- Selective and sensitive fluorescent chemosensors for Cu2+ ion based upon bis-1,8-naphthalimide dyads
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A series of new fluorescent chemosensors 5a-5e, composed of two aminonaphthalimide fluorophores and 2,6-bis((N-aminoalkyl)aminocarboxy) pyridines, were prepared, characterized, and their fluorescent properties towards heavy and transition metal (HTM) ions were investigated. Chemosensors 5c-5e exhibited high selectivity and sensitivity for Cu2+ ion over other HTM ions with fluorescent quenching (green to colourless). It clearly demonstrated that the length of the linkers (diamines) between the aminonaphthalimides and 2,6-dicarboxypyridine of 5a-5e was very important for their sensitivity and selectivity for Cu2+ ion over other HTM ions. Three chemosensors 5c-5e exhibited high selectivity and sensitivity for Cu 2+ ion over other heavy and transition metal ions with fluorescent quenching (green to colourless). Copyright
- Dai, Huiling,Xu, Hui
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- Bis(hydroxylamino)triazines: High Selectivity and Hydrolytic Stability of Hydroxylamine-Based Ligands for Uranyl Compared to Vanadium(V) and Iron(III)
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The development of ligands with high selectivity and affinity for uranium is critical in the extraction of uranium from human body, radioactive waste, and seawater. A scientific challenge is the improvement of the selectivity of chelators for uranium over other heavy metals, including iron and vanadium. Flat ligands with hard donor atoms that satisfy the geometric and electronic requirements of the UVIO22+ exhibit high selectivity for the uranyl moiety. The bis(hydroxylamino)(triazine) ligand, 2,6-bis[hydroxy(methyl)amino]-4-morpholino-1,3,5-triazine (H2bihyat), a strong binder for hard metal ions (FeIII, TiIV, VV, and MoVI), reacted with [UVIO2(NO3)2(H2O)2]·4H2O in aqueous solution and resulted in the isolation of the complexes [UVIO2(bihyat)(H2O)], [UVIO2(bihyat)2]2-, and {[UVIO2(bihyat)(μ-OH)]}22-. These three species are in equilibrium in aqueous solution, and their abundance varies with the concentration of H2bihyat and the pH. Reaction of H2bihyat with [UVIO2(NO3)2(H2O)2]·4H2O in CH3CN gave the trinuclear complex [UVI3O6(bihyat)2(μ-bihyat)2]2-, which is the major species in organic solvents. The dynamics between the UVIO22+ and the free ligand H2bihyat in aqueous and dimethyl sulfoxide solutions; the metal binding ability of the H2bihyat over pyridine-2,6-dicarboxylic acid (H2dipic) or glutarimidedioxime for UVIO22+, and the selectivity of the H2bihyat to bind UVIO22+ in comparison to VVO43- and FeIII in either UVIO22+/VVO43- or UVIO22+/FeIII solutions were examined by NMR and UV-vis spectroscopies. The results revealed that H2bihyat is a superior ligand for UVIO22+ with high selectivity compared to FeIII and VVO43-, which increases at higher pHs. Thus, this type of ligand might find applications in the extraction of uranium from the sea and its removal from the environment and the human body.
- Hadjithoma, Sofia,Papanikolaou, Michael G.,Leontidis, Epameinondas,Kabanos, Themistoklis A.,Keramidas, Anastasios D.
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- A novel synthesis of 2,6-pyridinedicarboxylic acid by the PTC auto-oxidation of 2,6-lutidine
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2,6-Pyridinedicarboxylic acid was obtained in 69% yield by the oxidation of 2,6-dimethylpyridine with oxygen under the action of tert-BuOK in the presence of the phase-transfer catalyst 18-crown-6.
- Iovel,Shymanska
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Read Online
- High efficiency co-sensitized solar cell based on luminescent lanthanide complexes with pyridine-2,6-dicarboxylic acid ligands
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Two lanthanide complexes, Ln(HPDA)3·4EtOH (Ln = Tb, Dy) (H2PDA = pyridine-2,6-dicarboxylic acid, EtOH = ethanol), have been successfully synthesized using hydrothermal or solvothermal methods, and their crystal structures were analyz
- Wang, Xin,Yang, Yu-Lin,Wang, Ping,Li, Liang,Fan, Rui-Qing,Cao, Wen-Wu,Yang, Bin,Wang, Hui,Liu, Jing-Yao
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- Preparation method of 2,6-chloromethylpyridine hydrochloride (by machine translation)
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The invention belongs to the field, of organic synthesis, and particularly relates to 2,6 -chloromethylpyridine hydrochloride, preparation method :(1), which comprises the following steps 2,6 - reacting,dimethylaminopyridine as a raw material 2,6 - to prepare ;(2)2,6 -picolinic acid dimethyl 2,6 -picolinic acid dimethyl ;(3)2,6 -pyridine dimethanol and thionyl chloride to obtain a target product 2,6 -dichloromethylpyridine dihydrochloride with methanol in an acidic condition ;(4)2,6 - The method comprises the following steps: reacting 2,6 - with a commonly-used chemical raw material containing a pyridine ring and methanol in an acidic condition. The method disclosed by the invention is suitable for industrial, production : (by machine translation)
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Paragraph 0018; 0021; 0022; 0026; 0027; 0031; 0032
(2020/03/03)
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- Preparation method of 2,6-pyridinedicarboxylic acid
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The invention provides a preparation method of 2,6-pyridinedicarboxylic acid. The preparation method comprises the following steps: taking 1,7-pimelic acid or 1,7-pimelic acid diester (I) as a raw material to carry out a halogenation reaction to obtain 2,2,6,6-tetrahalide (II), then carrying out a cyclization reaction with ammonia to prepare a dihydropyridine derivative (III), and carrying out oxidation by an oxidizing agent or carrying out oxidation-hydrolysis to obtain the 2,6-pyridinedicarboxylic acid. According to the method disclosed by the invention, raw materials are cheap and easily available, and the preparation method is simple, is easy to implement, and is safe and environmentally friendly. The amount of wastewater is small, cost is low, the yield and selectivity are high, byproducts are fewer, and the preparation method is suitable for industrial production.
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Paragraph 0043-0047; 0054; 0055
(2019/10/01)
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- A 2, 6 - dichloro methyl pyridine hydrochloride preparation method (by machine translation)
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The invention belongs to the field of organic synthesis, in particular relates to a 2, 6 - dichloro methyl pyridine hydrochloride of the preparation method, the method comprises the following steps: (1) to 2, 6 - lutidine as a raw material, preparation 2, 6 - pyridine dicarboxylic acid; (2) 2, 6 - pyridine dicarboxylic acid with methanol under acidic conditions to produce the 2, 6 - pyridine dicarboxylic acid dimethyl ester; (3) 2, 6 - pyridine dicarboxylic acid dimethyl ester is reduced to 2, 6 - pyridine-methanol; (4) 2, 6 - pyridine-methanol with thionyl chloride reaction to obtain the target product 2, 6 - dichloro methyl pyridine hydrochloride. The beneficial effect of the invention is: the invention adopts the commonly used chemical raw materials containing a pyridine [...] reaction, reaction steps is small, low cost, low toxicity, high yield, it is suitable for industrial production. (by machine translation)
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Paragraph 0021-0022; 0026-0027
(2019/05/28)
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- Method for synthesizing 2,6-dipicolinic acid
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The invention discloses a method for synthesizing 2,6-dipicolinic acid. The method comprises the following steps: under the condition of air isolation, by using anhydrous diethyl ether or THF (tetrahydrofuran) as solvent, reacting 2,6-dichloropyridine used as a raw material with active metal under the action of an initiator to obtain a Grignard reagent; and cooling, then introducing excessive dry carbon dioxide gas, and acidifying to obtain the 2,6-dipicolinic acid. According to the invention, the cheap 2,6-dichloropyridine is used as the raw material, so the cost is low; and the synthesis process route is simple and easy to control, and can easily implement industrial production.
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Paragraph 0020; 0021
(2017/02/09)
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- Co(ii), a catalyst for selective conversion of phenyl rings to carboxylic acid groups
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An inexpensive protocol for the conversion of -C6H4R into -COOH groups using Co(ii)-Oxone mixture as the catalytic system is described. A series of substrates containing substituted and non-substituted phenyl groups could be selectively converted into carboxylic acids. Initial mechanistic data have been provided.
- Sinha, Shashi Bhushan,Campos, Jess,Brudvig, Gary W.,Crabtree, Robert H.
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p. 49395 - 49399
(2014/12/10)
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- Lightening Agents and/or Dyes that Contain Aldehyde(s)
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Agents for dyeing and/or lightening keratin fibers, in particular human hair, containing, relative to the weight thereof, 0.001 to 15 wt. % of at least one aldehyde of the formula (I): wherein X represents —CH(R2)—SO2—Y—R1, —CR3R4R5, or wherein Y represents —CH(CHO)— or —CH2— or a chemical bond, and wherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 independently represents —H or —CN or —F or —Cl or —Br or —I or —CHO or —NH2 or —NO2 or —CF3 or —CCl3 or —CF2CF3 or —CCl2CCl3 or an optionally substituted (C1-C6) alkyl group or a hydroxyalkyl group or a polyhydroxyalkyl group or an optionally substituted (C1-C6) alkylene group, and wherein the agent contains no oxidation dye precursors of developer and coupler type.
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- Amino-acid templated assembly of sucrose-derived macrocycles
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C2-Symmetrical chiral macrocyles containing two sucrose units were prepared by an amino acid templated macrocyclization reaction between appropriate sucrose-based linear precursors and ethylenediamine.
- Lewandowski, Bartosz,Jarosz, Slawomir
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scheme or table
p. 2532 - 2535
(2010/07/20)
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- Co-sensitized dye-sensitized solar cells based on d10 coordinate complexes towards their optoelectronic properties
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Three five-coordinate transition metal complexes [2,6-(PhNCMe) 2C5H3NMCl2·CH3CN] (M = Zn, Cd, Hg) (named M1) have been assembled onto a nanocrystalline TiO 2 film to prepare transition meta
- Wang, Xin,Yang, Yulin,Fan, Ruiqing,Jiang, Zhaohua
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experimental part
p. 2599 - 2604
(2011/01/12)
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- Novel late transition metal catalysts based on iron: Synthesis, structures and ethylene polymerization
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In this article we reported synthesis, characterization and ethylene polymerization behavior of two new late transition metal 2,6-bis(imino)pyridine catalysts based on iron(II) possessing different substituents of NO2 (catalyst b) and OMe (catalyst c) at the para position of the pyridine ring. Theoretical study exhibited more positive charge on the central metal of the catalyst b, leading to higher activity offset by lower thermal stability and life time.
- Zohuri, Gholam Hossein,Seyedi, Seyed Mohammad,Sandaroos, Reza,Damavandi, Saman,Mohammadi, Ali
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scheme or table
p. 160 - 166
(2011/10/03)
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- Synthesis of novel donor -π- acceptor chromophores with dipicolinate as acceptor
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Three novel donor - acceptor (D - A) chromophores, with dipicolinate as acceptor, have been synthesized. All the compounds were characterized by 1H NMR, infrared (IR) spectroscopy, mass spectrometry (MS), and elemental analysis.
- Xiao, Haibo,Tao, Xiaoming,Li, Hui,Shi, Guanghao
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scheme or table
p. 1472 - 1477
(2009/09/26)
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- Dipicolinate as acceptor in D-π-A chromophores: synthesis, characterization and fluorescence following single- and two-photon excitation
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Three novel donor-π-acceptor type compounds with dipicolinate as acceptor have been synthesized. Their absorption, photoluminescence as well as their two-photon absorption properties have been investigated. Two of them show strong two-photon absorption and two-photon excited up-conversion fluorescence.
- Xiao, Haibo,Tao, Xiaoming,Wang, Yaochuan,Qian, Shixiong,Shi, Guanghao,Li, Hui
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scheme or table
p. 6819 - 6822
(2009/04/07)
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- Controlled synthesis of 2-acetyl-6-carbethoxypyridine and 2,6-diacetylpyridine from 2,6-dimethylpyridine
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The controlled syntheses of mono- and bis-acetylpyridine from the same starting material (2,6-dimethylpyridine) are reported, including the asymmetrical compound 2-acetyl-6-carbethoxypyridine, which has not before been reported. The influences of the amount of catalyst EtONa and the reaction conditions to the final products are also explored. A modification of the reported preparation for the 2,6-dipicolinic acid, 2,6-dicarbethoxypyridine and 2,6-diacetylpyridine with higher purity and improved yields is provided here, and the physical and spectral properties of these products are identical to those reported in the literature. Copyright Taylor & Francis, Inc.
- Su, Biyun,Zhao, Jianshe,Cui, Yong,Liang, Yongqing,Sun, Wenhua
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p. 2317 - 2324
(2007/10/03)
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- Chelate bis(imino)pyridine cobalt complexes: Synthesis, reduction, and evidence for the generation of ethene polymerization catalysts by Li+ cation activation
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Treatment of the bis(iminobenzyl)pyridine chelate Schiff-base ligand 8 (ligPh) with FeCl2 or CoCl2 yielded the corresponding (ligPh)MCl2 complexes 9 (Fe) and 10 (Co). The reaction of 10 with methyllithium or "butadiene-magnesium" resulted in reduction to give the corresponding (ligPh)Co(I)Cl product 11. Similarly, the bis(aryliminoethyl)pyridine ligand (ligMe) was reacted with CoCl2 to yield (ligMe)CoCl2 (12). Reduction to (ligMe)CoCl (13) was effected by treatment with "butadiene-magnesium". Complex 13 reacted with Li[B(C 6F5)4] in toluene followed by treatment with pyridine to yield [(ligMe)Co+-pyridine] (15). The reaction of the Co(II) complexes 10 or 12 with ca. 3 molar equiv of methyllithium gave the cobalt(I) complexes 16 and 17, respectively. Treatment of the (lig Me)CoCH3 (17) with Li[B(C6F5) 4] gave a low activity ethene polymerization catalyst. Likewise, complex 16 produced polyethylene (activity = 33 g(PE) mmol(cat)-1 h-1 bar-1 at room temperature) upon treatment with a stoichiometric amount of Li[B(C6F5)4]. A third ligand (ligOMe) was synthesized featuring methoxy groups in the ligand backbone (22). Coordination to FeCl2 and CoCl2 yielded the desired compounds 23 and 24. Reaction with MeLi gave (lig OMe)CoMe (25/26). Treatment of 25/26 with excess B(C 6F5)3 gave the η6-arene cation complex 27, where one Co-N linkage was cleaved. Activation of 25/26 with Li[B(C6F5)4] again gave a catalytically active species.
- Kleigrewe, Nina,Steffen, Winfried,Bloemker, Tobias,Kehr, Gerald,Froehlich, Roland,Wibbeling, Birgit,Erker, Gerhard,Wasilke, Julia-Christina,Wu, Guang,Bazan, Guillermo C.
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p. 13955 - 13968
(2007/10/03)
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- Coloring agent comprising transition metals
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The present invention relates to a composition for coloring keratin fibers and a method of using the same. The composition of the present invention contains at least one dye precursor, and one or more clathrate compounds that contain transition metal complexes.
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- Compositions of matter having bioactive properties
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Particles of coordinated complex comprising a basic, hydrous polymer and a capacitance adding compound, as well as methods for their production, are described. These complexes exhibit a high degree of bioactivity making them suitable for a broad range of applications through their incorporation into conventional vehicles benefiting from antimicrobial and similar properties.
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- Composition of matter having bioactive properties
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Particles of coordinated complex comprising a basic, hydrous polymer and a capacitance adding compound, as well as methods for their production, are described. These complexes exhibit a high degree of bioactivity making them suitable for a broad range of applications through their incorporation into conventional vehicles benefiting from antimicrobial and similar properties.
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- Synthesis of a key intermediate in the diaminopimelate pathway to L-lysine: 2,3,4,5-tetrahydrodipicolinic acid
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2,3,4,5-Tetrahydrodipicolinic acid (3) is a key intermediate in the diaminopimelate (DAP) pathway to L-lysine (7). It was synthesized as the stable racemic potassium salt (25) from dipicolinic acid (14) by esterification, hydrogenation to the cis-diester (17), followed by elimination of p-toluenesulfinic acid from the N-toluenesulfonyl derivative (24) of dimethyl cis-piperidine-2,6-dicarboxylate with concomitant cleavage of the esther groups. (±)-2,3,4,5-Tetrahydrodipicolinic acid is unstable in neutral or acidic solution, and in basic solution it exists in equilibrium with the corresponding enamine (27) and 2-oxo-6-aminoadipate (26).
- Chrystal, Ewan J. T.,Couper, Lynda,Robins, David J.
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p. 10241 - 10252
(2007/10/02)
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- ANODIC OXIDATION OF METHYL-SUBSTITUTED NITROGEN-CONTAINING HETEROCYCLIC COMPOUNDS AT THE ACTIVATED NICKEL OXIDE ELECTRODE
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Methyl derivatives of several nitrogen-containing heterocyclic compounds were converted into the corresponding carboxylic acids by means of electrochemical oxidation at the nickel oxohydroxide anode in alkaline medium, using a nondiaphragm electrolyzer.The oxidation of 2,5-dimethylpyrazine was used to demonstrate the effect of adding chromium (III) and cobalt (II) compounds to the reaction mixture.The composition and electronic state of the anode surface were studied using x-ray diffraction and XPS methods.
- Feldman, D.,Chervenka, M.,Stokh, E.,Shimanska, M.,Khaber, E.
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- A Ring Opening Reaction of Hydroperoxides of Cyclic Ethers
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2-Hydroperoxides of cyclic esters react with pyridine-2,6-di(monothiocarboxylic acid) in form of its iron complex by attack of the thiocarboxylate anion at C-3, opening of the ether ring and formation of a thioester carrying a acyloxy group in the alcohol portion.A typical example is the formation of pyridine-2,6-di(monothiocarboxylic acid)-di-S-(3-formoxypropyl)ester from tetrahydrofuran-2-hydroperoxide. - Keywords: Ring Opening Reaction, Hydroperoxides, Cyclic Ethers
- Ockels, W.,Stein, J.,Budzikiewicz, H.
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- 1,1-Alkanediol dicarboxylate linked antibacterial agents
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Useful antibacterial agents in which a penicillin and/or a beta-lactamase inhibitor are linked via 1,1-alkanediol dicarboxylates are of the formula STR1 where A is the residue of certain dicarboxyic acids, R3 is H or (C1 -C3), n is zero or 1 such that when n is zero R is P or B and R1 is the residue of certain esters, H or a salt thereof; and when n is 1, one of R and R1 is P and the other is B, and P is STR2 where R2 is H or certain acyl groups, and B is the residue of a beta-lactamase inhibiting carboxylic acid; a method for their use, pharmaceutical compositions thereof and intermediates useful in their production.
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- METAL ION CATALYSIS OF ANHYDRIDE HYDROLYSIS. METAL ION PROMOTED WATER AND HYDROXIDE ION CATALYZED REACTIONS OF MIXED CINNAMIC ACID ANHYDRIDES.
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Rate constants have been determined for hydrolysis of cinnamic picolinic anhydride and cinnamic 6-carboxypicolinic monoanhydride in 50% dioxane-H//2O at 30 degree C. At pH values less than 7, both water and hydronium ion catalyzed reactions are observed in hydrolysis of cinnamic picolinic anhydride. The latter reaction is also seen with cinnamic isonicotinic anhydride and is very likely associated with protonation of the pyridine nitrogen. Divalent metal ions (Cu**2** plus , Ni**2** plus , Co**2** plus , and Zn**2** plus ) exert a significant catalytic effect in the hydrolysis of cinnamic picolinic anhydride even though binding is weak (saturation effects were not observed). Rate enhancements ranging from 200-fold with 0. 0005 M Cu**2** plus to 10-fold with 0. 0005 M Zn**2** plus were obtained. The reactions at constant metal ion concentration are pH independent. Metal ion catalysis is not observed in the hydrolysis of cinnamic isonicotinic anhydride. Therefore, metal ion catalysis in the hydrolysis of cinnamic picolinic anhydride must be specifically associated with a chelation effect. The metal ion binding to cinnamic 6-carboxypicolinic monoanhydride is quite strong, and saturation occurs at low metal ion concentrations.
- Fife,Przystas
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p. 1638 - 1642
(2007/10/02)
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- Steric factors and stability of the complexes of pyridinecarboxylate ions with group IIA cations. A thermodynamic study
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Heats and entropies of complex formation of 2-pyridinecarboxylate and 2,6-pyridinedicarboxylate with Mg(II), Ca(II), Sr(II) and Ba(II) cations were determined by direct calorimetry, and using the stability constants in the literature.The measurements were carried out in aqueous solution at 25 deg C and I = 0.2 mol.l(-1) (NaNO3).Examination of the results shows that the cause of the comparatively high stability of the complexes of pyridinecarboxylic ligands with group IIA cations is enthalpic.This is probably due to the coplanar position of the pyridine ring and the carboxylic groups.This factor acts more strongly in the case of Ca, Sr and Ba than of Mg, probably for reasons connected with the cation dimension.The different order of stability of the Mg and Ca complexes with the present ligands is probably due to the same cause.
- Aruga, Roberto
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- Two stage process for preparing 2,6-pyridin-dicarboxylic acid
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This invention relates to a two stage process for preparing 2,6-pyridin-dicarboxylic acid or dipicolinic acid from 2,6-dimethyl-pyridine through oxidation of the latter in an acid environment with hexavalent chromium salts and formation of a molar addition compound between dicarboxylic acid, being formed by oxidation, and chromic anhydride in the first stage, and subsequent hot hydrolysis of the addition product so obtained, thus isolating 2,6-pyridin-dicarboxylic acid therefrom in the second stage. The invention also comprises the above mentioned intermediate complex addition compound and the 2,6-pyridin-dicarboxylic acid of high purity, obtained by the process according to said invention.
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- POLYORGANOMETALLIC HETEROCYCLES. 2,6-DILITHIOPYRIDINE
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Metal-halogen exchange between 2,6-diiodo- and 2,6-dibromopyridine and two equivalents of n-butyllithium gives 2,6-dilithiopyridine.On quenching with either carbon dioxide followed by esterification, methanol or dimethyl disulfide the dilithio compound gives a methyl 2,6-pyridinedicarboxylate, pyridine, or 2,6-dithiomethylpyridine, respectively.A convenient procedure for halogen-halogen exchange is also described.
- Newkome, George R.,Roper, Jerry M.
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p. 147 - 153
(2007/10/02)
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- Hydroformylation of olefins using azoxy-dentated ligands
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At a temperature in the range 100° C to 225° C the destructive dissociation of cobalt carbonyl compounds to cobalt metal and residue is inhibited by the action of one or more azoxy-dentated chelation ligands.
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