- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
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Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- Yi, Jaeeun,Kim, Hyun Tae,Jaladi, Ashok Kumar,An, Duk Keun
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p. 129 - 132
(2021/11/17)
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- Synthesis of β-Chiral Amines by Dynamic Kinetic Resolution of α-Branched Aldehydes Applying Imine Reductases
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Imine reductases (IREDs) allow the one-step preparation of optically active secondary and tertiary amines by reductive amination of ketones. Until now, mainly α-chiral amines have been prepared by this route. In this study, we explored the possibility of synthesizing β-chiral amines, a class of compounds which is also frequently found as structural motif in pharmaceuticals but much more challenging to prepare due to the following reasons: (i) The aldehyde substrate already contains the chiral center and needs to be racemized to enable full conversion. (ii) Because the intermediate imine bears the stereo center two carbon atoms remote to the imine nitrogen, it is more challenging to achieve high enantioselectivity compared to α-chiral amine synthesis. For investigating the proof of concept, we first confirmed that different IREDs are able to convert a variety of α-branched aldehydes when combined with five different amine substrates. The IRED from Streptomyces ipomoeae was a suitable enzyme facilitating the dynamic kinetic resolution of 2-phenylpropanal and a substituted 2-methyl-3-phenylpropanal: the corresponding N-methylated β-chiral amines were obtained with '95 % conversion and 78 and 95 %ee. Other amines were formed with low to moderate enantiomeric excess. This exemplifies the potential of IREDs for the one-step synthesis of secondary β-chiral amines, but also the challenge to identify highly selective enzymes for a desired amine product.
- Matzel, Philipp,Wenske, Sebastian,Merdivan, Simon,Günther, Sebastian,H?hne, Matthias
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p. 4281 - 4285
(2019/08/20)
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- Design of a bifunctional Ir-Zr based metal-organic framework heterogeneous catalyst for the N-alkylation of amines with alcohols
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The direct N-alkylation of amines with alcohols was performed with an Ir-Zr-based metal-organic framework multifunctional heterogeneous catalyst. This system is efficient and environmentally benign for the synthesis of various organic amines in air in the absence of a base. The catalyst was recovered and reused without significant loss of activity, and only water was produced as a byproduct. Better be direct than elusive: The direct N-alkylation of amines with alcohols is performed with an Ir-Zr-based metal-organic framework multifunctional heterogeneous catalyst. This system is efficient and environmentally benign for the synthesis of various organic amines in air in the absence of a base. The catalyst is recovered and reused without significant loss of activity, and only water is produced as a byproduct.
- Rasero-Almansa,Corma,Iglesias,Sanchez
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p. 1794 - 1800
(2014/06/24)
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- Catalytic hydrogenation of amides to amines under mild conditions
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Under (not so much) pressure: A general method for the hydrogenation of tertiary and secondary amides to amines with excellent selectivity using a bimetallic Pd-Re catalyst has been developed. The reaction proceeds under low pressure and comparatively low temperature. This method provides organic chemists with a simple and reliable tool for the synthesis of amines. Copyright
- Stein, Mario,Breit, Bernhard
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supporting information
p. 2231 - 2234
(2013/03/28)
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- PNP pincer osmium polyhydrides for catalytic dehydrogenation of primary alcohols
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This paper reports the synthesis, structure, and properties of a series of PNP pincer complexes of osmium OsH3Cl[HN(C2H 4PiPr2)2] (1), OsH 3[N(C2H4PiPr2) 2] (2), OsH4[HN(C2H4P iPr2)2] (3), and OsH2(PMe 3)[HN(C2H4PiPr2) 2] (4). The tetrahydride 3 operates as an efficient catalyst at 0.1 mol% loading for the reactions of amination and dehydrogenative coupling of primary alcohols, producing secondary amines and symmetrical esters, respectively. The catalyst 3 is distinguished by outstanding stability, and it can be used in an aqueous environment at temperatures as high as 200 °C. The Royal Society of Chemistry 2011.
- Bertoli, Marcello,Choualeb, Aldjia,Gusev, Dmitry G.,Lough, Alan J.,Major, Quinn,Moore, Brandon
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experimental part
p. 8941 - 8949
(2011/10/12)
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- First example of direct reductive amination of aldehydes with primary and secondary amines catalyzed by water-soluble transition metal catalysts
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An unprecedented efficient and highly selective direct reductive amination of aldehydes with primary and secondary amines in water using gaseous hydrogen and water-soluble catalysts is developed. The catalytic system formed in situ from Pd(PhCN)2Cl2 and 2,2′-biquinoline-4,4′-dicarboxylic acid dipotassium salt (BQC), allows full conversion of aldehydes and the formation of desired alkylated amines with excellent yields and selectivities. The catalytic system is stable and can be recycled and reused three times without loss of activity.
- Robichaud, André,Nait Ajjou, Abdelaziz
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p. 3633 - 3636
(2007/10/03)
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- Reductive monoalkylation of aromatic and aliphatic nitro compounds and the corresponding amines with nitriles
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(Chemical Equation Presented) A simple, selective, rapid, and efficient procedure for the synthesis of secondary amines from the reductive alkylation of either aliphatic or aromatic nitro compounds and the corresponding amines is reported. Ammonium formate is used as the hydrogen source and Pd/C as the hydrogen transfer catalyst. The reaction is carried out at room temperature. The rate differences for the preferential formation of secondary over tertiary products are due to both steric and electronic factors.
- Nacario, Ruel,Kotakonda, Shailaja,Fouchard, David M. D.,Tillekeratne, L. M. Viranga,Hudson, Richard A.
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p. 471 - 474
(2007/10/03)
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- Synthesis of secondary amines via N-(benzoyloxy)amines and organoboranes
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A variety of primary amines (R-NH2) were converted to their corresponding N-(benzoyloxy)amines (i.e., R-NHOCOPh) under biphasic conditions in excellent yields (63-90%). The intermediate N- (benzoyloxy)amines were converted to their N-ethylamine derivatives upon reaction with triethylborane in THF in good yield (54-89%). These experiments demonstrated the similar chemistry of N-chloro- and N-(benzoyloxy)amines with organoboranes.
- Phanstiel IV,Wang,Powell,Ospina,Leeson
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p. 803 - 806
(2007/10/03)
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- Hydrogenation of amides by the use of bimetallic catalysts consisting of group 8 to 10, and group 6 or 7 metals
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Hydrogenation of amides can be catalyzed by bimetallic systems, which consist of Group 8 to 10 late transition-metals and Group 6 or 7 early transition-metals, under the mild conditions to afford the corresponding amines selectively in good to excellent yields.
- Hirosawa, Chitaru,Wakasa, Noriko,Fuchikami, Takamasa
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p. 6749 - 6752
(2007/10/03)
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- ELECTROCHEMICAL REDUCTIVE AMINATION. II. AMINATION OF ALIPHATIC ALDEHYDES WITH PRIMARY AMINES
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The formation of a secondary amine by the electrolysis of an aqueous solution containing an aldehyde and a primary amine was studied.The formation of the secondary amines passes through the intermediate stage of an aldimine.The highest yield of secondary amine is attained at a molar ratio of primary amine to aldehyde of 1.2:1.As electrode material lead, cadmium, zinc, and copper may be used.As supporting electrolyte a phosphate buffer with a pH close to the pKa of the primary amine is recommended.By the method developed 32 amines with various structures were synthesized.
- Smirnov, Yu. D.,Pavlichenko, V. F.,Tomilov, A. P.
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p. 374 - 380
(2007/10/02)
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- Reductive Amination of Ketones and Aldehydes at the Mercury-Cathode
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Secondary amines are prepared in good yields by potential-controlled reduction of aldehydes or ketones at a mercury cathode in an aqueous solution containing a primary amine.For cyclic ketones, high diastereoselectivities are obtained in some cases.
- Pienemann, Thomas,Schaefer, Hans-J.
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p. 1005 - 1007
(2007/10/02)
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