Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting...Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.展开更多
This research took 2,6-dimethylpyridine as raw materials under microwave irradiation to syntheses pyridine 2,6-dicarboxylic acid by adding oxidation potassium permanganate. However, there are lots of factors affecting...This research took 2,6-dimethylpyridine as raw materials under microwave irradiation to syntheses pyridine 2,6-dicarboxylic acid by adding oxidation potassium permanganate. However, there are lots of factors affecting the yield including the amount of potassium permanganate and sulfuric acid, reaction time, power, 2,6-dimethylpyridine dosage. We made the further research, using orthogonal experiment to find the optimal process conditions. Thus our research changed the synthesis process from a traditional method to a new type of microwave technology.展开更多
A new coordination polymer {[Cd（C_（21）H_（14）N_6）（C_8H_4O_4）]·H_2O}_n（1） was synthesized by an elaborate design via the reaction of 3-（2,6-di（pyrazin-2-yl）pyridin-4-yl）-1H-indole（bppi）,1,4-benzene-...A new coordination polymer {[Cd（C_（21）H_（14）N_6）（C_8H_4O_4）]·H_2O}_n（1） was synthesized by an elaborate design via the reaction of 3-（2,6-di（pyrazin-2-yl）pyridin-4-yl）-1H-indole（bppi）,1,4-benzene-dicarboxylic acid（H2bdc） and cadmium（Ⅱ） nitrate in CH_3OH/H_2O mixed solvents. Complex 1 crystallizes in orthorhombic,space group Ccca with a = 20.012（4）,b = 31.881（6）,c = 19.808（4） ？,V = 12638（4） ？~3,Z = 16,C_（29）H_（20）CdN_6O_5,M_r = 644.91,D_c = 1.356 g·cm^（-3）,μ = 0.735 mm^（-1）,F（000） = 5184,GOOF = 1.046,the final R = 0.0405 and wR = 0.1063 for 6870 observed reflections（I 〉 2σ（I））. The Cd（Ⅱ） centre is hepta-coordinated by three N and four O atoms from one bppi terminal ligand and two bdc2– ligands,respectively,displaying a capped trigonal prism geometry. Structure extension gives coordination polymeric chains,in which the bdc2– linkers connect Cd（Ⅱ） cations into a one-dimensional（1D） coordination polymer along the c axis,giving zigzag chains with the Cd···Cd separation of 11.178（1） ？. The adjacent bppi terminal ligands in the chains are anti-periplanar conformation. The three-dimensional（3D） structure is stabilized by π···π stacking and hydrogen-bonding interactions to form a supramolecular self-penetrating network with 1D channels. In 1,there are voids 2999.7 ？~3 with 23.7% of per unit cell volume. Thermal analysis indicates that the framework of 1 is stable until 651 K and the photoluminescence of 1 in the solid shows very weak fluorescence at 382 and 560 nm upon excitation at 310 nm.展开更多
In an effort to investigate the use of short peptide chains as carriers of new anti-tumor agents, we synthesized four tripeptide-cytotoxic agent conjugates: DMQ-MA-Lys(DMQ-MA)-Phe -Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Ile-Arg-...In an effort to investigate the use of short peptide chains as carriers of new anti-tumor agents, we synthesized four tripeptide-cytotoxic agent conjugates: DMQ-MA-Lys(DMQ-MA)-Phe -Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Ile-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Val-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Lys(Cbz)-Arg-Ome. The cytotoxic agent conjugated to the N-terminal and the xi -amino group of Lysine of the tripeptide is 2,6-dimethoxyhydroquinone-3-mercaptoacetic acid (DMQ-MA). The tripeptides were synthesized by coupling protected amino acid residues according to Pfp/DCC methods (Pfp: pentafluorophenol, DCC:N,N'-dicyclohexyl-carbodiimide) in solution. Agarose gel electrophoresis showed that these compounds can cleave supercoiled DNA into open-circular form in drug concentration as low as 4-50 mu M without H2O2 and UV irradiation. Further studies on their cytotoxicity for these conjugates are ongoing.展开更多
This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of he...This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.展开更多
A new trinuclear nickel complex,[Ni3（pdc）3（2,2＇-bipy）3（H2O）2]·2H2O（H2pdc = pyridine 2,6-dicarboxylic acid,2,2＇-bipy = 2,2＇-bipyridine） has been hydrothermally synthesized and characterized by IR,elemen...A new trinuclear nickel complex,[Ni3（pdc）3（2,2＇-bipy）3（H2O）2]·2H2O（H2pdc = pyridine 2,6-dicarboxylic acid,2,2＇-bipy = 2,2＇-bipyridine） has been hydrothermally synthesized and characterized by IR,elemental analysis and X-ray diffraction methods.Crystal data for this complex：monoclinic,space group P21/n,a = 21.206（4）,b = 10.002（2）,c = 28.066（6）,β = 108.18（3）°,C51H41N9Ni3O16,Mr = 1212.06,V = 5.656（2） nm3,Dc = 1.423 g·cm-3,μ（MoKα） = 1.062 mm-1,Z = 4,F（000） = 2488,GOOF = 1.034,the final R = 0.0543 and wR = 0.1237 for 6149 observed reflections with Ⅰ 〉 2σ（Ⅰ）.In the complex,three nickel（Ⅱ） ions are bridged by the pyridine 2,6-dicarboxylic acid groups,and all nickel（Ⅱ） ions are seven-coordinated by nitrogen atoms of 2,2＇-bipyridine and pyridine 2,6-dicarboxylic acid and oxygen atoms from pyridine 2,6-dicarboxylic and water to adopt a severely distorted pentagonal bipyramidal geometry.The emission and excitation peaks of the complex in ethanol solutions are located at 336 and 316 nm,respectively.展开更多
The binary and ternary solid complexes of Eu 3+ and La 3+ with pyridine 2,6 dicarboxylic acid (H 2DPC) and 1,10 phen anthroline were synthesized. Their compositions confirmed by elemental analysis are N...The binary and ternary solid complexes of Eu 3+ and La 3+ with pyridine 2,6 dicarboxylic acid (H 2DPC) and 1,10 phen anthroline were synthesized. Their compositions confirmed by elemental analysis are Na 3[Ln(DPC) 3]·2H 2O(Ln=La, Eu) and NaEu(DPC) 2·phen·4H 2O. The coordination mode of ligands with metal ions was studied by NMR. The influences on NMR spectra by induciton effect, screening effect and paramagnetic character of rare earth ions are discussed in this paper. The NMR studies show that these three complexes have similar symmetry and regular change of chemical shifts. Pyridine 2,6 dicarboxylic acid is a tridentate ligand. The coordination number of europium and lanthanum is nine in each of the binary complexes. The coordination number of europium is at least eight in the ternary complex.展开更多
The facile and efficient total syntheses of monoterpenoid acid 7a and its ester 7b, isolated from Artemisia siebert and Piper aduncum respectively, can be completed in four steps with an overall yield 41%.
A novel title complex, C23H19N2O19Na4Y （Mr= 808.27）, has been synthesized by hydrothermal reaction and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a = 13.56...A novel title complex, C23H19N2O19Na4Y （Mr= 808.27）, has been synthesized by hydrothermal reaction and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a = 13.560（3）, b = 14.016（3）, c = 14.948（4） A, β = 99.492（4）°, Z = 4, V = 2802.2（12） A^3, Dc = 1.916 g/cm^3,μ（MoKα） = 2.241 mm^-1, F（000） = 1624, the final R = 0.0337 and wR = 0.0828 for 4044 observed reflections（I〉 2σ（I））. In the crystal, each eight- coordinated Y（Ⅲ） atom is linked by carboxyl groups of BTC to form a one-dimensional helical network structure.展开更多
A manganese（Ⅱ） complex （tataH）2[Mn（pydc）2]·4H2O （C20H28MBN14O12, Mr = 711.50, tata = 2,4,6-triamino-1,3,5-triazine, pydcH2 = pyridine-2,6-dicarboxylic acid） has been synthesized and its crystal structure...A manganese（Ⅱ） complex （tataH）2[Mn（pydc）2]·4H2O （C20H28MBN14O12, Mr = 711.50, tata = 2,4,6-triamino-1,3,5-triazine, pydcH2 = pyridine-2,6-dicarboxylic acid） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1^-, with a = 9.9847（3）, b = 10.9813（3）, c = 15.2616（5）A, a = 101.5310（10）, β = 90.2610（10）, γ = 116.4600（ 10）% V = 1459.44（8）A^3, Z = 2, Dc = 1.619 g/cm^3,μ = 0.539 mm^-1, F（000） = 734, the final R = 0.0292 and wR = 0.0745. In the crystal the Mnn atom is six-coordinated by four carbonyl oxygen atoms and two pyridine nitrogen atoms from two tridentate pydc ligands to furnish a distorted octahedral geometry. The complex shows the A…D…D＇…A＇ H-bonded tetramer. The molecules are packed in a three-dimensional framework structure by the combination of O-H…O, N-H…O and N-H…N hydrogen bonds between （tataH）^＋, [Mn（pydc）2]^2- and crystal water.展开更多
文摘Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6- lutidine. Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6-dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.
文摘This research took 2,6-dimethylpyridine as raw materials under microwave irradiation to syntheses pyridine 2,6-dicarboxylic acid by adding oxidation potassium permanganate. However, there are lots of factors affecting the yield including the amount of potassium permanganate and sulfuric acid, reaction time, power, 2,6-dimethylpyridine dosage. We made the further research, using orthogonal experiment to find the optimal process conditions. Thus our research changed the synthesis process from a traditional method to a new type of microwave technology.
基金supported by the National Natural Science Foundation of China(Nos.21571118&21271121)
文摘A new coordination polymer {[Cd（C_（21）H_（14）N_6）（C_8H_4O_4）]·H_2O}_n（1） was synthesized by an elaborate design via the reaction of 3-（2,6-di（pyrazin-2-yl）pyridin-4-yl）-1H-indole（bppi）,1,4-benzene-dicarboxylic acid（H2bdc） and cadmium（Ⅱ） nitrate in CH_3OH/H_2O mixed solvents. Complex 1 crystallizes in orthorhombic,space group Ccca with a = 20.012（4）,b = 31.881（6）,c = 19.808（4） ？,V = 12638（4） ？~3,Z = 16,C_（29）H_（20）CdN_6O_5,M_r = 644.91,D_c = 1.356 g·cm^（-3）,μ = 0.735 mm^（-1）,F（000） = 5184,GOOF = 1.046,the final R = 0.0405 and wR = 0.1063 for 6870 observed reflections（I 〉 2σ（I））. The Cd（Ⅱ） centre is hepta-coordinated by three N and four O atoms from one bppi terminal ligand and two bdc2– ligands,respectively,displaying a capped trigonal prism geometry. Structure extension gives coordination polymeric chains,in which the bdc2– linkers connect Cd（Ⅱ） cations into a one-dimensional（1D） coordination polymer along the c axis,giving zigzag chains with the Cd···Cd separation of 11.178（1） ？. The adjacent bppi terminal ligands in the chains are anti-periplanar conformation. The three-dimensional（3D） structure is stabilized by π···π stacking and hydrogen-bonding interactions to form a supramolecular self-penetrating network with 1D channels. In 1,there are voids 2999.7 ？~3 with 23.7% of per unit cell volume. Thermal analysis indicates that the framework of 1 is stable until 651 K and the photoluminescence of 1 in the solid shows very weak fluorescence at 382 and 560 nm upon excitation at 310 nm.
文摘In an effort to investigate the use of short peptide chains as carriers of new anti-tumor agents, we synthesized four tripeptide-cytotoxic agent conjugates: DMQ-MA-Lys(DMQ-MA)-Phe -Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Ile-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Val-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Lys(Cbz)-Arg-Ome. The cytotoxic agent conjugated to the N-terminal and the xi -amino group of Lysine of the tripeptide is 2,6-dimethoxyhydroquinone-3-mercaptoacetic acid (DMQ-MA). The tripeptides were synthesized by coupling protected amino acid residues according to Pfp/DCC methods (Pfp: pentafluorophenol, DCC:N,N'-dicyclohexyl-carbodiimide) in solution. Agarose gel electrophoresis showed that these compounds can cleave supercoiled DNA into open-circular form in drug concentration as low as 4-50 mu M without H2O2 and UV irradiation. Further studies on their cytotoxicity for these conjugates are ongoing.
基金Project supported by the National Natural Science Foundations of China (Grant Nos.20673050 and 20973089)
文摘This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.
基金Supported by the Science and Technology Fund of Hengyang Science and Technology Bureau (No. 2008KS035)the Construct Program of the Key Discipline in Hunan Province
文摘A new trinuclear nickel complex,[Ni3（pdc）3（2,2＇-bipy）3（H2O）2]·2H2O（H2pdc = pyridine 2,6-dicarboxylic acid,2,2＇-bipy = 2,2＇-bipyridine） has been hydrothermally synthesized and characterized by IR,elemental analysis and X-ray diffraction methods.Crystal data for this complex：monoclinic,space group P21/n,a = 21.206（4）,b = 10.002（2）,c = 28.066（6）,β = 108.18（3）°,C51H41N9Ni3O16,Mr = 1212.06,V = 5.656（2） nm3,Dc = 1.423 g·cm-3,μ（MoKα） = 1.062 mm-1,Z = 4,F（000） = 2488,GOOF = 1.034,the final R = 0.0543 and wR = 0.1237 for 6149 observed reflections with Ⅰ 〉 2σ（Ⅰ）.In the complex,three nickel（Ⅱ） ions are bridged by the pyridine 2,6-dicarboxylic acid groups,and all nickel（Ⅱ） ions are seven-coordinated by nitrogen atoms of 2,2＇-bipyridine and pyridine 2,6-dicarboxylic acid and oxygen atoms from pyridine 2,6-dicarboxylic and water to adopt a severely distorted pentagonal bipyramidal geometry.The emission and excitation peaks of the complex in ethanol solutions are located at 336 and 316 nm,respectively.
文摘The binary and ternary solid complexes of Eu 3+ and La 3+ with pyridine 2,6 dicarboxylic acid (H 2DPC) and 1,10 phen anthroline were synthesized. Their compositions confirmed by elemental analysis are Na 3[Ln(DPC) 3]·2H 2O(Ln=La, Eu) and NaEu(DPC) 2·phen·4H 2O. The coordination mode of ligands with metal ions was studied by NMR. The influences on NMR spectra by induciton effect, screening effect and paramagnetic character of rare earth ions are discussed in this paper. The NMR studies show that these three complexes have similar symmetry and regular change of chemical shifts. Pyridine 2,6 dicarboxylic acid is a tridentate ligand. The coordination number of europium and lanthanum is nine in each of the binary complexes. The coordination number of europium is at least eight in the ternary complex.
基金Supported by the Natural Science FoundationofChina(No.2 0 0 6 2 0 0 1) ,and the Natural Science Foundation ofGuangxi Province( No.0 135 0 2 0 and No.0 0 0 70 16 )
文摘The facile and efficient total syntheses of monoterpenoid acid 7a and its ester 7b, isolated from Artemisia siebert and Piper aduncum respectively, can be completed in four steps with an overall yield 41%.
基金The work was supported by the Natainal Natural Science Foundation of China (No. 50242001)
文摘A novel title complex, C23H19N2O19Na4Y （Mr= 808.27）, has been synthesized by hydrothermal reaction and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a = 13.560（3）, b = 14.016（3）, c = 14.948（4） A, β = 99.492（4）°, Z = 4, V = 2802.2（12） A^3, Dc = 1.916 g/cm^3,μ（MoKα） = 2.241 mm^-1, F（000） = 1624, the final R = 0.0337 and wR = 0.0828 for 4044 observed reflections（I〉 2σ（I））. In the crystal, each eight- coordinated Y（Ⅲ） atom is linked by carboxyl groups of BTC to form a one-dimensional helical network structure.
基金supported by the Postdoctor Foundation of Jiangsu Province (No. 0701001B)the Foundation of Taishan University (No. Y04-2-02)
文摘A manganese（Ⅱ） complex （tataH）2[Mn（pydc）2]·4H2O （C20H28MBN14O12, Mr = 711.50, tata = 2,4,6-triamino-1,3,5-triazine, pydcH2 = pyridine-2,6-dicarboxylic acid） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1^-, with a = 9.9847（3）, b = 10.9813（3）, c = 15.2616（5）A, a = 101.5310（10）, β = 90.2610（10）, γ = 116.4600（ 10）% V = 1459.44（8）A^3, Z = 2, Dc = 1.619 g/cm^3,μ = 0.539 mm^-1, F（000） = 734, the final R = 0.0292 and wR = 0.0745. In the crystal the Mnn atom is six-coordinated by four carbonyl oxygen atoms and two pyridine nitrogen atoms from two tridentate pydc ligands to furnish a distorted octahedral geometry. The complex shows the A…D…D＇…A＇ H-bonded tetramer. The molecules are packed in a three-dimensional framework structure by the combination of O-H…O, N-H…O and N-H…N hydrogen bonds between （tataH）^＋, [Mn（pydc）2]^2- and crystal water.
