F:Flammable;
78-81-9Relevant articles and documents
Electron spin-lattice relaxation in radicals containing two methyl groups, generated by γ-irradiation of polycrystalline solids
Harbridge, James R.,Eaton, Sandra S.,Eaton, Gareth R.
, p. 195 - 206 (2002)
The effects of methyl rotation on electron spin-lattice relaxation times were examined by pulsed electron paramagnetic resonance for the major radicals in γ-irradiated polycrystalline α-amino isobutyric acid, dimethyl-malonic acid, and L-valine. The domin
Synthesis of Chiral Amines via a Bi-Enzymatic Cascade Using an Ene-Reductase and Amine Dehydrogenase
Fossey-Jouenne, Aurélie,Jongkind, Ewald P. J.,Mayol, Ombeline,Paul, Caroline E.,Vergne-Vaxelaire, Carine,Zaparucha, Anne
, (2021/12/23)
Access to chiral amines with more than one stereocentre remains challenging, although an increasing number of methods are emerging. Here we developed a proof-of-concept bi-enzymatic cascade, consisting of an ene reductase and amine dehydrogenase (AmDH), to afford chiral diastereomerically enriched amines in one pot. The asymmetric reduction of unsaturated ketones and aldehydes by ene reductases from the Old Yellow Enzyme family (OYE) was adapted to reaction conditions for the reductive amination by amine dehydrogenases. By studying the substrate profiles of both reported biocatalysts, thirteen unsaturated carbonyl substrates were assayed against the best duo OYE/AmDH. Low (5 %) to high (97 %) conversion rates were obtained with enantiomeric and diastereomeric excess of up to 99 %. We expect our established bi-enzymatic cascade to allow access to chiral amines with both high enantiomeric and diastereomeric excess from varying alkene substrates depending on the combination of enzymes.
One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
Coeck, Robin,De Vos, Dirk E.
supporting information, p. 5105 - 5114 (2020/08/25)
The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
Half-sandwiched ruthenium complex containing carborane schiff base ligand and preparation and application thereof
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Paragraph 0067-0071, (2020/12/09)
The invention relates to a half-sandwiched ruthenium complex containing a carborane schiff base ligand and a preparation and an application thereof. The preparation method specifically comprises the following steps; i) dissolving o-carborane formaldehyde and aromatic amine in an organic solvent, carrying out reaction at 60-100 DEG C for 8-12h, cooling to room temperature after the reaction; ii) adding n-butyllithium, carrying out reaction at room temperature for 1.5-2.5h; ii) adding phellandrene ruthenium chloride dimer, carrying out reaction at room temperature for 3-6h, and obtaining the half-sandwiched ruthenium complex through separation. The half-sandwiched ruthenium complex is applied to catalyze transfer hydrogenation reaction of nitrile compounds. Compared with the prior art, the complex of the present invention is not sensitive to air and water, has stable properties, and shows high-efficiency catalytic activity in catalyzing the transfer hydrogenation reaction of nitrile compounds. The preparation method of the complex is simple and green, high in yield, mild in reaction conditions and good in universality.
Organocatalytic Decarboxylation of Amino Acids as a Route to Bio-based Amines and Amides
Claes, Laurens,Janssen, Michiel,De Vos, Dirk E.
, p. 4297 - 4306 (2019/08/26)
Amino acids obtained by fermentation or recovered from protein waste hydrolysates represent an excellent renewable resource for the production of bio-based chemicals. In an attempt to recycle both carbon and nitrogen, we report here on a chemocatalytic, metal-free approach for decarboxylation of amino acids, thereby providing a direct access to primary amines. In the presence of a carbonyl compound the amino acid is temporarily trapped into a Schiff base, from which the elimination of CO2 may proceed more easily. After evaluating different types of aldehydes and ketones on their activity at low catalyst loadings (≤5 mol%), isophorone was identified as powerful organocatalyst under mild conditions. After optimisation many amino acids with a neutral side chain were converted in 28–99 % yield in 2-propanol at 150 °C. When the reaction is performed in DMF, the amine is susceptible to N-formylation. This consecutive reaction is catalysed by the acidity of the amino acid reactant itself. In this way, many amino acids were efficiently transformed to the corresponding formamides in a one-pot catalytic system.
Preparation of nitrogen-doped carbon supported cobalt catalysts and its application in the reductive amination
Yuan, Ziliang,Liu, Bing,Zhou, Peng,Zhang, Zehui,Chi, Quan
, p. 347 - 356 (2019/01/24)
The use of non-noble metal catalysts with high activity is of great importance for organic transformations. Herein, nitrogen-doped carbon supported cobalt catalysts with high surface area up to 981.2 m2/g were prepared via the simple pyrolysis of cobalt coordinated organic polymers with silica as the hard template. The pyrolysis temperature showed a great effect on the structure and properties of the as-prepared catalysts. The Co@NC-800 catalyst with the pyrolysis temperature of 800 °C demonstrated a high activity for the selective reductive amination of carbonyl compounds to primary amines with ammonia and hydrogen. Structurally-diverse primary amines with yields in the range from 81.8% to 100% were attained under the optimal conditions. The Co@NC-800 catalyst could be reused without the loss of its activity. The Co@NC-800 catalyst demonstrated comparable activity as the reported heterogeneous noble metal catalysts.
Chemo-selective reduction of nitro and nitrile compounds using Ni nanoparticles immobilized on hyperbranched polymer-functionalized magnetic nanoparticles
Tabatabaei Rezaei, Seyed Jamal,Mashhadi Malekzadeh, Asemeh,Poulaei, Sima,Ramazani, Ali,Khorramabadi, Hossein
, (2017/09/06)
The nitro and nitrile groups in aromatic and aliphatic compounds containing various reducible substituents such as carboxylic acid, ketone, aldehyde and halogen are selectively reduced to the corresponding amines in water as a green solvent with excellent yields by employing NaBH4 in the presence of Fe3O4@PAMAM/Ni(0)-b-PEG nanocatalyst. The morphology and structural features of the catalyst were characterized using various microscopic and spectroscopic techniques. The designed catalyst system because of it being covered with hydrophilic polymers is soluble in a wide range of solvents (e.g. water and ethanol) and suitable for immobilizing and stabilizing Ni nanoparticles in aqueous mediums. In addition, the catalyst can be easily recovered from a reaction mixture by applying an external magnetic field and can be reused up to six runs without significant loss of activity.
Generation of novel family of reductases from PCR based library for the synthesis of chiral alcohols and amines
Sehajpal, Pallvi,Kirar, Seema,Ghosh, Saptarshi,Banerjee, Uttam Chand
, p. 83 - 91 (2018/08/17)
Biocatalysis has shown tremendous potential in the synthesis of drugs and drug intermediates in the last decade. Screening of novel biocatalysts from the natural genome space is the growing trend to replenish the harsh chemical synthetic routes, commonly used in the pharmaceutical and chemical industry. Here, we report a novel ketoreductase (KERD) and a nitrile reductase isolated from the PCR based library generated from the genome of Rhodococcus ruber and Bacillus subtilis, respectively. Both the proteins are hypothetical in nature as there is no putative homology found in the database, although both the enzymes have significant activity towards the synthesis of chiral alcohols and amines. Enzyme activity over a wide range of substrates (aromatic and aliphatic) for both the novel catalysts was observed. From the unique gene sequence to activity over a broad range of substrate and >99% conversion at higher concentrations (100 mM and above) entitles both the hypothetical enzymes as novel. The novel KERD has shown >99% selectivity for the synthesis of (S)-phenylethanol which makes it a potential candidate for industrial catalysis. The novel nitrile reductase has also shown promising activity for the synthesis of (R)-2-phenylethanolamine, which is a difficult moiety to synthesize chemically. In this report, starting from a homology based library, two highly potent whole cell biocatalysts are obtained.
Metal-free hypervalent iodine/TEMPO mediated oxidation of amines and mechanistic insight into the reaction pathways
Bansode, Ajay H.,Suryavanshi, Gurunath
, p. 32055 - 32062 (2018/09/29)
A highly efficient metal free approach for the oxidation of primary and secondary amines to their corresponding aldehydes and ketones using PhI(OAc)2 in combination with a catalytic amount of TEMPO as an oxidizing agent is described. This protocol is rapid and provides diverse products under milder reaction conditions in excellent yields. In addition, the mechanistic study is well demonstrated by spectroscopic methods.
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
supporting information, p. 4746 - 4749 (2017/09/23)
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.
