93-90-3Relevant articles and documents
Borane-Trimethylamine Complex as a Reducing Agent for Selective Methylation and Formylation of Amines with CO2
Zhang, Yanmeng,Zhang, He,Gao, Ke
supporting information, p. 8282 - 8286 (2021/10/25)
We report herein that a borane-trimethylamine complex worked as an efficient reducing agent for the selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline serves as a highly efficient catalyst for the methylation of various secondary amines, whereas in its absence, the formylation of primary and secondary amines was achieved in high yield with high chemoselectivity. Mechanistic studies suggest that the 6-amino-2-picoline-borane catalytic system operates like an intramolecular frustrated Lewis pair to activate CO2.
Aza-Matteson Reactions via Controlled Mono-and Double-Methylene Insertions into Nitrogen-Boron Bonds
Xie, Qiqiang,Dong, Guangbin
, p. 14422 - 14427 (2021/09/29)
Boron-homologation reactions represent an efficient and programmable approach to prepare alkylboronates, which are valuable and versatile synthetic intermediates. The typical boron-homologation reaction, also known as the Matteson reaction, involves formal carbenoid insertions into C-B bonds. Here we report the development of aza-Matteson reactions via carbenoid insertions into the N-B bonds of aminoboranes. By changing the leaving groups of the carbenoids and altering Lewis acid activators, selective mono- and double-methylene insertions can be realized to access various α- and β-boron-substituted tertiary amines, respectively, from common secondary amines. The derivatization of complex amine-containing bioactive molecules, diverse functionalization of the boronate products, and sequential insertions of different carbenoids have also been achieved.
Preparation method of methylamine
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Paragraph 0040-0046, (2020/12/14)
The invention provides a preparation method of methylamine. The preparation method comprises the following step: preparing methylamine by utilizing an amine methylation reaction, wherein in the aminemethylation reaction, the catalyst is dodecyldimethylamine caprolactone. According to the invention, additives required by the reaction are effectively reduced, and the post-treatment process after the reaction is finished is simplified.
Ru-Catalyzed Switchable N-Hydroxyethylation and N-Acetonylation with Crude Glycerol
Xin, Zhuo,Jia, Le,Huang, Yuxing,Du, Chen-Xia,Li, Yuehui
, p. 2007 - 2011 (2020/03/19)
Highly efficient Ru-catalyzed selective C?C or C?O bond cleavage of polyols (e.g., crude glycerol) for N-hydroxyethylation or N-acetonylation of amines was achieved through the hydrogen-borrowing approach. A variety of amines were transformed to the desired amino alcohols/ketones in moderate-to-excellent yields, opening up new avenues for generation of oxygenated pharmaceuticals and fine chemicals from renewable raw materials. The use of new redox-active catalysts containing bisphosphine/thienylmethylamine ligands allows this hydrogen-borrowing system to be operated selectively under both basic and acidic conditions.
Visible light-mediated Smiles rearrangements and annulations of non-activated aromatics
Lawson, Connor A.,Dominey, Andrew P.,Williams, Glynn D.,Murphy, John A.
supporting information, p. 11445 - 11448 (2020/10/12)
We report the first examples of radical cation Smiles rearrangements. A series of aryloxy alkylamines underwent spontaneous reaction, with the amino group displacing theipso-alkoxy group through substitution, at ambient temperature and under photoactivation by visible light in the presence of an acridinium catalyst (5 mol%). The study was extended to 3-(2-methoxyphenyl)propan-1-amine derivatives, which lack an appropriateipsoleaving group. Here, efficient cyclisations resulted in displacement of the methoxy group and formation of tetrahydroquinolines.
Direct hydroxyethylation of amines by carbohydrates: Via ruthenium catalysis
Jia, Le,Makha, Mohamed,Du, Chen-Xia,Quan, Zheng-Jun,Wang, Xi-Cun,Li, Yuehui
, p. 3127 - 3132 (2019/06/18)
An efficient and halogen-free catalytic methodology for the synthesis of β-amino alcohols from aromatic amines and biomass-derived carbohydrates is demonstrated for the first time. The activation of C5/C6 sugars by a ruthenium catalyst selectively generates the C2 alkylating reagent glycolaldehyde. The transformation involves metal-catalyzed hydrogen borrowing for the reduction of the imine intermediate. A series of arylamines bearing various substituents were successfully transformed into the desired products in good to excellent yields.
Practical and regioselective amination of arenes using alkyl amines
Ruffoni, Alessandro,Juliá, Fabio,Svejstrup, Thomas D.,McMillan, Alastair J.,Douglas, James J.,Leonori, Daniele
, p. 426 - 433 (2019/05/01)
The formation of carbon–nitrogen bonds for the preparation of aromatic amines is among the top five reactions carried out globally for the production of high-value materials, ranging from from bulk chemicals to pharmaceuticals and polymers. As a result of this ubiquity and diversity, methods for their preparation impact the full spectrum of chemical syntheses in academia and industry. In general, these molecules are assembled through the stepwise introduction of a reactivity handle in place of an aromatic C–H bond (that is, a nitro group, halogen or boronic acid) and a subsequent functionalization or cross-coupling. Here we show that aromatic amines can be constructed by direct reaction of arenes and alkyl amines using photocatalysis, without the need for pre-functionalization. The process enables the easy preparation of advanced building blocks, tolerates a broad range of functionalities, and multigram scale can be achieved via a batch-to-flow protocol. The merit of this strategy as a late-stage functionalization platform has been demonstrated by the modification of several drugs, agrochemicals, peptides, chiral catalysts, polymers and organometallic complexes.
Tailored Cobalt-Catalysts for Reductive Alkylation of Anilines with Carboxylic Acids under Mild Conditions
Liu, Weiping,Sahoo, Basudev,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
supporting information, p. 11673 - 11677 (2018/09/10)
The first cobalt-catalyzed hydrogenative N-methylation and alkylation of amines with readily available carboxylic acid feedstocks as alkylating agents and H2 as ideal reductant is described. Combination of tailor-made triphos ligands with cobalt(II) tetrafluoroborate significantly improved the efficiency, thus promoting the reaction under milder conditions. This novel protocol allows for a broad substrate scope with good functional group tolerance, even in the presence of reducible alkenes, esters, and amides.
A Multiaddressable Dyad with Switchable Cyan/Magenta/Yellow Colors for Full-Color Rewritable Paper
Qin, Tianyou,Han, Jiaqi,Geng, Yue,Ju, Le,Sheng, Lan,Zhang, Sean Xiao-An
supporting information, p. 12539 - 12545 (2018/09/10)
Reversible multicolor displays on solid media created from single-molecule pigments are a long-awaited goal. Herein, a new and simple molecular dyad, which can undergo switchable cyan (C), magenta (M), and yellow (Y) color changes in both solution and the solid state upon exposure to light, water/acid, and nucleophiles, has been designed and synthesized. The stimuli used herein can be applied independent of each other, which is beneficial for color changes without mutual interference. For comparison, mixtures of the two molecular switching motifs that form the basis of the dyad were also studied. The dyad greatly outperforms the corresponding mixed system with respect to reversible color switching on the paper substrate. Its potential for full-color rewritable paper with excellent reversibility has been demonstrated. Legible multicolor prints, that is, high color contrast and resolution, good dispersion, and excellent reversibility, were achieved by using common water-jet and light-based printers. This work provides a very promising approach for the further development of full-color switchable molecules, materials, and displays.
Betaine Catalysis for Hierarchical Reduction of CO2 with Amines and Hydrosilane To Form Formamides, Aminals, and Methylamines
Liu, Xiao-Fang,Li, Xiao-Ya,Qiao, Chang,Fu, Hong-Chen,He, Liang-Nian
supporting information, p. 7425 - 7429 (2017/06/13)
An efficient, sustainable organocatalyst, glycine betaine, was developed for the reductive functionalization of CO2 with amines and diphenylsilane. Methylamines and formamides were obtained in high yield by tuning the CO2 pressure and reaction temperature. Based on identification of the key intermediate, that is, the aminal, an alternative mechanism for methylation involving the C0 silyl acetal and aminal is proposed. Furthermore, reducing the CO2 amount afforded aminals with high yield and selectivity. Therefore, betaine catalysis affords products with a diversified energy content that is, formamides, aminals and methylamines, by hierarchical two-, four- and six-electron reduction, respectively, of CO2 coupled with C?N bond formation.
