- Reduction of dipyrido ureas via 6-alkyloxydipyrido[1,2-c;2′,1′- e]imidazolium salts
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Dipyrido uronium salts can readily be synthesized by alkylation of dipyrido ureas with Meerwein's reagent. Compared to the corresponding ureas, the uronium salts are more reactive towards basic or reducing agents like metal hydrides. Reactivity studies show that the uronium salts can react as alkylating agents towards DMSO, DBU and NaOEt along with release of the respective dipyrido ureas. In contrast, reduction of the dipyrido uronium salts with sodium borohydride or sodium trimethoxyborohydride in dry and degassed acetonitrile leads to the imidazolium salts 7a and 7b in moderate yields. Analysis of the by-products reveals an in situ carbene formation which can be reversed by using degassed but wet acetonitrile as solvent. The yield of 7b was increased significantly by these means.
- Kunz, Doris,Deissler, Christine,Gierz, Verena,Rominger, Frank,Oeser, Thomas
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- 4,4′-Bis(tert-butyl)-2,2′-bipyridinedichlorometal(II) -Synthesis, structure and EPR spectroscopy
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Due to the better solubility of the 4,4′-substituted bipyridine ligand a series of 4,4′-bis(tert-butyl)-2,2′- bipyridinedichlorometal(II) complexes, [M(tbbpy)Cl2], with M = Cu, Ni, Zn, Pd, Pt was synthesised and characterised. The blue copper complex 4,4′-bis(tert-butyl)-2,2′-bipyridinedichlorocopper(II) was isolated in two different polymorphic forms, as prisms 1 with a solvent inclusion and solvent-free as needles 2. Both structures were determined by X-ray structure analysis. They crystallise in the monoclinic space group P21/c with four molecules in the unit cell, but with different unit cells and packing motifs. Whereas in the prisms 1, with the unit cell parameters a = 12.1613(12), b = 10.6363(7), c = 16.3074(15) ?, β = 94.446(8)°, the packing is dominated by intra-and intermolecular hydrogen bonds, in the needles 2, with a = 7.738(1), b = 18. 333(2), c = 13.291(3) ?, β = 97.512(15)°, only intramolecular hydrogen bonds appear and the complex molecules are arranged in columns which are stabilised by π-π-stacking interactions. In both complexes the copper has a tetrahedrally distorted coordination sphere. These copper complexes were also studied by EPR spectroscopy in solution, as frozen glass and diamagnetically diluted powder with the analogue [Pd(tbbpy)Cl 2] as host lattice.
- Awad, Duha Jawad,Schilde, Uwe,Strauch, Peter
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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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- 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 0057; 0127-0130
(2018/10/21)
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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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- 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 0083; 0090; 0091; 0100-0102
(2017/09/16)
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- Dehydrogenative Coupling of 4-Substituted Pyridines Catalyzed by a Trinuclear Complex of Ruthenium and Cobalt
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The dehydrogenative coupling of 4-substituted pyridines catalyzed by a heterometallic trinuclear complex composed of Ru and Co, (Cp?Ru)2(Cp?Co)(μ-H)3(μ3-H) (1, Cp? = η5-C5Me5), was investigated. When the pyridine substrate contains an electron-donating group at the 4-position, complex 1 showed a high catalytic activity compared to di- and triruthenium complexes (Cp?Ru)2(μ-H)4 (4) and (Cp?Ru)3(μ-H)3(μ3-H)2 (5). The catalytic activity of 1 was also remarkably higher than the congeners of other group 9 metals, Ru2Rh (2) and Ru2Ir analogues (3). The distinctive reactivity of 1 was attributed to a paramagnetic intermediate, (Cp?Ru)2{(dmbpy)Co}(μ-H)(μ3-H)2 (12, dmbpy = 4,4′-dimethyl-2,2′-bipyridine), which was formed by the reaction of 1 with 4-picoline accompanied by the dissociation of the Cp? at the Co atom. The reaction of 12 with unsubstituted pyridine resulted in the elimination of 4,4′-dimethyl-2,2′-bipyridine, indicating that the Co atom in 12 acts as a dissociation site. In contrast to the reaction of 1 with 4-picoline, the reaction of 2 and 3 with 4-picoline afforded the corresponding μ3-pyridyl complexes (Cp?Ru)2(Cp?M)(μ-H)3(μ3-η2(||)-C5H3NCH3) (15, M = Rh; 16, M = Ir). 4-(Trifluoromethyl)pyridine was not dimerized by 1; however, a similar μ3-pyridyl complex, (Cp?Ru)2(Cp?Co)(μ-H)3(μ3-η2(||)-C5H3NCF3) (13), was obtained. The stability of the μ3-pyridyl complex is probably one of the reasons for the low catalytic activity of 2 and 3 in the coupling reaction.
- Nagaoka, Masahiro,Kawashima, Takashi,Suzuki, Hiroharu,Takao, Toshiro
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p. 2348 - 2360
(2016/08/02)
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- Carbon-Carbon Bond-Forming Reductive Elimination from Isolated Nickel(III) Complexes
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This manuscript describes the design, synthesis, characterization, and reactivity studies of organometallic NiIII complexes of general structure TpNiIII(R)(R1) (Tp = tris(pyrazolyl)borate). With appropriate selection of th
- Bour, James R.,Camasso, Nicole M.,Meucci, Elizabeth A.,Kampf, Jeff W.,Canty, Allan J.,Sanford, Melanie S.
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supporting information
p. 16105 - 16111
(2016/12/22)
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- Substituted 2,2′-bipyridines by nickel catalysis: 4,4′-Di- tert -butyl-2,2′-bipyridine
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A simple, ligand-free synthesis of the important bipyridyl ligand 4,4′-di-tert-butyl-2,2′-bipyridine is presented. 5,5′-Bis(trifluoromethyl)-2,2′-bipyridine is also synthesized by the same protocol. The syntheses efficiently couple the parent 2-chloropyridines by a nickel-catalyzed dimerization with manganese powder as the terminal reductant. Georg Thieme Verlag Stuttgart New York.
- Buonomo, Joseph A.,Everson, Daniel A.,Weix, Daniel J.
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p. 3099 - 3102
(2013/12/04)
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- Synthesis and characterisation of new platinum-acetylide complexes containing diimine ligands
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A new class of platinum-bipyridyl compounds has been synthesized by the dehydrohalogenative reaction of [4,4'-bis(tert-butyl)-2,2'-bipyridyl]platinum dihcloride [PtCl2(tBu2bipy)] 1 with terminal alkynes HCCR, in the presence of copper(I) iodide and diisopropylamine. The products [Pt(CCR)2(tBu2bipy)] (R=C6H4NO2-p 2, C6H5 3, C6H4CH3-p 4 or SiMe3 5), have been characterised by spectroscopic and analytical methods, and a single crystal molecular structure determination has been carried out on 4. Extended Hueckel molecular orbital calculations have also been carried out, and the results are used to help rationalise the voltammetric, EPR and spectroelectrochemical properties of the new compounds. These show that compounds 3,4 and 5 undergo a one-electron bipyridyl based redox process, but that 2 has an unresolved two-electron process located on the nitro groups.
- Adams, Christopher J.,James, Stuart L.,Liu, Xiaoming,Raithby, Paul R.,Yellowlees, Lesley J.
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- 176. Synthese, spektroskopische Eigenschaften und elektrochemisches Verhalten von Ruthenium(II)-Komplexen mit zweizaehnigen Stikstoffliganden
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The syntheses of coordination compounds of ruthenium(II) with bidentate nitrogen donors (aa) is described.The ligands (aa) used are related to dipyridyl, but differ from the latter in size of the ?-electron systems.In some ligands, e.g. 10, the two halves of the molecule are forced to be non planar by the aliphatic bridge between the two rings accomodating the nitrogen ligand atoms.The syntheses of the complexes Ru(dipy)2(aa)2+, Ru(dipy)(aa)22+ and Ru(aa)32+ ((aa) 1-17) are described.Generally the crystalline salts with PF6- as counter-ion have been obtained.The complexes are characterized by elemetary analysis, electronic spectra, infrared spectra, cyclic voltammogramms, proton nuclear magnetic resonance spectra and, for those which have been obtained in optically active forms also by circular dicroism.In the discussion special emphasis is given to the change of properties compared to the well investigated Ru(dipy)32+ complex.In the visible range of the spectrum all complexes show one or several spin allowed charge transfer transitions at longer wavelengths then Ru(dipy)32+.The ground state oxidation potential to the 3+ state are little affected by substitution of one or more of the dipy ligands in Ru(dipy)32+ by the ligands (aa), whereas the reduction behavior is strongly influenced by such substitutions.The 1H-NMR spectra indicate rigid conformations of some nonplanar (aa)-ligands in the complexes.
- Belser, Peter,Zelewsky, Alex von
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p. 1675 - 1702
(2007/10/02)
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- Substituted 2,2'-bipyridyl compounds and process for preparing same
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A process for preparing substituted 2,2'-bipyridyl compounds and several compounds so prepared, the process comprising the steps of first selecting a substituted pyridine of the formula defined herein, then mixing a stoichiometric excess of the substituted pyridine with an amount of sodamide, causing the resultant mixture to be at a temperature sufficiently high to cause substituted 2,2'-bipyridyl formation, and isolating the substituted 2,2'-bipyridyl thereby formed. The new substituted 2,2'-bipyridyl compounds are selected from the group consisting of 4,4'-di-(5-nonyl)-2,2'-bipyridyl; 4,4'-di-(3-pentyl)-2,2'-bipyridyl; 6,6'-di-(3-pentyl)-2,2'-bipyridyl; 6,6'-di-(5-nonyl)-2,2'-bipyridyl; 4,4'-di-(cyclohexylmethyl)-2,2'-bipyridyl; 5,5'-di-(5-nonyl)-2,2'-bipyridyl; 4,4'-di-(3-phenylpropyl)-2,2'-bipyridyl; 4,4'-di-(4-tetrahydropyranyl)-2,2'-bipyridyl; 4,4'-di-benzyl-2,2'-bipyridyl; 6,6'-di-isoamyl-2,2'-bipyridyl; and 4,4'-di-(t-butyl)-2,2'-bipyridyl.
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