122-05-4Relevant articles and documents
Uncoordinated carbonyl groups of MOFs as anchoring sites for the preparation of highly active Pd nano-catalysts
Pan, Yingyi,Ma, Deyun,Liu, Huimin,Wu, Hao,He, Dehua,Li, Yingwei
, p. 10834 - 10839 (2012)
A novel Tm-containing metal-organic framework, [Tm(μ2-L) (μ4-L)0.5(H2O)2]·3H 2O (Tm-MOF), was prepared from the hydrothermal reaction of Tm(NO3)3 with 5-methylpyrazine-2-carboxylic acid in water. The 2,5-pyrazinedicarboxylate ligand (L) in Tm-MOF was formed in situ from 5-methylpyrazine-2-carboxylic acid under the above conditions. Tm-MOF is a three-dimensional (3D) coordination network with 1D open channels running across the coordination layers. Each L in bridging mode μ2 contains two uncoordinated carbonyl groups which point to the channels. By using the predesigned Tm-MOF as a host, we have successfully incorporated small palladium nanoparticles into the channels by a simple impregnation method. The Pd/Tm-MOF catalyst exhibited a high catalytic activity in the hydrogenation of styrene. Moreover, the catalyst could be reused at least three times without loss of any activity. In contrast, a low dispersion of metal and a low activity in styrene hydrogenation were observed over the Pd catalyst supported on ZIF-8, which has a similar surface area as the Tm-MOF, but no uncoordinated carbonyl groups. The results suggest that the uncoordinated carbonyl groups in the Tm-MOF may play an important role in facilitating the dispersion of Pd nanoparticles through an intermolecular interaction with the Pd cations in the course of immobilization. The Royal Society of Chemistry 2012.
Dinuclear copper(II) complexes of two homologous pyrazine-based bis(terdentate) diamide ligands
Klingele, Julia,Moubaraki, Boujemaa,Murray, Keith S.,Boas, John F.,Brooker, Sally
, p. 1530 - 1541 (2005)
The 1:1 reactions of the new bis(terdentate) diamide ligand N, N′-bis(2-pyridylmethyl)pyrazine-2,5-dicarboxamide (H2L 1) and its higher homologue N,N′-bis[2-(2-pyridyl)ethyl] pyrazine-2,5-dicarboxamide (H2L2) with Cu(BF 4)2·4H2O in the absence of added base have consistently afforded dicopper(II) complexes of the doubly deprotonated ligands (L1)2- and (L2)2-. The complex [CuII2(L2)(H2O) 2(MeCN)2](BF4)2 (2a) has been structurally characterised. Subsequently, reactions employing a correct stoichiometric 2:1 metal-to-ligand ratio in MeCN have afforded bulk samples of the dinuclear complexes. The compounds [CuII2(L 1)(MeCN)2(H2O)2)(BF 4)2·H2O (1a·H2O) and [CuII2(L2)(H2O)4(BF 4)2]-2H2O (2b-2H2O) have been structurally characterised. While complex 1a-H2O of the lower ligand homologue exhibits very weak antiferromagnetic spin coupling (J = -0.24 cm -1), complex 2b of the higher ligand homologue exhibits very weak ferromagnetic spin coupling (J = +0.67 cm-1). EPR studies have been carried out on polycrystalline powders and frozen DMF solutions of 1a-H 2O and 2b·2H2O. The EPR spectra of the polycrystalline powders indicate the presence of dipolar broadening and weak intermolecular exchange, while those of the frozen DMF solutions are characteristic of dipolar-coupled CuII pairs within the dinuclear molecules, with no evidence of intraor intermolecular exchange. The spectral simulations confirm that the binuclear structure and the Cu...Cu distances are retained in frozen solution. Dinuclear SiF22- containing compounds, [CuII2(L1)(H2O) 4](SiF6) (1b) and [[CuII2(L 1)(H2O)2(μSiF6))·4H 2O]∞ (1c-4H2O). were obtained serendipitously, in nearly quantitative yield, by the 2:1 reaction of Cu(BF 4)2· 4H2O with H2L 1 in H2O. The unexpected SiF62- anions were generated in the course of the reaction by partial hydrolysis of the BF4- anions employed, thus forming traces of HF which reacted with the glassware.
AUTOOXIDATION OF METHYLHETEROCYCLES UNDER PHASE TRANSFER CATALYSIS CONDITIONS
Iovel', I. G.,Gol'dberg, Yu. Sh.,Gaukhman, A. P.,Zolotoyabko, R. M.,Shimanskaya, M. V.
, p. 768 - 771 (1991)
The autooxidation of methyl- and dimethyl-substituted N-, S-, and O-heterocyclic compound derivatives has been studied in 1,2-dimethoxyethane-t-BuOK in the presence of 18-crown-6.Mono- and dicarboxylic acid derivatives of pyrazine, pyridine, pyrimidine, and thiophene have been synthesized.
Design, synthesis, and biological evaluation of bone-targeted proteasome inhibitors for multiple myeloma
Agyin, Joseph K.,Santhamma, Bindu,Roy, Sudipa S.
, p. 6455 - 6458 (2013)
Multiple myeloma (MM) is an incurable neoplasm characterized by devastating and progressive bone destruction. Standard chemotherapeutic agents have not been effective at significantly prolonging the survival of MM patients and these agents are typically a
Self-Assembly of Cyclohelicate [M3L3] Triangles Over [M4L4] Squares, Despite Near-Linear Bis-terdentate L and Octahedral M
Hogue, Ross W.,Dhers, Sébastien,Hellyer, Ryan M.,Luo, Jingwei,Hanan, Garry S.,Larsen, David S.,Garden, Anna L.,Brooker, Sally
, p. 14193 - 14199 (2017)
Self-assembly of 1:1:2 MII(BF4)2 (M=Zn or Fe), pyrazine-2,5-dicarbaldehyde (1) and 2-(2-aminoethyl)pyridine gave trimetallic triangle architectures rather than the anticipated tetrametallic [2×2] squares. Options for the n
OXIDATION OF 2,5-DIMETHYLPYRAZINE WITH OXYGEN IN THE VAPOR PHASE ON OXIDE CATALYSTS AND IN THE LIQUID PHASE IN THE PRESENCE OF BASES
Iovel', I. G.,Yansone, I. Ya.,Gol'dberg, Yu. Sh.,Shimanskaya, M. V.
, p. 456 - 461 (1990)
The vapor-phase oxidation of 2,5-dimethylpyrazine with oxygen on vanadium-molybdenum oxide catalysts modified with silver oxide gives 5-methyl-2-formylpyrazine and 2,5-diformylpyrazine in 37percent and 35percent yields, respectively.Pyrazine-2,5-dicarboxylic acid was obtained in 53percent yield by the liquid-phase oxidation of 2,5-dimethylpyrazine with oxygen in the presence of a strong base and an interphase catalyst.
METHOD FOR PRODUCING HETEROAROMATIC CARBOXYLIC ACID
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Paragraph 0039; 0040, (2018/08/09)
PROBLEM TO BE SOLVED: To provide a method for producing heteroaromatic carboxylic acids at good yields, when producing the heteroaromatic carboxylic acids by the oxidation of methyl-substituted heteroaromatic compounds. SOLUTION: A method for producing a heteroaromatic carboxylic acid includes oxidizing a methyl-substituted heteroaromatic compound, having one or more methyl groups on a heteroaromatic ring, with a basic compound and a permanganate. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
SUBSTITUTED PIPERAZINE COMPOUND, AND ABSORBENT AND LIQUID ABSORBENT FOR ACIDIC GAS
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Paragraph 0031; 0032; 0033, (2018/10/19)
PROBLEM TO BE SOLVED: To provide a substituted piperazine compound that can suppress composition change when used by preparing a liquid absorbent, to provide an absorbent containing the substituted piperazine compound as an active ingredient and to provide a liquid absorbent for the treatment of an acidic gas such as carbon dioxide or the like that is prepared by using the substituted piperazine compound. SOLUTION: The substituted piperazine compound is represented by the following general formula. The liquid absorbent for absorption treatment of an acidic gas such as carbon dioxide or the like is prepared by using the absorbent containing the substituted piperazine compound as an active ingredient and water. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2018,JPOandINPIT
A chiral β-diketone complex [...] method for preparing light-emitting material
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Paragraph 0057; 0058, (2017/03/28)
The invention discloses a method for preparing a chiral dual-core europium beta-diketone complex luminescent material. The method comprises the following steps: dissolving Eu(tta)3.2H2O into ethanol to prepare a solution a of which the concentration is 0.01mol/L at normal temperature; dissolving an organic bridging ligand (-)-2,5-bi(4,5-pinene-2-pyridyl) of chiral pinene pyridine pyrazine derivatives into acetone to prepare a solution b of which the concentration is 0.005mol/L; mixing the solution a with the solution b at equal volume and then agitating for 20 minutes; standing the mixed solution; filtering after 6-8 days; and washing by using absolute ether and drying in vacuum, so as to prepare the chiral dual-core europium beta-diketone complex luminescent material. The luminescent material is mild in synthesis condition, high in yield, strong in stability, and easy to separate and purify, and is expected to have a broad application prospect in the aspects such as an electroluminescent device, a bioluminescent probe, a nonlinear optical material and a light conversion molecular device as a novel luminescent material.
Synthesis of highly functionalized pyrazines by ortho-lithiation reactions. Pyrazine ladder polymers
Zhang, Carol Y.,Tour, James M.
, p. 8783 - 8790 (2007/10/03)
Several novel transformations on sensitive pyrazine cores are disclosed while preparing monomers for condensation polymerizations to planar polypyrazines. Two pyrazine monomers for the step growth polymerization are prepared starting from ethyl acetoacetate and proceeding via pyrazine-2,5-dicarboxylic acid as the common intermediate. The dicarboxylic acid serves as the key intermediate for the preparation of both the A and B components for the step-growth polymerization. A bis(Curtius) rearrangement followed by tert-butyl alcohol capture of the diisocyanate effects the high-yielding conversion of carbonyl moieties to the tert-butoxycarbonyl-protected aryldiamine. Since electrophilic halogenation of the pyrazine nucleus was unsuccessful due to the inherent electron deficiency of pyrazines, a directed ortho-metalation is disclosed using tert-butoxycarbonyl-protected amines and neopentyl glycol acetals as the metalation directing groups. Pd/Cu-catalyzed couplings of diiodopyrazines with distannylpyrazines are utilized for the polymerization schemes. This approach permits the ladder linkages of the planar polymers to (i) form in high yields upon ZnCl2 activation once the polymer backbone is intact, (ii) be substituted so that the newly formed polypyrazines are soluble, unlike many other aromatic ladder polymers, and (iii) contain double-bonded ladder units to keep the consecutive aryl moieties planar which maximizes extended π-conjugation through the polymer backbones, thereby increasing the bandwidths and lowering the optical band gaps.
