3218-01-7Relevant articles and documents
Highly Selective Hydrogenative Conversion of Nitriles into Tertiary, Secondary, and Primary Amines under Flow Reaction Conditions
Yamada, Tsuyoshi,Park, Kwihwan,Furugen, Chikara,Jiang, Jing,Shimizu, Eisho,Ito, Naoya,Sajiki, Hironao
, (2021/12/13)
Flow reaction methods have been developed to selectively synthesize tertiary, secondary, and primary amines depending on heterogeneous platinum-group metal species under catalytic hydrogenation conditions using nitriles as starting materials. A 10 % Pd/C-packed catalyst cartridge affords symmetrically substituted tertiary amines in good to excellent yields. A 10 % Rh/C-packed catalyst cartridge enables the divergent synthesis of secondary and primary amines, with either cyclohexane or acetic acid as a solvent, respectively. Reaction parameters, such as the metal catalyst, solvent, and reaction temperature, and continuous-flow conditions, such as flow direction and second support of the catalyst in a catalyst cartridge, are quite important for controlling the reaction between the hydrogenation of nitriles and nucleophilic attack of in situ-generated amines to imine intermediates. A wide variety of aliphatic and aromatic nitriles could be highly selectively transformed into the corresponding tertiary, secondary, and primary amines by simply changing the metal species of the catalyst or flow parameters. Furthermore, the selective continuous-flow methodologies are applied over at least 72 h to afford three different types of amines in 80–99 % yield without decrease in catalytic activities.
Catalyst-Dependent Selective Hydrogenation of Nitriles: Selective Synthesis of Tertiary and Secondary Amines
Monguchi, Yasunari,Mizuno, Masahiro,Ichikawa, Tomohiro,Fujita, Yuki,Murakami, Eri,Hattori, Tomohiro,Maegawa, Tomohiro,Sawama, Yoshinari,Sajiki, Hironao
, p. 10939 - 10944 (2017/10/27)
In the presence of palladium on carbon (Pd/C) as a catalyst, hydrogenation of aliphatic nitriles in cyclohexane efficiently proceeded at 25-60 °C under ordinary hydrogen gas pressure to afford the corresponding tertiary amines. However, the use of rhodium on carbon (Rh/C) led to the highly selective generation of secondary amines. Hydrogenation of aromatic nitriles and cyclohexanecarbonitrile selectively produced secondary amines in the presence of either Pd/C or Rh/C.
The "borrowing hydrogen strategy" by supported ruthenium hydroxide catalysts: Synthetic scope of symmetrically and unsymmetrically substituted amines
Yamaguchi, Kazuya,He, Jinling,Oishi, Takamichi,Mizuno, Noritaka
scheme or table, p. 7199 - 7207 (2010/09/05)
The N-alkylation of ammonia (or its surrogates, such as urea, NH 4HCO3, and (NH4)2CO3) and amines with alcohols, including primary and secondary alcohols, was efficiently promoted under anaerobic conditions by the easily prepared and inexpensive supported ruthenium hydroxide catalyst Ru(OH)x/TiO2. Various types of symmetrically and unsymmetrically substituted "tertiary" amines could be synthesized by the N-alkylation of ammonia (or its surrogates) and amines with "primary" alcohols. On the other hand, the N-alkylation of ammonia surrogates (i.e., urea and NH 2HCO3) with "secondary" alcohols selectively produced the corresponding symmetrically substituted "secondary" amines, even in the presence of excess amounts of alcohols, which is likely due to the steric hindrance of the secondary alcohols and/or secondary amines produced. Under aerobic conditions, nitriles could be synthesized directly from alcohols and ammonia surrogates . The observed catalysis for the present N-alkylation recations was intrinsically heterogeneous, and the retrieved catalyst could be reused without any significant loss of catalytic performance. The present catalytic transformation would proceed through consecutive N-alkylation reactions, in which alcohols act as alkylating reagents. On the basis of deuterium-labeling experiments, the formation of the ruthenium dihydride species is suggested during the N-alkylation reactions.
