T:Toxic;
119-65-3Relevant academic research and scientific papers
Reversible aerobic oxidative dehydrogenation/hydrogenation of N-heterocycles over AlN supported redox cobalt catalysts
He, Zhen-Hong,Sun, Yong-Chang,Wang, Kuan,Wang, Zhong-Yu,Guo, Pan-Pan,Jiang, Chong-Shan,Yao, Man-Qing,Li, Zhu-Hui,Liu, Zhao-Tie
, (2020)
N-heterocycles with quinoline and tetrahydroquinoline structures are highly important in pharmaceutical and chemical industries, and their highly efficient mutual transformations are vital but still challenging. In the present work, AlN supported redox cobalt catalysts (Co3O4/AlN and Co/AlN) were prepared, which could achieve the reversible aerobic oxidative dehydrogenation/hydrogenation of N-heterocycles with good performances. The catalytic performances were stem from the strong interaction between Co species with AlN support, which were confirmed by the characterizations of Raman, XPS, UV–vis DRS, and H2-TPR etc. Both of the catalysts showed good stabilities and reusabilities for the titled reactions. Besides, the gram-scale experiments achieved with good yields to corresponding products, revealing the present protocol possesses great potential applications in industry. The strategy of using redox Co-based catalyst not only provides a potential catalyst for the reversible hydrogenation/oxidative dehydrogenation reactions but also replenishes methods for constructing of other redox catalyst, especially with AlN as a carrier.
Visible-Light-Mediated Photocatalytic Aerobic Dehydrogenation of N-heterocycles by Surface-Grafted TiO2 and 4-amino-TEMPO
Balayeva, Narmina O.,Zheng, Nan,Dillert, Ralf,Bahnemann, Detlef W.
, p. 10694 - 10704 (2019)
Herein, the visible-light-induced dehydrogenation of N-heterocycles such as tetrahydroquinolines, tetrahydroisoquinolines, and indolines in O2-containing suspensions of a commercially available titanium dioxide photocatalyst yielding the corresponding heteroarenes is presented. 4-Amino-2,2,6,6-tetramethylpipiridinyloxyl (4-amino-TEMPO) was found to exhibit a beneficial role, as it increased the yield and improved the selectivity of the dehydrogenation reaction. Both the selectivity and the yield are further enhanced by grafting 0.1 wt % of Ni(II) ions onto the TiO2 surface. It is proposed that the basic reactant adsorbs at Lewis acid sites present at the TiO2 surface. The dehydrogenation reaction is initiated by visible-light excitation of the resulting surface complex and a subsequent single-electron transfer from the excited N-heterocycle via the conduction band of TiO2 to O2. Ni(II) ions possibly serve as an electron transfer bridge between the conduction band of TiO2 and O2, while the TEMPO derivative is assumed to act as a selective redox mediator involved in reactions of the generated reactive oxygen species.
Reversible Dehydrogenation and Hydrogenation of N-Heterocycles Catalyzed by Bimetallic Nanoparticles Encapsulated in MIL-100(Fe)
Zhang, Jia-Wei,Li, Dan-Dan,Lu, Guo-Ping,Deng, Tao,Cai, Chun
, p. 4980 - 4986 (2018)
Pd?Ni bimetallic nanoparticles (BMNPs) encapsulated in MIL-100(Fe) (Pd-Ni@MIL-100(Fe) was fabricated and employed as an efficient catalyst for the reversible dehydrogenation/hydrogenation of N-Heterocycles derivatives in water under mild conditions. Excellent catalytic performance for both reactions endows Pd-Ni@MIL-100(Fe) great potential value in organic chemistry. Alloying Pd with Ni can enhance the catalytic performance due to the bimetallic synergy. Both Lewis acidity and ordered mesoporous structure of MIL-100(Fe) are beneficial to the performance of the catalyst owing to its stabilization of BMNPs, reduction of the electron density of Pd atoms and enhancement of substrates adsorption capacity.
Structural verification of a tetrahydrotetrazole compound
Breton, Gary W.,Hahn, Lauren A.,Martin, Kenneth L.
, p. 1208 - 1212 (2019)
Tetrahydrotetrazoles are five-membered-ring heterocycles containing four contiguous saturated nitrogen atoms. Very few examples of such compounds have been reported in the literature. Our previous attempt at the synthesis of a member of this class of compound suggested that the N - N bonds may be more labile than expected. This finding raised the question as to whether the structures of any of the previously reported tetrahydrotetrazoles had been properly assigned. We have reproduced the synthesis of a reported tetrahydrotetrazole, namely 1,2-di-tert-butyl 3-phenyl-1H,2H,3H,10bH-[1,2,3,4]tetrazolo[5,1-a]isoquinoline-1,2-dicarboxylate, C25H30N4O4, and have now confidently confirmed its structure via X-ray crystallography. However, while sufficiently stable in the crystal phase, we discovered that it remains very labile in solution (having a half-life of only 15min at 20°C in CDCl3). A tentative reaction pathway for its dissociation based on 1H NMR spectral evidence is provided.
Green synthesis of pyrido[2,1-a]isoquinolines and pyrido[1,2-a]quinolins using Fe3O4-MNPs as efficient nanocatalyst: Study of antioxidant activity
Azad, Leila,Faal Hamedani, Naghmeh,Ghazvini, Maryam,Noushin, Annataj
, (2019)
In this work, synthesis of pyrido[2,1-a]isoquinolines and pyrido[1,2-a]quinolins in excellent yield using multicomponent reaction of phthalaldehyde, methyl amine, methyl malonyl chloride, alkyl bromides, and triphenylphosphine in the presence of catalytic amount of Fe3O4-MNPs with aqueous sodium hydroxide at 80°C was investigated. The reduction of ferric chloride solution with Clover Leaf water extract caused to synthesis of magnetic iron oxide nanoparticles (Fe3O4-MNPs) as a green method. As well, antioxidant activity was studied for the some newly synthesized compounds such as 6a, 6c, 9b, and 9c using the DPPH radical trapping and reducing of ferric ion experiments and comparing results with synthetic antioxidants (TBHQ and BHT). As a result, compounds 6a, 6c, 9b, and 9c show good DPPH radical trapping and excellent reducing strength of ferric ion.
Heterogeneous nickel-catalysed reversible, acceptorless dehydrogenation of N-heterocycles for hydrogen storage
Ryabchuk, Pavel,Agapova, Anastasiya,Kreyenschulte, Carsten,Lund, Henrik,Junge, Henrik,Junge, Kathrin,Beller, Matthias
, p. 4969 - 4972 (2019)
Nickel-based nanocatalysts were used in acceptorless, reversible dehydrogenation and hydrogenation reactions of N-heterocycles. Both processes were realized in the same solvent using a single catalyst, without isolation of products and workup, which makes it attractive for hydrogen storage purposes. This concept has been demonstrated in a continuous hydrogenation/dehydrogenation sequence of quinaldine with negligible loss in activity of the nickel catalyst after three hydrogen storage cycles. The scope of acceptorless dehydrogenation has been explored and control experiments suggest that hydrogen liberation is initiated via amine dehydrogenation and supports the direct alkane dehydrogenation from the partially oxidized N-heterocycles.
Hydrogenation/dehydrogenation of N-heterocycles catalyzed by ruthenium complexes based on multimodal proton-responsive CNN(H) pincer ligands
álvarez, Eleuterio,Hernández-Juárez, Martín,López-Serrano, Joaquín,Paneque, Margarita,Rendón, Nuria,Sánchez, Práxedes,Santos, Laura L.,Suárez, Andrés
, p. 9583 - 9587 (2020)
Ru complexes based on lutidine-derived pincer CNN(H) ligands having secondary amine side donors are efficient precatalysts in the hydrogenation and dehydrogenation of N-heterocycles. Reaction of a Ru-CNN(H) complex with an excess of base produces the formation of a Ru(0) derivative, which is observed under catalytic conditions.
Metal–Organic Frameworks with Organogold(III) Complexes for Photocatalytic Amine Oxidation with Enhanced Efficiency and Selectivity
Han, Qing,Wang, Yue-Lin,Sun, Min,Sun, Chun-Yi,Zhu, Shan-Shan,Wang, Xin-Long,Su, Zhong-Min
, p. 15089 - 15095 (2018)
Luminescent organogold(III) complex AuIII with highly emissive triplet excited state was encapsulated in two metal–organic frameworks (MOFs) with different pore sizes and structures (MOF1 and ZJU-28). Compared with the AuIII complex in solution, the resultant composites AuIII@MOF1 and AuIII@ZJU-28 exhibit enhanced emission intensity, lifetime, and quantum yield. Under irradiation, AuIII@MOFs are efficient, selective, and recyclable catalysts for light-induced aerobic C?N bond formation. When used as a heterogeneous catalyst for oxidizing secondary amines to the corresponding imines, AuIII@ZJU-28 achieved high TONs of 876–1548, which are about 2.8–3.5 times higher than that of the homogenous AuIII complex. In addition, different selectivities in oxidizing mixed substrates is realized by means of different host MOFs, and thus encapsulating the AuIII complex in an appropriate MOF allowed the desired product to be obtained. Inherent shortcomings of homogeneous catalysts in cyclic use are also overcome by using composite catalysts, and high conversion of the AuIII@ZJU-28 catalyst was still observed after ten cycles.
New light-induced iminyl radical cyclization reactions of acyloximes to isoquinolines
Alonso, Rafael,Campos, Pedro J.,Garcia, Barbara,Rodriguez, Miguel A.
, p. 3521 - 3523 (2006)
An efficient photochemical approach for the unusual generation of six-membered heterocyclic rings is reported. Iminyl radicals, generated by the irradiation of acyloximes, participate in intramolecular cyclization processes and in intermolecular addition-intramolecular cyclization sequences.
The selective deiodination of iodoheterocycles using the PhSiH3 - In(OAc)3 system
Sugimoto, Osamu,Sugiyama, Minami,Tanji, Ken-ichi
, p. 601 - 606 (2010)
Nitrogen-containing π-deficient heterocyclic iodides such as iodoquinolines or iodopyridines were deiodinated by treatment with phenylsilane catalyzed by indium acetate to give the corresponding deiodinated heterocycles at ambient temperature.
