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.
Ceria supported Ru0-Ruδ+ clusters as efficient catalyst for arenes hydrogenation
Cao, Yanwei,Zheng, Huan,Zhu, Gangli,Wu, Haihong,He, Lin
supporting information, p. 770 - 774 (2020/08/24)
Selective hydrogenation of aromatic amines, especially chemicals such as aniline and bis(4-aminocyclohexyl)methane for non-yellowing polyurethane, is of particular interests due to the extensive applications. To conquer the existing difficulties in selective hydrogenation, the Ru0-Ruδ+/CeO2 catalyst with solid frustrated Lewis pairs was developed for aromatic amines hydrogenation with excellent activity and selectivity under relative milder conditions. The morphology, electronic and chemical properties, especially the Ru0-Ruδ+ clusters and reducible ceria were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), CO2 temperature programmed desorption (CO2-TPD), H2 temperature programmed reduction (H2-TPR), H2 diffuse reflectance Fourier transform infrared spectroscopy (H2-DRIFT), Raman, etc. The 2% Ru/CeO2 catalyst exhibited good conversion of 95% and selectivity greater than 99% toward cyclohexylamine. The volcano curve describing the activity and Ru state was found. Owning to the “acidic site isolation” by surrounding alkaline sites, condensation between the neighboring amine molecules could be effectively suppressed. The catalyst also showed good stability and applicability for other aromatic amines and heteroarenes containing different functional groups.
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.
Cobalt-bridged secondary building units in a titanium metal-organic framework catalyze cascade reduction of N-heteroarenes
Feng, Xuanyu,Song, Yang,Chen, Justin S.,Li, Zhe,Chen, Emily Y.,Kaufmann, Michael,Wang, Cheng,Lin, Wenbin
, p. 2193 - 2198 (2019/02/20)
We report here a novel Ti3-BPDC metal-organic framework (MOF) constructed from biphenyl-4,4′-dicarboxylate (BPDC) linkers and Ti3(OH)2 secondary building units (SBUs) with permanent porosity and large 1D channels. Ti-OH groups from neighboring SBUs point toward each other with an O-O distance of 2 ?, and upon deprotonation, act as the first bidentate SBU-based ligands to support CoII-hydride species for effective cascade reduction of N-heteroarenes (such as pyridines and quinolines) via sequential dearomative hydroboration and hydrogenation, affording piperidine and 1,2,3,4-tetrahydroquinoline derivatives with excellent activity (turnover number ～ 1980) and chemoselectivity.
An approach to the synthesis of 3-substituted piperidines bearing partially fluorinated alkyl groups
Subota, Andrii I.,Ryabukhin, Sergey V.,Gorlova, Alina O.,Grygorenko, Oleksandr O.,Volochnyuk, Dmitriy M.
, p. 61 - 66 (2019/05/29)
An approach to the synthesis of 3-substituted piperidines bearing partially fluorinated alkyl groups was proposed. The method was based on the DAST-mediated nucleophilic fluorination of easily available 2-bromopyridin-3-yl alcohols and ketones affording 2-bromo-3-(1-fluoroalkyl)pyridines and 2-bromo-3-(1,1-difluoroalkyl)pyridines, respectively, followed by catalytic hydrogenation. The hydrogenation step was studied with common heterogeneous Pd-, Pt-, and Rh-based catalyst. It was found that in the case of fluoroalkyl derivatives, the pyridine core reduction was accompanied by hydrodefluorination, which became a limitation of the strategy. Nevertheless, the method worked well with 1,1-difluoroalkyl derivatives
Cascade Biotransformation to Access 3-Methylpiperidine in Whole Cells
Borlinghaus, Niels,Weinmann, Leonie,Krimpzer, Florian,Scheller, Philipp N.,Al-Shameri, Ammar,Lauterbach, Lars,Coquel, Anne-Sophie,Lattemann, Claus,Hauer, Bernhard,Nestl, Bettina M.
, p. 5738 - 5742 (2019/07/16)
Synthesis of 3-methylpiperidine from 1,5-diamino-2-methylpentane in preparative scale is reported by using recombinant Escherichia coli cells expressing a variant of the diamine oxidase from Rhodococcus erythroprolis and an imine reductase from Streptosporangium roseum. Optimization of process parameters for cultivation and bioconversion led to substantial improvements in the initial laboratory procedure. The transformation of the methyl-substituted diamine substrate to the N-heterocyclic product was successfully scaled-up from shake-flask to a 20 L bioreactor with increased substrate concentrations. Remarkably, we obtained 67 % of 3-methylpiperidine product from 140 g substrate within 52 h.
AMMONIUM SALT, ELECTROLYTE FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY USING THEM
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Paragraph 0079, (2017/12/01)
PROBLEM TO BE SOLVED: To provide: ammonium salt with low viscosity; an electrolyte for a lithium secondary battery; and the lithium secondary battery. SOLUTION: This invention relates to an ammonium salt expressed by the following chemical formula (1). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPO&INPIT
PROMOTER FOR SELECTIVE NITRILE HYDROGENATION
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Paragraph 00100-00101, (2017/09/08)
Disclosed is a process for hydrogenating a dinitrile comprising contacting the dinitrile with hydrogen over catalyst comprising at least 90 wt.% iron in the presence of promoter comprising at least one selected from alkali metal and alkaline earth metal promoters.
Catalytic hydrogenation of substituted pyridines with PtO2 catalyst
Sreenivasulu, Reddymasu,Ranganath, Kalluri Venkata Sri,Raju, Rudraraju Ramesh
, p. 4358 - 4360 (2015/11/28)
The challenging methodology for the hydrogenation of substituted pyridines with mild reducing catalyst PtO2 in glacial acetic acid as a protic solvent using clean hydrogen under 50 to 70 bar atmospheric pressure leads to the synthesis of piperidine derivatives is reported. All the hydrogenated compounds were characterized by 1H NMR and ESI-MS.
