- Isolation and X-Ray Crystal Structure of a Novel Dihydroterpyridine Dimer formed via an Anionic Cycloaddition
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The identity of a novel dimer (2), isolated as a by-product from the reaction of 2-lithiopyridine with 2,2'-bipyridine, has been assigned on the basis of X-ray crystal structure analysis.
- Newkome, George R.,Hager, David C.,Fronczek, Frank R.
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- An improved, two-step synthesis of 2,2′:6′,2″-terpyridine
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The important tridentate ligand 2,2′:6′,2″-terpyridine has been synthesized in two steps in an overall yield of 47%. The reaction can be scaled up to provide multigram quantitites of the ligand.
- Jameson, Donald L.,Guise, Lisa E.
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- A new approach to symmetric 2,2':6',2'-terpyridines
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A novel four step process for the preparation of symmetric terpyridines is presented. The title compound, 2,2':6',2'-terpyridine (1a) and a substituted derivative, 5,5'-dimethyl-2,2':6',2'-terpyridine (1b) are prepared. Both 1a and 1b share a common precursor, 2,6-diacetylpyridine (2) and are prepared in overall yields of 73 and 93% respectively. The purities of the crude terpyridine products are in the 90-95% range.
- Adrian Jr., James C.,Hassib, Lamyaa,De Kimpe, Norbert,Keppens, Marian
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- New Approaches to the Synthesis of 2,2′: 6′,2″-Terpyridine and Some of Its Derivatives
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A new two-step procedure has been developed for the synthesis of 2,2′: 6′,2″-terpyridine and 4′-methylsulfanyl-2,2′: 6′,2″-terpyridine in more than 70% yield on the basis of Potts’ condensation. Efficient methods have been proposed for purification of all condensation products.
- Zamalyutin,Bezdenezhnykh,Nichugovskiy,Flid
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- Syntheses, crystal structures, luminescence and thermal properties of three lanthanide complexes with 2-bromine-5-methoxybenzoate and 2,2:6′,2″-terpyridine
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Three new mononuclear lanthanide complexes [Ln(2-Br-5-MOBA)3(terpy)(H2O)] (Ln = Gd (1), Tb (2), Er (3); 2-Br-5-MOBA = 2-bromine-5-methoxybenzoate; terpy = 2,2:6′,2″-terpyridine) have been successfully synthesized and characterized by single-crystal X-ray diffraction. The complexes 1–3 were isostructural and eight-coordinated, which is different from the binuclear structure of the previously reported complexes. The molecular structure of complexes 1–3 is very interesting: two adjacent mononuclear units are connected through hydrogen bonding giving rise to a pseudo binuclear structure. These pseudo binuclear units are further linked via O–H?Br hydrogen bonds and slightly offset π–π stacking interactions to from 1D and 2D supramolecular structures. The thermal decomposition mechanism of complexes 1–3 was studied by TG analysis and further authenticated by TG/DSC-FTIR techniques. The solid-state luminescent property of complex 2 was investigated at room temperature. The result indicates that Tb (III) complex appear to be promising candidate for the application as green luminescent material.
- Zhao, Qing-Qing,Ren, Ning,Zhang, Jian-Jun
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- Complexing Equilibria and Redox Potentials of the Ag(II)/Ag(I) System in the Presence of 2,2':6',2''-Terpyridine in Water
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The conditional protonation constants (μ = 0.1) for 2,2':6',2''-terpyridine, log K1 = 4.93, log K2 = 3.69, were determined by the pH-metric method.The compositions of complexes of Ag2+ and Ag+ ions with 2,2':6',2''-terpyridine (tp) were studied and equilibria of the complex formation process were described.The values of conditional complex formation constants are as follows: for Ag(tp)2+: log β01 = 5.79, log β02 = 9.68, for Ag(tp)22+: log β02 = 25.31, while the conditional constant of the Ag(tp)NO3 precipitate formation is : KSO = 2.45*104.Using coulometric and chronovoltamperometric measurements, the redox systems being formed in the complex solutions of Ag(II) and Ag(I) were determined and described including their formal potentials. - Keywords: Chronovoltammetry; Formal potential; pH-metry; Redox systems with silver ions; Silver complexes
- Ignaczak, Maksymilian,Grzejdziak, Andrzej,Olejniczak, Barbara
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- Studies on organometallic compounds. IX. Synthesis of bipyridine N-oxides and terpyridines by palladium catalyzed cross-coupling reaction of trimethylstannylpyridines with bromopyridines
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Reaction of trimethylstannylpyridines with bromopyridines in the presence of Pd(PPh3)4 directed toward a practical use was accomplished, giving all nine pyridinylpyridine N-oxides in satisfactory yields. Similarly, nicotelline and 2,2′:6′,2″-terpyridine were produced in good yields.
- Yamamoto, Yutaka,Tanaka, Takuo,Yagi, Masayoshi,Inamoto, Masayuki
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- Synthesis, Characterization, and DFT Analysis of Bis-Terpyridyl-Based Molecular Cobalt Complexes
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Terpyridine ligands are widely used in chemistry and material sciences owing to their ability to form stable molecular complexes with a large variety of metal ions. In that context, variations of the substituents on the terpyridine ligand allow modulation of the material properties. Applying the Stille cross-coupling reaction, we prepared with good yields a new series of terpyridine ligands possessing quinoline-type moieties in ortho, meta, and para positions and dimethylamino substituents at central or distal positions. The corresponding cobalt(II) complexes were synthesized and fully characterized by elemental analysis, single-crystal X-ray crystallography, mass spectrometry, and UV-vis, 1H NMR, and Fourier transform infrared (FT-IR) spectroscopy as well as by cyclic voltammetry (CV). Density functional theory (DFT) calculations were performed to investigate the electronic structure of all the Co(II) bis-terpyridyl molecular complexes. In this work, we show that terpyridine ligand functionalization allows tuning the redox potentials of the Co(III)/Co(II), Co(II)/Co(I), and Co(I)/Co(I) (tpy)?- couples over a 1 V range.
- Aroua, Safwan,Todorova, Tanya K.,Hommes, Paul,Chamoreau, Lise-Marie,Reissig, Hans-Ulrich,Mougel, Victor,Fontecave, Marc
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- A new and simple 'LEGO' system for the synthesis of 2,6-oligopyridines
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The condensation of α-arylglyoxals with carboxamidrazones 1 - 2 is the best method for the synthesis of aryl or hetaryl substituted 1,2,4-triazines 3 - 4. These 1,2,4-triazines can be easily transformed to pyridines by [4+2] cycloaddition with bicyclo[2.2.1]hepta-2,5-diene followed by [4+2] cycloreversions of nitrogen and cyclopentadiene. This reaction sequence offers a new, simple and general access to 2,6-oligopyridines 8 - 11.
- Pabst, Gunther R.,Sauer, Juergen
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- Convenient one-pot procedures for the synthesis of 2,2′:6′, 2″-terpyridine
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One-pot reactions to produce 2,2′:6′,2″-terpyridine (tpy) under mild conditions are described under both solventless and solvent-assisted conditions. Tpy can be obtained in 32% yield in a simple one-pot reaction, which can readily be scaled-up to give large quantities of tpy. These new approaches are superior to those previously described because of the fast and efficient synthesis and purification of tpy. Copyright Taylor & Francis Group, LLC.
- Cooke, Michael W.,Wang, Jianhua,Theobald, Isabelle,Hanan, Garry S.
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- A Mitochondrion-Localized Two-Photon Photosensitizer Generating Carbon Radicals Against Hypoxic Tumors
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The efficacy of photodynamic therapy is typically reliant on the local concentration and diffusion of oxygen. Due to the hypoxic microenvironment found in solid tumors, oxygen-independent photosensitizers are in great demand for cancer therapy. We herein report an iridium(III) anthraquinone complex as a mitochondrion-localized carbon-radical initiator. Its emission is turned on under hypoxic conditions after reduction by reductase. Furthermore, its two-photon excitation properties (λex=730 nm) are highly desirable for imaging. Upon irradiation, the reduced form of the complex generates carbon radicals, leading to a loss of mitochondrial membrane potential and cell death (IC50light=2.1 μm, IC50dark=58.2 μm, PI=27.7). The efficacy of the complex as a PDT agent was also demonstrated under hypoxic conditions in vivo. To the best of our knowledge, it is the first metal-complex-based theranostic agent which can generate carbon radicals for oxygen-independent two-photon photodynamic therapy.
- Chao, Hui,Chen, Yu,Ji, Liangnian,Kuang, Shi,Liao, Xinxing,Rees, Thomas W.,Sun, Lingli,Zeng, Leli,Zhang, Xianrui,Zhang, Xiting
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- 4,4″-disubstituted terpyridines and their homoleptic FeII complexes
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A novel synthetic route to 4,4″-disubstituted-2,2′:6′, 2″-terpyridine ligands by Suzuki-Miyaura cross-coupling was elaborated by synthesizing compounds 4a-5c. The considerable stability of 4-substituted lithium triisopropyl 2-pyridylborates 2a-c, which are less prone to protodeboronation than similarly functionalized neutral boronic acid derivatives, enabled this synthetic route. The terpyridine core structure was further functionalized by exposing 4,4″-dichloroterpyridine (4b) to Suzuki coupling conditions to yield 4,4″-diarylterpyridines 5a-c. Homoleptic FeII complexes 8a-f of the reported terpyridine ligands were formed quantitatively, which demonstrates the lack of steric repulsion of substituents at the 4- and 4″-positions during complexation. The solid-state structures of particular ligands and FeII complexes were analyzed by single-crystal X-ray crystallography. UV/Vis absorption data for the Fe II complexes are also provided to complement the results reported here. A novel synthetic route to terpyridine ligands is reported. Pyridine building blocks are interlinked by Suzuki-Miyaura cross-coupling reactions. The potential of the method is demonstrated by assembling the 4,4″- disubstituted terpyridine ligands shown, which are subsequently converted into their homoleptic FeII complexes. Copyright
- Harzmann, Gero D.,Neuburger, Markus,Mayor, Marcel
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- Method for large-scale production α, α, α .
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The invention discloses a method for large-scale production α, α, α . The reaction operation in Step a was as follows: At room temperature 2 - acetyl pyridine was added. Then N mL of N -dimethyl formamide dimethyl acetal and a catalyst are added to the organic solvent, and after the reaction is completed, the reaction solution is poured into an aqueous sodium hydroxide solution, and then the resulting organic phase is washed, dried, concentrated and recrystallized to obtain an intermediate: 1 - (3 - pyridyl) -3 - (dimethylamino) -2 - propylene -1 - ketone. The method disclosed by the invention is easy to implement large-scale production, high in yield, low in cost, simple to operate and mild in reaction condition.
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Paragraph 0030; 0043-0051
(2021/09/08)
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- Design and photophysical studies of iridium(iii)-cobalt(iii) dyads and their application for dihydrogen photo-evolution
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We report several new dyads constituted of cationic iridium(iii) photosensitizers and cobalt(iii) catalyst connected via free pendant pyridine on the photosensitizers. These dyads were studied by X-ray crystallography, electrochemistry, absorption and emission spectroscopy as well as theoretical calculations and were shown to efficiently produce H2 under visible light irradiation. In every case, the dyad outperformed the equivalent system without a pendant pyridine. The dependence between irradiation wavelength and photocatalytic performances was also studied, with H2 being evolved with turn-over numbers up to 295, 251, 188 and 78 molH2 molPS-1 under blue, green, yellow and red light, respectively.
- Lentz, Cédric,Schott, Olivier,Auvray, Thomas,Hanan, Garry S.,Elias, Benjamin
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supporting information
p. 15567 - 15576
(2019/11/03)
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- Preparation method for terpyridine pyridinium complex and application thereof in reverse transcriptase inhibition
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The invention belongs to the field of research and development of HIV inhibitors, and discloses a preparation method for a terpyridine pyridinium (II) complex and application thereof in HIV reverse transcriptase inhibition. The structure of a cationic moiety of the terpyridine pyridinium (II) complex is as shown in a formula I. A preparation process for the terpyridine pyridinium (II) complex is optimized, the raw material cost is low, and the reaction time is short. The obtained complex is high in purity and yield and has good water solubility and excellent spectral properties. The terpyridine pyridinium (II) complex has the capability of selective binding to a TAR region on HIV RNA, and can block the reverse transcription process of viral RNA by reverse transcriptase and inhibit the replication of viral RNA. The terpyridine pyridinium (II) complex is a highly affinitive HIV RNA selective binding reagent and a highly active HIV reverse transcriptase inhibitor, and is an HIV drug having a great application potential.
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- Radical Hydrodehalogenation of Aryl Bromides and Chlorides with Sodium Hydride and 1,4-Dioxane
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A practical method for radical chain reduction of various aryl bromides and chlorides is introduced. The thermal process uses NaH and 1,4-dioxane as reagents and 1,10-phenanthroline as an initiator. Hydrodehalogenation can be combined with typical cyclization reactions, proving the nature of the radical mechanism. These chain reactions proceed by electron catalysis. DFT calculations and mechanistic studies support the suggested mechanism.
- Hokamp, Tobias,Dewanji, Abhishek,Lübbesmeyer, Maximilian,Mück-Lichtenfeld, Christian,Würthwein, Ernst-Ulrich,Studer, Armido
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supporting information
p. 13275 - 13278
(2017/10/09)
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- Attachment of a RuII Complex to a Self-Folding Hexaamide Deep Cavitand
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We report the design, synthesis and characterization of a new RuII metallocavitand that is catalytically active in alkene epoxidation reactions. The elaboration of the resorcin[4]arene's aromatic cavity produced a self-folding, deep hexaamide cavitand featuring a single diverging terpyridine (tpy) group installed at its upper rim. The construction of the metallocavitand involved the initial chelation of a RuIII chloride complex by the tpy ligand followed by the incorporation of 2-(phenylazo)pyridine (azpy) as an ancillary ligand. The resulting RuII chloro complex was converted into the catalytically active aqua counterpart by a ligand exchange process.
- Korom, Sa?a,Ballester, Pablo
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p. 12109 - 12112
(2017/09/12)
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- Solution, structural and photophysical aspects of substituent effects in the N^N ligand in [Ir(C^N)2(N^N)]+ complexes
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The syntheses and properties of a series of eleven new [Ir(ppy) 2(N^N)][PF6] complexes (Hppy = 2-phenylpyridine) are reported. The N^N ligands are based on 2,2-bipyridine (bpy), substituted in the 6- or 5-positions with groups that are structurally and electronically diverse. All but two of the N^N ligands incorporate an aromatic ring, designed to facilitate intra-cation face-to-face π-interactions between the N^N and one [ppy]- ligand. Within the set of ligands, 6-(3-tolyl)-2,2′- bipyridine (5), 4,6-bis(4-nitrophenyl)-2,2′-bipyridine (9), and 4,6-bis(3,4,5-trimethoxyphenyl)-2,2′-bipyridine (10) are new and their characterization includes single crystal structures of 9, and two polymorphs of 10. A representative [Ir(ppy)2(N^O)]+ complex is also described. We report solution NMR spectroscopic, photophysical and electrochemical properties of the complexes, as well as representative solid-state structural data. The solution 1H NMR spectroscopic data illustrate different dynamic processes involving the substituents attached to the bpy domain in the ligands. In degassed MeCN and at room temperature, the [Ir(ppy)2(N^N)][PF6] complexes are orange emitters with λemmax in the range 575 to 608 nm; however, quantum yields are very low. The most promising complexes were evaluated in light-emitting electrochemical cells leading to bright and stable devices with rather good external quantum efficiencies.
- Constable, Edwin C.,Housecroft, Catherine E.,Kopecky, Peter,Martin, Colin J.,Wright, Iain A.,Zampese, Jennifer A.,Bolink, Henk J.,Pertegas, Antonio
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p. 8086 - 8103
(2013/07/28)
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- Rapid and efficient synthesis of functionalized bipyridines
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The Negishi reaction affords a mild and efficient method to convert chloro- and bromo-pyridines into functionalized 2,2′-bi-pyridines using commercially available starting materials. This method also extends to the conversion of dibromopyridines to 5- and 6-bromobipyridines, which are powerful synthons for incorporation into larger supramolecular systems.
- Fang, Yuan-Qing,Hanan, Garry S.
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p. 852 - 854
(2007/10/03)
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- The synthesis of 4′-aryl substituted terpyridines by Suzuki cross-coupling reactions: Substituent effects on ligand fluorescence
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Several 4′-aryl-substituted 2,2′:6′,2″-terpyridines (tpy-C6H4R) have been prepared by palladium-catalysed cross-coupling of 4′-bromoterpyridine or 4′-triflate-terpyridine (triflate = trifluoromethylsulfonyloxy) with aryl boronic acids or esters, RC6H4B(OR′)2 (R = H, m-NH2, p-CHO, -NO2, -CN, -NMe2, -NPh2). The new ligand 4′-mesityl-terpyridine (mesityl = 2,4,6-trimethylphenyl) was prepared in the same way. Similarly, 4′-bromophenylterpyridine (tpy-φ-Br) has been cross-coupled with aryl halides to generate several new biaryl-substituted terpyridines (tpy-φ-C6H4R where R = H, p-CN, NMe2, NPh2), together with two related compounds with pendent 3- or 4-pyridyl groups (tpy-φ-C6H4-py). For selected compounds, the alternative coupling strategy of reaction of a terpyridine-4-boronate or terpyridine-4-phenylboronate with the appropriate aryl halide has also been investigated (e.g. to prepare tpy-φ-C6H4NO2), but was generally found to be less satisfactory. All of the compounds are fluorescent in the UV region of the spectrum, the biaryl-substituted compounds being only slightly red-shifted compared to the monoaryl systems, but with the further red-shift that accompanies protonation being more significant for the former. Fluorescence lifetimes in solution are in the range 1-5 ns. The emission spectra of the aminobiphenyl-substituted compounds (tpy-φ-C6H4NR″2, where R″ = Me or Ph) display a large red-shift with increasing solvent polarity, suggesting the involvement of an intramolecular charge transfer state, as found previously for the two analogues omitting the phenyl ring (tpy-C6H4NR″2). In contrast to the latter, however, protonation or binding of a Lewis acidic metal ion to the aminobiphenyl compounds serves to quench almost completely their emission.
- Goodall, Wendy,Wild, Kerstin,Arm, Kathryn J.,Williams, J.A. Gareth
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p. 1669 - 1681
(2007/10/03)
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- Ipso substitution of 2-alkylsulfinylpyridine by 2-pyridyllithium; a new preparation of oligopyridine and their bromomethyl derivatives
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Unsymmetrical and symmetrical 2,2'-bipyridines have been prepared. The methods applied are new and offer efficient syntheses of higher oligopyridines and their bromomethyl derivatives.
- Uenishi,Tanaka,Wakabayashi,Oae,Tsukube
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p. 4625 - 4628
(2007/10/02)
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- Reactions of pyridine N-oxide with some hydroxypirimidines in the presence of platinated palladium-carbon catalyst
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The reactions of pyridine N-oxide (1) with hydroxypirimidine derivatives (2-7) in the presence of platinated palladium-carbon (Pd-Pt/C) catalyst were studied. 5-Hydroxypyrimidine (2), 4-hydroxypyrimidines (3 and 4) and 1-methyl-2-pyrimidinone (6) gave the corresponding dimers and 2-pyridyl derivatives by this condensation with high regioselectivity at the dehydrogenative position, while 2-hydroxypyrimidine (5) gave only the 2-pyridyl derivative. 2,4-Dihydroxypirimidine (7) did not react under similar reaction conditions.All the products obtained in these reactions are new compounds.These dimerization reactions may be useful for the synthesis of the dimers of N-heteroaromatic compounds.Keywores - pyridine N-oxide; hydroxypyrimidine; platinated palladium-carbon catalyst; bipyrimidine; dimer; dehydrogenative dimerization; regioselectivity.
- Murakoshi, Isamu,Sekine, Toshikazu,Higuchi, Yoshihiro,Ohyama, Nobuyuki,Yamada, Tomoko
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p. 1984 - 1986
(2007/10/02)
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- Dimerizations of ?-Rich N-Heteroaromatic Compounds and Xantin Derivatives
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Dimerization reactions of six ?-rich N-heteroaromatic compounds (2-7) and five xantin derivatives (8-12) in the presence of platinated palladium-carbon (Pd-Py/C) catalyst were investigated.N-Methylimidazole (2), benzimidazole (4) and N-methylbenzimidazole (5) condensed dehydrogenatively to afford the corresponding symmetric dimers when heated in the presence of Pd-Pt/C catalyst and pyridine oxide (1).On the other hand, imidazole (3), pyrazole (6) and N-methylpyrazole (7) did not dimerize under the same conditions.The same reactions using caffeine (10), 1,7-dimethylhypoxanthine (9) gave the corresponding dimers.
- Sekine, Toshikazu,Higuchi, Yoshihiro,Yamada, Tomoko,Murakoshi, Isamu
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p. 1987 - 1989
(2007/10/02)
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- Synthesis of 2,6-Disubstituted Pyridines, Polypyridinyls, and Annulated Pyridines
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1,5-Enediones containing a variety of substituents in the 1,5-positions are formed in good yields by the reaction of methyl ketone enolates, generated with potassium tert-butoxide, with α-oxoketene dithioacetals, the latter being prepared from alkyl, cycloalkyl, aryl, or heteryl methyl ketones, NaH, CS2, and CH3I.Ring closure of the 1,5-enediones with NH4OAc gave 2,6-disubstituted 4-(methylthio)pyridines in good to excellent yields.This procedure is particularly suited for the synthesis of 2,6-diheterylpyridines and provides a simple synthesis of terpyridinyl and other oligopyridines.The methylthio groups in the α-oxoketene dithioacetals may be oxidized to the mono- and disulfoxides with m-chloroperbenzoic acid, but with excess peracid, in addition to oxidation to the disulfone, epoxidation of the double bond also occurs.The pyridine 4-methylthio substituent may also be oxidized to the sulfoxide and to the sulfone, and the latter may be displaced with cyanide ion to form the corresponding 4-carbonitrile.
- Potts, Kevin T.,Cipullo, Michael J.,Ralli, Philip,Theodoridis, George
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p. 3027 - 3038
(2007/10/02)
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