- Factors Controlling Amination of 2-Methylpropene over Proton-exchanged Zeolite Catalysts
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The number and strength of Broensted acid sites are factors controlling the amination of 2-methylpropene over proton-exchanged zeolites.Owing to the appropriate possession of the above two factors, proton-exchanged ZSM-5 zeolite with a silica:alumina ratio of 81 was the most active, among the catalysts tested, for the amination.
- Mizuno, Noritaka,Tabata, Masahiro,Uematsu, Takeshi,Iwamoto, Masakuzu
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- Reactions of bromoacetylene with primary amine on a butterfly-type tetrairon core to give isonitrile and methyne through oxidation and deprotonation
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Reaction of [(η5-C5H4Me) 4Fe4(HCCH)(HCC-Br)](PF6) with tBuNH2 forms [(?5-C5H 4Me)4Fe4(HCCH)(HCC-NHtBu)](PF 6), of which one electron oxidation leads to carbon-carbon bond cleavage to give [(η5-C5H4Me) 4Fe4(HCCH)(μ3-CH)(μ3-CNH tBu)](PF6)2, and further treatment with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) affords [(η5-C 5H4Me)4Fe4(HCCH)(μ3- CH)(μ3-η1-CNtBu)](PF6). Thus, the HCCBr group is converted to tBuNC and CH groups on the redox-responsive tetrairon core.
- Okazaki, Masaaki,Tsuchimoto, Takahiro,Nakazawa, Yuki,Takano, Masato,Ozawa, Fumiyuki
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- A shaped binderless ZSM-11 zeolite catalyst for direct amination of isobutene to tert-butylamine
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A shaped binderless and two binder-containing ZSM-11 zeolite catalysts were prepared and characterized by powder X-ray diffraction, N2adsorption-desorption, and pyridine adsorption-infrared measurements. The binderless catalyst was synthesized using a dry-gel conversion technique, in which 1,6-hexanediamine and tetrabutylammonium bromide were used as structure-directing agents and no other alkaline materials were added. The catalytic performance of the zeolites in the direct amination of isobutene to tert-butylamine was evaluated in a fixed-bed reactor. By virtue of its high crystallinity as well as its good mechanical strength, the shaped binderless ZSM-11 catalyst showed a higher rate of formation of tert-butylamine than did the binder-containing catalysts.
- Zhang, Wanshuo,Gao, Shangyao,Xie, Sujuan,Liu, Hui,Zhu, Xiangxue,Shang, Yongchen,Liu, Shenglin,Xu, Longya,Zhang, Ye
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- Amination of 2-Methylpropene over Proton-Exchanged ZSM-5 Zeolite Catalysts
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The reaction between 2-methylpropene and ammonia over various zeolite catalysts having a wide range of silica/alumina ratios from 5.6 to 1340, and over solid acid catalysts (CsxH3-xPW12O40 (x = 0.15, 0.5), SiO2-Al2O3, and SiO2-TiO2) and the solid base MgO was investigated.The significant decrease of activity following substitution of Na+ for H+ in H-MFI-40 or by preadsorption of diisopropylamine showed that amination is catalyzed by the acid sites.A similar change in the catalytic activity of H-MFI-40 with the number of Broensted acid sites at elevated temperatures, as well as the appearance of activities of CsxH3-xPW12O40 (x = 2.5, 2.85), which has only Broensted acid sites, indicated amination on the Broensted acid site.The dependence of conversion into t-butylamine, the number of Broensted acid sites, and the turnover frequencies on the SiO2/Al2O3 ratio suggested that the number and strength of the Broensted acid sites are the factors controlling the title reaction.Due to the above two factors having the proper values, proton-exchanged ZSM-5 zeolite with a silica/alumina ratio of 81 was the most active for amination among the catalysts tested.
- Mizuno, Noritaka,Tabata, Masahiro,Uematsu, Takeshi,Iwamoto, Masakazu
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- Pd nanoparticles prepared by grafting of Pd complexes on phenol-functionalized carbon supports for liquid phase catalytic applications
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An activated carbon was functionalized by oxidation with HNO3 or H2O2 to increase the number of acidic groups on its surface. A sample of HNO3-oxidized carbon was treated thermally to remove unstable functions. Detailed characterization by a combination of techniques revealed that this stabilization procedure allowed selecting weaker acid sites of phenolic type. H2O2 functionalization gave also mainly surface phenols but in lower amounts. Palladium grafting was carried out in water at room temperature by ligand exchange between a carboxylate complex and the surface oxygenated groups. Activation was carried out thermally and the samples grafted on the most oxidized supports proved more difficult to reduce. The catalytic activity of the obtained Pd/C catalysts was evaluated in the reduction of 2-methyl-2-nitropropane (MNP) into t-butylamine (TBA). The most active materials were those prepared on H2O2-modified carbon and on the stabilized support. In the latter case, the superior activity was explained by the robustness of the grafting anchors which could not decompose during thermal activation together with the active role of weak acidic groups in the catalytic reaction itself.
- Hermans, Sophie,Diverchy, Chantal,Dubois, Vincent,Devillers, Michel
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- Organic promoter-driven fast synthesis of zeolite beta and its acceleration mechanism
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Zeolite beta, an important catalytic material widely applied in the petrochemical field, is typically prepared under hydrothermal conditions. However, it usually suffers from the drawback of relatively long crystallization time. Herein, we show that the crystallization rate of zeolite beta can be accelerated by a factor of as much as about nine via the addition of the low-toxic and cost-effective pentacyclic lactam N-methyl-2-pyrrolidone (NMP) as a 'promoter'. Using characterization techniques, we demonstrate that the pentacyclic lactam induces the fast formation of secondary building units (SBUs) and enhances the formation rate of the activated TEA+ species responsible for the nucleation of beta crystals. More importantly, the as-synthesized beta exhibited high product yield (above 85 wt%) and good performance in the direct amination of isobutene (i-C4H8) to tert-butylamine reaction.
- Zhao, Dongpu,Chu, Weifeng,Wang, Yanan,Zhu, Xiangxue,Li, Xiujie,Xie, Sujuan,An, Jie,Xin, Wenjie,Liu, Shenglin,Xu, Longya
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- C?H Bond Activation by an Imido Cobalt(III) and the Resulting Amido Cobalt(II) Complex
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The 3d-metal mediated nitrene transfer is under intense scrutiny due to its potential as an atom economic and ecologically benign way for the directed amination of (un)functionalised C?H bonds. Here we present the isolation and characterisation of a rare, trigonal imido cobalt(III) complex, which bears a rather long cobalt–imido bond. It can cleanly cleave strong C?H bonds with a bond dissociation energy of up to 92 kcal mol?1 in an intermolecular fashion, unprecedented for imido cobalt complexes. This resulted in the amido cobalt(II) complex [Co(hmds)2(NHtBu)]?. Kinetic studies on this reaction revealed an H atom transfer mechanism. Remarkably, the cobalt(II) amide itself is capable of mediating H atom abstraction or stepwise proton/electron transfer depending on the substrate. A cobalt-mediated catalytic application for substrate dehydrogenation using an organo azide is presented.
- Kraus, Florian,Pietzonka, Clemens,Reckziegel, Alexander,Werncke, C. Gunnar
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- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
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supporting information
(2022/01/04)
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- PROCESS FOR PREPARATION OF TERT-BUTYLAMINE AND PROPIONIC ACID SALTS FROM N-TERTIARY BUTYL ACRYLAMIDE
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Disclosed is a process (100) for conversion of N-tertiary butyl acrylamide to tert-butylamine and salts of propionic acid. The process comprises of first selectively reducing the vinylic double bond in N-tertiary butyl acrylamide by catalytic hydrogenation of an alcoholic solution of N-tertiary butyl acrylamide to provide N-tertiary buyl propanamide; recovering the hydrogenation catalyst by filtering the solution and treating the solution with an alkali to produce N-tertiary butylamine and corresponding alkali salt of propionic acid. The process converts of N-tertiary butyl acrylamide into value added products at milder reaction conditions, without producing any hazardous byproducts and effluents.
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(2021/11/13)
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- Diverse Oxidative C(sp2)-N Bond Cleavages of Aromatic Fused Imidazoles for Synthesis of α-Ketoamides and N-(pyridin-2-yl)arylamides
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An efficient and chemoselective C(sp2)-N bond cleavage of aromatic imidazo[1,2-a]pyridine molecules is developed. A broad scope of amide compounds such as α-ketoamides and N-(pyridin-2-yl)arylamides are afforded as the final products in up to quantitative yields. Diverse C-N bond cleavages are controlled by the oxidative species used in this transformation, with various amide products afforded in a chemoselective fashion. A preliminary study indicated that some α-ketoamides exhibit anti-Tobacco Mosaic Virus activity for potential use in plant protection.
- Xu, Fangzhou,Wang, Yanyan,Xun, Xiwei,Huang, Yun,Jin, Zhichao,Song, Baoan,Wu, Jian
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p. 8411 - 8422
(2019/05/17)
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- Application of Silicon-Initiated Water Splitting for the Reduction of Organic Substrates
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The use of water as a donor for hydrogen suitable for the reduction of several important classes of organic compounds is described. It is found that the reductive water splitting can be promoted by several metalloids among which silicon shows the best efficiency. The developed methodologies were applied for the reduction of nitro compounds, N-oxides, sulfoxides, alkenes, alkynes, hydrodehalogenation as well as for the gram-scale synthesis of several substrates of industrial importance.
- Gevorgyan, Ashot,Mkrtchyan, Satenik,Grigoryan, Tatevik,Iaroshenko, Viktor O.
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p. 375 - 382
(2018/06/04)
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- Pd nanoparticles supported on a covalent triazine-based framework material: An efficient and highly chemoselective catalyst for the reduction of nitroarenes
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Pd nanoparticles anchored on a covalent triazine framework (Pd@CTF) were fabricated and employed to catalyze the transfer hydrogenation of nitro-compounds with formic acid as the hydrogen source. The results demonstrated that Pd@CTF displayed excellent catalytic activity and high chemoselectivity for the hydrogenation reaction at room temperature. Various substituted nitro-compounds were successfully converted to the corresponding amines in 0.2-2.5 h with other reducible functional moieties remaining intact. The high performance of Pd@CTF can be attributed to the synergistic interaction between the highly dispersed Pd nanoparticles and the covalent triazine framework support. The Pd@CTF catalyst can be readily reused for at least five consecutive runs without an obvious loss of its catalytic activity.
- Li, Jie,Zhang, Lihong,Liu, Xiaotong,Shang, Ningzhao,Gao, Shutao,Feng, Cheng,Wang, Chun,Wang, Zhi
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p. 9684 - 9689
(2018/06/18)
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- High catalytic activity of a bimetallic AgPd alloy supported on UiO-66 derived porous carbon for transfer hydrogenation of nitroarenes using formic acid-formate as the hydrogen source
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Bimetallic AgPd nanoparticles anchored on metal-organic framework (UiO-66) derived N-doped porous carbon (NPC-UiO-66) was fabricated and used as a catalyst for the catalytic transfer hydrogenation of nitroarenes using formic acid-formate as the hydrogen source. The results demonstrated that the Ag1Pd9@NPC-UiO-66 composite exhibited extraordinary catalytic activity toward the hydrogenation of nitroarenes to anilines at room temperature. A series of substituted nitroarenes were successfully converted to the corresponding anilines in high yields under ambient conditions with other reducible groups remaining intact. The superior catalytic performance of the prepared catalyst can be attributed to the synergistic effect between the highly dispersed AgPd nanoparticles and the unique structure of the NPC-UiO-66 support, as well as the high adsorption ability of the catalyst for the nitroarenes.
- Cheng, Saisai,Shang, Ningzhao,Zhou, Xin,Feng, Cheng,Gao, Shutao,Wang, Chun,Wang, Zhi
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p. 9857 - 9865
(2017/09/18)
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- An improved and one-pot procedure to the synthesis of symmetric amines by domino reactions of 5-methyl-1,3,4-thiadiazole-2-amine, a new nitrogen atom donor, and alkyl halides
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Abstract: A new one-pot method has been introduced in this work for the synthesis of symmetrical primary, secondary, and tertiary alkyl amines from alkyl halides and 5-methyl-1,3,4-thiadiazole-2-amine as a nitrogen-transfer reagent. In this method, all three types of amines have been successfully prepared after changing the ratio of substrates and base control. In addition to the introduction of a new nitrogen-transfer reagent, other important features of this work include normal atmospheric conditions and excellent yields under mild reaction conditions.
- Soleiman-Beigi, Mohammad,Mohammadi, Fariba
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p. 2123 - 2128
(2017/10/26)
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- O -Phthalaldehyde catalyzed hydrolysis of organophosphinic amides and other P(O)-NH containing compounds
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Over 50 years ago, Jencks and Gilchrist showed that formaldehyde catalyses the hydrolysis of phosphoramidate through electrophilic activation, induced by covalent attachment to its nitrogen atom. Given our interest in the use of aldehydes as catalysts, this work was revisited to identify a superior catalyst, o-phthalaldehyde, which facilitates hydrolyses of various organophosphorus compounds bearing P(O)-NH subunits under mild conditions. Interestingly, chemoselective hydrolysis of the P(O)-N bonds could be accomplished in the presence of P(O)-OR bonds.
- Li, Bin-Jie,Simard, Ryan D.,Beauchemin, André M.
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supporting information
p. 8667 - 8670
(2017/08/10)
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- A Reusable Mesoporous Nickel Nanocomposite Catalyst for the Selective Hydrogenation of Nitroarenes in the Presence of Sensitive Functional Groups
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The synthesis of aromatic amines from nitroarenes through hydrogenation is an industrially and academically important reaction. In addition, the employment of base metal catalysts in reactions that are preferentially mediated by rare noble metals is a desirable aim in catalysis and an attractive element-conservation strategy. Especially appealing is the observation of novel selectivity patterns with such inexpensive metal catalysts. Herein, we report a novel mesostructured Ni nanocomposite catalyst. It is the first example of a reusable Ni catalyst that is able to hydrogenate nitroarenes selectively to anilines in the presence of highly sensitive functional groups such as C=C bonds and nitrile, aldehyde, and iodo substituents.
- Hahn, Gabriela,Ewert, Julia-Katharina,Denner, Christine,Tilgner, Dominic,Kempe, Rhett
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p. 2461 - 2465
(2016/08/24)
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- Gold-Catalyzed Reductive Transformation of Nitro Compounds Using Formic Acid: Mild, Efficient, and Versatile
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Developing new efficient catalytic systems to convert abundant and renewable feedstocks into valuable products in a compact, flexible, and target-specific manner is of high importance in modern synthetic chemistry. Here, we describe a versatile set of mild catalytic conditions utilizing a single gold-based solid catalyst that enables the direct and additive-free preparation of four distinct and important amine derivatives (amines, formamides, benzimidazoles, and dimethlyated amines) from readily available formic acid (FA) and nitro starting materials with high level of chemoselectivity. By controlling the stoichiometry of the employed FA, which has attracted considerable interest in the area of sustainable chemistry because of its potential as an entirely renewable hydrogen carrier and as a versatile C1 source, a facile atom- and step-efficient transformation of nitro compounds can be realized in a modular fashion. Renewable formic acid as a flexible feedstock: A versatile heterogeneous gold-based catalytic system has been developed for the controlled, flexible, and target-specific reductive transformation of nitro compounds using stoichiometric equivalents of formic acid as a key starting material under mild and convenient conditions. The overall operational simplicity, high chemoselectivity, functional-group tolerance, and reusability of the catalyst make this approach an attractive and reliable tool for organic and process chemists.
- Yu, Lei,Zhang, Qi,Li, Shu-Shuang,Huang, Jun,Liu, Yong-Mei,He, He-Yong,Cao, Yong
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p. 3029 - 3035
(2015/09/28)
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- Trinuclear {Co2+-M3+-Co2+} complexes catalyze reduction of nitro compounds
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This work presents synthesis and characterization of trinuclear {Co2+-Co3+-Co2+} and {Co2+-Fe3+-Co2+} complexes with accessible peripheral Co(ii) ions. Both trinuclear complexes function as efficient reusable heterogeneous catalysts for the selective reduction of assorted nitro compounds to the corresponding amines. The mechanistic investigations suggest the involvement of a Co(ii)-Co(i) cycle in the catalysis.
- Srivastava, Sumit,Dagur, Manvender S.,Ali, Afsar,Gupta, Rajeev
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p. 17453 - 17461
(2015/10/19)
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- Aerobic oxidative N-dealkylation of secondary amines in aqueous solution catalyzed by rhodium porphyrins
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N-dealkylation demonstrates an important biochemical oxidation reaction by cytochrome P450 and other monooxygenases. In this article, catalytic oxidative N-dealkylation of secondary amines was achieved using rhodium(III) tetra (p-sulfonato-phenyl) porphyrin ((TSPP)RhIII) in aqueous solution with oxygen as the sole oxidant. Addition of benzaldehyde to trap primary amine product inhibited catalyst deactivation and dramatically increased reaction turnover numbers (TONs). Substrate scope examination suggested the reaction was performed with a preference for bulkier secondary amines. Kinetic study exhibited first-order kinetics with regard of (TSPP)RhIII catalyst. Results from the Hammett study gave a ρ value of -1.38, suggesting formation of an iminium ion intermediate in the rate determining step.
- Yun, Lin,Zhen, Ling,Wang, Zikuan,Fu, Xuefeng
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p. 937 - 943
(2015/06/16)
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- Room-temperature chemoselective reduction of nitro groups using non-noble metal nanocatalysts in water
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Purely aqueous-phase chemoselective reduction of a wide range of aromatic and aliphatic nitro substrates has been performed in the presence of inexpensive Ni- and Co-based nanoparticle catalysts using hydrazine hydrate as a reducing agent at room temperature. Along with the observed high conversions and selectivities, the studied nanoparticle catalysts also exhibit a high tolerance to other highly reducible groups present in the nitro substrates. The development of these potential chemoselective reduction catalysts also provides a facile route for the synthesis of other industrially important fine chemicals or biologically important compounds, where other highly reducible groups are present in close proximity to the targeted nitro groups.
- Rai, Rohit K.,Mahata, Arup,Mukhopadhyay, Sushobhan,Gupta, Sampa,Li, Pei-Zhou,Nguyen, Kim T.,Zhao, Yanli,Pathak, Biswarup,Singh, Sanjay K.
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p. 2904 - 2909
(2014/04/03)
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- Aerobic oxidative N-dealkylation of secondary amines in aqueous solution catalyzed by rhodium porphyrins
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N-dealkylation demonstrates an important biochemical oxidation reaction by cytochrome P450 and other monooxygenases. In this article, catalytic oxidative N-dealkylation of secondary amines was achieved using rhodium(III) tetra (p-sulfonato-phenyl) porphyrin ((TSPP)RhIII) in aqueous solution with oxygen as the sole oxidant. Addition of benzaldehyde to trap primary amine product inhibited catalyst deactivation and dramatically increased reaction turnover numbers (TONs). Substrate scope examination suggested the reaction was performed with a preference for bulkier secondary amines. Kinetic study exhibited first-order kinetics with regard of (TSPP)RhIII catalyst. Results from the Hammett study gave a σ value of -1.38, suggesting formation of an iminium ion intermediate in the rate determining step.
- Yun, Lin,Zhen, Ling,Wang, Zikuan,Fu, Xuefeng
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p. 937 - 943
(2015/05/27)
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- Novel approach for the synthesis of hexaazaisowurtzitane derivatives
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A novel synthetic route to hexaazaisowurtzitane derivatives via transimination of N,N0-di-t-butyl- 1,2-ethanediimine with benzylamine, allylamine, and furfurylamine is reported.
- Il'yasov, Sergey G,Chikina, Maya V.
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supporting information
p. 1931 - 1932
(2013/04/10)
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- CATALYSTS AND METHOD FOR THE HYDROAMINATION OF OLEFINS
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The present invention relates to a hydroamination catalyst comprising boron beta zeolites, wherein the hydroamination catalyst is doped with lithium, and also a process for producing it. The present patent application further relates to a process for preparing amines by reaction of ammonia or primary or secondary amines with olefins at elevated temperatures and pressures in the presence of the hydroamination catalyst of the invention.
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Page/Page column 4
(2012/03/08)
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- A mild and efficient rhenium-catalyzed transfer hydrogenation of terminal olefins using alcoholysis of amine-borane adducts as a reducing system
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[ReBr2(NO)(CH3CN)(PTA)2] (PTA = 1, 3, 5-triaza-7-phosphaadamantane) catalyzes the alcoholysis of ammonia-borane and amine-boranes and the catalytic transfer hydrogenations of various terminal olefins. Excellent yields were achieved at 70 °C in isopropanol using tBuOK as a co-catalyst affording TOF values up to 396 h-1.
- Dong, Hailin,Berke, Heinz
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experimental part
p. 1803 - 1808
(2011/06/19)
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- PROCESS FOR PREPARING A PRIMARY AMINE WITH A TERTIARY ALPHA CARBON ATOM BY REACTING A TERTIARY ALCOHOL WITH AMMONIA
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A process for preparing a primary amine with a tertiary alpha-carbon atom by reacting a tertiary alcohol with ammonia in the presence of a heterogeneous catalyst, by performing the reaction in the presence of a non-microporous, non-zeolitic aluminosilicate as a catalyst, where the aluminosilicate has a molar Al/Si ratio in the range from 0.1 to 30.
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Page/Page column 5
(2011/02/15)
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- IMPROVED PROCESS FOR CONVERSION OF ISOBUTYLENE TO TERTIARY BUTYLAMINE
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The invention discloses an improved process for the conversion of isobutylene to tertiary butylamine with conversion up to 50 % at pressure lower than 40 bar.
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Page/Page column 7
(2012/01/06)
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- Convenient reduction of nitro compounds to their corresponding amines with promotion of NaBH4/Ni(OAc)2.4H2O system in wet CH3CN
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NaBH4 in the presence of catalytic amounts of Ni(OAc) 2.4H2O reduces varieties of nitro compounds to their corresponding amines. Reduction reactions were carried out in a mixture of CH3CN and H2O (3.0:0.3 ml) at room temperature with high to excellent yields of products.
- Setamdideh, Davood,Khezri, Behrooz,Mollapour, Manouchehr
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experimental part
p. 991 - 996
(2012/03/27)
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- Fe3O4 nanoparticles: A conveniently reusable catalyst for the reduction of nitroarenes using hydrazine hydrate
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A magnetic personality: Commercially available Fe3O4 nanoparticles were utilized for efficient nitroarene reductions, and could be recycled up to 10 times using magnetic separation, whilst retaining activity (99 % aniline yield in each case without any side-products). Excellent chemoselectivity for reduction of the nitro versus other functional groups, such as halogen, ester, O-benzyl, and N-Cbz groups, was observed.
- Kim, Seyoung,Kim, Eunsuk,Kim, B. Moon
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experimental part
p. 1921 - 1925
(2011/10/17)
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- Supported p-toluenesulfonic acid as a highly robust and eco-friendly isocyanide scavenger
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We document here the use of polymer-supported p-toluenesulfonic acid as a highly effective, robust, economical and eco-friendly isocyanide scavenger. The herein described strategy circumvent the intense and repulsive odor of volatile isocyanides, enabling simplified and odorless workup and purifications. The usefulness of the new scavengers has been validated in a set of diverse isocyanide-based organic transformations and this approach is also amenable to parallel synthesis techniques.
- Azuaje, Jhonny,Coelho, Alberto,Maatougui, Abdelaziz El,Blanco, Jose Manuel,Sotelo, Eddy
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experimental part
p. 89 - 95
(2011/04/15)
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- Discovery of a selective small-molecule melanocortin-4 receptor agonist with efficacy in a pilot study of sexual dysfunction in humans
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The relevance of the melanocortin system to sexual activity is well established, and nonselective peptide agonists of the melanocortin receptors have shown evidence of efficacy in human sexual dysfunction. The role of the MC4 receptor subtype has received particular scrutiny, but the sufficiency of its selective activation in potentiating sexual response has remained uncertain owing to conflicting data from studies in preclinical species. We describe here the discovery of a novel series of small-molecule MC4 receptor agonists derived from library hit 2. The addition of methyl substituents at C3 and C5 of the 4-phenylpiperidin-4-ol ring was found to be markedly potency-enhancing, enabling the combination of low nanomolar potencies with full rule-of-five compliance. In general, the series shows only micromolar activity at other melanocortin receptors. Our preferred compound 40a provided significant systemic exposure in humans on both sublingual and oral administration and was safe and well tolerated up to the maximum tested dose. In a pilot clinical study of male erectile dysfunction, the highest dose of 40a tested (200 mg) provided a similar level of efficacy to sildenafil.
- Lansdell, Mark I.,Hepworth, David,Calabrese, Andrew,Brown, Alan D.,Blagg, Julian,Burring, Denise J.,Wilson, Peter,Fradet, David,Brown, T. Bruce,Quinton, Faye,Mistry, Neela,Tang, Kim,Mount, Natalie,Stacey, Peter,Edmunds, Nick,Adams, Cathryn,Gaboardi, Samantha,Neal-Morgan, Stevie,Wayman, Chris,Cole, Susan,Phipps, Joanne,Lewis, Mark,Verrier, Hugh,Gillon, Val,Feeder, Neil,Heatherington, Anne,Sultana, Stefan,Haughie, Scott,Martin, Steven W.,Sudworth, Maria,Tweedy, Sarah
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scheme or table
p. 3183 - 3197
(2010/09/15)
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- In situ formation of thermally stable, room-temperature ionic liquids from CS2 and amidine/amine mixtures
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Amidinium dithiocarbamates salts with diverse structures are prepared in situ by adding one equivalent of CS2 to an equimolar mixture of two nonionic molecules, an amidine and an amine. Many of the salts made in this way are room temperature ionic liquids (RTILs) and the others (ILs) melt well below the decomposition temperature of the salts, ca. 80 °C. Unlike the analogous amidinium carbamate RTILs, which are made by adding CO2 to amidine/amine mixtures and decompose near 50 °C, the amidinium dithiocarbamates do not revert to their amidine/amine mixtures when they are heated. The thermal, rheological, conductance, and spectroscopic properties of representative examples from a total of 50 of these ILs and RTILs are reported, comparisons between them and their nonionic phases (as well as with their amidinium carbamates analogues) are made, and the thermolysis pathways of the ammonium dithiocarbamates are investigated.
- Yu, Tao,Yamada, Taisuke,Weiss, Richard G.
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scheme or table
p. 5492 - 5499
(2011/12/14)
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- Selective synthesis of N-Alkyl hydroxylamines by hydrogenation of nitroalkanes using supported palladium catalysts
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The selective hydrogenation of nitroalkanes to the corresponding N-alkyl hydroxylamines is achieved at room temperature with excellent yields (up to 98 %), by using common supported palladium catalysts. The reaction temperature is key to the highly selective formation of the hydroxylamines, which proceeds smoothly in a H2 atmosphere without additives. The catalyst can be recycled up to five times.
- Takenaka, Yasumasa,Kiyosu, Takahiro,Choi, Jun-Chul,Sakakura, Toshiyasu,Yasuda, Hiroyuki
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experimental part
p. 1166 - 1168
(2011/12/02)
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- Synthesis, crystal structure, and interconversions of new N-aryl-1,3,5-dithiazinanes, 1,3,5-thiadiazinanes, and 1,5-dithia-3,7- diazacyclooctanes
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Chemoselectivity of multicomponent reaction of anilines with the CH 2O-H2S thiomethylating mixture in the synthesis of N-aryl-substituted 1,3,5-dithiazinanes, 1,3,5-thiadiazinanes, and 1,5-dithia-3,7-diazacyclooctanes has been studied depending on the type and mutual arrangement of substituents in the starting anilines, ratio of reagents, temperature, and reaction time. Conformation of the synthesized heterocycles in crystal has been found by X-ray diffraction. Interconversion of the heterocycles showed stability of N-aryl-1,3,5-dithiazinanes.
- Akhmetova,Niatshina,Khabibullina,Bushmarinov,Borisova,Starikova,Korzhova,Kunakova
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scheme or table
p. 1002 - 1009
(2011/02/26)
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- 1-acylsemicarbazides by ring opening of iminodiaziridines with carboxylic acids: Novel, expeditious access to the azapeptide motif
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Carboxylic acids react rapidly and quantitatively with iminodiaziridines to afford 1,2,4-trisubstituted 1-acylsemicarbazides in a multistep sequence. In this way, a carboxy group is readily converted into an azapeptide motif. Broad signals in high-field H and C NMR spectra recorded for the products are indicative of dynamic processes. Georg Thieme Verlag Stuttgart New York.
- Quast, Helmut,Schmitt, Edeltraud,Ross, Karl-Heinz
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experimental part
p. 3358 - 3362
(2010/11/16)
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- Alkoxy isothiocyanates as intermediates in the flash vacuum pyrolysis of alkoxythioureas
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Methoxy isothiocyanate MeONCS 2b was detected by matrix isolation IR spectroscopy following flash vacuum pyrolysis (FVP) of N-methoxythioureas, N-tert-butyl-N′-methoxythiourea 1d being the best precursor. Isothiocyanates 3, amines, and aldehydes are also
- Pedersen, Carl Th.,Jensen, Frank,Flammang, Robert
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experimental part
p. 69 - 74
(2009/07/18)
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- Process for Preparing Alkylamines by Reacting Olefins With Ammonia
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A process for preparing alkylamines by reacting olefins with ammonia under hydroaminating conditions over a calcined zeolitic catalyst in an adiabatically operated reactor unit, wherein the reaction mixture comprising the starting olefin, ammonia and the corresponding alkylamine is taken off at one or more points and brought into indirect thermal contact with the reaction mixture at one or more points in the reactor unit having in each case a lower concentration of alkylamine compared to the point from which the reaction mixture was taken off, is proposed.
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Page/Page column 3
(2009/01/24)
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- Stabilization of Nitrogen-Containing and Oxygen-Containing Organosilanes Using Weakly Basic Ion-Exchange Resins
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A process to stabilize nitrogen-containing or oxygen-containing organosilane from acid catalyzed attack and retard the resulting decomposition is disclosed. Such organosilanes, and the nitrogen-containing organosilane in particular, with a least one Si-H or N-H group are susceptible to this type of product decomposition. Treatment with a weakly basic ion exchange media retards this decomposition by scavenging the anions or acids that are attacking the Si-H group. Dilute exposures to these anions can initiate significant decomposition and effect product stability and long-term shelf-life for semiconductor processing for the use of silicon oxide, silicon oxynitride and silicon nitride films.
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Page/Page column 5-7
(2008/06/13)
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- Pharmaceutically active pyrrolidine derivatives
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The present invention is related to pyrrolidine derivatives of formula (I). Said compounds are preferably for use as pharmaceutically active compounds. Specifically, pyrrolidine derivatives of formula (I) are useful in the treatment and/or prevention of premature labor, premature birth and dysmenorrhea. In particular, the present invention is related to pyrrolidine derivatives displaying a substantial modulatory, notably an antagonist activity of the oxytocin receptor. More preferably, said compounds are useful in the treatment and/or prevention of disease states mediated by oxytocin, including premature labor, premature birth and dysmenorrhea. The present invention is furthermore related to novel pyrrolidine derivatives as well as to methods of their preparation, wherein X is selected from the group consisting of CR6R7, NOR6, NNR6R7; A is selected from the group consisting of —(C═O)—, —(C═O)—O—, —C(═NH)—, —(C═O)—NH—, —(C═S)—NH, —SO22—, —SO2NH—, —CH2—,B is either a group —(C═O)—NR8R9 or represents a heterocyclic residue having the formula (a) wherein Q is NR10, O or S; n is an integer selected of 0, 1 or 2; Y, Z and E form together with the 2 carbons to which they are attached a 5-6 membered aryl or heteroaryl ring.
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- Pharmaceutically active pyrrolidine derivatives as bax inhibitors
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The present invention is related to new substituted pyrrolidine derivatives of formula (I). Said compounds are preferably for use as pharmaceutically active compounds. Specifically, pyrrolidine derivatives of formula (I) are useful in the treatment and/or prevention of neurodegenerative disorders, diseases associated with polygultamine tracts, epilepsy, ischemia, infertility, cardiovascular disorders renal hypoxia, hepatitis and AIDS. Said pyrrolidine derivatives display a modulatory and most notably a down-regulating-up to an inhibitory-activity with respect to the cellular death agonist Bax and/or the activation pathways leading to Bax and allows therefore to block the release of cytochrome (c). The present invention is furthermore related to novel pharmaceutically activity substituted pyrrolidine derivatives as well as to methods of their preparation, wherein X is selected from the group consisting of O, S, CRR, NOR, NNRR; A is selected from the group consisting of —(C═O)—, —(C═O)—O—, —C(═NH)—, —(C═O)—NH—, —(C═S)—NH, —SO2-, —SO2NH—; —CH2-; B is either a group —(C═O)—NRR or represents a heterocyclic residue having the formula (II) wherein Q is NR, O or S; n is an integer selected of 0, 1 or 2; Y, Z and E form together with the 2 carbons to which they are attached a 5-6 membered aryl or heteroaryl ring.
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- First and efficient method for reduction of aliphatic and aromatic nitro compounds with zinc borohydride as pyridine zinc tetrahydroborato complex: A new stable ligand-metal borohydride
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Pyridine zinc tetrahydroborate, [(Py)Zn(BH4)2], as a new stable ligand-metal borohydride, is prepared quantitatively by complexation of 1:1 zinc borohydride and pyridine at room temperature. This reagent efficiently reduces different aromatic and aliphatic nitro compounds to their primary amines in refluxing THF. In addition, the reduction shows chemoselectivity for aliphatic nitro compounds over the aromatic nitro compounds.
- Zeynizadeh, Behzad,Zahmatkesh, Karam
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p. 267 - 271
(2007/10/03)
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- Chemical properties of polyamines with relevance to the biomineralization of silica
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Polyamines mimicking substances which occur naturally in biosilicas have been synthesized and show an accelerating effect on silica condensation, which depends on the chemical nature, the architecture (linear or branched), and the degree of polymerization.
- Menzel, Henning,Horstmann, Sandra,Behrens, Peter,Baernreuther, Petra,Krueger, Ilka,Jahns, Michael
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p. 2994 - 2995
(2007/10/03)
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- Preparation of amines from olefins over zeolites having an NES structure
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In a process for preparing amines of the general formula I where R1,R2,R3,R4,R5,R6are hydrogen, C1-C20-alkyl, C2-C20-alkenyl, C2-C20-alkynyl, C3-C20-cycloalkyl, C4-C20-alkyl-cycloalkyl, C4-C20-cycloalkyl-alkyl, aryl, C7-C20-alkylaryl or C7-C20-aralkyl, R1and R2are together a saturated or unsaturated divalent C3-C9-alkylene chain and R3or R5are C21-C200-alkyl, C21-C200-alkenyl or together a divalent C2-C12-alkylene chain, by reacting olefins of the general formula II where R3, R4, R5and R6are as defined above, with ammonia or primary or secondary amines of the general formula III where R1and R2are as defined above, at from 200 to 350° C. and pressures of from 100 to 300 bar in the presence of a heterogeneous catalyst, the heterogeneous catalyst used is a zeolite having an NES structure.
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Page column 6-7
(2008/06/13)
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- Thermal study of [Pd(2-Phpy)Cl(L)] complexes (L=pyridines and amines)
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The complex [Pd(2-Phpy)(μ-Cl)]2 reacts with pyridines (L=pyridine, α-picoline and γ-picoline), amines (L=isopropylamine, tert-butylamine) and ammonia to form the corresponding ortho-palladated derivatives [Pd(2-Phpy)CIL]. The compounds have bee
- Perez,Sanchez,Garcia,Serrano,Lopez
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p. 361 - 370
(2008/10/08)
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- Estra-1,3,5(10),16-tetraene derivatives
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Estra-1,3,5(10),16-tetraene derivatives represented by the following formula (I): (wherein R1represents hydroxy, alkoxy, or NR2R3(wherein R2and R3are the same or different, and each represents hydrogen, straight-chain lower alkyl having 1 to 3 carbon atoms, or branched-chain lower alkyl having 3 to 8 carbon atoms)), or pharmaceutically acceptable salts thereof.
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- Di-tert-alkyl nitroxyl radicals. Synthesis, physical properties and applications as inhibitors of vinyl polmerization at elevated temperatures
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Stable di-tert-alkylnitroxyl radicals, tert-butyl-tert-pentylnitroxyl (4a), di-tert-pentylnitroxyl (4b) and tert-octyl-tert-pentylnitroxyl (4c), the homologs of di-tert-butylnitroxyl (1), were synthesized from tert-alkyl amines 7a-c via the 3-tert-alkylamino-3-methyl-1-butynes 8a-c. Oxidation of 8a,b with hydrogen peroxide lead to relatively unstable N-tert-alkyl-N-(1,1-dimethyl-prop-2-ynyl)nitroxyl radicals 15a,b. The thermal stability, vapor pressure data, ultraviolet, visible and electron paramagnetic resonance spectra of 4a-c were recorded. The radicals were explored as potential inhibitors of unwanted alkene polymerization reactions at elevated temperatures, in comparison with the aliphatic di-tert-butyl nitroxyl (1), the alicyclic nitroxyl radicals 2,2,6,6-tetramethylpiperidin-1-oxyl (2) and 4-hydroxy-2,2,6,6-tetramethyl-piperidin-1-oxyl (3), some commercial polymerization inhibitors, such as diethyl-hydroxylamine (Pennstop, 16), ammonium salt of N-hydroxy-N-nitrosobenzenamine (Cupferron, 17), bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (Tinuvin 770, 18), and the well-known spin traps 2-methyl-2-nitrosopropane (19) and tert-butylhydroxylamine (20).
- Sosnovsky, George,Jawdosiuk, Mikolaj,Clumpner, J. Michael
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p. 109 - 126
(2007/10/03)
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- Process for the preparation of metal nitride coatings from single source precursors and precursors suitable therefor
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Metal nitride coatings are deposited effectively by the decomposition of single source metal imido-amido-amine precursors prepared by the reaction of a pentavalent metal halide with a primary amine or hydrazine. With hydrazine-derived precursors, TaN coatings may be deposited at temperatures as low as 400 degrees Celcius or lower.
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- Increased intensity of tert-butoxyl radical emission in 4-chloro-2- methylphenoxyacetic acid (MCPA) synthesis
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The important herbicide, 2-methyl-4-chlorophenoxyacetic acid (MCPA) was synthesized by the chlorination of 2-methylphenoxyacetic acid with tert-butyl hypochlorite in the presence of methyl N,N-dimethylglycinate as a catalyst, giving a high yield and regioselectivity. The reaction was investigated using the spin-trapping technique in electron paramagnetic resonance measurement conditions, with nitrosodurene as a spin trap. Increased intensity emission of the tert-butoxyl radical (2.9 times in relation to the starting level) was observed after the catalyst had been introduced into the reaction mixture, indicating a free radical mechanism for the reaction.
- Jezierski, Adam,Zakrzewski, Jerzy,Moszczyski, Wiesaw
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p. 1229 - 1232
(2007/10/03)
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- Transition metal imide/organic imine metathesis reactions: Unexpected observations
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Mixtures of [Ti(NBut)Cl2(py)3] 1 and PhC(NAr)H (Ar = C6H3Me2-2,6 or C6H4Me-4) gave quantitative conversion to [Ti(NAr)Cl2(py)3] and PhC(NBut)H, the products of Ti=N-But/C=NAr transition metal imide/organic imine metathesis; examination of the kinetics for Ar = C6H4Me-4 showed that the rate limiting step for this process is zero order in [1], demonstrating that these reactions do not involve metal imide particiption in the rate limiting step.
- McInnes, Jacqueline M.,Mountford, Philip
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p. 1669 - 1670
(2007/10/03)
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- Method for manufacturing tert-butylamine
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The invention relates to a method for manufacturing tert-butylamine from isobutene and ammonia in the presence of a silica alumina catalyst. The catalyst is in acid form, has an Si/Al ratio that has been adjusted by steam dealumination, has a crystallinity of at least 95%, and has an Na2 O content of less than 0.2 wt. %. The reaction is preferably conducted in the gas phase, with unreacted ammonia and unreacted isobutene being recycled into the reaction process. The selectivity of the catalyst for the formation of tert-butylamine is at least 99.5%.
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- Benzisothiazoles derivatives as inhibitors of 5-lipoxygenase biosynthesis
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This invention relates to new heterocyclic compounds which are selective inhibitors of 5-lipoxygenase (5-LO). The new heterocyclic compounds are useful in inhibiting 5-LO per se and in the treatment or alleviation of inflammatory disease or condition, allergy or cardiovascular diseases in mammals wherein the inflammatory disease or condition includes but is not limited to asthma, arthritis, bronchi chronic obstructive pulmonary disease, psoriasis, allergic rhinitis, dermatitis, shock, atopic dermatitis, rheumatoid arthritis or osteoa This invention also relates to pharmaceutical compositions useful therefor.
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- Cyanoketene and Iminopropadienones
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Cyanoketene (8) is generated in high yields on flash vacuum thermolysis (FVT) of suitably substituted Meldrum's acid derivatives (5-[(alkylamino)(methylthio or alkylamino)methylene]-2,2-dimethyl-1,3-dioxane-4,6-diones) (3e-j), and also on FVT of cyanoacetic acid derivatives 9e,f,g,j,k,m. The major reaction pathway from 3 proceeds via ketenimines 6 and (alkylimino)propadienones 7, the latter undergoing a retro-ene reaction to 8. A minor pathway is via imidoylketenes 4e,h and oxoketenimines 5e,h, which undergo retro-ene reactions to 9. All intermediates were characterized by Ar matrix FTIR and tandem mass spectrometry (collisional activation MS). Trapping of 4, 5, and 8 with nucleophiles is also reported. The preference of 1,3-X shifts over 1,5-H shifts in imidoylketenes 12 (X = SMe or NMe2) is corroborated by the calculated activation barriers. Neat cyanoketene is highly reactive, reacting at or below 80 K, and this is attributed to the availability of a low-lying ketene LUMO. The IR spectrum of cyanoketene (Ar, 14 K) is dominated by two absorptions at 2163 (s; C=C=O) and 2239 (w; CN) cm-1 in excellent agreement with density functional (B3-LYP/6-31G*) and ab initio (QCISD/6-31G*) calculations.
- Moloney, Daniel W. J.,Wong, Ming Wah,Flammang, Robert,Wentrup, Curt
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p. 4240 - 4247
(2007/10/03)
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