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.
Reductive amination of bio-based 2-hydroxytetrahydropyran to 5-Amino-1-pentanol over nano-Ni-Al2O3catalysts
Zhang, Jia,Yang, Jian,Tian, Junying,Liu, Hailong,Li, Xuemei,Fang, Weiguo,Hu, Xun,Xia, Chungu,Chen, Jing,Huang, Zhiwei
, p. 4236 - 4245 (2021)
The synthesis of useful amines from bio-based carbonyl compounds is highly desired owing to their mild reaction conditions and green sustainability. The reductive amination of bio-furfural-derived 2-hydroxytetrahydropyran (2-HTHP) to high-value-added 5-Amino-1-pentanol (5-AP) was carried out over efficient Ni-Al2O3catalysts prepared by a co-precipitation method. Among the Ni-Al2O3catalysts with different Ni loadings (0-100 wt%) tested, the 50Ni-Al2O3catalyst exhibited the highest5-APyield of 91.3% under mild conditions of 60 °C and 2 MPa H2. This catalyst also presented good stability during a 150 h time-on-stream without appreciable deactivation. Characterization results showed that the 50Ni-Al2O3catalyst exhibited small Ni0nanoparticles (5.5 nm), a high reduction degree (up to 95%), and a large amount of strong Lewis acid sites. The cooperative catalysis of the strong Lewis acid sites and highly dispersed metallic Ni sites is suggested to play an important role in achieving high efficiency in2-HTHPreductive amination.
Modulating: Trans -imination and hydrogenation towards the highly selective production of primary diamines from dialdehydes
Hao, Rui,Li, Lin,Liu, Fei,Qi, Haifeng,Su, Yang,Wang, Aiqin,Yang, Jingyi,Zhang, Leilei,Zhang, Tao
, p. 6897 - 6901 (2020)
Bio-based primary diamines are important building blocks for sustainable bio-polymers, but their synthesis remains challenging due to the high susceptibility to polymerization. Herein, we have developed a new strategy to suppress the polymerization by employing a more nucleophilic alkylamine to scavenge the dialdehyde and a Co/ZrO2 catalyst to regulate the trans-imination and hydrogenation activity. With this strategy, 2,5-bis(aminomethyl)furan (BAMF), a promising monomer for the production of new polyamides and polyureas, is successfully synthesized via the reductive amination of biomass-derived 2,5-diformylfuran (DFF) under a H2 and NH3 atmosphere with an unprecedentedly high selectivity up to 95%. This strategy is applicable to the reductive amination of other biomass-derived dialdehydes, thus paving a new way to bio-based diamine monomers. This journal is
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.
Aminoborohydrides. 8. A facile reduction of aliphatic and benzylic azides to the corresponding amines in high yield and purity using lithium N,N-dimethylaminoborohydride
Alvarez,Fisher,Singaram
, p. 2567 - 2570 (1995)
Lithium N,N-dimethylaminoborohydride (LiMe2NHB3) reduced both 3α-azidocholest-5-ene and 3β-azidocholest-5-ene in air to give the corresponding 3α-aminocholest-5-ene and 3β-aminocholest-5-ene in 98% isolated yields. Aliphatic and benzylic azides were also reduced with LiMe2NBH3 to give the corresponding amines in isolated yields ranging from 85 to 98%. The reductions were complete in 1-3 hours and required only a simple acid-base extraction to isolate the desired amines.
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.
Production of Primary Amines by Reductive Amination of Biomass-Derived Aldehydes/Ketones
Liang, Guanfeng,Wang, Aiqin,Li, Lin,Xu, Gang,Yan, Ning,Zhang, Tao
, p. 3050 - 3054 (2017)
Transformation of biomass into valuable nitrogen-containing compounds is highly desired, yet limited success has been achieved. Here we report an efficient catalyst system, partially reduced Ru/ZrO2, which could catalyze the reductive amination of a variety of biomass-derived aldehydes/ketones in aqueous ammonia. With this approach, a spectrum of renewable primary amines was produced in good to excellent yields. Moreover, we have demonstrated a two-step approach for production of ethanolamine, a large-market nitrogen-containing chemical, from lignocellulose in an overall yield of 10 %. Extensive characterizations showed that Ru/ZrO2-containing multivalence Ru association species worked as a bifunctional catalyst, with RuO2 as acidic promoter to facilitate the activation of carbonyl groups and Ru as active sites for the subsequent imine hydrogenation.
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.
The evolution of an amine dehydrogenase biocatalyst for the asymmetric production of chiral amines
Abrahamson, Michael J.,Wong, John W.,Bommarius, Andreas S.
, p. 1780 - 1786 (2013)
The reductive amination of ketones to produce chiral amines is an important transformation in the production of pharmaceutical intermediates. Therefore, industrially applicable enzymatic methods that enable the selective synthesis of chiral amines could be very useful. Using a phenylalanine dehydrogenase scaffold devoid of amine dehydrogenase activity, a robust amine dehydrogenase has been evolved with a single two-site library allowing for the direct production of (R)-1-(4-fluorophenyl)-propyl-2-amine from para- fluorophenylacetone with a kcat value of 6.85 s-1 and a KM value of 7.75 mM for the ketone substrate. This is the first example of a highly active amine dehydrogenase capable of accepting aliphatic and benzylic ketone substrates. The stereoselectivity of the evolved amine dehydrogenase was very high (>99.8% ee) showing that high selectivity of the wild-type phenylalanine dehydrogenase was conserved in the evolution process. When paired with glucose/glucose dehydrogenase, NADH cofactor can be effficiently regenerated and the reaction driven to over 93% conversion. The broad specificity, high selectivity, and near complete conversion render this amine dehydrogenase an attractive target for further evolution toward pharmaceutical compounds and subsequent application. Copyright
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.
