1003-03-8Relevant articles and documents
Morphology-Tuned Activity of Ru/Nb2O5 Catalysts for Ketone Reductive Amination
Guo, Wanjun,Tong, Tao,Liu, Xiaohui,Guo, Yong,Wang, Yanqin
, p. 4130 - 4138 (2019)
Amines are important compounds in natural products and medicines. Specifically, cyclopentylamine is one of the value-added chemicals widely used in the production of pesticides, cosmetics and medicines. In this work, three Ru/Nb2O5 catalysts with different Nb2O5 morphologies were used in the reductive amination of cyclopentanone under mild reaction conditions (90 °C, 2 MPa H2), among which 1 %Ru/Nb2O5?L catalyst exhibits best performance with the yield of cyclopentylamine reaching 84 %. This catalytic system is stable and has not significant deactivation even after 5 runs in the durability test. In addition, this catalyst can be extended to a series of aldehydes/ketones. Further comprehensive characterizations (XPS analysis and CO-adsorption DRIFT) reveal that the electronic effect of Ru species can be ruled out; instead, the activity of the catalyst is strongly influenced by the geometric effect. Layered Nb2O5 material possesses the highest surface area, resulting in the highest Ru dispersion, and therefore shows the highest catalytic activity. The in-situ DRIFT-MS technique was also used to reveal and understand the reaction mechanism. It is found that Ru species play a key role in activating carbonyl groups. This study illustrates a promising application of Ru/Nb2O5-Layer catalyst in the synthesis of amine and provides an understanding to the reaction mechanism.
Reactions of sodium borohydride in acetic acid: Reductive amination of carbonyl compounds
Panfilov,Markovich,Zhirov,Ivashev,Kirsanov,Kondrat'ev
, p. 371 - 373 (2000)
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Simple and efficient Fmoc removal in ionic liquid
Di Gioia,Costanzo,De Nino,Maiuolo,Nardi,Olivito,Procopio
, p. 36482 - 36491 (2017)
A mild method for an efficient removal of the fluorenylmethoxycarbonyl (Fmoc) group in ionic liquid was developed. The combination of a weak base such as triethylamine and [Bmim][BF4] makes the entire system more efficient for the cleavage at room temperature of various amines and amino acid methyl esters in short reaction times. The procedure works well even in the case of N-Fmoc amino acids bearing acid-sensitive protecting groups and of N-alkylated amino acid methyl esters. The solvent-free condition provides a complementary method for Fmoc deprotection in solution phase peptide synthesis and modern organic synthesis.
Organic reactions in a solid matrix-VII sodium on alumina: A convenient reagent for reduction of ketones, esters and oximes
Singh, Satendra,Dev, Sukh
, p. 10959 - 10964 (1993)
Sodium dispersed on alumina is described and evaluated as a convenient off-the-shelf reagent (in a wax-coated form) for reduction of ketones, esters and oximes. While isopropanol is the preferred proton donor for the reduction of ketones and oximes, t-butanol is the alcohol of choice for the reduction of esters.
Heterogeneous Catalytic Reductive Amination of Carbonyl Compounds with Ni-Al Alloy in Water as Solvent and Hydrogen Source
Sch?fer, Christian,Ni?anci, Bilal,Bere, Matthew P.,Da?tan, Arif,T?r?k, Béla
, p. 3127 - 3133 (2016)
The heterogeneous catalytic reductive amination of carbonyl compounds has been achieved by reactions of ammonium hydroxide and various amines with ketones and aldehydes. The process is based on the application of Raney type Ni-Al alloy in an aqueous medium. The reaction of the carbonyl compounds with the amine provided the corresponding Schiff bases that immediately underwent a reduction to provide primary and secondary amines as products. The controlled reaction of the Al content of the alloy with the solvent water generates hydrogen, and the in situ formed Raney Ni serves as a hydrogenation catalyst. The method is a simple and efficient way of preparing a broad variety of primary and secondary amines.
Ambient-Temperature Synthesis of Primary Amines via Reductive Amination of Carbonyl Compounds
Xie, Chao,Song, Jinliang,Hua, Manli,Hu, Yue,Huang, Xin,Wu, Haoran,Yang, Guanying,Han, Buxing
, p. 7763 - 7772 (2020)
Efficient synthesis of primary amines via low-temperature reductive amination of carbonyl compounds using NH3 and H2 as the nitrogen and hydrogen resources is highly desired and challenging in the chemistry community. Herein, we employed naturally occurring phytic acid as a renewable precursor to fabricate titanium phosphate (TiP)-supported Ru nanocatalysts with different reduction degrees of RuO2 (Ru/TiP-x, x represents the reduction temperature) by combining ball milling and molten-salt processes. Very interestingly, the obtained Ru/TiP-100 had good catalytic performance for the reductive amination of carbonyl compounds at ambient temperature, resulting from the synergistic cooperation of the support (TiP) and the Ru/RuO2 with a suitable proportion of Ru0 (52%). Various carbonyl compounds could be efficiently converted into the corresponding primary amines with high yields. More importantly, the conversion of other substrates with reducible groups could also be achieved at ambient temperature. Detailed investigations indicated that the partially reduced Ru and the support (TiP) were indispensable. The high activity and selectivity of Ru/TiP-100 catalyst originates from the relatively high acidity and the suitable electron density of metallic Ru0.
Selective monoalkylation of ammonia: A high throughput synthesis of primary amines
Bhattacharyya, Sukanta,Neidigh, Kurt A.,Avery, Mitchell A.,Williamson, John S.
, p. 1781 - 1783 (1999)
Primary amines are obtained in good to excellent yields by highly selective monoalkylation of ammonia with alkyl and aryl ketones using titanium(IV) isopropoxide and sodium borohydride.
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.
Biochemical and Structural Characterization of an (R)-Selective Transaminase in the Asymmetric Synthesis of Chiral Hydroxy Amines
Li, Fulong,Liang, Youxiang,Wei, Yuwen,Zheng, Yukun,Du, Yan,Yu, Huimin
, p. 4582 - 4589 (2021/08/07)
An (R)-selective transaminase RbTA with excellent stereoselectivity (>99% ee) in the asymmetric amination of hydroxy ketones was identified. Biochemical characterization showed that RbTA exhibited the highest activity toward 4-hydroxy-2-butanone among reported enzymes, and that it has broad substrate specificity, including for aliphatic, aromatic, and alicyclic ketones. Crystallization of RbTA were performed, as were molecular docking and mutagenesis studies. Residue Tyr125 plays a key role in substrate recognition by forming a hydrogen bond with hydroxy ketone. The applicability of the enzyme was determined in preparative-scale synthesis of (R)-3-amino-1-butanol, demonstrating the potential of RbTA as a green biocatalyst for production of value-added chiral hydroxy amines. This study provides an efficient tool for enzymatic synthesis of chiral hydroxy amines, as well as structural insight into substrate recognition by transaminases in the asymmetric amination of hydroxy ketones. (Figure presented.).
