- Efficient Copper-Catalyzed Multicomponent Synthesis of N-Acyl Amidines via Acyl Nitrenes
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Direct synthetic routes to amidines are desired, as they are widely present in many biologically active compounds and organometallic complexes. N-Acyl amidines in particular can be used as a starting material for the synthesis of heterocycles and have several other applications. Here, we describe a fast and practical copper-catalyzed three-component reaction of aryl acetylenes, amines, and easily accessible 1,4,2-dioxazol-5-ones to N-acyl amidines, generating CO2 as the only byproduct. Transformation of the dioxazolones on the Cu catalyst generates acyl nitrenes that rapidly insert into the copper acetylide Cu-C bond rather than undergoing an undesired Curtius rearrangement. For nonaromatic dioxazolones, [Cu(OAc)(Xantphos)] is a superior catalyst for this transformation, leading to full substrate conversion within 10 min. For the direct synthesis of N-benzoyl amidine derivatives from aromatic dioxazolones, [Cu(OAc)(Xantphos)] proved to be inactive, but moderate to good yields were obtained when using simple copper(I) iodide (CuI) as the catalyst. Mechanistic studies revealed the aerobic instability of one of the intermediates at low catalyst loadings, but the reaction could still be performed in air for most substrates when using catalyst loadings of 5 mol %. The herein reported procedure not only provides a new, practical, and direct route to N-acyl amidines but also represents a new type of C-N bond formation.
- Van Vliet, Kaj M.,Polak, Lara H.,Siegler, Maxime A.,Van Der Vlugt, Jarl Ivar,Guerra, Célia Fonseca,De Bruin, Bas
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supporting information
p. 15240 - 15249
(2019/10/19)
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- Synthesis and crystal structures of [(iPr3P)2Cu(μ- ESiMe3)(InMe3)] (E = S, Se): Lewis acid-base adducts with chalcogen atoms in planar coordination
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The structures of [(iPr3P)2Cu(μ-SSiMe 3)(InMe3)] and [(iPr3P)2Cu(μ- SeSiMe3)(InMe3)] were determined by single-crystal X-ray diffraction. Both complexes are Lewis acid-base adducts of the InMe3 acceptor and the chalcogen donor atom linking a Me3Si group and a (iPr3P)2Cu moiety. They are very unstable under atmospheric conditions and decompose at ambient temperatures. Results of DFT calculations for these complexes and the related hypothetical [(Me 3P)2Cu(μ-SSiMe3)(InMe3)] compound show that the unusual planar coordination of the chalcogen atoms is due to steric crowding. Lewis acid-base adducts of trimethylindium and phosphane-stabilized copper(I) (trimethylsilyl)chalcogenolates were synthesized and characterized by X-ray crystal structure determination. They are very unstable under atmospheric conditions and decompose at ambient temperatures. DFT calculations reveal that the unusual planar coordination of the chalcogen atoms is due to steric crowding. Copyright
- Biedermann, Ralf,Kluge, Oliver,Fuhrmann, Daniel,Krautscheid, Harald
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p. 4727 - 4731
(2013/09/24)
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- Structural studies and anticancer activity of a novel (N6O 4) macrocyclic ligand and its Cu(II) complexes
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A novel (N6O4) macrocyclic ligand (L) and its Cu(II) complexes have been prepared and characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and conductivity measurements. Quantum chemical calculations have also been carried out at B3LYP/6-31+G(d,p) to study the structure of the ligand and one of its complexes. The results show a novel macrocyclic ligand with potential amide oxygen atom, amide and amine nitrogen atoms available for coordination. Distorted square pyramidal ([Cu(L)Cl]Cl·2.5H2O (1), [Cu(L)NO3]NO 3·3.5H2O (2), and [Cu(L)Br]Br·3H 2O (4) and octahedral ([Cu(L)(OAc)2]·5H 2O (3)) geometries were proposed. The EPR data of 1, 2, and 4 indicate d1 x2 -y2 ground state of Cu(II) ion with a considerable exchange interaction. The measured cytotoxicity for L and its complexes (1, 2) against three tumor cell lines showed that coordination improves the antitumor activity of the ligand; IC50 for breast cancer cells are ≈8.5, 3, and 4 μg/mL for L and complexes (1) and (2), respectively.
- El-Boraey, Hanaa A.,Emam, Sanaa M.,Tolan, Dina A.,El-Nahas, Ahmed M.
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p. 360 - 370
(2011/03/21)
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- Copper(I) carboxylates of type [(nBu3P) mCuO2CR] (m = 1, 2, 3) - Synthesis, properties, and their use as CVD precursors
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Copper(I) carboxylates of type [(nBu3P)mCuO 2CR] (m = 1: 3a, R = Me; 3b, R = CF3; 3c, R = Ph; 3d, R = CH=CHPh. m = 2: 4a, R = Me; 4b, R = CF3; 4c, R = Ph; 4d, R = CH= CHPh. m = 3: 8a, R = Me; 8b, R = CF3; 8c, R = CH2Ph; 8d, R = (CH 2OCH2)3H; 8e, R = cC 4H7O) are accessible by following synthesis methodologies: the reaction of [CuO2CR] (1a, R = Me; 1b, R = CF3; 1c, R = Ph; 1d, R = CH=CHPh) with m equivalents of nBu3P (2) (m = 1, 2, 3), or treatment of [(nBu3P)mCuCl] (5a, m = 1; 5b, m = 2) with [KO2CCF3] (6). A more straightforward synthesis method for 8a - 8e is the electrolysis of copper in presence of HO2CR (7a, R = Me; 7b, R = CF3; 7c, R = CH2Ph; 7d, R = (CH2OCH2)3H; 7e, R = cC 4H7O) and 2, respectively. This method allows to prepare the appropriate copper(I) carboxylate complexes in virtually quantitative yield, analytically pure form, and on an industrial scale. IR spectroscopic studies reveal that the carboxylic units in 4, 5, and 8 bind in a unidentate, chelating or μ-bridging fashion to copper(I) depending on m and R. The thermal properties of 4, 6, and 8 were determined by TG and DSC studies. Based on TG-MS experiments a conceivable mechanism for the thermally induced decomposition of these species is presented. Hot-wall Chemical Vapor Deposition experiments (CVD) with precursor 4b showed that copper could be deposited at 480°C onto a TiN-coated oxidized silicon substrate. The copper films were characterized by SEM and EDX studies. Pure layers were obtained with copper particles of size 200 - 780 nm.
- Jakob, Alexander,Shen, Yingzhong,Waechtler, Thomas,Schulz, Stefan E.,Gessner, Thomas,Riedel, Ralf,Fasel, Claudia,Lang, Heinrich
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p. 2226 - 2234
(2009/05/08)
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- Cu(II)-nitroxyl radicals as catalytic galactose oxidase mimics.
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Results from Hammett correlation studies and primary kinetic isotope effects for the CuCl-TEMPO catalysed aerobic benzyl alcohol oxidations are inconsistent with an oxoammonium based mechanism. We postulate a copper-mediated dehydrogenation mechanism, in which TEMPO regenerates the active Cu(II)-species. This mechanism is analogous to that observed for Galactose Oxidase and mimics thereof.
- Dijksman, Arne,Arends, Isabel W C E,Sheldon, Roger A
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p. 3232 - 3237
(2007/10/03)
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- 5-CYANO-10-HYDROXY-10,11-DIHYDRO-5H-DIBENZ[B,F]AZEPINE, THE PROCESSES FOR ITS PREPARATION AND FOR ITS CONVERSION INTO 5-CARBAMOYL-10-OXO-10, 11-DIHYDRO-5H-DIBENZ[B,F]AZEPINE OR INTO 5-CARBAMOYL-5H-DIBENZ[B,F]AZEPINE
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5-Cyano-10-Hydroxy-10,11-Dihydro-5H-Dibenzi[b,f]azepine and the process for its preparation.
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- 5-Cyano-10-hydroxy-10,11-dihydro-5H-dibenz[b,f]azepine, processes for its preparation and for its conversion into 5-carbamoyl-10-oxo-10,11-dihydro-5H-dibenz[b,f]azepine or into 5-carbamoyl-5H-dibenz[b,f]azepine
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A process and intermediates useful for the preparation of carbamazepine and oxcarbamazepine are disclosed.
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- Reactions of certain antimony(III, V) methyl derivatives with aliphatic alcohols in the presence of copper(II)
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Trimethylantimony and copper diacetate (or copper dipelargonate) in a 1:2 molar ratio substitute the hydrogen atom of the hydroxy group in aliphatic alcohols to form methyl alkyl ethers (yield up to 46%). The activity of alcohols toward methylation depends on the structure of the organic radical of the alcohol. Reactions of trimethylantimony diacetate or dibenzoate with alcohols in the presence of catalytic amounts of copper yield methyl alkyl ethers in 10-12% yields.
- Usyatinskii,Gushchin,Dodonov
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p. 1109 - 1112
(2007/10/03)
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- Kinetic Study of the Reduction of Molecular Oxygen by Cuprous Chloride and Cuprous Acetate in Pyridine
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The solution-phase kinetics of the reaction of cuprous chloride with molecular oxygen in pyridine were studied by monitoring product formation.The reaction was found to be third order in cuprous chloride and first order in oxygen by initial rate studies and pseudo-first-order rate constant determinations.A single rate law was found for solutions in which initial cuprous chloride concentrations were varied by more than a factor of 350 and initial oxygen concentrations were varied by more than a factor of 40.The integrated form of the resulting rate expression was found to precisely predict product vs. time curves.A more limited kinetic study of the reaction of cuprous acetate with oxygen in pyridine demonstrated that this reaction is first order in oxygen and second order in cuprous acetate.
- Hopf, Frederick R.,Rogic, Milorad M.,Wolf, James F.
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p. 4681 - 4686
(2007/10/02)
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- Halogen derivatives of ascorbic acid and D-araboascorbic acid antioxidants
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The halogen derivatives of ascorbic acid and D-araboascorbic acid useful as antioxidants as well as a method for stabilizing oxidation-sensitive organic materials by incorporating said derivatives in oxidation sensitive materials.
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