- The Mechanism and Kinetic Models of the Catalytic Oxidation of Ethylene by p-Benzoquinone in Aqueous–Acetonitrile Solutions of Pd(II) Cationic Complexes
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A kinetic study of ethylene oxidation to acetaldehyde by p-benzoquinone in the Pd(OAc)2–HClO4?LiClO4–CH3CN–H2O system has been carried out under conditions when palladium(II) cationic complexes exist at a molar fraction of water of 0.67 and 30°С. For a reaction that mostly lead to the formation ofPd(CH3CN)(H2O)32+ two-route mechanism and a kinetic model have been proposed that describe adequately the experimental dependence of the reaction initial rate on the concentration of p-benzoquinone, HClO4, and palladium. The model takes into account previous findings on the H2O/D2O and C2H4/C2D4 kinetic isotope effects and the important role of Pd(0) quinone complexes.
- Martynov,Efremov,Bovyrina,Katsman,Temkin
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- Preparative synthesis of palladium(II) acetate: Reactions, intermediates, and by-products
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Comparison of various laboratory procedures for the synthesis of palladium acetate demonstrated that the purest product containing no nitrite or nitrate impurities is formed in up to 90% yields upon the reaction of palladium nitrate with alkali metal acetates in aqueous acetic acid. Other laboratory syntheses are more labor-consuming and do not ensure high purity of the product. The synthesis by-products are described and possible reaction schemes are proposed.
- Stolyarov,Demina,Cherkashina
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- Oxidation of adamantane by palladium acetate systems
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Only low yields have been found for the oxidative substitution of adamantane catalysed by diacetatopalladium(II) in trifluoroacetic acid. Addition of copper(II) acetate produced a significant increase in conversion, exclusively to 1-adamantanol. The addition of potassium persulfate gave even higher yields, but at the expense of selectivity, with some 2-adamantanol product.
- Beattie, James K.,MacLeman, Susan,Masters, Anthony F.
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- Palladium(II) acetates: Synthesis and molecular transformation scheme
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Known methods for synthesis of a trinuclear molecular form of palladium(II) acetate, [Pd3(CH3COO)6], are analyzed and a number of new techniques that enable reliable control over the type of the product obtained and provide its high yield are suggested. A molecular transformation scheme is suggested. This scheme takes into account the formation of both forms of palladium acetate and also the formation of the structurally similar [Pd3(CH3COO)3NO2].
- Mulagaleev,Kirik
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- [Pd(CH3COO)2]n from X-ray powder diffraction data
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The synthesis and crystal structure of [Pd(C2H3O 2)2]n was analyzed. X-ray powder diffraction technique was used to determine the crystal structure of the compound. It was found that palladium acetate complexes were connected into a polymeric in which two Pd atoms were bridged by two acetate groups. It was observed that Pd atom occupied the special position (0,1/2,1/2) and formed rows with a Pd....Pd distance of 2.9192(I)A.
- Kirik, Sergei D.,Mulagaleev, Ruslan F.,Blokhin, Alexander L
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- Synthesis of Indoles by Reductive Cyclization of Nitro Compounds Using Formate Esters as CO Surrogates
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Alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of 2-nitrostyrenes to give indoles. Whereas the use of alkyl formates requires the presence of a ruthenium catalyst such as Ru3(CO)12, the reaction with phenyl formate can be performed by using a Pd/phenanthroline complex alone. Phenyl formate was found to be the most effective CO source and the desired products were obtained in excellent yields, often higher than those previously reported using pressurized CO. The reaction tolerates many functional groups, including sensitive ones like a free aldehydic group or a pendant pyrrole. Detailed experiments and kinetic studies allow to conclude that the activation of phenyl formate is base-catalyzed and that the metal doesn't play a role in the decarbonylation step. The reactions can be performed in a single thick-walled glass tube with as little as 0.2 mol-% palladium catalyst and even on a 2 g scale. The same protocol can be extended to other nitro compounds, affording different heterocycles.
- Ahmed Fouad, Manar,Ferretti, Francesco,Formenti, Dario,Milani, Fabio,Ragaini, Fabio
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supporting information
p. 4876 - 4894
(2021/09/20)
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- Can Donor Ligands Make Pd(OAc)2a Stronger Oxidant? Access to Elusive Palladium(II) Reduction Potentials and Effects of Ancillary Ligands via Palladium(II)/Hydroquinone Redox Equilibria
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Palladium(II)-catalyzed oxidation reactions represent an important class of methods for selective modification and functionalization of organic molecules. This field has benefitted greatly from the discovery of ancillary ligands that expand the scope, reactivity, and selectivity in these reactions; however, ancillary ligands also commonly poison these reactions. The different influences of ligands in these reactions remain poorly understood. For example, over the 60-year history of this field, the PdII/0 redox potentials for catalytically relevant Pd complexes have never been determined. Here, we report the unexpected discovery of (L)PdII(OAc)2-mediated oxidation of hydroquinones, the microscopic reverse of quinone-mediated oxidation of Pd0 commonly employed in PdII-catalyzed oxidation reactions. Analysis of redox equilibria arising from the reaction of (L)Pd(OAc)2 and hydroquinones (L = bathocuproine, 4,5-diazafluoren-9-one), generating reduced (L)Pd species and benzoquinones, provides the basis for determination of (L)PdII(OAc)2 reduction potentials. Experimental results are complemented by density functional theory calculations to show how a series of nitrogen-based ligands modulate the (L)PdII(OAc)2 reduction potential, thereby tuning the ability of PdII to serve as an effective oxidant of organic molecules in catalytic reactions.
- Bruns, David L.,Musaev, Djamaladdin G.,Stahl, Shannon S.
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supporting information
p. 19678 - 19688
(2020/12/18)
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- Total synthesis and neuroprotective effect of O-methylmurrayamine A and 7-methoxymurrayacine
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O-Methylmurrayamine A (7) and 7-methoxymurrayacine (8) are natural products isolated from Murraya koenigii and Murraya siamensis, respectively. In this paper, we report the synthesis of 7 and 8 which are featured in the key step of cyclization to form carbazole intermediate 5 with mild conditions. The structures were confirmed by 1H NMR, 13C NMR, and HR-ESI-MS. In addition, compounds 7 and 8 were tested for their neuroprotective effects against H2O2-induced PC12 cell damage. The results showed that compounds 7 and 8 have neuroprotective effect.
- Zang, Ying-Da,Li, Chuang-Jun,Song, Xiu-Yun,Ma, Jie,Yang, Jing-Zhi,Chen, Nai-Hong,Zhang, Dong-Ming
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p. 623 - 629
(2017/05/26)
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- Detection of Palladium(I) in Aerobic Oxidation Catalysis
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Palladium(II)-catalyzed oxidation reactions exhibit broad utility in organic synthesis; however, they often feature high catalyst loading and low turnover numbers relative to non-oxidative cross-coupling reactions. Insights into the fate of the Pd catalyst during turnover could help to address this limitation. Herein, we report the identification and characterization of a dimeric PdI species in two prototypical Pd-catalyzed aerobic oxidation reactions: allylic C?H acetoxylation of terminal alkenes and intramolecular aza-Wacker cyclization. Both reactions employ 4,5-diazafluoren-9-one (DAF) as an ancillary ligand. The dimeric PdI complex, [PdI(μ-DAF)(OAc)]2, which features two bridging DAF ligands and two terminal acetate ligands, has been characterized by several spectroscopic methods, as well as single-crystal X-ray crystallography. The origin of this PdI complex and its implications for catalytic reactivity are discussed.
- Jaworski, Jonathan N.,McCann, Scott D.,Guzei, Ilia A.,Stahl, Shannon S.
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supporting information
p. 3605 - 3610
(2017/03/21)
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- ORGANIC COMPOUND AND ELECTROCHROMIC DEVICE USING THE SAME
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The present invention provides an organic compound represented by the following general formula [1], the organic compound having high solubility in a polar solvent used in an EC device, high transparency in the bleached state and high stability against repetition of an oxidation-reduction reaction.
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- Can Palladium Acetate Lose Its "saltiness"? Catalytic Activities of the Impurities in Palladium Acetate
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Commercially available palladium acetate often contains two major impurities, whose presence can impact the overall catalytic efficacy. This systematic study provides a comparison of the differences in catalytic activity of pure palladium acetate, Pd3(OAc)6, with the two impurities: Pd3(OAc)5(NO2) and polymeric [Pd(OAc)2]n in a variety of cross-coupling reactions. The solid state 13C NMR spectra of all three compounds in conjunction with DFT calculations confirm their reported geometries.
- Carole, William A.,Bradley, Jonathan,Sarwar, Misbah,Colacot, Thomas J.
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supporting information
p. 5472 - 5475
(2015/11/18)
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- Competing reactions of hydrophenylation and phenylation in tetraphenylantimony chloride methyl acrylate palladium chloride system
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A new catalytic reaction of the competing phenylation and hydrophenylation in air of methyl acrylate with tetraphenylantimony chloride in the presence of PdCl2 (0.04 mol per 1 mol of organometallic compound) in acetonitrile at 50°C for 6 h was studied. The yields of methyl cynnamate and methyl hydrocynnamate were 0.73 and 0.27 mol mol-1 respectively. The products ratio obtained depends slightly on the process duration, the Ph 4SbCl and methyl acrylate ratio, and the structure of Pd salt [PdCl2, Pd(OAc)2, Li2PdCl4], but significantly on the nature of a solvent (MeCN > DMF > THF). The use of Ph4SbCl instead of Ph4SbBr leads to decrease in the yield of methyl hydrocynnamate to 0.04 mol mol-1. In the reactions of Ph4SbX (X = F, I, OAc, O2CEt) the product is not formed at all. Pleiades Publishing, Inc., 2006.
- Morugova,Gushchin,Skvortsov,Moiseev
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p. 747 - 752
(2008/02/02)
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- Palladium-catalyzed asymmetric iodination of unactivated C-H bonds under mild conditions
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(Chemical Equation Presented) Specific, asymmetric, and mild: Oxazoline (Oxa), a removable chelating chiral auxiliary, assists in the asymmetric activation of C(sp3)-H bonds at the β position and C(sp 2)-H bonds at the γ position. Pd-(OAc)2 is an effective catalyst for the selective and asymmetric iodination of methyl, cyclopropyl, and aryl groups at room temperature (see formulae).
- Giri, Ramesh,Chen, Xiao,Yu, Jin-Quan
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p. 2112 - 2115
(2007/10/03)
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- Process for the preparation of anthracycline derivatives
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The present invention discloses a process for the semi-synthesis of 4-demethoxydaunomycinone, (8s-cis)-acetyl-10-hydroxy-7,8,9,10-tetrahydro-6,8,11-trihydroxy-5,12-naphthacenedione, of formula (I).
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- Catalytic C-phenylation of methyl acrylate with tetraphenylantimony(v) halides and carboxylates
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Catalytic C-phenylation of methyl acrylate to methyl cinnamate with the Ph4SbX complexes (X = F, Cl, Br, OH, OAc, O2CEt) in the presence of the palladium compounds PdCl2, Pd(OAc)2, Pd2(dba)3, Pd(Ph3P)2Cl2, and Pd(dppf)Cl2 (dba is dibenzylideneacetone and dppf is bis(diphenylphosphinoferrocene)) was studied in organic solvents (MeCN, THF, DMF, MeOH, and AcOH). The highest yield of methyl cinnamate (73% based on the starting organometallic compound) was obtained for the Ph4SbCl- PdCl2 (1:0.04) system in acetonitrile.
- Gushchin,Grunova,Moiseev,Morozov,Shavyrin,Dodonov
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p. 1376 - 1379
(2007/10/03)
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- Aminoalcohol derivatives and their use as beta 3 adrenergic agonists
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This invention relates to new aminoalcohol derivatives or salts thereof represented by the following formula [I]: wherein each symbol is as defined in the specification or salts thereof which have gut selective sympathomimetic, anti-ulcerous, anti-pancreatitis, lipolytic, anti-urinary incontinence and anti-pollakiuria activities, to processes for the preparation thereof, to a pharmaceutical composition comprising the same and to a method for the prevention and/or treatment diseases indicated in the specification to a human being or an animal.
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- Quinoline derivatives
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Compounds of general formula I as well as pharmaceutically acceptable salts and esters thereof, are potent inhibitors of neuropeptide Y and can be used in the form of pharmaceutical preparations for the treatment or prevention of various disease states and related morbidities including obesity.
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- Ligand and solvent effects in the alternating copolymerization of carbon monoxide and olefins by palladium-diphosphine catalysis
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The substitution of two hydrogen atoms by methyl groups in the 1,2 positions of 1,2-bis-(diphenylphosphino)ethane (dppe) gives meso- and rac-2,3-bis(diphenylphosphino)butane (meso-2,3-dppb and rac-2,3-dppb). The corresponding Pd(II) complexes Pd(OTs)2(meso-2,3-dppb) and Pd(OTs)2(rac-2,3-dppb) are effective catalyst precursors for the alternating copolymerization and terpolymerization of carbon monoxide with ethene and ethene/propene in MeOH with productivities that are higher than those of the unsubstituted dppe catalyst Pd(OTs)2(dppe) even by a factor of 10 (OTs = p-toluenesulfonate). It has been found that the low productivity of the dppe-based catalyst in MeOH is due to the autoionization of the precursor Pd(OAc)2(dppe) in MeOH to give the catalytically inactive bis-chelate species [Pd-(dppe)2](OAc)2 and palladium acetate. In an attempt to evaluate and rationalize the effective ligand control on the intrinsic catalytic activity, the methyl complexes [Pd(Me)(MeCN)(P-P)]PF 6 have been synthesized and employed in CH2Cl2 to catalyze the alternating carbon monoxide/ethene copolymerization. The intrinsic activity of the three precursors decreases in the order [Pd(Me)(MeCN)(meso-2,3-dppb)]+ > [Pd(Me)(MeCN)(rac-2,3-dppb)] + > [Pd(Me)-(MeCN)(dppe)]+. High-pressure NMR experiments and the determination of activation barriers of migratory insertions agree to indicate the relative stability of the β-chelate ring in [Pd(CH2CH2C(O)Me)(P-P)]+ as the factor that controls the copolymerization rate in aprotic solvents. The impact of the different diphosphines on both productivity and intrinsic catalytic activity has been attributed to the different stereochemical rigidity of the Pd(P-P) five-membered metallarings. The β-chelate complexes [Pd(CH 2CH2C(O)Me)(P-P)]PF6 with diphosphine ligands containing two carbon atoms between the phosphorus donors have been isolated for the first time and employed to study the chain-transfer by protonolysis, which proceeds via the enolate mechanism. It has been shown that the chain-transfer products [Pd(OH)(P-P)]22+ do not represent a dead end for the alternating CO/ethene copolymerization.
- Bianchini, Claudio,Lee, Hon Man,Meli, Andrea,Oberhauser, Werner,Peruzzini, Maurizio,Vizza, Francesco
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- PROCESS FOR THE PREPARATION OF 2,3-DIHYDROAZEPINE COMPOUNDS
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As a process for preparing 2,3-dihydroazepine compounds at low cost in a simple and easy manner, there is provided a process for the preparation of compounds of the formula: or salts thereof, characterized in that compounds of the formula: or salts thereof are reacted with compounds of the formula: or salts thereof to give compounds of the formula: or salts thereof, which are then subjected to esterification and ring-closing reaction.
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- Process for the preparation of new transition metal complexes
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The present invention relates to novel group VIII transition metal complexes represented by the formula (I) as: wherein M is the central transition metal; +Z represents a semilabile anionic chelating ligand; R1, R2 and R3 are substituents on the phosphine ligand, X is chosen from sulphonato, carboxylato, formato group or halides and 1n10. The invention also provides a process for the preparation of said transition metal complex.
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- The effects of the solvent and the ligand chirality on the regioselectivity of alkene oxidative esterification by PdII carboxylates
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The effects of the solvent and the ligand chirality on the regioselectivity of oxidative esterificanon of propylene and cyclohexene by PdII carboxylates were studied using achiral (MeCO2-, Me2CHCH2CO2-), racemic ((±)-CF3CF2CF2OC*F(CF3) CO2-) and chiral ((S)-(+)-MeC*H(Et)CO2-, (+)-CF3CF2CF2OC*F(CF3)CO2 -) carboxylate ligands. The oxidation of alkenes in aprotic media (CHCl3, CH2C12, CO2, THF) affords mainly allylic esters (in the case of cyclohexene also homoallylic esters) and the oxidative esterification at the vinylic position is absent. In weakly solvating media (CHCl3, CH2Cl2) the regioselectivity of cyclohexene oxidation (the allyl to homoallyl ratio) increases substantially on going from achiral or racemic acido ligands to chiral acido ligands. In a more donor medium (THF) the ligand chirality effect almost vanishes. The effects of the ligand chirality and the nature of the solvent on the mechanism of alkene oxidation by PdII complexes are discussed.
- Kozitsyna,Martens,Stolyarov,Gekhman,Vargaftik,Moiseev
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p. 1673 - 1681
(2007/10/03)
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- Manufacture of palladous carboxylates
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A novel method for preparing soluble STR1 by reaction of palladium metal with a carboxylic acid of the formula RCOOH wherein R is a hydrocarbon or halogenated hydrocarbon group having from 1 to 10 carbon atoms in the presence of a member selected from the group consisting of A. HNO3 plus NO, B. HNO2, C. nitric oxide plus oxygen, D. nitric oxide plus nitrogen dioxide, E. nitrogen dioxide, and F. nitrosyl acetate, is described.
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- Palladium complex
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The palladium complex disclosed herein is bis[tri(orthotolyl)phosphine] palladium which is produced by reacting a palladium salt with tri(ortho-tolyl)phosphine and reducing the resultant bis[tri(ortho-tolyl)phosphine] palladium salt with an alcoholic alkali. This complex is useful as a catalyst for the production of 1,3-diene oligomers.
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- Process for producing biphenylpolycarboxylic acid ester
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The oxidative coupling of benzenecarboxylic acid esters to form the corresponding biphenylpolycarboxylic acid esters, comprising contacting a benzenecarboxylic acid ester having at least one hydrogen atom bonded to the nuclear carbon atom of the benzene ring, such as methyl benzeate, with molecular oxygen in a liquid phase using a catalyst comprising at least one compound selected from organic carboxylates of palladium, such as palladium acetate and β-dikete complexes of palladium, such as acetylacetone-palladium complex. Use of at least one zirconium compound, such as zirconium oxystearate in conjunction with the catalyst gives rise to an increased catalytic activity.
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