626-56-2Relevant articles and documents
Method for preparing piperidine compound by reducing pyridine compound through hydrogen transfer
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Paragraph 0022; 0023; 0024; 0025; 0026, (2021/04/28)
The invention discloses a method for preparing a piperazine compound through a hydrogen transfer reduction of a pyridine compound, belonging to the field of organic synthesis. Under mild conditions, pyridine derivatives are used as raw materials, oxazolidine is used as a hydrogen transfer reagent, and cheap transition metals such as copper, cobalt, silver, palladium and the like are used as catalysts for catalysis of a hydrogen transfer reaction on 1,2,3,4-substitution sites, so a series of hydrogen transfer reduction product piperidine compounds are prepared, wherein the oxazaborolidine is obtained by a reaction of amino acid with a tetrahydrofuran complex of borane. The method has the advantages that product yield is high, reaction conditions are mild, the general applicability of raw materials is good, a hydrogen transfer reagent is cheap and easy to obtain, and good reproducibility can still be shown after quantitative reaction is conudcted. Therefore, the method of the invention provides an effective scheme for the industrial production of other high-value compounds containing the structure in the future.
Powering Artificial Enzymatic Cascades with Electrical Energy
Al-Shameri, Ammar,Apfel, Ulf-Peter,Lauterbach, Lars,Nestl, Bettina M.,Petrich, Marie-Christine,junge Puring, Kai
supporting information, p. 10929 - 10933 (2020/05/04)
We have developed a scalable platform that employs electrolysis for an in vitro synthetic enzymatic cascade in a continuous flow reactor. Both H2 and O2 were produced by electrolysis and transferred through a gas-permeable membrane into the flow system. The membrane enabled the separation of the electrolyte from the biocatalysts in the flow system, where H2 and O2 served as electron mediators for the biocatalysts. We demonstrate the production of methylated N-heterocycles from diamines with up to 99 percent product formation as well as excellent regioselective labeling with stable isotopes. Our platform can be applied for a broad panel of oxidoreductases to exploit electrical energy for the synthesis of fine chemicals.
Hydrogenation of N-Heteroarenes Using Rhodium Precatalysts: Reductive Elimination Leads to Formation of Multimetallic Clusters
Kim, Sangmin,Loose, Florian,Bezdek, Máté J.,Wang, Xiaoping,Chirik, Paul J.
, p. 17900 - 17908 (2019/11/19)
A rhodium-catalyzed method for the hydrogenation of N-heteroarenes is described. A diverse array of unsubstituted N-heteroarenes including pyridine, pyrrole, and pyrazine, traditionally challenging substrates for hydrogenation, were successfully hydrogenated using the organometallic precatalysts, [(η5-C5Me5)Rh(N-C)H] (N-C = 2-phenylpyridinyl (ppy) or benzo[h]quinolinyl (bq)). In addition, the hydrogenation of polyaromatic N-heteroarenes exhibited uncommon chemoselectivity. Studies into catalyst activation revealed that photochemical or thermal activation of [(η5-C5Me5)Rh(bq)H] induced C(sp2)-H reductive elimination and generated the bimetallic complex, [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H]. In the presence of H2, both of the [(η5-C5Me5)Rh(N-C)H] precursors and [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H] converted to a pentametallic rhodium hydride cluster, [(η5-C5Me5)4Rh5H7], the structure of which was established by NMR spectroscopy, X-ray diffraction, and neutron diffraction. Kinetic studies on pyridine hydrogenation were conducted with each of the isolated rhodium complexes to identify catalytically relevant species. The data are most consistent with hydrogenation catalysis prompted by an unobserved multimetallic cluster with formation of [(η5-C5Me5)4Rh5H7] serving as a deactivation pathway.