Effect of DNA and bivalent metal ions on the interaction of thermostable DNA polymerase <Emphasis Type="Italic">Tte</Emphasis> with dNTPs

The interaction of DNA polymerase Tte from Thermus thermophilus B35 with dUTP analog containing a fluorescein residue bound to C(5) of the base (Flu-dUTP) was studied by fluorescence titration. The dissociation constants of the enzyme—substrate complexes in the absence and in the presence of a DNA duplex containing an extended template and bivalent metal ions and the kinetic parameters of polymerization by DNA polymerase Tte in the presence of Flu-dUTP were determined. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1268–1272, May, 2005.     

Structural refinement of Nd[Fe(CN)6]·4H2O and study of NdFeO3 obtained by its oxidative thermal decomposition at very low temperatures

The crystal structure of Nd[Fe(CN)₆]·4H₂O has been refined by Rietveld analysis using high resolution synchrotron powder X-ray diffraction data. It belonged to the orthorhombic crystal system, Cmcm space group, with cell parameters: , and . The change in space group from P6₃/m which is observed in the pentahydrates (LnFe(CN)₆·5H₂O) to Cmcm in the tetrahydrates has been analyzed to be a consequence of the change in 9-fold coordination of Nd³⁺ in the pentahydrates to 8-fold coordination in the tetrahydrates, which changes the Nd³⁺ environment from tricapped trigonal prism to a distorted tricapped trigonal prism or square antiprism. Its decomposition process in air to produce NdFeO₃ has been followed by thermogravimetric and differential thermal analysis, IR spectroscopy and laboratory powder XRD. We found that it is possible to synthesize crystalline NdFeO₃ at temperatures as low as 380 °C and refine the structure of single phase crystalline NdFeO₃ synthesized by this method at 600 °C.     

[Cu3(μ10-bta)(μ2-C2O4)(H2O)2]n的水热合成与结构表征

有机-无机杂化材料因其在催化、化学吸附、磁性和电子导体等方面具有广泛的应用而成为人们的研究热点[1,2]. 通过过渡金属离子和特殊的有机配体之间的反应, 一系列具有独特结构的配位聚合物已被合成出来. 多齿有机配体可螯合两个或多个金属离子, 这些金属离子之间存在良好的电子交换[3], 可形成一维、二维或三维的配位聚合物. 均苯三甲酸和均苯四甲酸都是良好的桥连多齿配体, Chui等采用均苯三甲酸合成了具有吸附作用的大孔道的[Cu3(tma)2(H2O)]n[4] (tma=benzene-1,3,5-tricarb-oxylate)三维配位聚合物, 并且[Ni(C12H3ON6O2)]3(tma)*H2O[5], [M(tma)2]*12H2O(M=Co,Ni,Zn)[6], Na2[Co(H2O)6(bta)]*4H2O[7] (bta=benzene-1,2,4,5-tetracarboxylate)和[Co(phen)(md)][8] (phen=1,10-phenanthroline, md=benzene-1,3-dicarboxylate)等配位聚合物也先后被合成出来.     

SYNTHESIS OF DBN AND ITS CATALYTIC PERFORMANCE FOR METHANOL CARBONYLATION TO METHYL FORMATE

1 , 5-diazabicyclo['1, 3, 0]non-5-ene(DBN) has been synthesized in our laboratory, and its catalytic activity and selectivity for methanol carbonylation to methyl formate (MF) have been studied. The experimental results have demonstrated that the synthetic processes of DBN used for the present work are reasonable and feasible. The total yield of three steps of DBN synthsis is approximate to 80%. The activity evaluation has shown that DBN can effectively catalyze the carbonylation reaction of methanol in the presence of propylene oxide (PO) promoter. PO-promoted DBN is a novel catalytic system superior to sodium methoxide.     

Synthesis and Crystal Structure of Ag2（admtrz）2（CF3CO2）2（admtrz=4—amino—3,5—dimethyl—1,2,4—triazole）

1 INTRODUCTION Transition metal complexes bridged by 1, 2, 4-triazole group can produce interesting structures and specific properties[1]. Many attempts have been made to synthesize a variety of complexes with paramagnetic centers by using such ligands, and their structures and magnetic properties have been characterized[2]. However, the polynuclear Ag(I) complexes bridged by 1, 2, 4-triazole have been poorly studied[3]. Recently, we have prepared a series of silver(I) triazole complex…     

Asymmetric synthesis of 3,4-dihydroxyglutamic acids via enantioselective reduction of cyclic meso-imide

Stereoselective synthesis of (3S,4S)- and (3R,4R)-series of 3,4-dihydroxyglutamic acids was investigated. The key reaction in this synthesis is asymmetric reduction of meso-imide derived from meso-tartaric acid. Lewis acid-promoted cyanation of the obtained optically active lactam via the acyliminium intermediate followed by standard deprotection procedure afforded the desired 3,4-dihydroxyglutamic acids.     

超声辐射下金属锰诱发芳香醛的还原偶联

在超声辐射下，Mn-NH4Cl-THF：H2O(1：4，V：V)或Mn-MnCl2-THF:H2O(1：4， V：V)体系中，于室温2-3h内可使芳香醛还原偶联成邻二醇，收率为30％-95％．与 传统方法相比，反应时间缩短，还原剂用量降低，产品收率提高．     

Synthesis of 2-Aminochromene Derivatives Catalyzed by KF／Al2O3

A series of 2-aminochromene derivatives including 2-amino-ben-zo[ h ] chromene, 2-amino-benzo [ f ] chromene and 2-amino-pyrano [3,2-h ]quinolin derivatives was synthesized from aryl-aldehyde, malononitrile or ethyl cyanoacetate and 1-naphthol or 2-naphthoi or 8-hydroxyquinoline in refluxing ethyl alcohol cat-alyzed by KF-Al2O3. The structures were confirmed by X-ray analysis.     

N-5-四唑基-N′-芳甲酰基脲的合成及其生物活性

合成了 15个新的含四唑基的芳甲酰基脲类化合物 ,用IR ,1HNMR和元素分析证实了它们的结构 ,并进行了初步的生物活性试验 ,生测结果证明一些目标化合物具有优良的植物生长调节活性 ,其中N 5 四唑基 N′ 对甲氧基苯基甲酰基脲(2h)和N 5 四唑基 N′ 对溴苯基甲酰基脲 (2j)具有很好的生长素活性 ,2h ,2j和N 5 四唑基 N′ 对甲基苯基甲酰基脲 (2m )具有优良的细胞分裂素活性     

Precipitation polymerization of aniline in the presence of water‐soluble organic acids

The precipitation polymerization of aniline in the presence of organic acids, including toluene‐4‐sulfonic acid, phenylphosphonic acid, 4‐aminophenylphosphonic acid, and acetophosphonic acid, led in one step to conductive polyaniline. The polyaniline showed very good affinity for water and was easily modified to be water‐soluble. In comparison with the widely studied postpolymerization of doped polyaniline, this reaction allowed reasonably good conductivity to be achieved at a lower acid/polyaniline ratio. Moreover, the easy in situ incorporation of the dopant into the polymer structure caused high stability of the created salt; that is, no dedoping was observed after it was washed with water, methanol, or other solvents. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3562–3569, 2002