Highly efficient Michael addition reactions of malonates to nitroalkenes catalyzed by novel chiral thioureas derived from optically pure BINOL and amino acids are reported. Various trans-nitroalkenes reacted with malo...Highly efficient Michael addition reactions of malonates to nitroalkenes catalyzed by novel chiral thioureas derived from optically pure BINOL and amino acids are reported. Various trans-nitroalkenes reacted with malonates affording the desired products in up to 95% yield with excellent enantioselectivities （up to 97% ee）.展开更多
Introduction 5-Monosubstituted isopropylidene malonates arc important synthetic organic intermediates. Since isopropylidene malonate has a stronger acidity （pK;=4.57）, its direct alkylation with alkyl halides usuall...Introduction 5-Monosubstituted isopropylidene malonates arc important synthetic organic intermediates. Since isopropylidene malonate has a stronger acidity （pK;=4.57）, its direct alkylation with alkyl halides usually gives 5,5-disubstitutcd isopropylidene malonates.展开更多
Multicomponent alkene 1,2-dicarbofunctionalizations(DCFs)have emerged as a powerful strategy to rapidly incorporate both two carbon subunits across one C-C double bond in one step for enhancing molecular complexity an...Multicomponent alkene 1,2-dicarbofunctionalizations(DCFs)have emerged as a powerful strategy to rapidly incorporate both two carbon subunits across one C-C double bond in one step for enhancing molecular complexity and diversity.To the best of our knowledge,there is only one report on photoredox-catalyzed three-component DCFs with malonates through the radical−radical cross-coupling,while photoredox-catalyzed radical-polar crossover(RPC)-type DCFs with malonates were still rare.Herein,we describe a redox-neutral RPC-type 1,2-dialkylation of styrenes with malonates and aldehydes through the synergistic Brønsted base/photoredox catalysis system.This transition-metal-free strategy provides an efficient and clean approach to a broad variety ofδ-hydroxy esters and also features exceptionally mild conditions,wide compatibility of substrate scope and functional groups,and high atomic economy.Moreover,three-component 1,2-alkylacylation from the same starting materials was achieved in one-pot manner through such RPC-type coupling and subsequent two-electron oxidation process,providing a set ofδ-keto esters of interest in pharmaceutical research.展开更多
Binaphthyl sulfonimides have been developed to catalyze the asymmetric Michael addition of ketone to alky- lidene malonates, affording the corresponding Michael products in good to high yields （up to 98%） with good ...Binaphthyl sulfonimides have been developed to catalyze the asymmetric Michael addition of ketone to alky- lidene malonates, affording the corresponding Michael products in good to high yields （up to 98%） with good to excellent diastereoselectivity （up to 99 ; 1 dr） and enantioselectivity （up to 92% ee） under mild conditions using environmentally benign water as the solvent.展开更多
Cu/SiO2 catalysts prepared by the ammonia evaporation method were applied to hydrogenation of diethyl malonate to 1,3‐propanediol. The calcination temperature played an important role in the structural evolution and ...Cu/SiO2 catalysts prepared by the ammonia evaporation method were applied to hydrogenation of diethyl malonate to 1,3‐propanediol. The calcination temperature played an important role in the structural evolution and catalytic performance of the Cu/SiO2 catalysts, which were systematically characterized by N2 adsorption‐desorption, inductively coupled plasma‐atomic emission spectros‐copy, N2O chemisorption, X‐ray diffraction, Fourier transform infrared spectroscopy, H2 tempera‐ture‐programmed reduction, transmission electron microscopy, and X‐ray photoelectron spectros‐copy. When the Cu/SiO2 catalyst was calcined at 723 K, 90.7%conversion of diethyl malonate and 32.3%selectivity of 1,3‐propanediol were achieved. Compared with Cu/SiO2 catalysts calcined at other temperatures, the enhanced catalytic performance of the Cu/SiO2 catalyst calcined at 723 K can be attributed to better dispersion of copper species, larger cupreous surface area and greater amount of copper phyllosilicate, which results in a higher ratio of Cu＋/Cu0. The synergetic effect of Cu0 and Cu＋is suggested to be responsible for the optimum activity.展开更多
In two experiments, the effects of succinate and NADH（reduced nicotinamide adenine dinucleotide） on metmyoglobin reductase activity and electron transport chain-linked metmyoglobin reduction were investigated and co...In two experiments, the effects of succinate and NADH（reduced nicotinamide adenine dinucleotide） on metmyoglobin reductase activity and electron transport chain-linked metmyoglobin reduction were investigated and compared. In experiment 1, metmyoglobin（MetMb）, substrate and inhibitors were incubated with mitochondria. Comparsion of the effects of succinate and NADH on MetMb reduction was investigated. The MetMb percentage in sample treated with 8 mol L-1 succinate decreased by about 69% after 3 h incubation, and the effect was inhibited by the addition of 10 mol L-1 electron transfer chain complex II inhibitor malonic acid; the MetMb percentage in samples treated with 2 mol L-1 NADH decreased by 56% and the effect was inhibited by the addition of 0.02 mol L-1 electron transport chain complex I inhibitor rotenone. These results indicated that electron transport chain played an important role in MetMb reduction. Both complex II and complex I take part in the MetMb reduction in mitochondria through different pathways. NADH-MetMb reduction system was less stable than succinateMetMb system. In experiment 2, the beef longissimus dorsi muscle was blended with different concentrations of succinate or NADH. Enhancing patties with higher concentration of succinate or NADH improved colour stability in vacuum packaged samples（P〈0.05）. These results verified that mitochondria electron transport chain is related to the MetMb reduction in meat system.展开更多
A new ternary complex [Ni（phen）（pmal）]·8H2O （phen = 1,10-phenanthroline, pmal^2- = phenethyl malonic acid） has been synthesized by the reaction of nickel acetate, phen and phenethyl malonic acid. Elemental ...A new ternary complex [Ni（phen）（pmal）]·8H2O （phen = 1,10-phenanthroline, pmal^2- = phenethyl malonic acid） has been synthesized by the reaction of nickel acetate, phen and phenethyl malonic acid. Elemental analysis, IR spectra and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure. Crystal data for this complex： triclinic system, space group PI^-, a = 10.387（5）, b = 13.112（6）, c = 14.229（6） °A, α= 76.176（7）, β = 83.778（8）, γ = 71.770（6）°, C35H42N4O12Ni, Mr= 769.44, Z = 2, F（000） = 808, V = 1786.1°A^3, Dc = 1.431 g/cm^3,μ= 0.612 mm^-1, the final R = 0.0653 and wR = 0.1033 for 9379 （Rint = 0.0244） independent reflections and 4730 observed reflections （I〉 2σ（I））. Structural analysis shows that the coordination geometry of Ni（Ⅱ） is a distorted octahedron. A novel two-dimensional structure is constructed from （H2O）4 and （H2O）12 water clusters, and the complex forms a 3-D network supramolecular structure by hydrogen bonds and π-π stacking of neighboring phens.展开更多
The reaction of 4,4?-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]22H2O. It crystallizes in monoclinic, ...The reaction of 4,4?-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]22H2O. It crystallizes in monoclinic, space group P21/c with a = 15.231(3), b = 11.847(2), c = 9.801(2) ? b = 106.75(3)o, V = 1693.5(6) 3, Z = 2, C32H40Cu2N4O12, Mr = 799.76, Dc = 1.568 g/cm3, ?(MoKa) = 0.71073 ? = 1.325 mm-1, F(000) = 828, the final R = 0.0531 and wR = 0.1244 for 3421 observed reflections with I > 2s(I). Each Cu(II) is coordinated by two oxygen atoms from a mal ligand, two nitrogen atoms from two dadm ligands and a water oxygen atom to form a triangle bipyramidal motif. The title compound possesses a distorted macrocycle enclosed by dadm with approximate dimensions of 8.3 ??5.9 ?展开更多
Ionic liquids （ILs） based on 1,3-dialkylimidazolium and tetraalkylammonium cations were employed as a series of efficient, environmentally benign phase-transfer catalysts （PTCs） for the base-promoted monoalkylatio...Ionic liquids （ILs） based on 1,3-dialkylimidazolium and tetraalkylammonium cations were employed as a series of efficient, environmentally benign phase-transfer catalysts （PTCs） for the base-promoted monoalkylation of diethyl malonate. The influence of various heterogeneous bases on yields was studied. Good yields and high selectivity were obtained. Solvent-free, mild reaction condition, short reaction time, and easy purification were the merits of this method. The catalytic system （IL-hase） could also be recycled after the extraction of products with ether.展开更多
Two dinuclear compounds [Ln2（acetate）6（H2O）4]-4H2O （Ln=Tb（1）, Sm（2）） were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, ...Two dinuclear compounds [Ln2（acetate）6（H2O）4]-4H2O （Ln=Tb（1）, Sm（2）） were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln（Ⅲ） ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb（Ⅲ） in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.展开更多
A green synthesis route of diethyl malonate by palladium catalyzed carbonylation of ethyl chloroacetate in the presence of phase transfer agent is carried out under mild conditions in good yield. The effects of reacti...A green synthesis route of diethyl malonate by palladium catalyzed carbonylation of ethyl chloroacetate in the presence of phase transfer agent is carried out under mild conditions in good yield. The effects of reaction temperature and different bases on the yield of diethyl malonate are also discussed.展开更多
Carboxycoumsrins were synthesized via the solid phase synthesis conviently. The resin bound cyclic malonic ester reacted with o-methoxy or o-hydroxybenzaldehydes. Then cyclization was processed under H2SO4 to afford...Carboxycoumsrins were synthesized via the solid phase synthesis conviently. The resin bound cyclic malonic ester reacted with o-methoxy or o-hydroxybenzaldehydes. Then cyclization was processed under H2SO4 to afford the products in excellent purities and yields.展开更多
A new complex of malonic acid with lanthanum,La(Hmal)·(mal)·3H_2O,was synthesized and characterized by elemental analysis and IR spectra.The thermal decomposition process and their kinetic parameters n and E...A new complex of malonic acid with lanthanum,La(Hmal)·(mal)·3H_2O,was synthesized and characterized by elemental analysis and IR spectra.The thermal decomposition process and their kinetic parameters n and E_a were studied by means of TG and DTG.All of the intermediate and end products were determined and characterized by the mass loss in TG curve,elemental analysis and IR spectra.展开更多
A novel method of preparing dimethyl malonate by carbonylation of methyl chloroacetate catalyzed by Na[Co(CO)(4)] was proposed. Na[Co(CO)(4)] was synthesized in situ in the presence of Na2S2O3 and iron powder. The eff...A novel method of preparing dimethyl malonate by carbonylation of methyl chloroacetate catalyzed by Na[Co(CO)(4)] was proposed. Na[Co(CO)(4)] was synthesized in situ in the presence of Na2S2O3 and iron powder. The effects of some reaction parameters such as temperature. CO pressure and the concentrations of catalyst on the yields of dimethyl malonate were discussed. The kinetic data were studied and a possible reaction mechanism was proposed.展开更多
The title complex [CaCo（C3H2O4）2（H2O）4]n with a formula of C6HI2CaCoO12 and Mr=375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2/c with a...The title complex [CaCo（C3H2O4）2（H2O）4]n with a formula of C6HI2CaCoO12 and Mr=375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 14,195（9）, b = 7.708（5）, c = 13.441（8） A, β =119.575（9）°, V = 1279.0（14） A3, Dc= 1.948 g/cm^3,μ=1.803 mm^-1, F（000） = 764 and Z = 4. The final R = 0.0245 and wR = 0.0652 for 1344 observed reflections with I 〉 2σ（I）. The structure of the title complex consists of CaO8 polyhedra and CoO6 octahedra linked together by malonate ligands. The Ca（Ⅱ） cation on a twofold axis is coordinated by two water molecules and six malonate O atoms. The Co（Ⅱ） cation which lies in a centre of symmetry in an octahedral arrangement is coordinated by four malonate O atoms and two water molecules, The structure comprises alternating layers along the [101] plane, with the shortest Co-Co distance of 6.961（5）A. The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds.展开更多
Abnormal TAR DNA-binding protein 43 （TDP-43） inclusion bodies can be detected in the degen- erative neurons of amyotrophic lateral sclerosis. In this study, we induced chronic oxidative stress injury by applying mal...Abnormal TAR DNA-binding protein 43 （TDP-43） inclusion bodies can be detected in the degen- erative neurons of amyotrophic lateral sclerosis. In this study, we induced chronic oxidative stress injury by applying malonate to cultured mouse cortical motor neurons. In the later stages of the malonate insult, TDP-43 expression reduced in the nuclei and transferred to the cytoplasm. This was accompanied by neuronal death, mimicking the pathological changes in TDP-43 that are seen in patients with amyotrophic lateral sclerosis. Interestingly, in the early stages of the response to malonate treatment, nuclear TDP-43 expression increased, and neurons remained relatively intact, without inclusion bodies or fragmentation. Therefore, we hypothesized that the increase of nuclear TDP-43 expression might be a pro-survival factor against oxidative stress injury. This hypothesis was confirmed by an in vitro transgenic experiment, in which overexpression of wild type mouse TDP-43 in cultured cortical motor neurons significantly reduced malonate-induced neuronal death. Our findings suggest that the loss of function of TDP-43 is an important cause of neuronal degen- eration, and upregulation of nuclear TDP-43 expression might be neuroprotective in amyotrophic lateral sclerosis.展开更多
基金support from Natural Science Foundation of China(No.20772097)Sichuan Provincial Science Foundation for Outstanding Youth(No.05ZQ026-008)Key Project of the Education Department of Sichuan Province(No.2006A081).
文摘Highly efficient Michael addition reactions of malonates to nitroalkenes catalyzed by novel chiral thioureas derived from optically pure BINOL and amino acids are reported. Various trans-nitroalkenes reacted with malonates affording the desired products in up to 95% yield with excellent enantioselectivities （up to 97% ee）.
基金Supported by the National Natural Science Foundation of Chinathe Basic Research Foundation of Zhejian Educational Commission.
文摘Introduction 5-Monosubstituted isopropylidene malonates arc important synthetic organic intermediates. Since isopropylidene malonate has a stronger acidity （pK;=4.57）, its direct alkylation with alkyl halides usually gives 5,5-disubstitutcd isopropylidene malonates.
基金supported by the National Natural Science Foundation of China(Nos.22101237,22171233)the Science and Technology Program of Sichuan Province(No.2022NSFSC1219)+1 种基金the Science and Technology Program of Luzhou City(Nos.2021-SYF-34,2023LZXNYDJ019)and the Open Project Program of Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province(No.HYX21003).
文摘Multicomponent alkene 1,2-dicarbofunctionalizations(DCFs)have emerged as a powerful strategy to rapidly incorporate both two carbon subunits across one C-C double bond in one step for enhancing molecular complexity and diversity.To the best of our knowledge,there is only one report on photoredox-catalyzed three-component DCFs with malonates through the radical−radical cross-coupling,while photoredox-catalyzed radical-polar crossover(RPC)-type DCFs with malonates were still rare.Herein,we describe a redox-neutral RPC-type 1,2-dialkylation of styrenes with malonates and aldehydes through the synergistic Brønsted base/photoredox catalysis system.This transition-metal-free strategy provides an efficient and clean approach to a broad variety ofδ-hydroxy esters and also features exceptionally mild conditions,wide compatibility of substrate scope and functional groups,and high atomic economy.Moreover,three-component 1,2-alkylacylation from the same starting materials was achieved in one-pot manner through such RPC-type coupling and subsequent two-electron oxidation process,providing a set ofδ-keto esters of interest in pharmaceutical research.
基金Acknowledgment We are grateful for financial support from the National Natural Science Foundation of China （No. 21072020）, the Science and Technology Innovation Program of Beijing Institute of Technology （No. 2011CX01008） and the Development Program for Distinguished Young and Middle-aged Teachers of Beijing Institute of Technology.
文摘Binaphthyl sulfonimides have been developed to catalyze the asymmetric Michael addition of ketone to alky- lidene malonates, affording the corresponding Michael products in good to high yields （up to 98%） with good to excellent diastereoselectivity （up to 99 ; 1 dr） and enantioselectivity （up to 92% ee） under mild conditions using environmentally benign water as the solvent.
文摘Cu/SiO2 catalysts prepared by the ammonia evaporation method were applied to hydrogenation of diethyl malonate to 1,3‐propanediol. The calcination temperature played an important role in the structural evolution and catalytic performance of the Cu/SiO2 catalysts, which were systematically characterized by N2 adsorption‐desorption, inductively coupled plasma‐atomic emission spectros‐copy, N2O chemisorption, X‐ray diffraction, Fourier transform infrared spectroscopy, H2 tempera‐ture‐programmed reduction, transmission electron microscopy, and X‐ray photoelectron spectros‐copy. When the Cu/SiO2 catalyst was calcined at 723 K, 90.7%conversion of diethyl malonate and 32.3%selectivity of 1,3‐propanediol were achieved. Compared with Cu/SiO2 catalysts calcined at other temperatures, the enhanced catalytic performance of the Cu/SiO2 catalyst calcined at 723 K can be attributed to better dispersion of copper species, larger cupreous surface area and greater amount of copper phyllosilicate, which results in a higher ratio of Cu＋/Cu0. The synergetic effect of Cu0 and Cu＋is suggested to be responsible for the optimum activity.
基金the National Natural Science Foundation of China (31071624)
文摘In two experiments, the effects of succinate and NADH（reduced nicotinamide adenine dinucleotide） on metmyoglobin reductase activity and electron transport chain-linked metmyoglobin reduction were investigated and compared. In experiment 1, metmyoglobin（MetMb）, substrate and inhibitors were incubated with mitochondria. Comparsion of the effects of succinate and NADH on MetMb reduction was investigated. The MetMb percentage in sample treated with 8 mol L-1 succinate decreased by about 69% after 3 h incubation, and the effect was inhibited by the addition of 10 mol L-1 electron transfer chain complex II inhibitor malonic acid; the MetMb percentage in samples treated with 2 mol L-1 NADH decreased by 56% and the effect was inhibited by the addition of 0.02 mol L-1 electron transport chain complex I inhibitor rotenone. These results indicated that electron transport chain played an important role in MetMb reduction. Both complex II and complex I take part in the MetMb reduction in mitochondria through different pathways. NADH-MetMb reduction system was less stable than succinateMetMb system. In experiment 2, the beef longissimus dorsi muscle was blended with different concentrations of succinate or NADH. Enhancing patties with higher concentration of succinate or NADH improved colour stability in vacuum packaged samples（P〈0.05）. These results verified that mitochondria electron transport chain is related to the MetMb reduction in meat system.
基金Project supported by the Natural Science Foundation of Liaoning Province (No. 20052014), the Foundation of Education Committee of Liaoning Province (2004C021) and the Ph. D. Programs Foundation of Shenyang Institute of Chemical Technology
文摘A new ternary complex [Ni（phen）（pmal）]·8H2O （phen = 1,10-phenanthroline, pmal^2- = phenethyl malonic acid） has been synthesized by the reaction of nickel acetate, phen and phenethyl malonic acid. Elemental analysis, IR spectra and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure. Crystal data for this complex： triclinic system, space group PI^-, a = 10.387（5）, b = 13.112（6）, c = 14.229（6） °A, α= 76.176（7）, β = 83.778（8）, γ = 71.770（6）°, C35H42N4O12Ni, Mr= 769.44, Z = 2, F（000） = 808, V = 1786.1°A^3, Dc = 1.431 g/cm^3,μ= 0.612 mm^-1, the final R = 0.0653 and wR = 0.1033 for 9379 （Rint = 0.0244） independent reflections and 4730 observed reflections （I〉 2σ（I））. Structural analysis shows that the coordination geometry of Ni（Ⅱ） is a distorted octahedron. A novel two-dimensional structure is constructed from （H2O）4 and （H2O）12 water clusters, and the complex forms a 3-D network supramolecular structure by hydrogen bonds and π-π stacking of neighboring phens.
文摘The reaction of 4,4?-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]22H2O. It crystallizes in monoclinic, space group P21/c with a = 15.231(3), b = 11.847(2), c = 9.801(2) ? b = 106.75(3)o, V = 1693.5(6) 3, Z = 2, C32H40Cu2N4O12, Mr = 799.76, Dc = 1.568 g/cm3, ?(MoKa) = 0.71073 ? = 1.325 mm-1, F(000) = 828, the final R = 0.0531 and wR = 0.1244 for 3421 observed reflections with I > 2s(I). Each Cu(II) is coordinated by two oxygen atoms from a mal ligand, two nitrogen atoms from two dadm ligands and a water oxygen atom to form a triangle bipyramidal motif. The title compound possesses a distorted macrocycle enclosed by dadm with approximate dimensions of 8.3 ??5.9 ?
文摘Ionic liquids （ILs） based on 1,3-dialkylimidazolium and tetraalkylammonium cations were employed as a series of efficient, environmentally benign phase-transfer catalysts （PTCs） for the base-promoted monoalkylation of diethyl malonate. The influence of various heterogeneous bases on yields was studied. Good yields and high selectivity were obtained. Solvent-free, mild reaction condition, short reaction time, and easy purification were the merits of this method. The catalytic system （IL-hase） could also be recycled after the extraction of products with ether.
基金the National Natural Science Foundation of China (20772037)the Natural Science Foundation of Guangdong Province (06025033)
文摘Two dinuclear compounds [Ln2（acetate）6（H2O）4]-4H2O （Ln=Tb（1）, Sm（2）） were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln（Ⅲ） ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb（Ⅲ） in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.
文摘A green synthesis route of diethyl malonate by palladium catalyzed carbonylation of ethyl chloroacetate in the presence of phase transfer agent is carried out under mild conditions in good yield. The effects of reaction temperature and different bases on the yield of diethyl malonate are also discussed.
基金Project.20072032 was supported by the National Natural Science Foundation of China.
文摘Carboxycoumsrins were synthesized via the solid phase synthesis conviently. The resin bound cyclic malonic ester reacted with o-methoxy or o-hydroxybenzaldehydes. Then cyclization was processed under H2SO4 to afford the products in excellent purities and yields.
基金Project supported by the National Natural Science Foundation of China
文摘A new complex of malonic acid with lanthanum,La(Hmal)·(mal)·3H_2O,was synthesized and characterized by elemental analysis and IR spectra.The thermal decomposition process and their kinetic parameters n and E_a were studied by means of TG and DTG.All of the intermediate and end products were determined and characterized by the mass loss in TG curve,elemental analysis and IR spectra.
文摘A novel method of preparing dimethyl malonate by carbonylation of methyl chloroacetate catalyzed by Na[Co(CO)(4)] was proposed. Na[Co(CO)(4)] was synthesized in situ in the presence of Na2S2O3 and iron powder. The effects of some reaction parameters such as temperature. CO pressure and the concentrations of catalyst on the yields of dimethyl malonate were discussed. The kinetic data were studied and a possible reaction mechanism was proposed.
基金This work was supported by the Education Office of Anhui Province (No. 200161) and the Hubei Key Laboratory of Novel Chemical Reactor and Green Chemical Technology (No. RCT2004011)
文摘The title complex [CaCo（C3H2O4）2（H2O）4]n with a formula of C6HI2CaCoO12 and Mr=375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 14,195（9）, b = 7.708（5）, c = 13.441（8） A, β =119.575（9）°, V = 1279.0（14） A3, Dc= 1.948 g/cm^3,μ=1.803 mm^-1, F（000） = 764 and Z = 4. The final R = 0.0245 and wR = 0.0652 for 1344 observed reflections with I 〉 2σ（I）. The structure of the title complex consists of CaO8 polyhedra and CoO6 octahedra linked together by malonate ligands. The Ca（Ⅱ） cation on a twofold axis is coordinated by two water molecules and six malonate O atoms. The Co（Ⅱ） cation which lies in a centre of symmetry in an octahedral arrangement is coordinated by four malonate O atoms and two water molecules, The structure comprises alternating layers along the [101] plane, with the shortest Co-Co distance of 6.961（5）A. The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds.
基金supported by the State Key Program of the Natural Science Foundation of China,No.81030019the National Science Foundation for Young Scholars of China,No.81200969the Peking University Third Hospital Scientific Research Foundation for Returned Scholars,No.73526-01
文摘Abnormal TAR DNA-binding protein 43 （TDP-43） inclusion bodies can be detected in the degen- erative neurons of amyotrophic lateral sclerosis. In this study, we induced chronic oxidative stress injury by applying malonate to cultured mouse cortical motor neurons. In the later stages of the malonate insult, TDP-43 expression reduced in the nuclei and transferred to the cytoplasm. This was accompanied by neuronal death, mimicking the pathological changes in TDP-43 that are seen in patients with amyotrophic lateral sclerosis. Interestingly, in the early stages of the response to malonate treatment, nuclear TDP-43 expression increased, and neurons remained relatively intact, without inclusion bodies or fragmentation. Therefore, we hypothesized that the increase of nuclear TDP-43 expression might be a pro-survival factor against oxidative stress injury. This hypothesis was confirmed by an in vitro transgenic experiment, in which overexpression of wild type mouse TDP-43 in cultured cortical motor neurons significantly reduced malonate-induced neuronal death. Our findings suggest that the loss of function of TDP-43 is an important cause of neuronal degen- eration, and upregulation of nuclear TDP-43 expression might be neuroprotective in amyotrophic lateral sclerosis.
