438495-24-0Relevant academic research and scientific papers
Ag-Catalyzed or Ag/PPh3-Catalyzed Chemoselective Switchable Cascade Reactions of N-Propargyl Thiocarbamoyl Fluorides and Malonate Esters
Cai, Zhongliang,Zhou, Junyi,Yu, Miao,Jiang, Liqin
supporting information, p. 293 - 298 (2022/01/12)
The divergent chemoselective synthesis of 2-methylene-2,3-dihydrothiazoles and 4-benzylidene pyrrolidine-2-thiones (most with E stereoselectivity) from N-propargyl thiocarbamoyl fluorides and malonate esters in moderate to excellent yields with a broad substrate scope and functional group tolerance has been accomplished. AgNTf2 catalyst at 60 °C in dichloroethane provided 4-benzylidene pyrrolidine-2-thiones. AgOTf catalyst and PPh3 ligand in refluxing acetonitrile resulted in a complete switch in the reactivity of formed α,α-diester thioamide intermediates followed by isomerization to access 2-methylene-2,3-dihydrothiazoles.
Structural and Electronic Control of the Bidentate 1-(2-pyridyl)benzotriazole Ligand in Copper Chemistry with Application to Catalysis in the A3 Coupling Reaction
Sampani, Stavroula I.,Zdorichenko, Victor,Devonport, Jack,Rossini, Gioia,Leech, Matthew C.,Lam, Kevin,Cox, Brian,Abdul-Sada, Alaa,Vargas, Alfredo,Kostakis, George E.
supporting information, p. 4394 - 4400 (2021/01/29)
The hybrid bidentate 1-(2-pyridyl)benzotriazole (pyb) ligand was introduced into 3d transition metal catalysis. Specifically, [CuII(OTf)2(pyb)2]?2 CH3CN (1) enables the synthesis of a wide range of propargylamines by the A3 coupling reaction at room temperature in the absence of additives. Experimental and high-level theoretical calculations suggest that the bridging N atom of the ligand imposes exclusive trans coordination at Cu and allows ligand rotation, while the N atom of the pyridine group modulates charge distribution and flux, and thus orchestrates structural and electronic precatalyst control permitting alkyne binding with simultaneous activation of the C?H bond via a transient CuI species.
Solvent-free synthesis of propargylamines via A3 coupling reaction and organic pollutant degradation in aqueous condition using Cu/C catalyst
Rathod, Pramod V.,Puguan, John Marc C.,Kim, Hern
, (2020/09/04)
The present report focuses on the efficient and operationally simple synthesis of biomass-derived carbon as support to immobilize copper particles as a catalyst for the one-pot synthesis of propargylamines from furfural via the A3 coupling reaction. This new catalyst showed remarkable catalytic performance leading to a 97% yield within 5 h at 80 °C using 5 mg (0.0022 mmol Cu) of Cu/C catalyst under solvent-free condition. Moreover, nitro-substituted compounds such as 4-nitrophenol (4-NP) are highly toxic and not easily degradable. Hence, a quick and effective method is required to neutralize these toxic compounds. The synthesized active support Cu/C catalyst having various electron-donating groups containing small amounts of Cu plays an essential role in the catalytic reduction of 4-NP (0.1 g). Using only 3 mg (0.0013 mmol Cu) of Cu/C catalyst and NaBH4 (10 mmol), a 99% yield (100% selectivity) in the aqueous condition at 25 °C was achieved. The catalytic reduction follows the pseudo-first-order kinetics with reaction rate constant of 0.028 s?1. Moreover, results demonstrate that the Cu/C catalyst has superior catalytic activity due to the presence of electron-donating molecules such as O, S, and N atoms, which enable synergistic effect in enhancing the overall catalytic performance. Notably, the recoverability and recyclability of the synthesized catalyst were evaluated for up to four cycles, which confirmed its stability in these cycles.
Shedding light on the use of Cu(ii)-salen complexes in the A3 coupling reaction
Sampani, Stavroula I.,Zdorichenko, Victor,Danopoulou, Marianna,Leech, Matthew C.,Lam, Kevin,Abdul-Sada, Alaa,Cox, Brian,Tizzard, Graham J.,Coles, Simon J.,Tsipis, Athanassios,Kostakis, George E.
supporting information, p. 289 - 299 (2020/01/21)
One Cu(ii) complex, {Cu(ii)L} (1S), has been synthesised, in two high yielding steps under ambient conditions, and characterised by single-crystal X-Ray diffraction (SXRD), IR, UV-Vis, circular dichroism (CD), elemental analysis, thermogravimetric analysis (TGA) and electron spray ionization mass spectroscopy (ESI-MS). This air-stable compound enables the generation, at room temperature and in open-air, of twenty propargylamines, nine new, from secondary amines, aliphatic aldehydes and alkynes with a broad scope with yields up to 99%. Catalyst loadings can be as low as 1 mol%, while the recovered material retains its structural integrity and can be used up to 5 times without loss of its activity. Control experiments, SXRD, cyclic voltammetry and theoretical studies shed light on the mechanism revealing that the key to success is the use of phenoxido salen based ligands. These ligands orchestrate topological control permitting alkyne binding with concomitant activation of the C-H bond and simultaneously acting as a template temporarily accommodating the abstracted acetylenic proton, and continuously generating, via in situ formed radicals and a Single Electron Transfer (SET) mechanism, a transient Cu(i) active site to facilitate this transformation. The scope and limitations of this protocol are discussed and presented.
Synthesis of Fully Substituted Pyrroles through a Copper-Catalyzed Aza-Michael/Claisen Rearrangement/Cyclization Cascade
Cui, Hai-Lei,Jiang, Lu,Jiang, Xue-Fei,Li, Meng-Fan,Liu, Si,Liu, Si-Wei,Tan, Hao,Tang, Xue,Yuan, Chang
supporting information, p. 723 - 729 (2020/04/07)
We have developed a copper-catalyzed aza-Michael/Claisen rearrangement/cyclization cascade sequence that affords structurally diverse pentasubstituted pyrroles in acceptable to good yields (31-84%).
Transition-Metal-Free Superbase-Catalyzed C-H Vinylation of Aldimines with Acetylenes to 1-Azadienes
Schmidt, Elena Yu.,Bidusenko, Ivan A.,Protsuk, Nadezhda I.,Demyanov, Yan V.,Ushakov, Igor A.,Vashchenko, Alexander V.,Trofimov, Boris A.
, p. 3417 - 3425 (2020/03/23)
Aldimines react with aryl- and hetarylacetylenes in the presence of KOBut/dimethyl sulfoxide (DMSO) or NaOBut/DMSO systems under exceptionally mild conditions (14 °C, 1 h) to afford C-H-vinylated products, 1-azadienes of E configuration relative to the C-C bond, in up to 72% yield. Vinylation involves the unprecedentedly fast multiposition proton transfer in the intermediate adducts of acetylene to the C≠N bond. This new Csp2-Csp2 bond-forming reaction opens a straightforward pot-, atom-, step-, and energy-economic access to synthetically valuable 1-azadienes.
Chiral 1,8-naphthyridine based ligands: Syntheses and characterization of Di- and tetranuclear copper (I) and silver (I) complexes
Sarkar, Mithun,Pandey, Pragati,Bera, Jitendra K.
supporting information, p. 518 - 528 (2018/11/24)
Oxazoline and camphor-pyrazole units are introduced on the 1,8-naphthyridine scaffold to access chiral ligands L1, L2 and L3. Metalation of these chiral ligands with Cu(I) and Ag(I) precursors afforded di- and tetranuclear complexes [Cu4I4(L1)2] (1), [Cu4I4(L2)2] (2), [Cu2I2(L3)] (3), [Cu2I(L2)2](OTf) (4), [Ag2(L1)2](OTf)2 (5) and [Ag4(L2)4Br](OTf)3 (6), containing [M4Xn] (n = 1,4 and X = Br, I) or [M2Xn] (n = 0, 1, 2 and X = I) core. All complexes are structurally characterized. Naphthyridine-derived ligands reveal bridge-chelate coordination motif and hold two metal centers in close proximity. The tetranuclear complexes are dimer of dinuclear complexes bridged by the halides. Electronic absorption and emission spectra of copper complexes are reported. Catalytic utility of all complexes are examined for asymmetric transformations but they showed poor activity probably due to limited solubility and coordinative saturation at the metal centers. The best results are obtained with [L3/Cu salt] combination for cyclopropanation of styrene, N–H bond insertion and nitroaldol (Henry) reactions with very low enantioselectivity.
New method for synthesis of propargylamine compound
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Paragraph 0046-0047, (2018/07/15)
The invention relates to a new method for synthesis of a propargylamine compound. The method is characterized by: under a solvent-free condition, taking Ag2CO3 as the catalyst, using terminal alkyne,aldehyde and amine as starting materials, and carrying out efficient and rapid reaction at 60-110DEG C by "one-pot method" to synthesize a propargylamine compound.
A facile synthesis methodology for preparation of Ag-Ni-reduced graphene oxide: a magnetically separable versatile nanocatalyst for multiple organic reactions and density functional study of its electronic structures
Chandel, Madhurya,Makkar, Priyanka,Ghosh, Barun Kumar,Moitra, Debabrata,Ghosh, Narendra Nath
, p. 37774 - 37788 (2018/11/26)
Here, we report a simple ‘in situ' co-precipitation reduction synthesis method for the preparation of nanocatalysts composed of Ag, Ni nanoparticles, and reduced graphene oxide (RGO). First-principles calculations based on Density Functional Theory (DFT) were performed to obtain the electronic structures and properties of Ag-Ni-graphene superlattice and to understand the interfacial interactions which exist at the interface between Ag, Ni, and graphene. The catalytic performance of the synthesized catalysts (AgxNi(1?x))yRGO(100?y) were evaluated for four reactions (i) reduction of 4-nitrophenol (4-NP) in the presence of excess NaBH4 in aqueous medium, (ii) A3 coupling reaction for the synthesis of propargylamines, (iii) epoxidation of styrene, and (iv) ‘Click reaction' for the synthesis of 1,2,3-triazole derivatives. For all of these reactions the catalyst composed of Ag, Ni, and RGO, exhibited significantly higher catalytic activity than that of pure Ag, Ni, and RGO. Moreover, an easy magnetic recovery of this catalyst from the reaction mixture after completion of the catalytic reactions and the good reusability of the recovered catalyst is also reported here. To the best of our knowledge, this is the first time the demonstration of the versatile catalytic activity of (AgxNi(1?x))yRGO(100?y) towards multiple reactions, and the DFT study of its electronic structure have been reported.
Copper-coordination polymer-controlled Cu@N-rGO and CuO@C nanoparticle formation: Reusable green catalyst for A3-coupling and nitroarene-reduction reactions
Vinod Kumar, Vadivel,Rajmohan, Rajamani,Vairaprakash, Pothiappan,Mariappan, Mariappan,Anthony, Savarimuthu Philip
, p. 11704 - 11714 (2017/09/18)
The intriguing structural properties of coordination polymers (COPs), together with the huge variety of metal ions and organic linkers to choose from, make COPs potential precursors for fabricating carbon-encapsulated metal and metal oxide nanoparticles (NPs). Herein, we have studied the role of the COP structural assembly, prepared through making subtle changes to the ligand structure, on the formation of NPs in a carbon matrix. Cu-COPs (Cu-COP-1-Cu-COP-7), generated using different amino acid-based reduced Schiff base phenolic chelating ligands, exhibited crystalline structures with differing structural organization in the solid state. Interestingly, the calcination of Cu-COP-1 and Cu-COP-5 at 330 °C produced pure CuNPs, whereas Cu-COP-2, Cu-COP-3, Cu-COP-4 and Cu-COP-7 gave CuONPs encapsulated by carbon matrix. The calcination of Cu-COP-6 produced both CuNPs and CuONPs together in the carbon matrix. The formation of CuNPs and CuONPs in the carbon matrices was unambiguously confirmed by PXRD and XPS studies. The sizes and morphologies of the Cu/CuONPs were analyzed using HR-TEM and FE-SEM. BET studies revealed higher surface areas with small pores for the CuNPs encapsulated by carbon and lower surface areas with higher porosity for the CuONP-carbon matrix. Raman spectra revealed the formation of a nitrogen-doped reduced graphene oxide (N-rGO) carbon matrix in CuNPs-1. The N-rGO coverage and high surface area with small pores provided CuNPs-1 with good stability in strong acid (10 M H2SO4). Importantly, the fabricated N-rGO-encapsulated CuNPs-1 and carbon-covered CuONPs-4 nanocomposites were used as green catalysts in solvent-free neat A3-coupling and nitroarene-reduction reactions, respectively. The products were confirmed using 1H-NMR spectra. The recovered CuNPs-1 and CuONPs-4 catalysts, after the completion of the reactions, also showed similar catalytic activity at up to five cycles, without significant loss of catalytic activity. Thus, the present studies demonstrate the influence of Cu-COP structural assembly on the formation of Cu/CuONPs as well as the carbon matrix, and open the possibility of fabricating functional nanomaterials from the vast number of available COPs with intriguing structural motifs.
