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Synthesis of a new tetradentate chelator with 1-Hydoroxy-2(1H)-pyridinone (HOPO) as chelating unit: Interaction with Fe (III), solution thermodynamics and DFT studies
1,2-Hydroxypyridinone (1,2-HOPO) forms very stable transition metal complexes that may be useful in various ways, among these the iron complexes have been long used for the treatment of iron overload diseases like β-Thalassemia. A new tetradentate chelator, 1-hydroxy-N-[3-[2-[2-[3-[(1-hydroxy-6-oxo-pyridine-2carbonyl)amino]propoxy]ethoxy]ethoxy]propyl]-6-oxo-pyridine-2-carboxamide (L) having two 1,2-HOPO units with long chain amine backbone has been synthesized and characterized through various techniques like TLC, solubility, melting point, FT-IR, 1H NMR, 13C NMR, ESI-MS, UV–Vis and emission spectroscopy. The protonation constants of the ligand were determined by both potentiometrically as well as spectrophotometrically in aqueous medium at 25° ±1 °C. The solution thermodynamics of the ligand its Fe(III) complexes in aqueous solution were also studied. The pKa values for ligand are found to be 7.34 and 6.06 and the formation constant of metal complex (M2L3) is found to be logβ230 = 42.45. To support the experimental data, theoretical calculation at DFT level of theory was done using GGA (Gradient Generalized Approximation) with BLYP functional and DZP basis set. The results of calculated thermodynamic properties suggest that, ΔG follows the same trend of protonation as determined by potentiometry and spectrophotometry. Studies of the DFT optimized structures of LH2, LH? shows that, there is π stacking interaction between the hydroxypyridinone rings in the species and the intramolecular π-stacking interaction decreases as the distance between two pyridine ring increases upon deprotonation and was found to be 2.7, 3.2 and 14.6 ? for LH2, LH? and L?2 respectively.
Baral, Minati,Dash, Dibyajit,Kanungo, B. K.
(2020)
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Synthesis and physico-chemical properties of homoleptic copper(I) complexes with asymmetric ligands as a dssc dye
To develop low-cost and efficient dye-sensitized solar cells (DSSCs), we designed and prepared three homoleptic Cu(I) complexes with asymmetric ligands, M1, M2, and Y3, which have the advantages of heteroleptic-type complexes and compensate for their synthetic challenges. The three copper(I) complexes were characterized by elemental analysis, UV-vis absorption spectroscopy, and electrochemical measurements. Their absorption spectra and orbital energies were evaluated and are discussed in the context of TD-DFT calculations. The complexes have high VOC values (0.48, 0.60, and 0.66 V for M1, M2, and Y3, respectively) which are similar to previously reported copper(I) dyes with symmetric ligands, although their energy conversion efficiencies are relatively low (0.17, 0.64, and 2.66%, respectively).
Hatano, Mayuka,Inomata, Tomohiko,Kawai, Yuya,Kitagawa, Takuma,Masuda, Hideki,Matsunaga, Ayaka,Ozawa, Tomohiro,Wasada-Tsutsui, Yuko
supporting information

(2021/11/27)

Transition-metal-free decarboxylative halogenation of 2-picolinic acids with dihalomethane under oxygen conditions
A convenient and efficient method for the synthesis of 2-halogen-substituted pyridines is described. The decarboxylative halogenation of 2-picolinic acids with dihalomethane proceeded smoothly via N-chlorocarbene intermediates to afford 2-halogen-substituted pyridines in satisfactory to excellent yields under transition-metal-free conditions. This new type of decarboxylative halogenation is operationally simple and exhibits high functional-group tolerance.
Zhang, Xitao,Feng, Xiujuan,Zhang, Haixia,Yamamoto, Yoshinori,Bao, Ming
supporting information
p. 5565 - 5570
(2019/10/22)

NEW COMPOUND
PROBLEM TO BE SOLVED: To provide a new compound that does not have structural similarity to ceramide and has excellent CERT inhibitory activity. SOLUTION: The present invention provides a new compound of structural formula (I). A bond group -X- is cis-cyclopropyl-, R1, R2, R3, R4, and R5 independently represent a hydrogen atom, a halogen atom, a linear or branched C1-C8 alkyl group that may have a halogen atom, or OR6. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0316; 0320

(2019/11/26)

Photocatalytic CO2 Reduction by Trigonal-Bipyramidal Cobalt(II) Polypyridyl Complexes: The Nature of Cobalt(I) and Cobalt(0) Complexes upon Their Reactions with CO2, CO, or Proton
The cobalt complexes CoIIL1(PF6)2 (1; L1 = 2,6-bis[2-(2,2′-bipyridin-6′-yl)ethyl]pyridine) and CoIIL2(PF6)2 (2; L2 = 2,6-bis[2-(4-methoxy-2,2′-bipyridin-6′-yl)ethyl]pyridine) were synthesized and used for photocatalytic CO2 reduction in acetonitrile. X-ray structures of complexes 1 and 2 reveal distorted trigonal-bipyramidal geometries with all nitrogen atoms of the ligand coordinated to the Co(II) center, in contrast to the common six-coordinate cobalt complexes with pentadentate polypyridine ligands, where a monodentate solvent completes the coordination sphere. Under electrochemical conditions, the catalytic current for CO2 reduction was observed near the Co(I/0) redox couple for both complexes 1 and 2 at E1/2 = -1.77 and -1.85 V versus Ag/AgNO3 (or -1.86 and -1.94 V vs Fc+/0), respectively. Under photochemical conditions with 2 as the catalyst, [Ru(bpy)3]2+ as a photosensitizer, tri-p-tolylamine (TTA) as a reversible quencher, and triethylamine (TEA) as a sacrificial electron donor, CO and H2 were produced under visible-light irradiation, despite the endergonic reduction of Co(I) to Co(0) by the photogenerated [Ru(bpy)3]+. However, bulk electrolysis in a wet CH3CN solution resulted in the generation of formate as the major product, indicating the facile production of Co(0) and [Co-H]n+ (n = 1 and 0) under electrochemical conditions. The one-electron-reduced complex 2 reacts with CO to produce [Co0L2(CO)] with νCO = 1894 cm-1 together with [CoIIL2]2+ through a disproportionation reaction in acetonitrile, based on the spectroscopic and electrochemical data. Electrochemistry and time-resolved UV-vis spectroscopy indicate a slow CO binding rate with the [CoIL2]+ species, consistent with density functional theory calculations with CoL1 complexes, which predict a large structural change from trigonal-bipyramidal to distorted tetragonal geometry. The reduction of CO2 is much slower than the photochemical formation of [Ru(bpy)3]+ because of the large structural changes, spin flipping in the cobalt catalytic intermediates, and an uphill reaction for the reduction to Co(0) by the photoproduced [Ru(bpy)3]+.
Shimoda, Tomoe,Morishima, Takeshi,Kodama, Koichi,Hirose, Takuji,Polyansky, Dmitry E.,Manbeck, Gerald F.,Muckerman, James T.,Fujita, Etsuko
supporting information
p. 5486 - 5498
(2018/05/17)

METHOD OF PRODUCING PHENOLIC COMPOUND
PROBLEM TO BE SOLVED: To provide a method of efficiently producing a phenolic compound by direct oxidation of an aromatic compound. SOLUTION: The present invention provides a method of producing a phenolic compound by oxidizing an aromatic compound by an oxidizer in the presence of a copper complex having as a ligand a compound represented by the formula (I) or (II) in the figure. (In the formulas, R1 to R9 each independently represent a methylene group or ethylene group.) SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0029

(2018/03/30)

METHOD OF PRODUCING PHENOLIC COMPOUND
PROBLEM TO BE SOLVED: To provide a method of efficiently producing a phenolic compound by direct oxidation of an aromatic compound. SOLUTION: A phenolic compound is produced by oxidation of an aromatic compound by an oxidant in the presence of a binuclear nickel complex having a ligand being a compound represented by the formula (I) or (II) in the figure. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Page/Page column 9; 13

(2017/04/27)

A 2-cyano-6-methyl pyridine preparation method (by machine translation)
The aim of the invention is to overcome the defects in the prior art, provides a 2-cyano-6-methyl pyridine preparation method, which belongs to the technical field of synthesis of pharmaceutical intermediates. The method is, will hydrobromidum and 2-amino-6-methyl pyridine mixed, heat insulation; and then cooling the solution, adding to the solution bromine Br 2, then maintain the low-temperature reaction; and then to the solution in the low temperature by adding sodium nitrite aqueous solution in the reaction; the end of the reaction the temperature of the reaction solution, adjusts pH value, then through steam distillation to obtain 2-bromo-6-methylpyridine; the cuprous cyanide and lithium bromide is added to the mass is 2-bromo-6-methylpyridine quality 2-5 times in DMF, after heating the solution, is added 2-bromo-6-methylpyridine, reaction of the; cooling the solution after the reaction, water, through the water vapor distillation to obtain the product. The security of operation of this method, low toxicity, high yield, is suitable for industrial production. (by machine translation)
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Paragraph 0028; 0029

(2016/10/07)

Template synthesis, characterization, and antimicrobial activity of a new lead (II) Schiff base complex
A novel lead (II) complex of Schiff base containing three bipyridine units was synthesized by the template reaction between a new amine compound, 6-methyl-6′-(2-aminophenoxymethyl)-2,2′-bipyridine, and 2,2′-bipyridine-6,6′-dicarboxaldehyde in the presence of a Pb(II) perchlorate ion. The new amino compound and Schiff base complex, [PbL](ClO4)2·2H2O, were characterized by using matrix-assisted laser desorption/ionization with time-of-flight mass spectroscopy, FAR FT-IR, UV/visible spectroscopy, 1H NMR, elemental analyses (CHN), and molar conductivity measurements. Then the synthesized complex was screened in vitro for its antibacterial and antifungal activities against three Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus by the microdilution broth method as a minimal inhibitory concentration. [PbL](ClO4)2·2H2O exhibits moderate activity on Staphylococcus aureus and Listeria monocytogenes when compared with standard drug and also shows moderate antifungal activity on the fungus Candida albicans.
Beynek, Nesrin,Tan, Nurcihan,Beynek, Hayrettin
p. 145 - 150
(2015/12/09)

Template synthesis and spectral characterization of new Lead(II)-Schiff base macrocyclic complexes incorporating phenanthroline and/or bipyridine units
Lead(II) complexes of Schiff-bases containing phenanthroline and/or bipyridine units were synthesized by the template reaction between new diamine compound, 6,6'-bis(2-aminophenoxymethyl)-2,2'-bipyridine and 2,2-bipyridine-6,6-dicarboxaldehyde or 1,10-phenanthroline- 2,9-dicarboxaldehyde in the presence of metal ions. These complexes, [PbL1]( ClO4)2and [PbL2](NO3)2, were characterized and investigated by using; MALDI-TOF and Q-TOF-MS spectroscopy, FTIR, UV/Visible spectroscopy, 1H NMR, Elemental analyses (CHN), magnetic susceptibility and molar conductivity measurements.
Beynek,Tan,Beynek
p. 4141 - 4144
(2015/12/23)

Na2(smbipy) - A bipyridine-derived ligand with chelating sulfonate tags and its 3d metal complexes
The sulfonated bipyridine derivative disodium 6,6′-bis(sulfonatomethyl)-2,2′-bipyridine [Na2(smbipy)] was synthesized, and its complexation behaviour towards divalent 3d metals in aqueous solution was explored. The complexes of late 3d metals [M(smbipy)(H2O)2]·H2O (M = Co, Ni, Zn) and [Cu(smbipy)(H2O)] are sparingly soluble in water, and their crystal structures show fourfold equatorial coordination (κ4N,N',O,O') of the smbipy ligand. Ammonia-rich solutions of the NiII and CuII aqua complexes yield the decomplexation products [Ni(NH3)6](smbipy), [Ni(NH3)5(H2O)](smbipy) and [Cu(NH3)4](smbipy)·2H2O. Buffered solutions with a reduced ammonia content lead to [Ni(smbipy)(NH3)2] and [Cu(smbipy)(NH3)3]·2H2O, and the latter shows twofold coordination of the smbipy ligand through the nitrogen atoms only (κ2N,N'). When nearly quantitative amounts of ammonia are applied, two closely related complexes with the core motif [(smbipy)Cu(μ-OH)2Cu] form. Crystal structures of all complexes were obtained, and their features are discussed.
Oelkers, Benjamin
p. 5838 - 5848
(2015/02/02)

Synthesis and in vitro/in vivo pharmacological evaluation of [ 11C]-ThioABP, a novel radiotracer for imaging mGluR5 with PET
We have designed a novel positron emission tomography (PET) radiotracer, [11C]-ThioABP, a thiazole based derivative for imaging the metabotropic glutamate receptor subtype 5 (mGluR5), and prepared the hydroxy oxime precursor 4 in a 15% overall yield. [11C]-ThioABP was radiosynthesized in the Veenstra module and obtained in a decay corrected radiochemical yield of 40% and specific activity of 80-250 GBq μmol -1 at the end of synthesis. ThioABP exhibited excellent binding affinity (Ki) in vitro of 1.9 ± 0.9 nM and [ 11C]-ThioABP showed an optimal log D7.4 of 2.4. The autoradiographic studies on rat brain slices revealed specific binding to mGluR5. In vivo evaluation of [11C]-ThioABP including a displacement study with MMPEP in a dynamic PET scan showed a specificity of [ 11C]-ThioABP for mGluR5. Radio-TLC metabolite studies showed a good metabolic stability of [11C]-ThioABP in vivo. The comparison of biological properties of [11C]-ThioABP and [11C]-ABP688 revealed similarity between these two compounds.
Sephton, Selena Milicevic,Mu, Linjing,Müller, Adrienne,Wanger-Baumann, Cindy A.,Schibli, Roger,Kr?mer, Stefanie D.,Ametamey, Simon M.
p. 520 - 526
(2013/04/24)

Generation and reactions of pyridyllithiums via Br/li exchange reactions using continuous flow microreactor systems
A continuous flow microreactor method for generating and carrying out reactions on pyridyllithiums has been developed based on Br/Li exchange reactions of bromopyridines and dibromopyridines. The reactions can be carried out without using cryogenic conditions by virtue of short residence times and efficient heat transfer, while very low temperatures such as-78 or-110°C are required for conventional batch macro methods. Moreover, sequential introduction of two different electrophiles has been successfully achieved using dibromopyridines in an integrated flow microreactor system composed of four micromixers and four microtube reactors.
Nagaki, Aiichiro,Yamada, Daisuke,Yamada, Shigeyuki,Doi, Masatomo,Ichinari, Daisuke,Tomida, Yutaka,Takabayashi, Naofumi,Yoshida, Jun-Ichi
p. 199 - 207
(2013/03/28)

Flow microreactor synthesis of disubstituted pyridines from dibromopyridines via Br/Li exchange without using cryogenic conditions
A flow microreactor method for the synthesis of disubstituted pyridines by generation of pyridyllithiums followed by reactions with electrophiles has been developed. By using a short residence time and efficient temperature control, the cryogenic conditions required for conventional batch macro processes can be avoided. Sequential introduction of two different electrophiles into dibromopyridines has been achieved using an integrated flow microreactor system composed of four micromixers and four microtube reactors, to obtain disubstituted pyridine compounds.
Nagaki, Aiichiro,Yamada, Shigeyuki,Doi, Masatomo,Tomida, Yutaka,Takabayashi, Naofumi,Yoshida, Jun-Ichi
supporting information; experimental part
p. 1110 - 1113
(2011/06/26)

LINEAR PYRIDAZINE AND PYRROLE COMPOUNDS, METHOD FOR OBTAINING THEM AND APPLICATIONS
The present invention relates to linear pyridazine compounds, and more particularly to those of these compounds which are oligopyridazine compounds, to processes for obtaining them, to their uses, and also to their reduction to pyrroles and to the uses of the pyrrole, pyridazinylpyrrole and oligopyrrole compounds obtained. The invention relates in particular to the uses as medicaments, in particular for treating pathologies such as cancer, bacterial infections or parasitic infections, and also the applications in the materials, environmental, electronics and optics field.
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(2010/02/16)

6,6′-Dimethyl-2,2′-bipyridine-4-ester: A pivotal synthon for building tethered bipyridine ligands
We describe an efficient and scalable synthesis of 4-carbomethoxy-6,6′-dimethyl-2,2′-bipyridine starting from easily available substituted 2-halopyridines and based on the application of modified Negishi cross-coupling conditions. This compound is a versatile starting material for the synthesis of 4-functionalized 2,2′-bipyridines bearing halide, alcohol, amine, and other functionalities, suitable for conjugation to biological material (2a-c, 3a-g). The utility of this compound in the construction of more complex architectures was further demonstrated by the synthesis of two bifunctional lanthanide chelators; an open chain ligand based on one 2,2′-bipyridine unit and a cryptand based on three 2,2′-bipyridine units [N2(bpy)3COOMe]. In the field of luminophoric biolabels, the photophysical properties of the corresponding Eu(III) cryptate are reported.
Havas, Fabien,Leygue, Nadine,Danel, Mathieu,Mestre, Béatrice,Galaup, Chantal,Picard, Claude
scheme or table
p. 7673 - 7686
(2009/12/06)

Synthesis, characterization of some transition-metal complexes of a new heptadentate N5S2 schiff-base ligand and the effects of these metal complexes on U2OS cells cytotoxicity and DNA cleavage activity
Metal complexes of a heptadentate N5S2 donor Schiff-base ligand were synthesized by the template reaction between 2,6-bis(2-aminothiophenoxymethyl) pyridine and 2,2 '-bipyridine-6,6 '-dicarboxaldehyde in the presence of Zn(II), Cd(II), Hg(II) and Pb(II) perchlorate salts. The complexes were characterized by IR, 1H NMR, MS-FAB+, and elemental analyses. The mitochondrial activity of U2OS cells after exposure to these complexes was determined by colorimetric assay, which detects the conversion of 3-(4,5-dimethylthiazolyl-2)-2,5- diphenyltetrazolium bromide (MTT) to formazon. DNA-binding activity of all complexes was also investigated using plasmid DNA pUC18 purified from E. coli. Copyright Taylor & Francis Group, LLC.
Ulucam,Beynek,Seller,Akalin,Turan,Benkli
experimental part
p. 2237 - 2247
(2009/08/07)

Synthesis and characterization of new binaphthyl-linked phenanthroline-, bipyridine-, or pyridine-derived ligands, and the study of their cytotoxic activity
In the present work, we describe the synthesis and characterization of five new versatile acyclic or macrocyclic ligands containing binaphthyl-linked pyridine, bipyridine, or phenanthroline groups in their framework (see Schemes 1-4). The structures of the ligands were elucidated on the basis of elemental analyses, IR, 1H-NMR, 13C-NMR, and FAB mass spectra. The cytotoxicity of these compounds was tested in vitro by using the tetrazolium salt reduction (MTT) assay on A549 (human lung carcinoma epithelial like) cells. All of the tested compounds induced time- and concentration-dependent cytotoxic effect.
Beynek, Nesrin,Ulucam, Gueherguel,Benkli, Kadriye,Koparal, Ayse Tansu
scheme or table
p. 2089 - 2096
(2009/02/08)

Structure and DNA cleavage properties of two copper(ii) complexes of the pyridine-pyrazole-containing ligands mbpzbpy and Hmpzbpya
The DNA-cleavage properties of the two copper(ii) complexes, [Cu(mbpzbpy)Br2](H2O)2.5 (1) and [Cu(mpzbpya)Cl](CH3OH) (2), obtained from the ligands 6,6′-bis(3,5-dimethyl-N-pyrazolmethyl)-2,2′-bipyridine) (mbpzbpy) and 6′-(3,5-dimethyl-N-pyrazolmethyl)-2,2′-bipyridine-6-carboxylic acid) (Hmpzbpya), respectively, are reported. Upon coordination to Cu II chloride in methanol, one arm of the ligand mbpzbpy is hydrolyzed to form mpzbpya. Under the same experimental conditions, the reaction of mbpzbpy with CuBr2 does not lead to ligand hydrolysis. The ligand mpzbpya is coordinated to a copper(ii) ion generating a CuN3OCl chromophore, resulting in a distorted square-pyramidal environment, whereas with the N 4 mbpzbpy ligand, the CuII ion is four-coordinated in a distorted square planar geometry. Both complexes promote the oxidative DNA cleavage of X174 phage DNA in the absence of reductant. The oxidative nature of the DNA cleavage reaction has been confirmed by religation and cell-transformation experiments. Studies using standard radical scavengers suggest the involvement of hydroxyl radicals in the oxidative cleavage of DNA. Although both compounds do convert form I (supercoiled) DNA to form II (nicked, relaxed form), only complex 1 is able to produce small amounts of form III (linearized DNA). This observation may be explained either by the attack of the copper(ii) complexes to only one single strand of DNA, or by a single cleavage event. Statistical analysis of relative DNA quantities present after the treatment with both copper(ii) complexes supports a random mode of DNA cleavage. This journal is The Royal Society of Chemistry.
Maheswari, Palanisamy Uma,Lappalainen, Kristian,Sfregola, Michael,Barends, Sharief,Gamez, Patrick,Turpeinen, Urho,Mutikainen, Ilpo,Van Wezel, Gilles P.,Reedijk, Jan
p. 3676 - 3683
(2008/02/12)

Catalytic etherification of N-protected tris(hydroxymethyl)aminomethane for the synthesis of ligands with C3 symmetry
The synthesis of two nonadentate ligands based on a N,N-dibenzylated- tris(hydroxy)methylaminomethane framework is described. The key step consists in tris-etherification of the precursor with elaborated pyridine and bipyridine derivatives and this was greatly improved by the introduction of catalytic amounts of tetrabutylammoniumiodide to the reaction mixture in DMF at room temperature. Analysis of the alkylation rates and an X-ray crystal structure of a bis-alkylated intermediate strongly support the presence of a tight intramolecular hydrogen bond, preventing a fast third alkylation step. The two acidic ligands were successfully prepared by combining a sequence of carboalkoxylation and hydrolysis of the corresponding esters. Both ligands react with europium and terbium chloride salts to generate water luminescent mononuclear complexes.
Weibel, Nicolas,Charbonnière, Lo?c,Ziessel, Raymond
p. 1793 - 1796
(2007/10/03)

The expedient access to bromo-pyridine carbaldehyde scaffolds using gem-dibromomethyl intermediates
A simple, efficient, and general two-step synthesis to bromo-pyridine carbaldehyde scaffolds is described. This direct route involves sequential reactions employing the dibromination of bromo-picolines followed by hydrolysis using an aqueous solution of calcium carbonate. Bromo-pyridine carbaldehyde scaffolds 1-7 were obtained in good overall yield. Bromo-dibromomethyl-pyridine intermediates have been isolated and characterized.
Mandal, Ashis Baran,Augustine, John Kallikat,Quattropani, Anna,Bombrun, Agnes
p. 6033 - 6036
(2007/10/03)

Engineering of Highly Luminescent Lanthanide Tags Suitable for Protein Labeling aad Time-Resolved Luminescence Imaging
The synthesis of a new ligand LH4 based on a glutamic acid skeleton bis-functionalized on its nitrogen atom by 6-methylene-6′ -carboxy-2,2′-bipyridine chromophoric units is described. UV-vis spectrophotometric titrations revealed the formation of 1:1 M:L complexes with lanthanide(III) cations, and complexation of LH4 with equimolar amounts of hydrated LnCl3 salts (Ln = Eu, Gd, and Tb) gave water-soluble and stable complexes of the general formula [LnL(H 2O)]Na, which were characterized by elemental analysis, IR, UV-vis absorption spectroscopy, 1H NMR (Ln = Eu), and mass spectrometry. The conditional stability constant for formation of the [EuL(H2O)]Na complex was determined by competitive complexation experiments to be log K= 16. 5 ± 0.6 in 0.01 M TRIS/HCl buffer (pH = 7.0). In water solution, the [EuL(H2O)]Na and [TbL(H2O)]Na complexes were highly luminescent with quantum yields of 8% and 31%, respectively, despite the presence of ca. one water molecule in the first coordination sphere of the metal ions. Activation of the appended carboxylate function of the glutamate moiety in the form of an N-hydroxysuccinimidyl ester allows for the covalent linking of the complexes to primary amino groups of biological compounds. Bovine serum albumin (BSA) was labeled with both Eu or Tb complexes, and the Ln-BSA conjugates were characterized by UV-vis absorption and emission spectroscopy and MALDI-TOF mass spectrometry. Labeling ratios (number of complex molecules per BSA) of ca. 8:1 and 7:1 were established for Eu-BSA and Tb-BSA, respectively. The suitability of the tagged compound for use in bioanalytical time-resolved luminescence microscopy was established by comparison with fluorescein-labeled probes.
Weibel, Nicolas,Charbonniere, Loic J.,Guardigli, Massimo,Roda, Aldo,Ziessel, Raymond
p. 4888 - 4896
(2007/10/03)

Preparation and characterization of methyl substituted 2,2′-dipyridyl diselenides and -ditellurides: X-ray structure of 6,6′-dimethyl-2,2′-dipyridyl diselenide
A convenient method for the preparation of various methyl substituted 2,2′-dipyridyl diselenides and -ditellurides by the aerial oxidation of lithium 2-pyridylselenolate/tellurolate, prepared from the lithium-halogen exchange between n-butyllithium and 2-bromo methyl substituted pyridines is reported. All the compounds prepared are new and have been characterized by elemental analysis, IR, 1H, 13C, 11Se NMR, and mass spectral studies. Crystal structure of 6,6′-dimethyl-2,2′-dipyridyl diselenide has been determined.
Bhasin,Venugopalan,Singh
p. 2579 - 2587
(2007/10/03)

Silyl-mediated halogen/halogen displacement in pyridines and other heterocycles
Heating with bromotrimethylsilane converts 2-chloropyridine into 2-bromopyridine and 2-chloro-6-methylpyridine into 2-bromo-6-methylpyridine. Both 2-chloropyridines and 2-bromopyridines give the corresponding iodo compound when treated with in situ generated iodotrimethylsilane. Although 3- and 4-chloropyridine are completely inert, 2,4-dichloropyridine undergoes the halogen/halogen exchange simultaneously at the 2- and 4-position. Halogen displacement takes place exclusively at the 2-position with 2,3-dichloropyridine and 2,5-dichloropyridine. In agreement with the intermediacy of N-trimethylsilylpyridinium salts as a prerequisite for the occurrence of halogen exchange, neither 2-fluoropyridine and 2-fluoro-6-methylpyridine nor any 2,6-dihalopyridine reacts. Finally, bromine/chlorine and iodine/chlorine substitution can also be accomplished with 2-or 4-chloroquinoline, 1-chloroisoquinoline, 2-chloropyrimidine, chloropyrazine and 2,3-dichloroquinoxaline as substrates. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002).
Schlosser, Manfred,Cottet, Fabrice
p. 4181 - 4184
(2007/10/03)

Synthesis of bisfunctionalized-oligopyridines bearing an ester group
The synthesis of 2,2′-bipyridine, 1,10-phenantroline and 2,2′:6′,2″-terpyridine substituted by an ethylester function is described. The 5- and 6-methyl-2,2′-bipyridines bearing an ethylester group on the 6′ position as well as the ethyl 6,6″-dimethyl-2,2′:6′,2″-terpyridine-4′- carboxylate moiety were synthesized via a Stille cross-coupling reaction, starting from bromo-picoline building blocks. A radical bromination of the methyl-oligopyridine gave selectively the corresponding benzylic bromide derivatives in fair yield.
Ulrich, Gilles,Bedel, Sébastien,Picard, Claude,Tisnès, Pierre
p. 6113 - 6115
(2007/10/03)

Stille-type cross-coupling - An efficient way to various symmetrically and unsymmetrically substituted methyl-bipyridines: Toward new ATRP catalysts
(matrix presented) Various mono- and disubstituted 2,2′-bipyridines were synthesized in high yields and multigram scales utilizing Stille-type coupling procedures. The corresponding bromo-picoline and tributyltin-picoline building blocks were prepared from commercially available amino-picoline compounds. As first examples of metal complexes, 4,5′-dimethyl-2,2′-bipyridine was reacted with copper(II) and iron(II) ions and investigated as catalyst in ATRP.
Schubert, Ulrich S.,Eschbaumer, Christian,Heller, Marcel
p. 3373 - 3376
(2007/10/03)

Synthesis of novel chromeno[3,4-b]pyridinones
A concise synthesis of two novel chromeno[3,4-b]pyridin-9-ones (as their ethylene ketals) has been achieved using, as a key step, the reaction between a mixed cuprate derived from 6-methoxy-2-methyl-3-lithiopyridine and 4-tert-butyldimethylsiloxycyclohex-2-enone.
Caprio, Vittorio,Mann, John
p. 3151 - 3155
(2007/10/03)

Synthesis and characterization of some new bipyridyl-based multidentate ligands and their CuI complexes
Four new 2,2′-bipyridyl-based ligands: 6,6′-bis(methylthiomorpholine)-2,2′-bipyridine (L1), 4,4′-dimethyl-6,6′-bis(methylthiomorpholine)-2,2′-bipyridine (L2), 6,6′-bis(methylpiperidine) -2,2′-bipyridine (L3) and 4,4′-dimethyl-6,6′-bis(methylpiperidine)-2,2′-bipyridine (L4), and dimeric CuI complexes of the ligands L1 and L2 have been synthetized. The X-ray crystal structures of the ligands L1 and L2 and the L1-CuI complex have been determined. Complexation of these ligands with other metals produced mainly compounds having very low solubilities. Acta Chemica Scandinavica 1997.
Laitinen, Riitta H.,Csoban, Katalin,Pursiainen, Jouni,Huuskonen, Juhani,Rissanen, Kari
p. 462 - 469
(2007/10/03)

Catalytic asymmetric synthesis of bis-armed aromatic amino acid derivatives. Problems related to the synthesis of enantiomerically pure bis-methyl ester of the (S,S)-pyridine-2,6-diyl bis-alanine
(S,S)-Pyridine-2,6-diyl bis-alanines 8 and 9 carrying protecting groups suitable for peptidc synthesis have been syntnesised from 2.6-pyridinedicarbaldenyde by the phosphonoglycine condensation route followed by catalytic hydrogenation with Rh{(COD)[(R,R)-DIPAMP]}BF4. The alternative route via double Heck coupling of 2,6-dibromopyndmc and benzyl Boc-amidoacry late was unsuccessful although mono-coupling could be achieved. The reasons for this failure are discussed as well as the failure of two mono-armed didehydroamino acid derivatives to undergo hydrogenation with Rh bisphosphme catalysts. The CuCl2 and RhCl3 complexes of the bis-amino derivative 9 were prepared: a 20% e.e. was achieved in the cyclopropanation of styrene with ethyl diazoacetate using the Cu(II)-complex as a catalyst. Acta Chemica Scandinavica 1996.
Basu,Frejd
p. 316 - 322
(2007/10/03)

Unusual Stabilities of 6,6'-Bis(aminomethyl)-2,2'-bipyridyl Chelates of Transition-metal Ions and Crystal Structures of the Ligand and its Copper(II) and Nickel(II) Complexes
An improved four-step synthesis of the tetradentate compound 6,6'-bis(aminomethyl)-2,2'-bipyridyl (badp) has been developed and the crystal structure of its dihydrochloride monohydrate determined: space group C2/c, a = 11.991(2), b = 5.703(1), c = 22.109(3) Angstroem, β = 97.17(1) deg and Z = 4.The complexes of copper(II) and nickel(II) with badp have also been synthesized and structurally characterized.The metal ion in Br2 is five-co-ordinated and the complex crystallizes in the monoclinic P21/c space group with a = 11.508(3), b = 9.584(3), c = 14.362(30 Angstroem, β = 107.93(2) deg and Z = 4.The complex Br contains six-co-ordinated Ni(II) and crystallizes in the monoclinic P21/c space group with a = 11.387(3), b = 9.417(2), c = 14.317(5) Angstroem, β = 106.21(2) deg and Z = 4.The stepwise stability constants of the 1 : 1 ligand to metal complexes of badp with divalent transition-metal ions have been determined in KCl as supporting electrolyte (0.100 mol dm-3) at 25.0 deg C: log KML = / for the Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes is 8.94, 10.16, 11.87, 15.05 and 10.02 respectively.Iron(II) and cobalt(II) also formed 2 : 1 complexes with badp.The unusually low stabilities of the transition-metal complexes are considered due to the low basicity of the ligand and to the unfavourable spacing of its donor groups as indicated by the structures of the complexes of Ni(II) and Cu(II).
Wang, Zheng,Reibenspies, Joseph,Motekaitis, Ramunas J.,Martell, Arthur E.
p. 1511 - 1518
(2007/10/02)

Pyridylthio-acylanilide herbicides
Novel herbicidally active pyridylthio-acylanilides of the formula STR1 in which R1, R2 and R3, independently of one another, represent hydrogen, halogen, cyano or trifluoromethyl or alkyl, alkoxy and alkylthio having 1 to 4 carbon atoms in each case, R4 represents halogen, methyl or methoxy, n represents a number 0, 1 or 2, z represents the group (Ia) STR2 or the group (Ib) STR3 where X represents oxygen, sulphur, an N--R10 or N--O--R11 group, or X and Rg tpgether represent the STR4 radical, and the other radicals can have various meanings. Intermediates of the formulae STR5 are also new.
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(2008/06/13)

Novel 1,4-dihydropyridine calcium antagonists. I. Synthesis and hypotensive activity of 4-(substituted pyridyl)-1,4-dihydropyridine derivatives
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Ashimori,Ono,Uchida,Ohtaki,Fukaya,Watanabe,Yokoyama
p. 2446 - 2458
(2007/10/02)

Wiitig-Synthesis and X-ray Structure of a 26-Membered Macrocycle Containing two Bipyridine Units
Wittig-type macrocyclization of bipyridinedicarbaldehyde 5 with bis(phosphonium bromide) 6 leads to the new bipyridinophanes 7, 8.The X-ray structural analysis of 8 reveals a steptype conformation, which according to 1H-NMR results is also present in solution.
Voegtle, Fritz,Hochberg, Robert,Kochendoerfer, Frank,Windscheif, Paul-Michael,Volkmann, Martin,Jansen, Martin
p. 2181 - 2185
(2007/10/02)

Phenoxypyridinemethyl esters of 4-alkenoic acids
Novel phenoxypyridinemethyl esters of 4-alkenoic acid compounds having pesticidal activity and methods of their preparation.
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(2008/06/13)