L-苏糖酸锌的制备及其性质

L-苏糖酸作为金属离子的载体 ,可使金属离子易于与氨基酸或蛋白质结合而被动物吸收和利用[1] ,L -苏糖酸钙就是一种优秀的钙补充剂 ,其吸收率达 95%以上 ,是传统钙补充剂的 2～ 3倍 ,无任何毒副作用 ,1 %的 L -苏糖酸钙能使维生素 C的吸收增加 1 .8倍[2 ,3 ] .国外已有苏糖酸产品及专利[4 ] ,国内也有苏糖酸钙产品问世 .文献 [5]报道 0 .1 mol/ L苏糖酸钙在生理 p H下 ,将有 87%钙为分子状态 ,这一结果显然支持了“分子补钙”的理论 ,也是其成为优秀钙补充剂的原因 .锌是人体中必需的 1 4种微量元素之一 ,与人体中不下2 0 0种金属酶有关 …     

L-苏糖酸氧钒的制备及其表征

L 苏糖酸作为金属离子的载体,可使金属离子易于与氨基酸或蛋白质结合而被动物吸收和利用[1-3],钒在1971年被确定为生物体必需的微量元素[4],具有多种生理作用和药理活性,与糖尿病的关系十分密切。近年来国内外用于抗糖尿病生物学研究的钒化合物绝大多数为简单的盐类化合物,脂溶性小,难以吸收,同时对胃肠道刺激性大[5]。本文以L 苏糖酸钙与草酸氧钒(VOC2O4)反应后的溶液加无水乙醇制得[VO(C4H6O5)]2·3H2O,并进行等离子发射光谱(ICP)、元素分析、IR光谱、TG DTG表征。1　实验部分1.1　试剂与仪器L 抗坏血酸(Vc),H2C2O4·2H2O…     

L-苏糖酸与金属离子的配位性能

本文在298K、I=0.1 mol·L^-1 KNO₃条件下测定了L-苏糖酸的质子化常数及其与钙(Ⅱ)、镉(Ⅱ)、锌(Ⅱ)、钴(Ⅱ)、铜(Ⅱ)二元配合物的生成常数。L-苏糖酸的质子化常数与葡萄糖酸的质子化常数一致，pKa为3.56。其与金属离子的配位方式也与葡萄糖酸一致，但其二元配合物的生成常数明显比葡萄糖酸大。L-苏糖酸与不同金属离子作用的方式不同，与钙(Ⅱ)、镉(Ⅱ)、锌(Ⅱ)、钴(Ⅱ)配位时不解离出醇羟基质子，而与铜(Ⅱ)配位时则     

L-苏糖酸铜的制备及其标准生成焓

L 苏糖酸作为金属离子的载体,可使金属离子易与氨基酸或蛋白质结合而被动物吸收和利用[1]。本文以L 苏糖酸与Cu2(OH)2CO3·xH2O反应后的溶液浓缩加无水甲醇制得水合物Cu(C4H6O5)·0 5H2O(经HPLC分析,纯度>99 9%),用化学分析、元素分析、IR光谱、TD DTG和量热法进行了表征。1　实验部分1 1　试剂与仪器L 抗坏血酸(Vc)、B.R.(东北制药总厂);H2O2、CaCO3、H2C2O4和Cu2(OH)2CO3·xH2O均为A.R.(西安化学试剂厂);2400型元素分析仪(PE公司);Cu2+含量用Na2S2O3滴定法测定;TG 7型热重分析仪(PE公司);BRUKEREQUINOX 5…     

电位滴定判断二元金属氢氧化物的复合化

尖晶石型纳米复合金属氧化物目前主要的合成方法还是共沉淀法 [1,2 ] .但是此种方法常因不能准确掌握共沉淀的 p H范围 ,而出现组分金属离子偏析 ,难制得不含杂相的纯净复合金属氧化物纳米微粒[3] .混合金属离子能否形成复合氢氧化物 ,在什么条件下形成 ,这方面的研究还未见报道 .电位滴定法通常是研究单一金属离子的水解或氢氧化物生成的有效方法 [4 ,5] ,为此 ,我们以 Al3+、Fe3+分别与 Ni2 +、Zn2 +、Cu2 +等金属离子形成的二元金属混和溶液为对象 ,使用自动电位滴定仪测定这些混合体系的电位滴定曲线 ,并通过与相应的单一金属离子的…     

计算机模拟研究Pu~(4+)在人体血浆中的分布

建立了由多种金属离子和小分子配体组成的多相人体血浆热力学平衡模型。模拟研究了Pu4+在血浆的形态分布及二乙三胺五乙酸(DTPA)和CO32-、Citrate3-浓度对细胞液中Pu4+形态分布的影响。血浆中的低浓度Pu(Ⅳ)易以Pu(OH)4(aq)的形态蓄积在肝脏中,钚浓度升高则形成沉淀Pu(OH)4(s)难以排出。在[DTPA]=2.5×10-5mol·L-1时,血浆中水溶性小分子[Pu(OH)DTPA]2-含量达到最高并保持稳定。酸性条件下随着[Citrate3-]的升高,血浆中Pu4+与Citrate3-结合形成可溶性的[PuCitrate2]2-和[PuCitrate]+离子化合物。[DTPA]4.6×10-5mol·L-1时,血浆中的DTPA以与Ca2+、Mg2+结合的[CaHDTPA]2-、[Ca2DTPA]-、[CaDTPA]3-、[MgHDTPA]2-、[MgDTPA]3-小分子结合态为主。     

2,7-萘二磺酸阴离子导向五元瓜环基超分子自组装体的制备及其荧光检测性能

通过引入2,7-萘二磺酸(2,7-NDA^2-)阴离子作为结构导向剂,与五元瓜环(Q[5])和过渡金属离子(Co²⁺、Ni²⁺、Zn²⁺、Cd²⁺)在水热条件下制备了4种新颖的Q[5]基超分子自组装体(Q[5]-SA),即{[M(H₂O)4(Q[5])]·(NDA)}·x H₂O(M=Co (1)、Ni (2)、Zn (3))和{[Cd2Cl2(H₂O)4(Q[5])]·(NDA)}·13H₂O (4)。单晶X射线衍射测试结果表明,自组装体1～3同构,其中Q[5]仅一端的部分端口羰基氧原子与金属离子配位形成简单配合物;而4中Q[5]的2个端口均与金属离子Cd²⁺配位形成了一维配位链。在自组装体1～4中,配体2,7-H2NDA均全脱质子,形成2,7-NDA2-阴离子平衡体系电荷,但均未能与金属离子配位,而在2,7-NDA2-阴离子与Q[5]外壁之间的瓜环外壁作用下进一步形成...     

二价金属离子对鲑鱼精DNA热稳定性的影响

二价金属离子与 DNA之间的作用在 DNA复制、转录以及新陈代谢过程中起到重要的作用 ,因此越来越受到关注 [1,2 ] .L uck等 [3 ]指出 ,碱土金属与 DNA分子的磷酸基团发生作用使 DNA的热稳定性升高 ,而二价过渡金属离子主要是与碱基作用而使 DNA热稳定性降低 . Eichhorn等 [4 ] 用变温紫外光谱法研究了在 DNA磷酸根离子的浓度较小 (0～ 4.0 )时 ,多种二价金属离子对小牛胸腺 DNA热稳定性的影响 ,发现 Mg2 + 及过渡金属离子 Mn2 + ,Co2 + 和 Ni2 + 都有利于 DNA的稳定 .最近 ,Duguid等 [5]用差示扫描量热法 (DSC)研究了在 c(M2 +…     

含有NH2CH2CH2CH2NH2和o-C6H4(NH2)2配体的镍配合物的合成、结构和它们在乙烯聚合中的作用

两种镍的配合物[Ni(NH2CH2CH2CH2NH2)3]Cl2 (1)和[Ni(C6H4N2H4)2Cl2] (2)已经被合成并且通过红外和单晶X射线衍射分析对其进行了表征。在配合物1中,镍原子处于手性假八面体[NiN6]的几何构型中,它与三个1,3-丙二胺分子形成了三个六元环。在配合物2中,镍原子除了与两个o-苯二胺分子通过四个Ni-N键形成两个五元环外,它还与两个Cl原子配位形成了反式Ni-Cl2,这不同于以往报道过的镍的二胺配合物。这两个镍的配合物被MAO, MMAO或Et2AlCl活化后,对乙烯的二聚合或三聚合显示了很好的催化活性[对于配合物2,催化活性达到3.59×106 g mol-1 (Ni) h-1]。     

动力学荧光光度法测定人发中痕量镍

镍是人体的必需微量元素之一,在人体内参与一些酶的组成和代谢;镍能增强胰岛素分泌,有降低血糖作用;适量的镍能促进脱氧核糖核酸(DNA)和核糖核酸(RNA)正常生理功能的发挥,但若量过多,会使RNA复制失真,DNA受到损伤,引起突变,甚至致癌[1].     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.     

Copper-catalyzed multicomponent reactions of 2-iodoanilines,benzylamines, and elemental sulfur toward 2-arylbenzothiazoles

A relatively cheap copper salt-catalyzed, three-component approach providing 2-arylbenzothiazoles in good to excellent yields from readily available 2-iodoanilines, benzylamines, and sulfur powder is reported. This methodology allows preparation of various classes of 2-arylbenzothiazoles and provides a general, reliable approach.