107-10-8Relevant articles and documents
Spectroscopy of Hydrothermal Reactions, Part 26: Kinetics of Decarboxylation of Aliphatic Amino Acids and Comparison with the Rates of Racemization
Li, Jun,Brill, Thomas B.
, p. 602 - 610 (2003)
The kinetics of decarboxylation of six α-amino acids (glycine, alanine, aminobutyric acid, valine, leucine, and isoleucine) and β-aminobutyric acid were studied in aqueous solution at 310-330 deg C and 275 bar over the pH25 range 1.5-8.5 by using an in situ FT-IR spectroscopy flow reactor. Based on the rate of formation of CO2, the first-order or pseudo-first-order rate constants were obtained along with the Arrhenius parameters. The decarboxylation rates of amino acids follow the order Gly > Leu ca. Ile ca. Val > Ala > α-Aib > β-Aib. Differences in the concentration between 0.05 and 0.5 m had only a minor effect on the decarboxylation rate. The effect of the position of the amino group on the decarboxylation rate was investigated for α-, β-, and γ-aminobutyric acid and the order was found to be α > β >> γ. Although the pH dependence is complex, the decarboxylation rates of α-amino acids qualitatively have the inverse trend of the racemization rates.
Merging constitutional and motional covalent dynamics in reversible imine formation and exchange processes
Kovaricek, Petr,Lehn, Jean-Marie
, p. 9446 - 9455 (2012)
The formation and exchange processes of imines of salicylaldehyde, pyridine-2-carboxaldehyde, and benzaldehyde have been studied, showing that the former has features of particular interest for dynamic covalent chemistry, displaying high efficiency and fast rates. The monoimines formed with aliphatic α,ω-diamines display an internal exchange process of self-transimination type, inducing a local motion of either "stepping-in- place" or "single-step" type by bond interchange, whose rate decreases rapidly with the distance of the terminal amino groups. Control of the speed of the process over a wide range may be achieved by substituents, solvent composition, and temperature. These monoimines also undergo intermolecular exchange, thus merging motional and constitutional covalent behavior within the same molecule. With polyamines, the monoimines formed execute internal motions that have been characterized by extensive one-dimensional, two-dimensional, and EXSY proton NMR studies. In particular, with linear polyamines, nondirectional displacement occurs by shifting of the aldehyde residue along the polyamine chain serving as molecular track. Imines thus behave as simple prototypes of systems displaying relative motions of molecular moieties, a subject of high current interest in the investigation of synthetic and biological molecular motors. The motional processes described are of dynamic covalent nature and take place without change in molecular constitution. They thus represent a category of dynamic covalent motions, resulting from reversible covalent bond formation and dissociation. They extend dynamic covalent chemistry into the area of molecular motions. A major further step will be to achieve control of directionality. The results reported here for imines open wide perspectives, together with other chemical groups, for the implementation of such features in multifunctional molecules toward the design of molecular devices presenting a complex combination of motional and constitutional dynamic behaviors.
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Johnson,Degering
, p. 3194 (1939)
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Boyer et al.
, p. 325 (1956)
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Rice husk-SiO2supported bimetallic Fe-Ni nanoparticles: as a new, powerful magnetic nanocomposite for the aqueous reduction of nitro compounds to amines
Ghadermazi, Mohammad,Moradi, Setareh,Mozafari, Roya
, p. 33389 - 33400 (2020)
This paper reports a novel green procedure for immobilization of bimetallic Fe/Ni on amorphous silica nanoparticles extracted from rice husk (RH-SiO2). The heterogeneous nanocomposite (Fe/Ni?RH-SiO2) was identified using SEM, EDX, TEM, BET, H2-TPR, TGA, XRD, VSM, ICP-OES, and FT-IR analyses. The Fe/Ni?RH-SiO2nanocomposite was applied as a powerful catalyst for the reduction of structurally diverse nitro compounds with sodium borohydride (NaBH4) in green conditions. This procedure suggests some benefits such as green chemistry-based properties, short reaction times, non-explosive materials, easy to handle, fast separation and simple work-up method. The catalyst was separated by an external magnet from the reaction mixture and was reused for 9 successive cycles with no detectable changes of its catalytic efficiency.
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Frieman,Jurewicz
, p. 1800 (1969)
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Insight into the mechanism of hydrogenation of amino acids to amino alcohols catalyzed by a heterogeneous MoOx-modified Rh catalyst
Tamura, Masazumi,Tamura, Riku,Takeda, Yasuyuki,Nakagawa, Yoshinao,Tomishige, Keiichi
, p. 3097 - 3107 (2015)
Hydrogenation of amino acids to amino alcohols is a promising utilization of natural amino acids. We found that MoOx-modified Rh/SiO2 (Rh-MoOx/SiO2) is an efficient heterogeneous catalyst for the reaction at low temperature (323 K) and the addition of a small amount of MoOx drastically increases the activity and selectivity. Here, we report the catalytic potential of Rh-MoOx/SiO2 and the results of kinetic and spectroscopic studies to elucidate the reaction mechanism of Rh-MoOx/SiO2 catalyzed hydrogenation of amino acids to amino alcohols. Rh-MoOx/SiO2 is superior to previously reported catalysts in terms of activity and substrate scope. This reaction proceeds by direct formation of an aldehyde intermediate from the carboxylic acid moiety, which is different from the reported reaction mechanism. This mechanism can be attributed to the reactive hydride species and substrate adsorption caused by MoOx modification of Rh metal, which results in high activity, selectivity, and enantioselectivity.
Catalytic Reductions and Tandem Reactions of Nitro Compounds Using in Situ Prepared Nickel Boride Catalyst in Nanocellulose Solution
Prathap, Kaniraj Jeya,Wu, Qiong,Olsson, Richard T.,Dinér, Peter
, p. 4746 - 4749 (2017)
A mild and efficient method for the in situ reduction of a wide range of nitroarenes and aliphatic nitrocompounds to amines in excellent yields using nickel chloride/sodium borohydride in a solution of TEMPO-oxidized nanocellulose in water (0.01 wt %) is described. The nanocellulose has a stabilizing effect on the catalyst, which increases the turnover number and enables low loading of nickel catalyst (0.1-0.25 mol % NiCl2). In addition, two tandem protocols were developed in which the in situ formed amines were either Boc-protected to carbamates or further reacted with an epoxide to yield β-amino alcohols in excellent yields.
Amination of alcohols with ammonia in water over Rhin catalyst
Takanashi, Tsukasa,Nakagawa, Yoshinao,Tomishige, Keiichi
, p. 822 - 824 (2014)
Amination of various C3 alcohols such as 1,2-propanediol with ammonia was catalyzed by RhIn/C in water while Rh/C was totally inactive. Activated carbon FAC-10 was the best support in terms of activity and resistance to metal leaching. In the amination of 1,2-propanediol, RhIn/C produced amino alcohols in 68% total selectivity and 38% conversion. XRD and TEM measurements showed that RhIn alloy particle with size of 34 nm was formed on the carbon support.
CoFe2O4?SiO2-NH2-CoII NPs: An effective magnetically recoverable catalyst for Biginelli reaction
Allahresani, Ali,Hemmat, Kaveh,Nasseri, Mohammad Ali,Sangani, Mehri Mohammadpour
, (2020)
Biginelli reaction entails acid-catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) with simply-accessible initial substances, specifically, aldehyde, urea, and active methylene compound. DHPMs have stimulated a resurgence of attention in the previous two decades because of their broad-ranging pharmacological actions and the existence of varied all-natural products. Currently, green methods to asymmetric Biginelli reaction have been researched for anti-inflammatory DHPMs. In materials chemistry, DHPMs are increasingly decision applications in the creation of materials like polymers, adhesives, fabric dyes, etc. In light of the simplicity by which the Biginelli reaction is conducted, numerous interesting prospects expect its exploitation in variety fields. CoFe2O4?SiO2-NH2-CoII is herein turned out to be an effective catalyst at a three-component Biginelli reaction. The yield of the corresponding DHPMs was rather large (20 cases; average 92 percent). Finally, we herein suggest a procedure that shows lots of advantages and benefits such as the whole lack of solvents, mild reaction conditions, comparatively short reaction times. Also, CoFe2O4?SiO2-NH2-CoII NPs catalyst has been readily recovered from the reaction combination and reused, without the decrease of catalytic action.
Comparison of the Activity and Lifetime of Raney Nickel and Nickel Boride in the Hydrogenation of Various Functional Groups
Schreifels, John A.,Maybury, P. Calvin,Swartz, William E.
, p. 1263 - 1269 (1981)
Nickel borides (Ni2B) are prepared by the reduction of a nickel salt with sodium borohydride.These materials have been shown to be active hydrogenation catalysts.The activity and lifetime of a P-1.50 nickel boride catalyst, which is prepared in a 50percent water/ethanol solvent, are reported for the hydrogenation of unsaturated carbon and nitrogen bonds and for aldehydes.The data are compared to those obtained for similar reductions which employ Raney nickel as the catalyst.The nickel boride is more active and productive than Raney nickel in the hydrogenation of hexene,cyclohexene, and acrylonitrile.The properties of the two catalysts are similar for the reduction of cinnamaldehyde, 2-ethylhexanal, and benzaldehyde.The data for the reduction of nitrobenzene, adiponitrile, and propionitrile indicate that the nickel boride is more susceptible to nitrogen poisoning than Raney nickel.
Zoerner,Huettig
, p. 145,156 (1933)
Kinetic study of the reaction between iodide and N-chloramines
Antelo, J. M.,Arce, F.,Campos, J.,Parajo, M.
, p. 391 - 396 (1996)
We carried out a kinetic study of the reaction between iodide ion and various primary N-chloramines and found it to be first-order in the latter.Experiments also showed the rate constant for the reaction to be directly proportional to the iodide and hydrogen ion concentrations.The influence of the concentration reveals the presence of general acid catalysis processes.
Mechanism of β-lactam ring opening in cephalosporins
Page,Proctor
, p. 3820 - 3825 (1984)
The mechanism of the aminolysis of cephalosporins is a stepwise process. A tetrahedral intermediate is formed by the reversible addition of the amine to the beta -lactam carbonyl carbon. Expulsion of the attacking amine from the tetrahedral intermediate occurs faster than fission of the beta -lactam C-N bond. The reaction proceeds by trapping the intermediate with base. Expulsion of a leaving group at C-3 prime in cephalosporins is not concerted with nucleophilic attack of the amine on the beta -lactam carbonyl carbon and makes little difference to the rate of beta -lactam C-N bond fission.
Development and Application of Efficient Ag-based Hydrogenation Catalysts Prepared from Rice Husk Waste
Unglaube, Felix,Kreyenschulte, Carsten Robert,Mejía, Esteban
, p. 2583 - 2591 (2021/04/09)
The development of strategies for the sustainable management and valorization of agricultural waste is of outmost importance. With this in mind, we report the use of rice husk (RH) as feedstock for the preparation of heterogeneous catalysts for hydrogenation reactions. The catalysts were prepared by impregnating the milled RH with a silver nitrate solution followed by carbothermal reduction. The composition and morphology of the prepared catalysts were fully assessed by IR, AAS, ICP-MS, XPS, XRD and STEM techniques. This novel bio-genic silver-based catalysts showed excellent activity and remarkable selectivity in the hydrogenation of nitro groups in both aromatic and aliphatic substrates, even in the presence of reactive functionalities like halogens, carbonyls, borate esters or nitriles. Recycling experiments showed that the catalysts can be easily recovered and reused multiple times without significant drop in performance and without requiring re-activation.
Highly selective synthesis of primary amines from amide over Ru-Nb2O5 catalysts
Guo, Wanjun,Guo, Yong,Jia, Hongyan,Liu, Xiaohui,Pan, Hu,Wang, Yangang,Wang, Yanqin,Xia, Qineng
supporting information, (2021/12/22)
Amines are an important class of compounds in natural products and medicines. The universal availability of amides provides a potential way for the synthesis of amines. Herein, Ru/Nb2O5 catalyst is demonstrated to be highly efficient and stable for the selective hydrogenation of propionamide to propylamine (as a model reaction), with up to 91.4% yield of propylamine under relatively mild conditions. Results from XPS analyses, CO chemisorption, TEM images and DRIFTS spectra revealed that the unique properties of Nb2O5 can effectively activate the C=O group of amides, and the smaller Ru particles on Nb2O5 could further promote the activation, leading to superior catalytic performance of Ru/Nb2O5 for amide hydrogenation. Meanwhile, reducing the surface acidity of Nb2O5 can greatly inhibit the side reactions to by-products, and further enhance the selectivity to amine. Moreover, this catalytic system is also applicable for the hydrogenation of a variety of amides and provides high potential for the industrial production of primary amines from amides.