- Dynamic Ureas with Fast and pH-Independent Hydrolytic Kinetics
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Low cost, high performance hydrolysable polymers are of great importance in biomedical applications and materials industries. While many applications require materials to have a degradation profile insensitive to external pH to achieve consistent release profiles under varying conditions, hydrolysable chemistry techniques developed so far have pH-dependent hydrolytic kinetics. This work reports the design and synthesis of a new type of hydrolysable polymer that has identical hydrolysis kinetics from pH 3 to 11. The unprecedented pH independent hydrolytic kinetics of the aryl ureas were shown to be related to the dynamic bond dissociation controlled hydrolysis mechanism; the resulting hindered poly(aryl urea) can be degraded with a hydrolysis half-life of 10 min in solution. More importantly, these fast degradable hindered aromatic polyureas can be easily prepared by addition polymerization from commercially available monomers and are resistant to hydrolysis in solid form for months under ambient storage conditions. The combined features of good stability in solid state and fast hydrolysis at various pH values is unprecedented in polyurea material, and will have implications for materials design and applications, such as sacrificial coatings and biomaterials.
- Cai, Kaimin,Ying, Hanze,Cheng, Jianjun
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supporting information
p. 7345 - 7348
(2018/06/11)
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- A second class of liquid phase in the production of asymmetrical cyclobutylamines tert-
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The present invention relates to a process for preparing unsymmetrical secondary tert-butylamines which, in addition to the tert-butyl radical, also contain an alkyl, cycloalkyl or benzyl radical. They are prepared by reacting corresponding aldehydes with tert-butylamine and hydrogen in the presence of hydrogenation catalysts (reductive amination) in the liquid phase.
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Paragraph 0057
(2017/03/23)
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- Deciphering ligands' interaction with Cu and Cu2O nanocrystal surfaces by NMR solution tools
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The hydrogenolysis of [Cu2{(iPrN)2(CCH3)}2] in the presence of hexadecylamine (HDA) or tetradecylphosphonic acid (TDPA) in toluene leads to 6-9 nm copper nanocrystals. Solution NMR spectroscopy has been used to describe the nanoparticle surface chemistry during the dynamic phenomenon of air oxidation. The ligands are organized as multilayered shells around the nanoparticles. The shell of ligands is controlled by both their intermolecular interactions and their bonding strength on the nanocrystals. Under ambient atmosphere, the oxidation rate of colloidal copper nanocrystals closely relies on the chemical nature of the employed ligands (base or acid). Primary amine molecules behave as soft ligands for Cu atoms, but are even more strongly coordinated on surface CuI sites, thus allowing a very efficient corrosion protection of the copper core. On the contrary, the TDPA ligands lead to a rapid oxidation rate of Cu nanoparticles and eventually to the re-dissolution of CuII species at the expense of the nanocrystals.
- Glaria, Arnaud,Cure, J??r??my,Piettre, Kilian,Coppel, Yannick,Turrin, C??dric-Olivier,Chaudret, Bruno,Fau, Pierre
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supporting information
p. 1169 - 1178
(2015/03/05)
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- Aerobic oxidative N-dealkylation of tertiary amines in aqueous solution catalyzed by rhodium porphyrins
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Aerobic oxidative N-dealkylation of a variety of aliphatic tertiary amines and anilines catalyzed by rhodium(iii) tetra (p-sulfonatophenyl) porphyrin ((TSPP)RhIII) is achieved in aqueous solution using dioxygen as the sole oxidant.
- Ling, Zhen,Yun, Lin,Liu, Lianghui,Wu, Bing,Fu, Xuefeng
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supporting information
p. 4214 - 4216
(2013/05/22)
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- PROCESS FOR PREPARING UNSYMMETRIC SECONDARY TERT-BUTYLAMINES IN THE LIQUID PHASE
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The present application relates to a process for preparing unsymmetric secondary tert-butylamines which, as well as the tert-butyl radical, also comprise an alkyl, cycloalkyl or benzyl radical. They are prepared by reacting corresponding aldehydes with tert-butylamine and hydrogen in the presence of hydrogenation catalysts (reductive amination) in the liquid phase.
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Page/Page column 5-6
(2011/10/19)
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- Preparation process of aminoacetamide derivative
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Disclosed herein are novel processes for preparing aminoacetamide derivatives, wherein: (1) a secondary amine is reacted with a 2-haloacetamide in the presence or absence of at least one solvent selected from water, lower alcohols, aromatic solvents and acetic acid esters; (2) an N-benzylideneamine derivative is reacted with dimethyl sulfate or diethyl sulfate to form a secondary amine, and this secondary amine is then reacted with a 2-haloacetamide; and (3) a primary amine is reacted with benzaldehyde to form an N-benzylideneamine derivative, this product is then reacted with dimethyl sulfate or diethyl sulfate to form a secondary amine, and this secondary amine is further reacted with a 2-haloacetamide. The 2-aminoacetamide derivatives are useful as intermediates for the preparation of novel antibiotics.
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- Stereodynamics of 2-(diethylamino)propane and 2-(dibenzylamino)propane. 1H and 13C{1H} DNMR studies. Molecular mechanics calculations
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2-(Diethylamino)propane (DEAP) and 2-(dibenzylamino)propane (DBAP) possess similar molecular symmetries. Interconversion among the stable equilibrium conformations occurs by inversion-rotation at the pyramidal nitrogen and by isolated rotation about carbon-nitrogen bonds. In DEAP and DBAP, the fact that stable equilibrium conformations cannot have destabilizing syn-1,5 interactions between methyl or phenyl groups limits the number of equilibrium conformations that will be present at concentrations high enough to be NMR detectable. The 1H and 13C{1H} NMR spectra of DEAP at 100 K show two diastereomeric pairs of enantiomeric conformations. One pair of enantiomers has the isopropyl methine proton and both ethyl methyl groups gauche to the lone pair (75%). The other pair has the methine proton anti to the lone pair with the ethyl methyl groups respectively gauche and anti to the lone pair (25%). The barrier to inversion-rotation in DEAP (ΔG? = 6.4 kcal/mol) is higher than barriers to isolated rotation about carbon-nitrogen bonds (ΔG? = 5.3-5.7 kcal/mol). The 1H and 13C{1H} NMR spectra of DBAP at 100 K show just one pair of enantiomeric conformations that have the isopropyl methine proton and both phenyl groups gauche to the lone pair. There is no evidence in the NMR spectrum at 100 K for those conformations of DBAP that have a phenyl group anti to the lone pair. The barrier to inversion-rotation in DBAP (ΔG? = 6.4 kcal/mol) is higher than the barrier to racemization via isolated rotation about carbon-nitrogen bonds (ΔG? = 5.5 kcal/mol). Molecular mechanics calculations of conformational energies are in good agreement with the observed conformational preferences.
- Brown, Jay H.,Bushweller, C. Hackett
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p. 12567 - 12577
(2007/10/03)
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- ELECTROCHEMICAL REDUCTIVE AMINATION. I. AMINATION OF ALIPHATIC KETONES BY PRIMARY AMINES
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The reductive amination of aliphatic ketones in aqueous solutions of primary amines was realized by an electrochemical method.The best yields of the secondary amines were obtained at lead and cadmium cathodes in an aqueous electrolytic solution at pH 11-12.Elongation and branching in the carbon chain of the radicals both of the ketone and of the primary amine lead to a reduction in the yield of the secondary amine.The yield of the secondary amine is mainly determined by the rate of the chemical reaction leading to the formation of the azomethine compound, preceding the electrochemical reduction stage.
- Smirnov, Yu. D.,Tomilov, A. P.
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- PHOSPHONIUM DIAZA-DIYLIDS AND AZA-YLDIID AS NEW AND EFFICIENT REAGENTS FOR PRIMARY AND SECONDARY AMINES SYNTHESIS
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Metallated aminophosphonium ylids, diaza-diylids and aza-yldiid, are investigated as reagents for primary and secondary amines synthesis.
- Cristau, Henri-Jean,Garcia, Chantal,Kadoura, Jumah,Torreilles, Eliane
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p. 151 - 154
(2007/10/02)
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- CONFORMATIONAL STUDIES BY DYNAMIC NMR-25 STEREOMUTATIONS IN TRIALKYLAMINES
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The trend toward steric acceleration for N-inversion and steric deceleration for C-N rotation has been verified in an homogeneous series of tertiary isopropylamines.Unambiguous evidence has been obtained that in a crowded amine (3-pentyl diisopropylamine) the barrier to rotation becomes higher than that to inversion.It has also been shown that this amine adopts an eclipsed, rather than a staggered dynamic conformation.
- Lunazzi, Lodovico,Macciantelli, Dante,Grossi, Loris
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p. 305 - 308
(2007/10/02)
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