3057-45-2Relevant academic research and scientific papers
Tandem Fe/Zn or Fe/In Catalysis for the Selective Synthesis of Primary and Secondary Amines?via Selective Reduction of Primary Amides
Wu, Jiajun,Darcel, Christophe
, (2022/03/18)
Tandem iron/zinc or iron/indium-catalysed reductions of various primary amides to amines under hydrosilylation conditions are reported under visible light activation. By a simple modification of the nature of the co-catalyst (Zn(OTf)2 vs In(OTf)3), Fe(CO)4(IMes) can promote the highly chemoselective reduction of primary amides into primary amines (21 examples, up to 93 % isolated yields) and secondary amines (8 examples, up to 51 % isolated yields), respectively. Notably, both benzamide and alkanamide derivatives can be reduced.
Understanding the binding properties of phosphorylated glycoluril-derived molecular tweezers and selective nanomolar binding of natural polyamines in aqueous solution
Heilmann, Michael,Knezevic, Melina,Piccini, Giovannimaria,Tiefenbacher, Konrad
supporting information, p. 3628 - 3633 (2021/05/04)
A modular synthetic platform for the construction of flexible glycoluril-derived molecular tweezers was developed. The binding properties of four exemplary supramolecular hosts obtained via this approach towards 16 organic amines were investigated by means of 1H NMR titration. In this work, we compare the Ka values obtained this way with those of three structurally related molecular tweezers and provide a computational approach towards an explanation of the observed behavior of those novel hosts. The results showcase that certain structural modifications lead to very potent and selective binders of natural polyamines, with observed binding of spermine below 10 nM. This journal is
A State-of-the-Art Heterogeneous Catalyst for Efficient and General Nitrile Hydrogenation
Formenti, Dario,Mocci, Rita,Atia, Hanan,Dastgir, Sarim,Anwar, Muhammad,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
supporting information, p. 15589 - 15595 (2020/10/02)
Cobalt-doped hybrid materials consisting of metal oxides and carbon derived from chitin were prepared, characterized and tested for industrially relevant nitrile hydrogenations. The optimal catalyst supported onto MgO showed, after pyrolysis at 700 °C, magnesium oxide nanocubes decorated with carbon-enveloped Co nanoparticles. This special structure allows for the selective hydrogenation of diverse and demanding nitriles to the corresponding primary amines under mild conditions (e.g. 70 °C, 20 bar H2). The advantage of this novel catalytic material is showcased for industrially important substrates, including adipodinitrile, picolinonitrile, and fatty acid nitriles. Notably, the developed system outperformed all other tested commercial catalysts, for example, Raney Nickel and even noble-metal-based systems in these transformations.
A Modular Phosphorylated Glycoluril-Derived Molecular Tweezer for Potent Binding of Aliphatic Diamines
Heilmann, Michael,Tiefenbacher, Konrad
supporting information, p. 12900 - 12904 (2019/11/05)
A molecular tweezer based on a glycoluril-derived framework bearing four phosphate groups was synthesized and shown to be capable of binding organic amines in aqueous solution. This work reports the Ka values for 30 complexes of this molecular tweezer and amine guests, determined by means of 1H NMR titrations. Both the hydrophobic cavity and the phosphate groups contribute to the binding. Bulkier molecules and molecules bearing negatively charged groups like carboxylates in amino acids bind less tightly due to a steric clash and coulombic repulsion. The narrow cavity and the strong ionic interactions of the phosphate groups with ammonium guests favor binding of aliphatic diamines. These binding properties clearly distinguish this system from structurally related molecular clips and tweezers.
Non-Pincer Mn(I) Organometallics for the Selective Catalytic Hydrogenation of Nitriles to Primary Amines
Gardu?o, Jorge A.,García, Juventino J.
, p. 392 - 401 (2019/01/11)
We report herein selective catalytic hydrogenation of nitriles to primary amines with the use of the non-pincer Mn(I) compound fac-[(CO)3Mn{iPr2P(CH2)2PiPr2}(OTf)] (2) as a catalytic precursor (3 mol %) in the presence of KOtBu (10 mol %) and 2-BuOH as solvent. Benchmark benzonitrile and electron-rich aromatic and aliphatic nitriles were hydrogenated under rather mild conditions (7 bar, 90 °C, 15 min) to produce the corresponding amines in excellent to very good isolated yields (83-97%, six examples). Increasing the H2 pressure and time (35 bar, 30 min) allowed for the production of (di)amines in excellent yields (94-98%, three examples) from electron-deficient aromatic nitriles and terephthalonitrile. Notably, adiponitrile was reduced to hexamethylenediamine in 53% isolated yield. Finally, mechanistic insights were performed and suggested unsaturated Mn-hydride species performing the elementary steps during catalytic turnover.
Old Concepts, New Application – Additive-Free Hydrogenation of Nitriles Catalyzed by an Air Stable Alkyl Mn(I) Complex
Weber, Stefan,Veiros, Luis F.,Kirchner, Karl
supporting information, p. 5412 - 5420 (2019/11/13)
An efficient additive-free manganese-catalyzed hydrogenation of nitriles to primary amines with molecular hydrogen is described. The pre-catalyst, a well-defined bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dpre)(CO)3(CH3)] (dpre=1,2-bis(di-n-propylphosphino)ethane), undergoes CO migratory insertion into the manganese-alkyl bond to form acyl complexes which upon hydrogenolysis yields the active coordinatively unsaturated Mn(I) hydride catalyst [Mn(dpre)(CO)2(H)]. A range of aromatic and aliphatic nitriles were efficiently and selectively converted into primary amines in good to excellent yields. The hydrogenation of nitriles proceeds at 100 °C with a catalyst loading of 2 mol % and a hydrogen pressure of 50 bar. Mechanistic insights are provided by means of DFT calculations. (Figure presented.).
Selective Catalytic Hydrogenations of Nitriles, Ketones, and Aldehydes by Well-Defined Manganese Pincer Complexes
Elangovan, Saravanakumar,Topf, Christoph,Fischer, Steffen,Jiao, Haijun,Spannenberg, Anke,Baumann, Wolfgang,Ludwig, Ralf,Junge, Kathrin,Beller, Matthias
supporting information, p. 8809 - 8814 (2016/07/29)
Hydrogenations constitute fundamental processes in organic chemistry and allow for atom-efficient and clean functional group transformations. In fact, the selective reduction of nitriles, ketones, and aldehydes with molecular hydrogen permits access to a green synthesis of valuable amines and alcohols. Despite more than a century of developments in homogeneous and heterogeneous catalysis, efforts toward the creation of new useful and broadly applicable catalyst systems are ongoing. Recently, Earth-abundant metals have attracted significant interest in this area. In the present study, we describe for the first time specific molecular-defined manganese complexes that allow for the hydrogenation of various polar functional groups. Under optimal conditions, we achieve good functional group tolerance, and industrially important substrates, e.g., for the flavor and fragrance industry, are selectively reduced.
NNP-Type Pincer Imidazolylphosphine Ruthenium Complexes: Efficient Base-Free Hydrogenation of Aromatic and Aliphatic Nitriles under Mild Conditions
Adam, Rosa,Alberico, Elisabetta,Baumann, Wolfgang,Drexler, Hans-Joachim,Jackstell, Ralf,Junge, Henrik,Beller, Matthias
, p. 4991 - 5002 (2016/04/05)
A series of seven novel NImNHP-type pincer imidazolylphosphine ruthenium complexes has been synthesized and fully characterized. The use of hydrogenation of benzonitrile as a benchmark test identified [RuHCl(CO)(NImNHPtBu)] as the most active catalyst. With its stable Ru-BH4 analogue, in which chloride is replaced by BH4, a broad range of (hetero)aromatic and aliphatic nitriles, including industrially interesting adiponitrile, has been hydrogenated under mild and base-free conditions.
Bistable cucurbituril rotaxanes without stoppers
Sinha, Mantosh K.,Reany, Ofer,Yefet, Maayan,Botoshansky, Mark,Keinan, Ehud
experimental part, p. 5589 - 5605 (2012/06/04)
Bistable rotaxanes are important design elements of molecular devices for a broad range of applications, such as controlled drug release, molecular rotary motors, and chemical sensors. The host-guest complexes of cucurbit[6]uril and 1,4-bis(alkylaminomethyl)benzene were found to exhibit two stable binding modes with an unexpectedly high barrier between them. Their structural and dynamic properties, kinetic and thermodynamic parameters, as well as different chemical reactivity towards the azide-alkyne [3+2] cycloaddition reaction (click chemistry), were discovered by NMR spectroscopy, X-ray crystallography, and isothermal titration microcalorimetry. The highly stable 2:1 complex, which is formed at room temperature, was found to be a kinetic product, which may be converted to the thermodynamic 1:1 complex upon prolonged heating to 100°C. The latter is a very stable rotaxane despite the fact that it lacks bulky end groups. Locked up and active: The host-guest complexes of cucurbit[6]uril and 1,4-bis(alkylaminomethyl)benzene exhibit two stable binding modes with a high barrier between them. The highly stable 2:1 complex that is formed at room temperature is a kinetic product that may be converted into the thermodynamic 1:1 complex upon prolonged heating in water (see scheme). The latter is a very stable rotaxane despite the fact that it lacks bulky end groups. These findings are significant for the design of molecular devices.
FRICTIONLESS MOLECULAR ROTARY MOTORS
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Page/Page column 33, (2010/02/17)
A rotaxane consisting of a cucurbituril and an uncharged guest molecule, having low or null affinity therebetween is provided as well as processes for providing the same. Various uses as energy converters (“frictionless” molecular motors), biochips and biosensors using the same are also provided.
