- INVESTIGATION OF THE INTERACTION OF PYRIDINE WITH THE SURFACE OF LAMINAR SILICATES BY THE METHOD OF OPTICAL ELECTRONIC SPECTROSCOPY.
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A study of the nature of the active sites on the surface of laminar silicates and an attempt to identify those that are responsible for the observed conversion of sorbed pyridine on the surface of laminar silicate to more complex formations characterized by a rather developed system of conjugated pi -bonds are discussed.
- Sivalov,Tarasevich
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- General Method for Synthesis of Bipyridines: Palladium Catalyzed Cross-coupling Reaction of Trimethylstannylpyridines with Bromopyridines
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Trimethylstannylpyridines 1 were treated with bromopyridines 2 in the presence of catalytic amount of tetrakis(triphenylphosphine)palladium to give the corresponding bipyridines 3 in moderate to good yields.Nicotelline (6) was similarly synthesized from 2,4-bis(trimethylstannyl)pyridine (5) and 3-bromopyridine (2b).
- Yamamoto, Yutaka,Azuma, Yutaka,Mitoh, Hiroyuki
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- Mild and efficient formation of symmetric biaryls via Pd(II) catalysts and Cu(II) oxidants
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Described herein is a mild and efficient palladium-catalyzed synthesis of symmetric biaryls from organostannanes. This methodology offers products rapidly in very high yields.
- Parrish, Jay P.,Flanders, Vincent L.,Floyd, Ryan J.,Jung, Kyung Woon
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- Cation-Assisted Ligand Photosubstitution in Transition-Metal Complexes. Photoreactions of Ru(bpy)32+ with Ag+ in Acetonitrile
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Irradiation of Ru(bpy)32+ in the presence of Ag+ in acetonitrile leads to the photosubstitution product Ru(bpy)2(CH3CN)22+.The reaction does not occur in the absence of Ag+ or acetonitrile; although Ag+ quenches the luminescent MLCT state of Ru(bpy)32+, a kinetic analysis indicates the photosubstitution does not originate from this excited state.The most reasonable mechanism for the process involves decay of the MLCT state via a d-d excited state to a ligand-labilized intermediate which is interpreted by Ag+ in a process which assists the substitution by removal of a bpy ligand.This mechanism is thus parallel to anion-induced substitution reactions which evidently proceed via competitive anion-ligand capture of the same or similar intermediates.
- Foreman, T. K.,Bonilha, J. B. S.,Whitten, D. G.
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- Photoactivatable RuII Complex Bearing 2,9-Diphenyl-1,10-phenanthroline: Unusual Photochemistry and Significant Potency on Cisplatin-Resistant Cell Lines
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The current study investigates [Ru(bipy)2(dpphen)]Cl2 [where bipy = 2,2′-bipyridine and dpphen = 2,9-diphenyl-1,10-phenanthroline] (complex 1) for photoactivatable chemotherapy (PACT) application on five cancer cell lines. [Ru(bipy)2(phen)]Cl2 [where phen = 1,10-phenanthroline] (complex 2) was included as an unstrained control. Upon excitation with visible light, complex 2 proved to be photostable while complex 1 underwent a quantitative dissociation of the bipy ligand and formation of a RuII polypyridyl aqua complex in water. Complex 1 demonstrated only marginal activity in the dark; its cytotoxicity increased significantly upon photoactivation with a high phototoxicity index (PI = [IC50 dark]/[IC50 light]) ranging from 39.2-fold in A549 to over 100-fold in MDA-MB-231. Complex 2, on the other hand, did not show much difference in anticancer activity between dark and light conditions. Importantly, the IC50 of the photoproduct of complex 1 was several folds lower than that of cisplatin in all tested cell lines. Furthermore, the dissociating ligand (bipy) was biologically inert in almost all cell lines investigated confirming that phototoxicity was mediated primarily by the Ru aqua complex that is released upon irradiation. In conclusion, the Ru-centered complex 1 could represent a potential photoactivatable chemotherapeutic drug that increases selectivity to tumors and offers alternative treatment in the light of increasing cisplatin resistance.
- Mansour, Najwa,Mehanna, Stephanie,Mroueh, Mohamad A.,Audi, Hassib,Bodman-Smith, Kikki,Daher, Costantine F.,Taleb, Robin I.,El-Sibai, Mirvat,Khnayzer, Rony S.
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- Acid directed in situ oxidation and decarboxylation of 4,4′,6, 6′-tetra-methyl-2,2′-bipyridine: Synthesis and structural characterisation of 4,4′,6-tri-carboxy-2,2′-bipyridine and its copper(II) coordination polymer
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The reaction of either 4,4′,6,6′-tetramethyl-2,2′- bipyridine, L, or 4,4′,6,6′-tetracarboxy-2,2′-bipyridine, H4L, with Cu(OAc)2·H2O under acidic hydrothermal conditions (50:1 H2O/HNO3; 160 °C) led to the formation of crystalline {[Cu(HL′)(H2O)]·H 2O}, 1, which was structurally characterised to identify H 3L′ as 4,4′,6-tricarboxy-2,2′-bipyridine. Clearly, in situ mono-decarboxylation of a tetracarboxylic acid ligand gave the tricarboxy-analogue, H3L′. The structure of 1 consists of a 1D coordination polymer that cross-links through hydrogen-bonding between adjacent carboxylic acid and carboxylate groups, as well as through an aqua ligand and lattice water molecule, to form a densely interconnected 3D network. Regioselective mono-decarboxylation of L or H4L at the 6′-carboxylic acid position may also be affected by heating L or H 4L in acidic solution under hydrothermal conditions (2:1 H 2O/HNO3; 160°C) to yield crystalline 4,4′,6-tricarboxy-2,2′-bipyridinium nitrate hydrate {[H 4L′][NO3]·H2O}, 2, which was also structural characterised. The structure of 2 features an array of hydrogen-bonding interactions that generate a 3D network. More forceful heating of the acidic solution at 180°C led to double decarboxylation and the formation of 4,4′-dicarboxy-2,2′-bipyridine, whereas heating at 200°C led to total decarboxylation and the formation of 2,2′- bipyridine. Details of the structures of 1 and 2 along with their synthesis are discussed.
- Kelly, Niamh R.,Goetz, Sandrine,Hawes, Chris S.,Kruger, Paul E.
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- Excited state dynamics of organo-lanthanide electroluminescent phosphors: The properties of Tb(tb-pmp)3 and Gd(tb-pmp)3
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The excitation energy transfer rates between the excited states of a Tb(III) complex containing the ligand 1-phenyl-3-methyl-4-(trimethylacetyl)pyrazol-4-one, are described. Energy transfer rate constants are derived from time-gated and time-correlated single photon counting measurements. Comparison with the analogous Gd(III) complex shows that there is efficient intramolecular energy transfer from a singlet state of the ligand to excited terbium f-electron states. There is no evidence of bi-exciton annihilation in these materials, even at very high exciton densities. The use of this complex as the active medium for electroluminescent device applications is addressed. We note the particular properties of the ligand which make it suitable for this application and suggest possible improvements.
- Thorne,Rey,Denning,Watkins,Etchells,Green,Christou
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- DIMER FORMATION IN THE REACTION OF ARYL HALIDES CATALYZED BY NICKEL COMPLEXES
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The synthesis of diaryls catalyzed by electrochemically generated zero-valent nickel with 2,2'-dipyridyl as the ligand was carried out from aryl halides in high yield.Feasibility was demonstrated for synthesizing the catalyst itself by the anodic dissolution of nickel in the presence of 2-bromopyridine in a diaphragmless cell.Keywords: synthesis, diaryls, aryl halides.
- Budnikova, Yu. G.,Kargin, Yu. M.,Yanilkin, V. V.
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- The use of Ni(CO)2(PPh3)2 in aryl and pyridyl coupling reactions
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The zerovalent nickel complex Ni(CO)2(PPh3)2 has been used for the coupling of aryl halides to form biaryls and for the coupling of bromopyridines to form polypyridines. The effects of solvent, halide and substituents have also been investigated.
- Leadbeater, Nicholas E.,Resouly, Sarah M.
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- Phototoxicity of strained Ru(II) complexes: Is it the metal complex or the dissociating ligand?
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A photochemically dissociating ligand in Ru(bpy)2(dmphen)Cl2 [bpy = 2,2′-bipyridine; dmphen = 2,9-dimethyl-1,10-phenanthroline] was found to be more cytotoxic on the ML-2 Acute Myeloid Leukemia cell line than Ru(bpy)2(H2O)22+ and prototypical cisplatin. Our findings illustrate the potential potency of diimine ligands in photoactivatable Ru(ii) complexes.
- Azar, Daniel F.,Audi, Hassib,Farhat, Stephanie,El-Sibai, Mirvat,Abi-Habib, Ralph J.,Khnayzer, Rony S.
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- Ligand-free Stille cross-coupling reaction using Pd/CaCO3 as catalyst reservoir
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Stille reactions between halobenzenes and other substituted (hetero)arenes and tributylphenyltin were carried out in ethanol-water solution using Pd/CaCO3 as catalyst in a ligand-free system. The catalyst could be recycled three times without any loss of activity. The ethanol-water solution, after removal of the catalyst and extraction of the product, was found to have catalytic activity, thus showing the presence of soluble Pd(0)/Pd(II) species that can be regarded as the true catalysts.
- Coelho, Aline V.,de Souza, Andréa Luzia F.,de Lima, Paulo G.,Wardell, James L.,Antunes
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- Novel synthesis method of 2, 2 '-dipyridyl
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The invention discloses a novel synthesis method of 2, 2 '-dipyridyl. According to the method, 2, 2'-dipyridyl with the purity of 99.8% or above is obtained by taking 2-chloropyridine as an initial raw material and adopting a supported catalyst through coupling reaction and aftertreatment at the temperature of 50-60 DEG C. The method has the advantages of mild reaction conditions, realization of the reaction at 50-60DEG C, short reaction time, completion of the reaction in 2-5h, simple extraction, freezing recrystallization, high conversion rate, repeated application of the catalyst, simple and efficient production operation, low cost and stable product quality, and overcomes the defects of high catalyst cost, difficult recovery, and low catalytic efficiency. Meanwhile, the problems of environment and safety in the production process are solved.
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Paragraph 0017-0020
(2021/03/10)
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- Pincerlike manganese complex and preparation method thereof, related ligand and preparation method thereof, catalyst composition and application
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The invention discloses a pincerlike manganese complex, a preparation method thereof, a ligand for preparation, a preparation method of the ligand, a catalyst composition taking the complex as an active component and application of the catalyst composition. According to the pincerlike manganese complex, a cycloalkyl ring is introduced into a ligand framework, and by regulating and controlling the cyclic tension, flexibility and steric hindrance of the cycloalkyl ring, the reactivity and stability of the manganese metal center can be effectively adjusted, and the catalytic activity and substrate applicability of a manganese metal system are remarkably improved. The catalyst composition taking the pincerlike manganese complex as an active component has the advantages of high catalyst activity, wide substrate application range, mild reaction conditions and the like in the process of preparing quinoline or pyridine derivatives by catalyzing dehydrogenation coupling reaction of o-amino aromatic alcohol or gamma-amino alcohol, ketone or secondary alcohol; and the synthesis advantages of low cost and stable performance are embodied, the operation is simple, and the yield is high.
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Paragraph 0159-0165
(2021/07/31)
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- Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents
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Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
- An, Ju Hyeon,Kim, Kyu Dong,Lee, Jun Hee
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supporting information
p. 2876 - 2894
(2021/02/01)
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- Pd-catalyzed oxidative homocoupling of arylboronic acids in WEPA: A sustainable access to symmetrical biaryls under added base and ligand-free ambient conditions
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Symmetrical and unsymmetrical biaryls comprises a diverse class of biologically eloquent organic compounds. We herein report, a quick and eco-friendly protocol for the synthesis of biaryls by an oxidative (aerobic) homocoupling of arylboronic acids (ABAs) using Pd(OAc)2 in water extract of pomogranate ash (WEPA) as an efficient agro-waste(bio)-derived aqueous (basic) media. The reactions were executed at ambient aerobic conditions in the absence of external base and ligand to result symmetrical biaryls in excellent yields. The use of renewable media with an effective exploitation of waste, short reaction times, excellent yields of products, easy separation of the products, unnecessating the external base, oxidant, ligand or volatile organic solvents and ambient reaction conditions are the vital insights of the present protocol.
- Appa, Rama Moorthy,Lakshmidevi, Jangam,Naidu, Bandameeda Ramesh,Venkateswarlu, Katta
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- Cationic tetra-and pentacoordinate complexes of nickel based on POCN-and POCOP-Type pincer ligands: Synthesis, characterization, and ligand exchange studies
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Stirring acetonitrile solutions of the charge-neutral pincer complexes (POCN)NiBr (1, POCN = κP,κC,κN-{2-(i-Pr)2PO,6-CH2{c-N(CH2)5}-C6H3) and (POCOP)NiBr (2, POCOP = κP,κC,κP′-2,6-(i-Pr2OP)2C6H3) with AgSbF6 facilitates Br- abstraction to give the corresponding cationic acetonitrile adducts [(POCN)Ni(NCMe)]+, 1a, and [(POCOP)Ni(NCMe)]+, 2a. Treating 1a and 2a with pyridine (py), 2,2′-bipyridine (bipy), phenanthroline (phen), or 4,4′-bipyridine (bipy?) gave the corresponding monocationic adducts [(POCN or POCOP)Ni(ligand)]+ (ligand = py: 1b and 2b; κN,κN′-bipy: 1c and 2c; κN,κN′-phen: 1d and 2d) and the dicationic dinuclear adducts [(POCN or POCOP)2Ni2(μ-bipy?)]2+ (1e and 2e). The new adducts 1a-1d and 2b-2e have been characterized by NMR spectroscopy; complex 1e proved to be insoluble and could not be analyzed by NMR. Single crystal X-ray diffraction studies were used to establish the solid-state structures of 1a-1e, and 2b-2d. UV-vis spectra have also been recorded for the pentacoordinated complexes 1c, 1d, 2c, and 2d. Studying the equilibria that govern the displacement of halides in (pincer)NiX (X = Cl, Br) by the in-coming nucleophiles py, bipy, and phen has allowed us to determine the following order for the relative nucleophilicities of the ligands involved in the halide substitution equilibria: Cl- > Br- > phen > bipy ? py > MeCN. Similar Keq measurements showed that cationic species are better stabilized with the POCN platform compared to POCOP. This implies that POCN is a better net donor of electron density compared to POCOP, such that the relative Lewis acidity (electrophilicity) of the cationic fragments should follow the order [(POCOP)Ni]+ > [(POCN)Ni]+. Cyclic voltammetry measurements on the bipy adducts showed reversible, one-electron oxidation events occurring at a lower value for [(POCN)Ni(bipy)]+, implying a more electron-rich Ni(ii) centre with POCN vs. POCOP. Consistent with these assertions, mixing (POCN)NiBr and [(POCOP)Ni(phen)]+ in acetonitrile gave [(POCN)Ni(phen)]+ and (POCOP)NiBr. Similarly, the Keq value of 0.19 for the equilibrium exchange (POCN)NiCl + (POCOP)NiBr ? (POCN)NiBr + (POCOP)NiCl indicates that the [(POCOP)Ni]+ fragment is better stabilized by Cl-vs. Br-. These exchange reactions do not occur in THF or CH2Cl2, implying that they are driven by the nucleophilic character of the solvent. This journal is
- Rahimi, Naser,Zargarian, Davit
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supporting information
p. 15063 - 15073
(2021/09/04)
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- Synthesis of Bis-heteroaryls Using Grignard Reagents and Pyridylsulfonium Salts
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Herein are reported ligand-coupling reactions of Grignard reagents with pyridylsulfonium salts. The method has wide functional group tolerance and enables the formation of bis-heterocycle linkages, including 2,4′-, 2,3′-, and 2,2′-bipyridines, as well as pyridines linked to pyrimidines, pyrazines, isoxazoles, and benzothiophenes. The methodology was successfully applied to the synthesis of the natural products caerulomycin A and E.
- Horan, Alexandra M.,Duong, Vincent K.,McGarrigle, Eoghan M.
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supporting information
p. 9089 - 9093
(2021/11/30)
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- Direct synthesis of ring-fused quinolines and pyridines catalyzed byNNHY-ligated manganese complexes (Y = NR2or SR)
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Four cationic manganese(i) complexes, [(fac-NNHN)Mn(CO)3]Br (Mn-1-Mn-3) and [(fac-NNHS)Mn(CO)3]Br (Mn-4) (whereNNHis a 5,6,7,8-tetrahydro-8-quinolinamine moiety), have been synthesized and evaluated as catalysts for the direct synthesis of quinolines and pyridines by the reaction of a γ-amino alcohol with a ketone or secondary alcohol;NNHS-ligatedMn-4proved the most effective of the four catalysts. The reactions proceeded well in the presence of catalyst loadings in the range 0.5-5.0 mol% and tolerated diverse functional groups such as alkyl, cycloalkyl, alkoxy, chloride and hetero-aryl. A mechanism involving acceptorless dehydrogenation coupling (ADC) has been proposed on the basis of DFT calculations and experimental evidence. Significantly, this manganese-based catalytic protocol provides a promising green and environmentally friendly route to a wide range of synthetically important substituted monocyclic, bicyclic as well as tricyclicN-heterocycles (including 50 quinoline and 26 pyridine examples) with isolated yields of up to 93%.
- Han, Mingyang,Lin, Qing,Liu, Qingbin,Liu, Song,Ma, Ning,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Yan, Xiuli
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p. 8026 - 8036
(2021/12/27)
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- Ligand-to-metal charge transfer of a pyridine surface complex on TiO2for selective dehydrogenative cross-coupling with benzene
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Dehydrogenative cross-coupling (DCC) between pyridine and benzene proceeded selectively using a TiO2 photocatalyst under visible light irradiation at optimized concentrations of the substrates. Visible light induces ligand-to-metal charge transfer (LMCT) between pyridine and a TiO2 surface to give a pyridine radical cation, which produces a pyridyl radical by its deprotonation or oxidation of another pyridine molecule. The pyridyl radical attacks a benzene ring to form an sp2C-sp2C bond and a hydrogen atom is subsequently removed to complete DCC. Selective excitation of the pyridine LMCT complex in the presence of an excess amount of benzene would be the key for higher selectivity. This journal is
- Hishitani, Shinichiro,Naniwa, Shimpei,Yamamoto, Akira,Yoshida, Hisao
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p. 11366 - 11373
(2021/05/31)
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- Reactions of organoplatinum complexes with dimethylamine-borane
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The reactions of dimethylamine-borane with platinum(ii) or platinum(iv) triflate complexes gave, not the anticipated σ-complexes, but the respective hydridoplatinum complexes. The reaction with [Pt(OTf)Me3(NN)], with NN = 2,2′-bipyridine (bipy) and 4,4′-di-t-butyl-2,2′-bipyridine (bu2bipy), gave the rare stable bridging hydridoplatinum(iv) complexes [μ-H{PtMe3(NN)}2][OTf] and the reaction with [Pt(O2CCF3)Me(NN)] gave the unstable hydridoplatinum(ii) complex [PtHMe(NN)]. The unstable hydridoplatinum(ii) complexes could be trapped by reaction with methyl acrylate by forming the insertion products [PtCl(CHMeCO2Me)(bipy)] and [Pt(CHMeCO2Me)2(bipy)]. The complex [PtCl(CHMeCO2Me)(bipy)] reacted with methyl iodide to give [PtClIMe(CHMeCO2Me)(bipy)], by cis oxidative addition, and the presence of two chiral centers in the product platinum(iv) complex allowed a detailed stereochemical pathway to be proposed. This journal is
- Puddephatt, Richard J.,Robinson, Shawn
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p. 14965 - 14972
(2021/09/04)
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- Base-Activated Latent Heteroaromatic Sulfinates as Nucleophilic Coupling Partners in Palladium-Catalyzed Cross-Coupling Reactions
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Heteroaromatic sulfinates are effective nucleophilic reagents in Pd0-catalyzed cross-coupling reactions with aryl halides. However, metal sulfinate salts can be challenging to purify, solubilize in reaction media, and are not tolerant to multi-step transformations. Here we introduce base-activated, latent sulfinate reagents: β-nitrile and β-ester sulfones. We show that under the cross-coupling conditions, these species generate the sulfinate salt in situ, which then undergo efficient palladium-catalyzed desulfinative cross-coupling with (hetero)aryl bromides to deliver a broad range of biaryls. These latent sulfinate reagents have proven to be stable through multi-step substrate elaboration, and amenable to scale-up.
- Blakemore, David C.,Cook, Xinlan A. F.,Moses, Ian B.,Pantaine, Lo?c R. E.,Sach, Neal W.,Shavnya, Andre,Willis, Michael C.
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supporting information
p. 22461 - 22468
(2021/09/09)
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- Palladium/Sensory Component-Catalyzed Homocoupling Reactions of Aryl Halides
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A novel and efficient catalyst system was developed for homocoupling reactions of aryl halides. The catalyst system consists of Pd(OAc) 2and the peppery sensory component of tobacco leaves. This is the first time that a sensory component has been used in an organic reaction. Experiments using the catalyst system showed that the reactions proceeded smoothly under air in the absence of both an additional ligand and a reductant. Furthermore, the catalyst system can be applied to the coupling reactions of hetaryl iodides. Many functional groups (including a hydroxy group) are tolerated.
- Bai, Haixin,Bao, Fengyu,Chai, Guobi,Liu, Pengfei,Liu, Zhikai,Zhang, Haiyan,Zhang, Qidong
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supporting information
(2020/09/09)
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- A Bio-Inspired Magnetically Recoverable Palladium Nanocatalyst for the Ullmann Coupling reaction of Aryl halides and Arylboronic acids In Aqueous Media
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Palladium nanoparticles supported on polydopamine-coated iron oxide nanoparticles (Pd/Fe3O4@PDA) were found to catalyze the Ullmann homocoupling of a wide variety of aryl halides, arylboronic acids and aryldiazonium salts in aqueous media in the presence of randomly methylated β-cyclodextrin (RM-β-CD). The synthesized nanoparticles were characterized by techniques such as TEM, SEM, EDX, XPS, ICP-AES and XRD. The synthesized catalyst can be easily recovered magnetically and reused up to five cycles without any significant loss of activity. This is the first report demonstrating the use of magnetically recoverable catalyst for Ullmann homocoupling reactions of aryl halides, arylboronic acids and aryldiazonium salts in water.
- Dubey, Abhishek V.,Kumar, A. Vijay
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- Convergent access to bis-1,2,4-triazinyl-2,2′-bipyridines (BTBPs) and 2,2′-bipyridines: Via a Pd-catalyzed Ullman-type reaction
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Multidentate, soft-Lewis basic, complexant scaffolds have displayed significant potential in the discrete speciation of the minor actinides from the neutron-absorbing lanthanides resident in spent nuclear fuel. Efforts to devise convergent synthetic strategies to targets of interest to improve liquid-liquid separation outcomes continue, but significant challenges to improve solubility in process-relevant diluents to effectively define meaningful structure-activity relationships remain. In the current work, a synthetic method to achieve the challenging 2,2′-bipyridine bond of the bis-1,2,4-triazinyl-2,2′-bipyridine (BTBP) complexant class leveraging a Pd-catalyzed Ullman-type coupling is reported. This convergent strategy improves upon earlier work focused on linear synthetic access to the BTBP complexant moiety. Method optimization, relevant substrate scope and application, as well as a preliminary mechanistic interrogation are reported herein.
- Carrick, Jesse D.,Waters, Gabrielle D.
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p. 10807 - 10815
(2020/03/27)
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- Synthesis of Pyridylsulfonium Salts and Their Application in the Formation of Functionalized Bipyridines
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An S-selective arylation of pyridylsulfides with good functional group tolerance was developed. To demonstrate synthetic utility, the resulting pyridylsulfonium salts were used in a scalable transition-metal-free coupling protocol, yielding functionalized bipyridines with extensive functional group tolerance. This modular methodology permits selective introduction of functional groups from commercially available pyridyl halides, furnishing symmetrical and unsymmetrical 2,2′- A nd 2,3′-bipyridines. Iterative application of the methodology enabled the synthesis of a functionalized terpyridine with three different pyridine components.
- Duong, Vincent K.,Horan, Alexandra M.,McGarrigle, Eoghan M.
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p. 8451 - 8457
(2020/11/12)
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- A Mild Method for Electrochemical Reduction of Heterocyclic N-Oxides
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Deoxygenation of heteroaromatic N-oxides is commonly accomplished using chemical or enzymatic methods. In this work, we report on an expedient protocol for electrochemical reduction of pyridine N-oxide derivatives under mild conditions. A diverse range of mono- and bis N-oxides were converted into the corresponding nitrogen bases in good yields. Importantly, the method is highly selective towards N-oxides and tolerates challenging halo and nitro substituents in the heteroaromatic ring.
- Fukazawa, Yasuaki,Rubtsov, Aleksandr E.,Malkov, Andrei V.
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supporting information
p. 3317 - 3319
(2020/05/25)
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- Catalyst-Free N-Deoxygenation by Photoexcitation of Hantzsch Ester
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A mild and operationally simple protocol for the deoxygenation of a variety of heteroaryl N-oxides and nitroarenes has been developed. A mixture of substrate and Hantzsch ester is proposed to result in an electron donor-acceptor complex, which upon blue-light irradiation undergoes photoinduced electron transfer between the two reactants to afford the products. N-oxide deoxygenation is demonstrated with 22 examples of functionally diverse substrates, and the chemoselective reduction of nitroarenes to the corresponding hydroxylamines is also shown.
- Cardinale, Luana,Jacobi Von Wangelin, Axel,Konev, Mikhail O.
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supporting information
(2020/02/15)
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- Green-Synthesized Nickel Nanoparticles on Reduced Graphene Oxide as an Active and Selective Catalyst for Suzuki and Glaser-Hay Coupling Reactions
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A mild and benign methodology to syntheses biaryls and 1,3-diynes has been demonstrated using the nickel nanoparticles supported on reduced graphene oxide (RGO-Ni) as a heterogeneous catalyst which is prepared using green reagents. A series of substituted biaryls and 1,3-diynes has been synthesised in good to excellent yields through C-C homocoupling reaction of arylboronic acids and terminal alkynes respectively using 1,4-dioxane as a benign solvent. The present ligand-free catalytic system proceeds smoothly under mild conditions, avoids noble and stoichiometric metal reagents and tolerates sensitive functional groups. Also has a wide substrate scope and feasible with other nitrogen and sulphur containing heteroaryl boronic acids. Hot filtration test unambiguously proves the true heterogeneity of the catalyst and which support for the further reusability of the catalyst for several times without any change in the activity. The easy preparation and simple magnetic separation, stability and reusability reveal that as-prepared RGO-Ni as a versatile catalyst for the synthesis of polyaromatic compounds both in academia and industries. Highlights: Green-synthesized RGO-Ni nanocomposite used as a heterogeneous catalyst for Suzuki type (C-C) and Glaser–Hay (C ≡ C) homocoupling coupling reactions. Ligand-free catalytic system and avoids noble and stoichiometric metal reagents Short reaction time with a minimum catalyst (nickel) loading RGO-Ni nanocomposite is highly stable, reusable, and magnetically retrievable.
- Murugan, Karthik,Nainamalai, Devarajan,Kanagaraj, Pavithara,Nagappan, Saravana Ganesan,Palaniswamy, Suresh
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- CuO grafted triazine functionalized covalent organic framework as an efficient catalyst for C-C homo coupling reaction
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Designing of low cost catalytic system for new C-C bond formation reactions is very challenging in synthetic organic chemistry. Herein, we report a new copper oxide immobilized covalent organic framework (COF) material CuII-TRIPTA by grafting of CuO nanoparticles at the surface of a nitrogen rich porous COF material TRIPTA. TRIPTA has been synthesized through the extended Schiff base reaction between 2,4,6-triformylphloroglucinol and 1,3,5-tris-(4-aminophenyl) triazine. The COF as well as CuO loaded materials are characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TG) and EPR spectroscopic analyses. CuII-TRIPTA material has been successfully applied as heterogeneous nanocatalyst for the C-C homo-coupling reaction of phenylboronic acids to synthesise wide range of biaryl compounds under mild and eco-friendly conditions (60 °C, methanol solvent). Remarkably high specific surface area of CuII-TRIPTA (583 m2 g?1) and highly accessible catalytic sites in the 2D-hexagonal COF nano-architecture potentially makes it excellent catalyst in the C-C bond formation reaction, which is evident from the high TON of the catalyst in this reaction. The catalyst was recollected and reused till 6th cycles without any noticeable change of its catalytic activity, suggesting its high catalytic efficiency in this C-C bond formation reaction.
- Das, Sabuj Kanti,Krishna Chandra, Bijan,Molla, Rostam A.,Sengupta, Manideepa,Islam, Sk. Manirul,Majee, Adinath,Bhaumik, Asim
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- Selective Formation of S4-and T-Symmetric Supramolecular Tetrahedral Cages and Helicates in Polar Media Assembled via Cooperative Action of Coordination and Hydrogen Bonds
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We report on the synthesis and self-assembly study of novel supramolecular monomers encompassing quadruple hydrogen-bonding motifs and metal-coordinating 2,2′-bipyridine units. When mixed with metal ions such as Fe2+ or Zn2+, the tetrahedron cage complexes are formed in quantitative yields and full diastereoselectivity, even in highly polar acetonitrile or methanol solvents. The symmetry of the complexes obtained has been shown to depend critically on the flexibility of the ligand. Restriction of the rotation of the hydrogen-bonding unit with respect to the metal-coordinating site results in a T-symmetric cage, whereas introducing flexibility either through a methylene linker or rotating benzene ring allows the formation of S4-symmetric cages with self-filled interior. In addition, the possibility to select between tetrahedral cages or helicates and to control the dimensions of the aggregate has been demonstrated with a three-component assembly using external hydrogen-bonding molecular inserts or by varying the radius of the metal ion (Hg2+ vs Fe2+). Self-sorting studies of individual Fe2+ complexes with ligands of different sizes revealed their inertness toward ligand scrambling.
- Shi, Qixun,Zhou, Xiaohong,Yuan, Wei,Su, Xiaoshi,Neni?kis, Algirdas,Wei, Xin,Taujenis, Lukas,Snarskis, Gustautas,Ward, Jas S.,Rissanen, Kari,De Mendoza, Javier,Orentas, Edvinas
-
supporting information
p. 3658 - 3670
(2020/03/06)
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- Nickel-Catalyzed Dehydrogenation of N-Heterocycles Using Molecular Oxygen
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Herein, an efficient and selective nickel-catalyzed dehydrogenation of five- and six-membered N-heterocycles is presented. The transformation occurs in the presence of alkyl, alkoxy, chloro, free hydroxyl and primary amine, internal and terminal olefin, trifluoromethyl, and ester functional groups. Synthesis of an important ligand and the antimalarial drug quinine is demonstrated. Mechanistic studies revealed that the cyclic imine serves as the key intermediate for this stepwise transformation.
- Banerjee, Debasis,Bera, Atanu,Bera, Sourajit
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supporting information
(2020/09/02)
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- METHOD FOR COUPLING HALOGENATED PYRIDINE COMPOUND WITH HALOGENATED AROMATIC COMPOUND
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There is a demand for the development of a technique according to which a reaction for coupling a halogenated pyridine compound with a halogenated aromatic compound can be performed in a simple manner through a small number of steps without using expensive agents such as a palladium catalyst. A method for coupling a halogenated pyridine compound with a halogenated aromatic compound includes a step of coupling a halogenated pyridine compound with a halogenated aromatic compound to obtain a pyridine compound by reacting, in a reaction solvent, the halogenated pyridine compound and the halogenated aromatic compound with a solution containing an alkali metal.
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Paragraph 0054; 0055
(2020/10/20)
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- Ligand-free palladium catalyzed Ullmann biaryl synthesis: 'Household' reagents and mild reaction conditions
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A palladium catalysed Ullmann biaryl synthesis has been developed using hydrazine hydrate as the reducing reagent at room temperature. The combination of Pd(OAc)2 and hydrazine hydrate works smoothly for the coupling of both electron-rich and electron-deficient aryl iodides, as well as hetero-aryl iodides, leading to a wide range of biaryls in good to excellent yields. The reaction requires only 1 mol% Pd(OAc)2 and the in situ generated palladium naoparticles are found to be active catalysts.
- Gong, Xinchi,Wu, Jie,Meng, Yunge,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
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supporting information
p. 995 - 999
(2019/03/12)
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- Aerobic and Ligand-Free Manganese-Catalyzed Homocoupling of Arenes or Aryl Halides via in Situ Formation of Aryllithiums
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Ligand-free manganese-catalyzed homocoupling of arenes or aryl halides can be carried out under aerobic conditions via the in situ formation of the corresponding aryllithiums. A wide range of biaryls and derivatives has been obtained, and a mechanism involving monomeric manganese-oxo complexes has been proposed on the basis of DFT calculations.
- Liu, Yujia,Bergès, Julien,Zaid, Yassir,Chahdi, Fouad Ouazzani,Van Der Lee, Arie,Harakat, Dominique,Clot, Eric,Jaroschik, Florian,Taillefer, Marc
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p. 4413 - 4420
(2019/03/26)
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- Dehydrogenative Synthesis of 2,2′-Bipyridyls through Regioselective Pyridine Dimerization
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2,2′-Bipyridyls have been utilized as indispensable ligands in metal-catalyzed reactions. The most streamlined approach for the synthesis of 2,2′-bipyridyls is the dehydrogenative dimerization of unfunctionalized pyridine. Herein, we report on the palladium-catalyzed dehydrogenative synthesis of 2,2′-bipyridyl derivatives. The Pd catalysis effectively works with an AgI salt as the oxidant in the presence of pivalic acid. A variety of pyridines regioselectively react at the C2-positions. This dimerization method is applicable for challenging substrates such as sterically hindered 3-substituted pyridines, where the pyridines regioselectively react at the C2-position. This reaction enables the concise synthesis of twisted 3,3′-disubstituted-2,2′-bipyridyls as an underdeveloped class of ligands.
- Yamada, Shuya,Kaneda, Takeshi,Steib, Philip,Murakami, Kei,Itami, Kenichiro
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supporting information
p. 8341 - 8345
(2019/04/30)
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- Preparation method of (S 2 2)-dipyridyl (S)-dipyridyl (S)-dipyridine
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The invention relates to a preparation method of bipyridine, in particular to a preparation method of 2, 2'-bipyridine. The method includes: taking pyridine as the raw material, adopting supported nickel as the catalyst, carrying out dehydrogenation coupling reaction on pyridine under certain conditions, then conducting filtration, distillation, washing, chromatography, recrystallization and other separation steps to purify the product, thus obtaining a 2, 2'-bipyridine product. Compared with the traditional direct coupling method and halogen method, the method provided by the invention is safe and convenient for operation, and is environment-friendly.
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Paragraph 0044-0062
(2019/10/22)
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- Nickel-Catalyzed Alkylation of Ketone Enolates: Synthesis of Monoselective Linear Ketones
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Herein we have developed a Ni-catalyzed protocol for the synthesis of linear ketones. Aryl, alkyl, and heteroaryl ketones as well as alcohols yielded the monoselective ketones in up to 90% yield. The catalytic protocol was successfully applied in to a gram-scale synthesis. For a practical utility, applications of a steroid derivative, oleyl alcohol, and naproxen alcohol were employed. Preliminary catalytic investigations involving the isolation of a Ni intermediate and defined Ni-H species as well as a series of deuterium-labeling experiments were performed.
- Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
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p. 769 - 779
(2019/01/24)
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- Unsymmetrical triazolyl-naphthyridinyl-pyridine bridged highly active copper complexes supported on reduced graphene oxide and their application in water
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A novel unsymmetrical triazolyl-naphthyridinyl-pyridine ligand was designed and synthesized, and employed in the synthesis of a heterogeneous copper complex on reduced graphene oxide. The resulting copper composite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX). This supported copper catalyst containing unsymmetrical triazolyl-naphthyridinyl-pyridine (only 0.1 mol%) showed excellent catalytic activity in water with good recyclability. Various functionalized quinoline derivatives were successfully synthesized in high yields through the green strategy in water. Other heterocyclic compounds, such as pyridine, 2-(pyridin-2-yl)quinoline, 1,8-naphthyridine, 5,6-dihydronaphtho[1,2-b][1,8]naphthyridine and 2-(pyridin-2-yl)-1,8-naphthyridine derivatives, were achieved in water with more than 80% yields. Mechanism studies revealed that this transformation occurs via dehydrogenation, condensation, and transfer hydrogenation and dehydrogenation processes which was supported by a deuterium labeling experiment.
- Hu, Wenkang,Zhang, Yilin,Zhu, Haiyan,Ye, Dongdong,Wang, Dawei
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supporting information
p. 5345 - 5351
(2019/10/11)
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- Nonsymmetrical Bis-Azine Biaryls from Chloroazines: A Strategy Using Phosphorus Ligand-Coupling
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Distinct approaches to synthesize bis-azine biaryls are in demand as these compounds have multiple applications in the chemical sciences and are challenging targets for metal-catalyzed cross-coupling reactions. Most approaches focus on developing new reagents as the formal nucleophilic coupling partner that can function in metal-catalyzed processes. We present an alternative approach using pyridine and diazine phosphines as nucleophilic partners and chloroazines where the heterobiaryl bond is formed via a tandem SNAr-phosphorus ligand-coupling sequence. The heteroaryl phosphines are prepared from chloroazines and are bench-stable solids. A range of bis-azine biaryls can be formed from abundant chloroazines using this strategy that would be challenging using traditional approaches. A one-pot cross-electrophile coupling of two chloroazines is feasible, and we also compared the phosphorus-mediated strategy with metal-catalyzed coupling reactions to show advantages and compatibility.
- Boyle, Benjamin T.,Hilton, Michael C.,McNally, Andrew
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supporting information
p. 15441 - 15449
(2019/11/02)
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- METHOD FOR SYNTHESIZING BIPYRIDINE COMPOUND AND METHOD FOR MANUFACTURING PYRIDINE COMPOUND
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A target bipyridine compound is synthesized with high purity and a high yield in a simple and safe manner in a short period of time. A method for synthesizing a di-tert-butyl-2,2′-bipyridine compound is provided, and the method includes a step of reacting, in a reaction solvent, a tert-butylpyridine compound with a dispersion product obtained by dispersing an alkali metal in a dispersion solvent. A method for synthesizing a bipyridine compound having no substituents is also provided, and the method includes a step of reacting, in a reaction solvent, pyridine with a dispersion product obtained by dispersing an alkali metal in a dispersion solvent.
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-
Paragraph 0060; 0139-0142
(2018/10/21)
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- WEPA: a bio-derived medium for added base, π-acid and ligand free Ullmann coupling of aryl halides using Pd(OAc)2
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A bio-derived sustainable medium based on water extract of pomegranate ash (WEPA) has, for the first time, been developed for the homocoupling of aryl halides under palladium-assistance. Avoiding the requirement of an external base, ligand and π-acid, the use of the proposed renewable medium offers remarkable attributes like wide substrate scope, good to nearly quantitative yields of biphenyls with exceptional chemoselectivity and scale up viability.
- Lakshmidevi, Jangam,Appa, Rama Moorthy,Naidu, Bandameeda Ramesh,Prasad, S. Siva,Sarma, Loka Subramanyam,Venkateswarlu, Katta
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supporting information
p. 12333 - 12336
(2018/11/30)
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- Dimerization of Aromatic Compounds Using Palladium-Carbon-Catalyzed Suzuki-Miyaura Cross-Coupling by One-Pot Synthesis
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The aromatic dimers play a significant role in many aspects. Herein, we report a simple palladium-carbon catalyst that is highly effective for the dimerization of brominated aromatic compounds under mild conditions using abundant brominated aromatic compounds, bis(pinacolate)diboron and potassium acetate by a 'one-pot' method. This process, which we believe proceeds via a Suzuki-Miyaura cross-coupling reaction mechanism, allows access to a variety of aromatic compounds under mild reaction conditions and has a good functional group tolerance with moderate to high yields.
- Du, Fangyu,Zhou, Qifan,Liu, Dongdong,Fang, Ting,Shi, Yajie,Du, Yang,Chen, Guoliang
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supporting information
p. 779 - 784
(2018/02/09)
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- Structural and Synthetic Insights into Pyridine Homocouplings Mediated by a β-Diketiminato Magnesium Amide Complex
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The reaction of [(DippNacnac)Mg(TMP)] (1) with 4-subtituted pyridines proceeds via sequential regioselective metallation and 1,2-addition to furnish a range of symmetric 4,4′-R2-2,2′-bipyridines in good yield, representing a new entry into bipyridine synthesis. Interestingly, the reaction of 1 with 2-OMe-pyridine led to formation of asymmetric bipyridine 6, resulting from the C6-magnesiation of the heterocycle followed by a C?C coupling step by addition to the C2 position of a second, non-metallated molecule, and subsequent elimination of [DippNacnacMgOMe]2 (7). Synthesis combined with spectroscopic and structural analysis help rationalise the underlying processes resulting in the observed reactivity, and elucidate the key role that the sterically encumbered β-diketiminate ligand plays in determining regioselectivity.
- Davin, Laia,Clegg, William,Kennedy, Alan R.,Probert, Michael R.,McLellan, Ross,Hevia, Eva
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supporting information
p. 14830 - 14835
(2018/09/25)
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- Method for preparing 2,2'-bipyridine and its derivatives
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The invention discloses a method for preparing 2,2'-bipyridine and its derivatives. The method is characterized in that the 2,2'-bipyridine represented by formula II is generated through dehydrogenation coupling of pyridine represented by formula I, or its derivative, in the presence of an additive under the action of a supported catalyst, wherein R in the formula I and the formula II is H, a C1-C2 alkyl group, Cr or Br. The method has the advantages of extensive applicability of the raw material, high atom utilization rate, and high activity, long life and few byproducts in the catalyst.
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-
Paragraph 0042-0045; 0048; 0051
(2018/06/15)
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- A mild and efficient H2O2 oxygenation of N-heteroaromatic compounds to the amine N-oxides and KI deoxygenation back to the tertiary amine with hexaphenyloxodiphosphonium triflate
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A mild and efficient method for the oxidation of N-heteroaromatic compounds to the corresponding N-oxides using H2O2 in the presence of hexaphenyloxodiphosphnium triflate (Hendrickson reagent) in EtOH at room temperature was reported. This methodology presented relatively fast and selective reactions to afford the N-oxides in good yields. The reverse reactions, deoxygenation reactions, were also carried out under the same reaction conditions by KI to produce the tertiary amines.
- Khodaei, Mohammad Mehdi,Alizadeh, Abdolhamid,Hezarkhani, Hadis Afshar
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p. 1843 - 1849
(2018/07/06)
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- Immobilization of an Aminobisphosphine–PdII Complex over Graphene Oxide: An Efficient and Reusable Catalyst for Suzuki–Miyaura, Ullmann Coupling and Cyanation Reactions
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The grafting of an aminobis(phosphine)–PdII complex (PNP–PdII) [PdCl2{(Ph2P)2N(CH2)3Si(OMe)3}] (2) on graphene oxide (GO) has been carried out by a condensation reaction between methoxysilane groups of 2 and hydroxyl groups of GO. The composite material was characterized by FTIR spectroscopy, solid-state 31P NMR spectroscopy, SEM, TEM, XPS and ICP-AES techniques. All these tools support the clean immobilization of compound 2 on GO. The composite material showed high catalytic activity in Suzuki–Miyaura, Ullmann coupling and cyanation reactions. The heterogeneity of the composite was confirmed by a hot filtration test. The immobilized PNP–PdII shows comparable activity to its homogeneous analogue 2. The recycling ability of the catalyst was examined for five consecutive runs, which showed little or no reduction in its catalytic efficiency.
- Sengupta, Debasish,Pandey, Madhusudan K.,Mondal, Dipanjan,Radhakrishna, Latchupatula,Balakrishna, Maravanji S.
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p. 3374 - 3383
(2018/05/08)
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- Visible-Light Photocatalyzed Deoxygenation of N-Heterocyclic N-Oxides
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A scalable and operationally simple method is described that allows for the chemoselective deoxygenation of a wide range of N-heterocyclic N-oxides (a total of 36 examples). This visible-light-induced protocol features the use of only commercially available reagents, room-temperature conditions, and unprecedented chemoselective removal of the oxygen atom in a quinoline N-oxide in the presence of a pyridine N-oxide in the same molecule through the judicious selection of a photocatalyst.
- Kim, Kyu Dong,Lee, Jun Hee
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supporting information
p. 7712 - 7716
(2019/01/03)
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- Perfluorocyclopentadienyl Radical Derivative as an Organocatalyst for Oxidative Coupling of Aryl- and Thienylmagnesium Compounds under Atmospheric Oxygen
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The oxidative homocoupling reaction of Grignard reagents in the presence of atmospheric oxygen molecules proceeded in the presence of a heptafluorotolyl-substituted perfluorocyclopentadienyl radical. The turnover number (TON) was over 30 for the coupling reactions of PhMgBr to give biphenyl. The organocatalyst could couple thienylmagnesium compounds to give bithiophene derivatives in up to 94% yield. Furthermore, a gram-scale synthesis of 6,6'-dimethoxybiphenyl-2,2'-diyl-bis(phosphonic acid diethyl ester) was demonstrated. Stabilization of the phenyl radical for the inhibition of the side reaction was also considered using DFT calculations.
- Korenaga, Toshinobu,Nitatori, Kaoru,Muraoka, Hiroki,Ogawa, Satoshi,Shimada, Kazuaki
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p. 4835 - 4839
(2018/04/26)
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- Production technology of 2,2'-bipyridine
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The invention discloses a production technology of 2,2'-bipyridine, and belongs to the field of chemical synthesis. The production technology comprises the following steps: with acetonitrile and acetylene as starting raw materials, performing cyclization under the catalysis of bis(cyclopentadienyl) cobalt to produce 2-methylpyridine, then performing a reaction on the 2-methylpyridine and ammonia gas under the catalysis of tetraphenylporphyrin cobalt to produce 2-cyanopyridine, and finally performing cyclization on the 2-cyanopyridine and acetylene under the catalysis of bis(cyclopentadienyl) cobalt to produce the 2,2'-methylpyridine. The production technology is safe and low in cost, few solid, liquid and gas wastes are produced, and the production technology is suitable for industrial production.
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Paragraph 0029; 0030; 0034; 0039
(2018/11/03)
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- Accessing Heterobiaryls through Transition-Metal-Free C-H Functionalization
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Herein we report a transition-metal-free synthetic protocol for heterobiaryls, one of the most important pharmacophores in the modern drug industry, employing a new multidonor phenalenyl (PLY)-based ligand. The current procedure offers a wide substrate scope (24 examples) with a low catalyst loading resulting in an excellent product yield (up to 95%). The reaction mechanism involves a single electron transfer (SET) from a phenalenyl-based radical to generate a reactive heteroaryl radical. To establish the mechanism, we have isolated the catalytically active SET initiator, characterizing by a magnetic study.
- Banik, Ananya,Paira, Rupankar,Shaw, Bikash Kumar,Vijaykumar, Gonela,Mandal, Swadhin K.
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p. 3236 - 3244
(2018/03/23)
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- Diflunisal-adjoined cobalt(iii)-polypyridyl complexes as anti-cancer stem cell agents
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We report a novel series of cobalt(iii)-polypridyl complexes, 4-6, that can selectively release diflunisal, a nonsteroidal anti-inflammatory drug, under reducing conditions. Remarkably, the 1,10-phenanthroline-bearing complex 5 displays selective potency towards hard-to-kill cancer stem cells (CSCs) (IC50 = 2.1 ± 0.1 μM) over bulk cancer (IC50 = 3.9 ± 0.2 μM) and normal cells (IC50 = 21.2 ± 1.3 μM). This complex induces CSC apoptosis by DNA damage and cyclooxygenase-2 inhibition.
- Abe, David O.,Eskandari, Arvin,Suntharalingam, Kogularamanan
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supporting information
p. 13761 - 13765
(2018/10/20)
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- Visible-light photoexcitation of pyridine surface complex, leading to selective dehydrogenative cross-coupling with cyclohexane
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Upon photoirradiation with visible light, a pyridine molecule adsorbed on a TiO2 surface can be photoexcited to give a pyridine radical cation via ligand-to-metal charge transfer (LMCT) between pyridine and titanium. This leads to dehydrogenative cross-coupling (DCC) between pyridine and cyclohexane with concomitant hydrogen evolution. Since the radical cation can selectively oxidize cyclohexane to a cyclohexyl radical, the cross-coupling between pyridine and cyclohexane proceeds with higher selectivity compared with that in photocatalysis by TiO2 under UV irradiation.
- Naniwa, Shimpei,Tyagi, Akanksha,Yamamoto, Akira,Yoshida, Hisao
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p. 28375 - 28381
(2018/11/30)
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- Csp2-Br bond activation of Br-pyridine by neophylpalladacycle: Formation of binuclear seven-membered palladacycle and bipyridine species
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In this work, the synthesis and reactivity of seven-membered palladacycles are described, and a novel bi-pyridine synthesis in a catalytic pathway is reported. Neophyl-palladacycle(i) reacts with an excess of 2-Br-pyridine, giving the desired new binuclear seven-membered palladacycle (1) and unexpectedly, a bipyridine complex, [Pd(BiPy)Br2]. ESI-HRMS experiments show that fragmentation of the Pd-Br bond in 1 can take place producing unusual two coordinated Pd(ii) molecular ions, [Pd(NeoPyR)]+.
- Nicasio-Collazo, Juan,Wrobel, Katarzyna,Wrobel, Kazimierz,Serrano, Oracio
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supporting information
p. 8729 - 8733
(2017/08/29)
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- Palladium-Catalyzed Directed Halogenation of Bipyridine N-Oxides
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The palladium-catalyzed directed C-H halogenation of bipyridine N-oxides was investigated. Using NCS or NBS (N-chloro- or N-bromosuccinimide) and 5 mol % Pd(OAc)2 in chlorobenzene (0.10 molar) at 110 °C, pyridine-directed functionalization took place and 3-chloro- or 3-bromobipyridine N-oxides were obtained in high yields. The reaction is sensitive to steric hindrance by 4- and 6′-substituents. Only in the latter case, where coordination of palladium by the pyridine is hindered, 3′-halogenation directed by the N-oxide function was observed. The halogenated products were deoxygenated by PCl3 or PBr3.
- Zucker, Sina P.,Wossidlo, Friedrich,Weber, Manuela,Lentz, Dieter,Tzschucke, C. Christoph
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p. 5616 - 5635
(2017/06/07)
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- MANUFACTURING METHOD OF BIPYRIDYL COMPOUND
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PROBLEM TO BE SOLVED: To provide various bipyridyl compounds by a reaction less in process number with a relief condition and short time. SOLUTION: A compound represented by the general formula, where Y represents a hydrogen atom or a nitrogen atom, R1 represents a cyano group, a halogen atom, an alkyl group which may be substituted, an alkoxy group which may be substituted, an aryl group which may be substituted, a heteroaryl group which may be substituted or a silyl group which may be substituted, n represents an integer of 0 to 4 and 2 R1 binding same benzene ring may bind each other to form a ring when n is 2 or more. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0081-0087; 0092-0095; 0100-0102
(2017/09/16)
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- Molybdenum-Catalyzed Deoxygenation of Heteroaromatic N-Oxides and Hydroxides using Pinacol as Reducing Agent
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A molybdenum-catalyzed deoxygenation of pyridine N-oxides and N-hydroxybenzotriazoles, as well as other azole N-oxides, has been developed using pinacol as an environmentally friendly oxo-acceptor. The only by-products are acetone and water making the process a convenient alternative to established protocols in terms of waste generation. The reaction is highly chemoselective and a variety of functional groups are tolerated. The processes are usually very clean allowing the isolation of the pure deoxygenated products after a simple extraction in most cases. (Figure presented.).
- Rubio-Presa, Rubén,Fernández-Rodríguez, Manuel A.,Pedrosa, María R.,Arnáiz, Francisco J.,Sanz, Roberto
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supporting information
p. 1752 - 1757
(2017/05/22)
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- A 2, 2' - bipyridyl preparation method
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The invention discloses a preparation method of 2, 2'-bipyridyl. In the preparation method, with a manganese salt or a cobalt salt as a catalyst, 2-chloropyridine Grignard reagent reacts with 2-chloropyridine to produce the 2, 2'-bipyridyl. The invention further discloses a method for performing Grignard reaction and coupling reaction with the 2-chloropyridine as a raw material by one-pot method to produce the final 2, 2'-bipyridyl. The preparation method of the 2, 2'-bipyridyl has the advantages of easily available raw materials, inexpensive and stable catalyst, environmental protection, and being low in cost, and simple and convenient to operate; by the preparation method, needs of large-scale industrial production can be met; the preparation method has a wide market prospect.
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Paragraph 0030; 0031
(2017/08/26)
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- Synthesis of 2-phenyl pyridine derivatives from aryl ketones and 1,3-diaminopropane using palladium acetate as a catalyst
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A simple and efficient method for the synthesis of 2-phenyl pyridine via cyclization of aryl ketone with 1,3-diaminopropane using palladium acetate is established. This method is mild, operationally simple, involves short reaction time and involves easy workup procedure to afford the corresponding 2-phenyl pyridines in moderate to good yield.
- Ghodse, Shrikant M.,Telvekar, Vikas N.
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supporting information
p. 524 - 526
(2017/01/17)
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- Synthetic method for 2,2'-bipyridine
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The invention specifically relates to a synthetic method for 2,2'-bipyridine, belonging to the field of chemical industrial synthesis. The synthetic method comprises the following successive steps: (1) reacting cyclooctadiene with anhydrous cobalt chloride under the catalysis of sodium amide (or metallic sodium) so as to produce cyclooctadiene-cyclopentadienyl cobalt which is a catalyst with high activity; and (2) reacting 2-cyanopyridine with acetylene gas under the catalysis of cyclooctadiene-cyclopentadienyl cobalt so as to produce 2,2'-bipyridine.
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Paragraph 0022-0023
(2017/09/01)
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