- Highly selective acylation of dimethylamine mediated by oxygen atoms on metallic gold surfaces
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"Chemical Equation Presented" Completely coupled: The acylation of dimethylamine through coupling to formaldehyde occurs with almost 100 % selectivity at low coverage of adsorbed O atoms on metallic gold and with a low activation energy. Oxygen creates an active intermediate (CH3) 2N(a), which attacks the carbonyl carbon of the aldehyde (see picture). A general mechanistic framework for efficient and selective acylation of amines promoted by Au is established.
- Xu, Bingjun,Zhou, Ling,Madix, Robert J.,Friend, Cynthia M.
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- Effects of Carbon-Bound Deuterium on the Affinities of Acetaldehyde-1-d and N-Methylformamide-1-d for Solvent Water
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With deuterium present in the formyl group, the equilibrium constant for transfer of N-methylformamide from chloroform to D2O at 25 deg C was encanced by factor of 3.1 +/- 0.15 percent, as estimated independently by proton magnetic resonance and by double-labeling experiments in which 14C and 3H were incorporated alternatively into the methyl group.The distribution coefficient of acetaldehyde-1-d between D2O and the vapor phase, on the other hand, differed from that of acetaldehyde by less than 0.5percent.
- Wolfenden, Richard,Kirkman, Sue
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- Degradation of gaseous unsymmetrical dimethylhydrazine by vacuum ultraviolet coupled with MnO2
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In this study, α-, β-, and δ-MnO2 were prepared by a uniform hydrothermal method and then coupled with vacuum ultraviolet (VUV) for the degradation of gaseous unsymmetrical dimethylhydrazine (UDMH). The performance in the removal of UDMH, by-product distribution and mechanism were systematically investigated. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption/desorption, Field Emission Scanning Electron Microscopy (FE-SEM), Raman, thermogravimetry (TG), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) to investigate the factors affecting the catalytic activity. The results showed that O2 and H2O were essential for the removal of UDMH. Photooxidation and ozone catalytic oxidation contribute to the removal and mineralization of UDMH. The integrated process considerably improved the removal and mineralization of UDMH by ozone catalytic oxidation. More reactive oxygen species were generated in the integrated process. The catalytic activity of the prepared catalysts follows the order: δ-MnO2 > α-MnO2 > β-MnO2. δ-MnO2 displayed the highest removal rate of 100% and a CO2 concentration of 42 ppmv. The good performance of δ-MnO2 was mainly attributed to the large number of surface oxygen vacancies.
- Huang, Yuanzheng,Jia, Ying,Shen, Keke,Hou, Ruomeng,Zhang, Yongyong,Hou, Li'an
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- The Generation of N-Alkylformamides from Synthesis Gas and Ammonia
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N,N-Dimethylformamide and N-methylformamide have been prepared from synthesis gas plus ammonia via ruthenium 'melt' catalysis.
- Knifton, John F.
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- Thermal behavior of ammonium dinitramide and amine nitrate mixtures
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This paper focuses on the thermal behavior of mixtures of ammonium dinitramide (ADN) and amine nitrates. Because some mixtures of ADN and amine nitrate exhibit low melting points and high-energy content, they represent potential liquid propellants for spacecraft. This study focused on the melting behavior and thermal-decomposition mechanisms in the condensed phase of ADN/amine nitrate mixtures during heating. We measured the melting point and exothermal behavior during constant-rate heating using differential scanning calorimetry and performed thermogravimetry–differential thermal analysis–mass spectrometry (TG–DTA–MS) to analyze the thermal behavior and evolved gases of ADN/amine nitrate mixtures during simultaneous heating to investigate their reaction mechanisms. Results showed that the melting point of ADN was significantly lowered upon the addition of amine nitrate with relatively low molecular volume and low melting point. TG–DTA–MS results showed that the onset temperature of the thermal decomposition of ADN/amine nitrates was similar to that of pure ADN. Furthermore, during thermal decomposition in the condensed phase, ADN produced highly acidic products that promoted exothermic reactions, and we observed the nitration and nitrosation of amines from the dissociation of amine nitrates.
- Matsunaga, Hiroki,Katoh, Katsumi,Habu, Hiroto,Noda, Masaru,Miyake, Atsumi
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- Ru/ceria-catalyzed direct formylation of amines and CO to produce formamides
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We herein report a new strategy of directly converting amines and CO to formamides with 100% atom utilization efficiency. It is suitable for up to 25 amine substrates with no additives. Ru/ceria is found to be an excellent catalyst for this reaction due the efficient co-activation of CO and amine on Ru species.
- Wang, Yehong,Zhang, Jian,Chen, Haijun,Zhang, Zhixin,Zhang, Chaofeng,Li, Mingrun,Wang, Feng
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- Development of an empirical kinetic model for sonocatalytic process using neodymium doped zinc oxide nanoparticles
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The degradation of Acid Blue 92 (AB92) solution was investigated using a sonocatalytic process with pure and neodymium (Nd)-doped ZnO nanoparticles. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The 1% Nd-doped ZnO nanoparticles demonstrated the highest sonocatalytic activity for the treatment of AB92 (10 mg/L) with a degradation efficiency (DE%) of 86.20% compared to pure ZnO (62.92%) and sonication (45.73%) after 150 min. The results reveal that the sonocatalytic degradation followed pseudo-first order kinetics. An empirical kinetic model was developed using nonlinear regression analysis to estimate the pseudo-first-order rate constant (kapp) as a function of the operational parameters, including the initial dye concentration (5-25 mg/L), doped-catalyst dosage (0.25-1 g/L), ultrasonic power (150-400 W), and dopant content (1-6% mol). The results from the kinetic model were consistent with the experimental results (R2 = 0.990). Moreover, DE% increases with addition of potassium periodate, peroxydisulfate, and hydrogen peroxide as radical enhancers by generating more free radicals. However, the addition of chloride, carbonate, sulfate, and t-butanol as radical scavengers declines DE%. Suitable reusability of the doped sonocatalyst was proven for several consecutive runs. Some of the produced intermediates were also detected by GC-MS analysis. The phytotoxicity test using Lemna minor (L. minor) plant confirmed the considerable toxicity removal of the AB92 solution after treatment process.
- Khataee, Alireza,Vahid, Behrouz,Saadi, Shabnam,Joo, Sang Woo
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- Nitromethane decomposition under high static pressure
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The room-temperature pressure-induced reaction of nitromethane has been studied by means of infrared spectroscopy in conjunction with ab initio molecular dynamics simulations. The evolution of the IR spectrum during the reaction has been monitored at 32.2 and 35.5 GPa performing the measurements in a diamond anvil cell. The simulations allowed the characterization of the onset of the high-pressure reaction, showing that its mechanism has a complex bimolecular character and involves the formation of the aci-ion of nitromethane. The growth of a three-dimensional disordered polymer has been evidenced both in the experiments and in the simulations. On decompression of the sample, after the reaction, a continuous evolution of the product is observed with a decomposition into smaller molecules. This behavior has been confirmed by the simulations and represents an important novelty in the scene of the known high-pressure reactions of molecular systems. The major reaction product on decompression is N-methylformamide, the smallest molecule containing the peptide bond. The high-pressure reaction of crystalline nitromethane under irradiation at 458 nm was also experimentally studied. The reaction threshold pressure is significantly lowered by the electronic excitation through two-photon absorption, and methanol, not detected in the purely pressure-induced reaction, is formed. The presence of ammonium carbonate is also observed.
- Citroni, Margherita,Bini, Roberto,Pagliai, Marco,Cardini, Gianni,Schettino, Vincenzo
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- Thermal Decomposition of Energetic Materials. 3. Temporal Behaviors of the Rates of Formation of Gaseous Pyrolysis Products from Condensed-Phase Decomposition of 1,3,5-Trinitrohexahydro-s-triazine
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Through the use of simultaneous thermogravimetry modulated beam mass spectrometry (STMBMS) measurements, time-of-flight (TOF) velocity-spectra analysis, and (2)H, (13)C, (15)N and (18)O labeled analogues of 1,3,5-trinitrohexahydro-s-triazine (RDX), the thermal decomposition products of RDX have been identified as H2O, HCN, CO, CH2O, NO, N2O, NH2CHO, NO2, HONO, (CH3)NHCHO, oxy-s-triazine (OST), and 1-nitroso-3,5-dinitrohexahydro-s-triazine (ONDNTA) and all of their gas formation rates have been measured as a function of time.From these results the primary reaction pathways that control the decomposition of RDX in both the solid and liquid phases have been discovered.Four primary reaction pathways control the decomposition of RDX in the liquid phase between 200 and 215 deg C.Two pathways are first-order reactions solely in RDX.One produces predominantly OST, NO, and H2O and accounts for approximately 30percent of the decomposed RDX, and the other produces predominantly N2O and CH2O with smaller amounts of NO2, CO, and NH2CHO and accounts for 10percent of the decomposed RDX.The third pathway consists of formation of ONDNTA by reaction between NO and RDX, followed by the decomposition of ONDNTA to predominantly CH2O and N2O.The fourth reaction pathway consists of decomposition of RDX through reaction with a catalyst that is formed from the decomposition products of previously decomposed RDX.The third and fourth reaction channels each account for approximately 30percent of the decomposed RDX.Experiments with solid-phase RDX have shown that its decomposition rate is very much slower than that of liquid-phase RDX.ONDNTA is the only product that appears to be formed during the early stages of decomposition of RDX in the solid phase.As the solid-phase decomposition progresses, N2O and lesser amounts of CH2O start to evolve and their rates of evolution increase until products associated with the liquid-phase RDX decomposition appear and the rates of gas formation of all products rapidly increase.This behavior strongly suggests the decomposition of solid RDX occurs through formation of ONDNTA within the lattice, the subsequent decomposition of it within the lattice to N2O and CH2O, followed by the dispersion of CH2O in the RDX, leading to its eventual liquefaction and the onset of the liquid-phase decomposition reactions.
- Behrens, Richard,Bulusu, Suryanarayana
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- N-Heterocyclic carbene catalyzed direct carbonylation of dimethylamine
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N-Heterocyclic carbene (NHC) catalyzed direct carbonylation of dimethylamine leading to the formation of DMF was successfully accomplished under metal-free conditions. The catalytic efficiency was investigated and the turnover numbers can reach as high as >300. The possible mechanism was also proposed.
- Li, Xiaonian,Liu, Kun,Xu, Xiaoliang,Ma, Lei,Wang, Hong,Jiang, Dahao,Zhang, Qunfeng,Lu, Chunshan
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- Catalytic asymmetric [3+2] cycloaddition of isomünchnones with methyleneindolinones
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An efficient enantioselective [3+2] cycloaddition of isomünchnones with methyleneindolinones that are generated by anin situintramolecular addition of the carbonyl group to rhodium carbenes is realized with a chiralN,N′-dioxide/Zn(ii) complex as a Lewis acid. A series of chiral oxa-bridged 3-spiropiperidines are obtained in high yields with excellent dr and excellent ee values.
- Feng, Xiaoming,Hu, Xinyue,Lin, Lili,Wang, Kaixuan,Xu, Chaoran,Zhou, Yuqiao
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supporting information
p. 8917 - 8920
(2021/09/10)
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- Evaluation of thioamides, thiolactams and thioureas as hydrogen sulfide (H2S)donors for lowering blood pressure
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Hydrogen sulfide (H2S)is a biologically important gaseous molecule that exhibits promising protective effects against a variety of pathological processes. For example, it was recognized as a blood pressure lowering agent. Aligned with the need for easily modifiable platforms for the H2S supply, we report here the preparation and the H2S release kinetics from a series of structurally diversified thioamides, thiolactams and thioureas. Three different thionation methods based on the usage of a phosphorus pentasulfide and Lawesson reagent were applied to prepare the target thioamides and thiolactams. Furthermore, obtained H2S donors were evaluated both in in vivo and in vitro studies. The kinetic parameters of the liberating H2S was determined and compared with NaHS and GYY4137 using two different detection technics i.e.; fluorescence labeling 7-azido-4-methyl-2H-chromen-2-one and 5,5‘-dithiobis (2-nitrobenzoic acid), sulfhydryl probe, also known as the Ellman's reagent. We have proved that the amount of releasing H2S from these compounds is controllable through structural modifications. Finally, the present study shows a hypotensive response to an intravenous administration of the developed donors in the anesthetized rats.
- Zaorska, Ewelina,Hutsch, Tomasz,Gawry?-Kopczyńska, Marta,Ostaszewski, Ryszard,Ufnal, Marcin,Koszelewski, Dominik
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supporting information
(2019/04/29)
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- Synthetic method of N-mono-substituted alkyl formamide
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The embodiment of the invention discloses a synthetic method of N-mono-substituted alkyl formamide. The synthetic method comprises the steps of enabling primary amine compounds to react with carbon monoxide, distilling, and rectifying to obtain the N-mono-substituted alkyl formamide under the catalytic action of a sodium alkoxide-alcohol solution, wherein the molar ratio of the primary amine compounds to the sodium alkoxide-alcohol solution is 1 to (0.002 to 0.008); according to the synthetic method disclosed by the invention, through selecting specific materials, the N-mono-substituted alkylformamide can be synthesized through a one-step method under the action of a specific catalyst, and the synthetic method has the advantages that the process is simple, no by-product is produced, the source of raw materials are rich, the cost is low, the production efficiency can be improved effectively, and the production cost can be reduced; in addition, the yield and purity of synthetic productscan also be improved.
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Paragraph 0044; 0045; 0046; 0047; 0048-0063; 0066; 0067
(2019/10/01)
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- Efficient synthetic method for N-methyl MF resin solution
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The invention discloses an efficient synthetic method for an N-methyl MF resin solution. The method comprises the following steps: firstly, preparing a catalyst precursor by means of a co-precipitating method; adding EDTA in the preparation process, wherein the growth speed of a precipitate is controlled effectively; then sintering the catalyst precursor to prepare catalyst powder; activating andmodifying the catalyst powder with N-isopropyl acrylamide and triethylene tetramine to prepare a catalyst; then carrying out dehydrogenizing catalytic treatment on methanol under catalysis of the catalyst to prepare methyl formate; and then reacting with methylamine to prepare a target product N-methyl formamide. The method is simple to operate, the adopted catalyst is high in catalytic activity,and the prepared target product is high in purity and high in yield.
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Paragraph 0025-0072
(2019/01/06)
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- Method for preparing methallyl alcohol and amide simultaneously
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A method for preparing methallyl alcohol and amide simultaneously is characterized in that methylallyl carboxylate taken as a raw material and an amine compound taken as an ammonolysis agent react under the action of a catalyst to produce methallyl alcohol and an amide compound. The methylallyl carboxylate and the amine compound taken as the ammonolysis agent are firstly adopted, and the methallyl alcohol and the amide compound are obtained under the action of the catalyst. The reaction process is a bulk reaction, no solvents are added, almost no wastewater or salt are produced, and byproduct methyl allyl ether is not produced; the defect that a large number of wastewater is produced through hydrolysis is overcome due to adoption of ammonolysis, the methallyl alcohol and the amide compound are coproduced directly by use of ammonoysis, coupling production is realized, and the cost is reduced.
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Paragraph 0026-0027
(2017/11/29)
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- Electronic-grade formamide compound preparation method
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The present invention discloses an electronic-grade formamide compound preparation method, which comprises that: the pure product of an organic amine compound and a pure product having purity of methyl formate enter a tube reactor, and a reaction is performed, wherein the organic amine compound is monomethylamine, mono ethylamine or diethylamine, and during the material adding, the organic amine compound excesses 2-5 wt%; after the reaction, cooling is performed by using a cooler, the cooled material enters a buffer tank, one part of the material discharged from the buffer tank returns to the tube reactor, the other part of the material discharged from the buffer tank enters a receiving tank and then is pumped into a coarse distillation tower, the tower kettle temperature is controlled at less than or equal to 130 DEG C, the tower top temperature is less than or equal to 64 DEG C, and the tower kettle liquid detection results show that the formamide compound content is more than or equal to 95 wt%, and the organic amine compound content is less than or equal to 5 wt%; extraction is performed from the tower bottom, the extracted material is pumped to a light removing tower, negative pressure distillation is performed, and the tower kettle liquid detection results show that the formamide compound content is more than or equal to 99.5 wt%, and the organic amine compound content is less than or equal to 0.5 wt%; and the material obtained from the tower bottom is pumped to a rectification tower, negative pressure distillation is performed, and N-methylformamide is extracted from the tower top. The product prepared through the process of the present invention has the low metal content, and the detection result shows that the product achieves the electronic grade.
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Paragraph 0033; 0034; 0035; 0036; 0037; 0038
(2016/11/14)
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- Nano rod-shaped and reusable basic Al2O3 catalyst for N-formylation of amines under solvent-free conditions: A novel, practical and convenient 'NOSE' approach
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An expeditious, simple, highly efficient, practical and green protocol for the N-formylation of alkyl/aryl amines and indole derivatives catalyzed by novel nano rod-shaped basic Al2O3 under solvent-free conditions has been developed. The catalyst is efficiently recycled up to the 5th run, an important point in the domain of green chemistry. The methodology provides cleaner conversion, shorter reaction times and high selectivity which makes the protocol attractive. The Royal Society of Chemistry 2012.
- Das, Vijay Kumar,Devi, Rashmi Rekha,Raul, Prasanta Kumar,Thakur, Ashim Jyoti
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supporting information; experimental part
p. 847 - 854
(2012/04/23)
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- Synthesis of 2-oxazolones and α-aminoketones via palladium-catalyzed reaction of β,β-dibromoenamides
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β,β-Dibromoenamides show two different interesting reactivities based on the choice of R group under the reaction conditions. On the basis of mechanistic studies, both reactions proceed via an intermolecular Suzuki-Miyaura C-C coupling and an intramolecular C-O coupling.
- Chai, David I.,Hoffmeister, Laura,Lautens, Mark
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supporting information; experimental part
p. 106 - 109
(2011/03/22)
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- N-carbonylation of lithium azaenolates of amides, formamides, ureas, and carbamates with carbon monoxide mediated by selenium
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N-Carbonylation of less nucleophilic nitrogen compounds was achieved by the reaction of the lithium azaenolates with carbon monoxide and selenium. This reaction proceeds in the cases of amides, formamides, ureas, and carbamates, leading to the formation of the corresponding carbamosele-noates in good to high yields after trapping with BuI.
- Fujiwara, Shin-Ichi,Okada, Kazuhiro,Shikano, Yasukazu,Shimizu, Yoshihiko,Tsutomu, Shin-Ike,Terao, Jun,Kambe, Nobuaki,Sonoda, Noboru
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p. 273 - 276
(2007/10/03)
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- Determination of the synthetic origin of methamphetamine samples by 2H NMR spectroscopy
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Samples of methamphetamine, prepared according to the most common synthetic pathways, were submitted to natural-abundance 2H NMR spectroscopy. The deuterium content at the various sites of the molecule was found to depend on its synthetic history. The technique provides a chemical fingerprint of methamphetamine samples and can give hints to trace back the starting materials and the synthetic procedures.
- Armellin, Silvia,Brenna, Elisabetta,Frigoli, Samuele,Fronza, Giovanni,Fuganti, Claudio,Mussida, Daniele
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p. 3113 - 3117
(2008/02/09)
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- Facile desulfurization of thioamides and thioureas with tetrabutylammonium periodate under mild conditions
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Thioamides and thioureas were reacted with tetrabutylammonium periodate at room temperature to afford the corresponding amides and ureas, respectively, under aprotic conditions. Springer-Verlag 2005.
- Pourali, Ali Reza
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p. 733 - 737
(2007/10/03)
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- Amine attack on the carbonyl ligands of the protonated dicyclopentadienyl-bridged diruthenium complex [{(η5-C5H3)2(SiMe 2)2}Ru2(CO)4(μ-H)]+
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Complexes [{(η5-C5H3)2(SiMe 2)2}Ru2(CO)4(μ-H)]+ (1H+BF4-, 1D+TfO-), with a protonated Ru-Ru bond, were prepared by protonation of {(η5-C5H3)2(SiMe 2)2}Ru2(CO)4 (1) with HBF4·Et2O or CF3SO3D. The bridging proton in 1H+ is removed only very slowly by amine bases even though it is thermodynamically acidic (pKaAN = 6.5 (±0.2)). This remarkable kinetic inertness of the bridging proton allows amines (NH3, NH2CH3, NH(CH3)2, morpholine, piperidine, pyrrolidine) to react with 1H+ by attacking the CO ligand to give a formamide (HC(=O)NR2) and the CO-substituted product {(η5-C5H3)2(SiMe 2)2}Ru2(CO)3(NHR2) (2). Thus, protonation of the metal-metal bond in 1H+ promotes reactions of the CO ligand that are not possible in the unprotonated 1. A proposed mechanism for these reactions is supported by kinetic studies of the reaction of 1D+TfO- with morpholine in nitromethane at 20.0 °C, as well as by deuterium-labeling experiments. The molecular structure of {(η5-C5H3)2-(SiMe 2)2}Ru2(CO)3(NH2CH 3) (2f), as determined by an X-ray diffraction investigation, is also presented.
- Ovchinnikov, Maxim V.,Guzei, Ilia A.,Angelici, Robert J.
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p. 691 - 696
(2008/10/08)
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- Kinetic Features of Formation of N-Methylformamide from Formic Acid and Methylamine in Dimethylsulfoxide
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The kinetics of formation of N-methylformamide from formic acid and methylamine in dimethyl-sulfoxide was studied. The rate constant of the reaction involving proton transfer between the reactants and its dependence on temperature and on acting concentration of formic acid were determined.
- Zeinalov
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- Electronic Structure and Gas-Phase Thermolysis of Carbonyl-Substituted Tetraz-2-enes Studied by Photoelectron Spectroscopy. Cleavage of Amidyl and Carbamyl Radicals
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The electronic structure of the 1,4-dicarbonyl-substituted 1,4-dimethyltetraz-2-enes 1-4 has been studied by He(I) photoelectron (PE) spectroscopy and semiempirical quantum chemical calculations.The compounds are characterized by five ionization potentials with energies less than 12 eV which are assigned to the molecular orbitals ?3 (HOMO), n+, ?2, n+OO, and n-OO.Gas-phase thermolysis of these compounds was investigated by variable temperature PE spectroscopy.The thermolysis commences by loss of molecular nitrogen and formation of short-lived amidyl CH3-N.-CO-R or carbamyl CH3-N.-CO-OR radicals which decompose by cleavage of the CO-R or CO-OR bond, respectively, (β scission).Thus, the former radicals disproportionate to methyl isocyanate and N-methylformamide (R=H) or loose a methyl radical affording methyl isocyanate (R=CH3), and the latter decompose to methyl isocyanate and an aldehyde.
- Awadallah, Adel,Kowski, Klaus,Rademacher, Paul
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p. 2610 - 2622
(2007/10/03)
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- Kinetics of Methyl Formate Aminolysis by Methylamine
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The formal-kinetic parameters of the formation of N-methylformamide from methyl formate and methylamine in the medium of the reaction product are successively approximated.First, a priori techniques of analyzing the identifiability of the parameters of nonlinear chemical kinetics models are used to show that the kinetic parameters of the reaction can, in principle, be determined unambiguously.The experimental design techniques are used to obtain the initial approximations to the sought for parameters.These approximations are refined by the methods of nonlinear estimation to the parameters of nonlinear chemical kinetics models.
- Zeinalov, M. Z.
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p. 1959 - 1961
(2007/10/03)
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- Synthesis of the salutaridine and aporphine skeleton via palladium(0) catalyzed cyclization and S(RN)1 reaction of 2'-bromoreticulines
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The intramolecular aryl-aryl-coupling reactions of 2'-bromoreticulines are described. Their regioselectivity depends on the cyclization method. The palladium(0) catalyzed reaction of 22 leads preferentially to the salutaridine derivative 27, whilst via the photochemically induced S(RN)1 reaction of 22 the aporphine skeleton 24 is obtained.
- Wiegand,Schafer
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p. 5341 - 5350
(2007/10/02)
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- Synthesis of L-histidine specifically labelled with stable isotopes
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(2'-13C)-, (1'-15N)- and (3'-15N)-L-Histidine were prepared according to a synthetic scheme that allows the 13C or 15N labelling of all carbon and nitrogen positions or any combination of positions.A 1,5-disubstituted imidazole ring was constructed via condensation of tosylmethyl isocyanide with 3-phenylpropenal and subsequent cycloaddition of benzylamine.The imidazole intermediate was converted into 1-benzyl-5-(chloromethyl)-imidazolium chloride which was coupled to a glycine moiety via an enantioselective coupling with the bislactim ether of cyclo-D-valylglycine.Deprotection of the coupling product afforded L-histidine in high optical purity.Syntheses for the isotopically labelled synthons were developed starting from simple, comercially available, highly enriched compounds.The labelled L-histidines were characterized by mass spectrometry and 1H-, 13C- and 15N-NMR spectroscopy.
- Cappon, J. J.,Witters, K. D.,Baart, J.,Verdegem, P. J. E.,Hoek, A. C.,et al.
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p. 318 - 328
(2007/10/02)
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- Catalytic Beckmann Rearrangement of Oximes in Homogeneous Liquid Phase
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Oximes such as cyclohexanone oxime and benzaldehyde oxime were catalytically transformed into the corresponding lactams in N,N-dimethylformamide solutions of alkylating reagents such as trialkyloxonium salts.Catalyst turnover attained 43 on the basis of the acid used to obtain alkylating reagent.O-Alkyl-N,N-dimethylformamidinium salt was suggested to be a catalyst species.
- Izumi, Yusuke
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p. 2171 - 2174
(2007/10/02)
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- 2,2'-Diphenyl-Δ3,3'-bi-3H-indole-1,1'-dioxide: Competitive Demethylation and Redox Reactions
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Competitve demethylation and redox reactions induced by 2,2'-diphenyl-Δ3,3'-bi-3H-indole-1,1'-dioxide, 1 (dinitrone) on several nitrogen bearing compounds (pyridines, amides, indoles, hydrazones and amines) are reported. - Keywords: 2,2'-Diphenyl-Δ3,3'-bi-3H-indole-1,1'-dioxide; Demethylation; Oxidation
- Bruni, Paolo,Conti, Carla,Tosi, Giorgio
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p. 1311 - 1316
(2007/10/02)
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- N-ALKYL-AMINOMETHYL-P-ETHYL- AND T-BUTYL-PHOSPHINIC ACID
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Convenient one-batch-synthetic routes leading to the title compounds are described using easily accessible educts like N-alkyl-formamides, paraformaldehyde and alkyl- or aryldichlorophosphines.
- Tyka, Roman,Haegele, Gerhard,Peters, Juergen
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p. 425 - 432
(2007/10/02)
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- Reactions of the 2,6-Di-tert-butyl-4-(N-tert-butylnitrono)-phenoxyl Radical
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The title compound, a phenoxyl radical containing a nitrono group, reacts with alcohols and tert-butylhydroperoxide yielding phenol and products of secondary solvent reactions.The reactions with lead tetraacetate, tert.-butoxy and 2-cyanoisopropyl radicals give high yields of cyclohexadienone adducts (6, 7 and 10) containing unchanged nitrono function.The reaction with dibenzoylperoxide, however, leads to the modification of the nitrono group yielding the N-benzoyloxycarboxamide (8).In the acidic decomposition of the tert-butoxy radical adduct we suggest a nitrenium ion (16) as an intermediate.
- Schulz, Manfred,Bach, Barbara,Reinhardt, Michael
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p. 579 - 587
(2007/10/02)
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- Nitrogen-15 Nuclear Magnetic Rasonance Spectroscopy. Natural Abundance Nitrogen-15 Spectra of the cis and trans Isomers of Secondary Alkylformamides
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The 15N NMR chemical shifts were measured of a number of N-substituted formamides and acetamides at the natural abundance level.The ratios of the cis and trans isomers for several N-alkylformamides were also determined.Substituent effects on the 15N chemical shifts of formamides are compared with those of some other nitrogen-containing compounds.There is a consistent pattern of behavior of the one bond spin-spin coupling constants 1J(15NH)> wherein the trans isomers of N-alkylformamides are larger than those of the cis isomers.
- Nakanishi, Hiroshi,Roberts, John D.
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- Benzophenone anti-oximes, diazepin-N-oxides, and their use as pharmaceutical agents and as intermediates for pharmaceutical agents
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N-Fluorohaloacetyl-N-methylaminobenzophenone anti-oxime, the corresponding diazepin-N-oxides, their use as tranquilizers, muscle relaxants and sedatives, and their use as intermediates in the preparation of 3-fluorobenzodiazepines, which are also useful as tranquilizers, muscle relaxants and sedatives.
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- Amides of leurosine, leuroformine, desacetylleurosine and desacetylleuroformine
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C-3 Carboxamides of leurosine, leuroformine, 4-desacetylleurosine and 4-desacetylleuroformine, useful as antitumor agents.
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- Hydroxyquinazolines and their use as intermediates for pharmaceutical agents
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6-Substituted-2-halofluoromethyl-1,2-dihydro-2-hydroxy-1-methyl-4-phenylquinazolines and their use as intermediates in the preparation of 3-fluorobenzodiazepines, which are useful as tranquilizers, muscle relaxants and sedatives.
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