to give N,N-bis(trimethylsilyl)alkylamines in good yield. Allyl iodide, allyl bromide and benzyl bromide were also effective to promote the silylation activity of silylamines.
- Hamada, Yoshitaka,Yamamoto, Yasushi,Shimizu, Hideaki
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- CONTRIBUTIONS TO THE CHEMISTRY OF ORGANIC SILICON-NITROGEN-COMPOUNDS, I. SYNTHESIS OF N,N-BIS-(TRIMETHYLSILYL)AMINES
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The preparation of N,N-bis-(trimethylsilyl)amines 1 has been investigated.Three convenient methods are reported: A, Transfer of (catalytically) activated Tms-groups to amines starting from N-silylated carbonamides, B, silylation of amines with trimethylsilylchloride 5/NEt3 in the presence of TiCl4, C, silylation of primary amines 4 or mono-(trimethylsilyl)amines 16 with CF3SO3 Tms/NEt3 or TmsI/NEt3.Methods A and B are limited to the silylation of (ar)alkylamines which have no branched α-position. Key words: N,N-bis-(trimethylsilyl)amines; N,N-bis-silylamines; N-silylcarbonamides.
- Schorr, Manfred,Schmitt, Wilfried
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- Cobalt Carbonyl Catalyzed Hydrosilylation of Nitriles: A New Preparation of N,N-Disilylamines
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Cobalt carbonyl catalyzed hydrosilylation of a wide variety of nitriles with HSiMe3 has been examined.The reaction generally proceeded at 60 deg C to give N,N-disilylamines in good yields.Electron-donating groups on aromatic nitriles facilitated the react
- Murai, Toshiaki,Sakane, Takehiko,Kato, Shinzi
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p. 449 - 453
(2007/10/02)
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- Silylated Amines II. A New, Highly Variable Amine Synthesis by the N,N-Bis(trimethylsilyl)aminomethylation of Grignard Compounds
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Sodium bis(trimethylsilyl)amide reacts with chloromethyl methylether (1) to form methoxy-N,N-bis(trimethylsilyl)aminomethane (3), which effects the aminomethylation of Grignard compounds 4 to form N,N-bis(trimethylsilyl)amines 5.
- Betsmann, Hans Juergen,Woelfel, Gerhard,Mederer, Karl
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p. 848 - 850
(2007/10/02)
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- COBALT CARBONYL CATALYZED REDUCTION OF AROMATIC NITRILES WITH A HYDROSILANE LEADING TO N,N-DISILYLAMINES
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Cobalt carbonyl catalyzed reaction of HSiMe3 with aromatic nitriles having various functional groups provided a novel route to N,N-disilylamines.
- Murai, Toshiaki,Sakane, Takehiko,Kato, Shinzi
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p. 5145 - 5148
(2007/10/02)
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- N,N-Bis(trimethylsilyl)methoxymethylamine as a Convenient Synthetic Equivalent for +CH2NH2: Primary Aminomethylation of Organometallic Compounds
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The introduction of the primary aminomethyl unit at carbon through N,N-bis(trimethylsilyl)aminomethylation of Grignard and organolithium compounds can be achieved in good yield using N,N-bis(trimethylsilyl)methoxymethylamine (1).
- Morimoto, Toshiaki,Takahashi, Toshio,Sekiya, Minoru
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p. 794 - 795
(2007/10/02)
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- A Simple Synthesis pf Primary Amines via their N,N-Bis(trimethylsilyl) Derivatives
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Primary halogen compounds 1 or the corresponding tosylates react with sodium bis(trimethylsilyl)amide (2) in hexamethyldisilazane to form N,N-bis(trimethylsilyl)amines 3, which are converted into the amine hydrochlorides 5 by treatment with aqueous HCl.
- Bestmann, Hans Juergen,Woelfel, Gerhard
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p. 1250 - 1254
(2007/10/02)
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