三丁基锡化合物与牛血清白蛋白相互作用的光谱研究

通过紫外光谱（UV）和圆二色光谱（CD），研究了三丁基锡（TBT）化合物与牛血清白蛋白（BSA）的相互作用以及浓度变化对TBT与BSA相互作用的影响。结果表明，TBT与BSA的相互作用是双重的。既有TBT中锡离子与BSA的配位作用，又有TBT中丁基的疏水作用，引起BSA构象变化和叶螺旋结构的改变。     

荧光光谱法结合分子对接研究邻苯二甲酸单环己酯与牛血清白蛋白的相互作用

通过荧光光谱、圆二色谱及计算机模拟技术研究了邻苯二甲酸单环己酯（MCHP）与牛血清白蛋白（BSA）的相互作用机制。结果表明：MCHP能够自发进入BSA的结合位点I，并引起BSA的内源荧光猝灭；BSA-MCHP复合物的稳定性随着温度上升而下降；除了氢键和范德华力，MCHP与BSA之间的Pi-Sigma、 Pi-Alkyl以及Alkyl作用力在结合过程中也发挥了重要作用；MCHP诱导BSA的二级结构发生改变，其中α-螺旋的含量从游离态的66.5%下降至复合态的59.0%；计算机模拟结果表明，BSA的Trp213和Arg198残基与MCHP的2个羰基上的氧原子形成2个氢键，并且Trp213与MCHP之间的相互作用是导致BSA荧光猝灭的重要因素。     

Cu(Ⅱ),Ni(Ⅱ)存在条件下盐酸小檗碱与牛血清白蛋白相互作用的研究

使用荧光光谱和紫外光谱研究Cu（Ⅱ），Ni（Ⅱ）存在的条件下对盐酸小檗碱（berberine chloride dihydrate，BC）与牛血清白蛋白（BSA）相互作用的影响。得到的猝灭常数Ksv表明，金属离子Cu（Ⅱ）或Ni（Ⅱ）的存在不影响其猝灭机理。基于Fcirster非辐射能量转移机理，获得了盐酸小檗碱与牛血清白蛋白的212位色氨酸残基问的距离：讨论了金属离子与BSA的结合构型对BC与BSA相互作用的影响。     

6-苄氨基嘌呤与牛血清白蛋白作用荧光特性的研究

应用荧光光谱法研究了6-苄氨基嘌呤（6-BA）与牛血清白蛋白（BSA）相互作用的荧光特性。测得了6-BA与BSA在10、27、40℃温度下的结合常数KA为：0.21×10^5、1.37×10^5、5.53×10^5L/mol,结合位点数n为：1.0、1.2、1.3。6-BA对BSA内源荧光的猝灭机理主要为静态猝灭,6-BA主要以疏水作用与BSA相互作用,BSA的荧光主要源于色氨酸残基,6-BA对BSA的构象有影响。     

全硫取代三苯甲基自由基酯基衍生物与牛血清白蛋白的相互作用

采用荧光光谱、电子顺磁共振（EPR）波谱、紫外-可见吸收光谱和分子对接等技术研究了全硫取代三苯甲基（TAM）自由基酯基衍生物ET-03与牛血清白蛋白（BSA）的相互作用,发现ET--03与BSA能自发发生结合作用;主要以疏水作用力结合在BSA亚结构域ⅡA（位点Ⅰ）和亚结构域ⅢA（位点Ⅱ）上;ET-03对BSA的荧光猝灭效应为动态、静态混合猝灭机制,且可能存在非辐射能量转移.研究结果表明,酯基衍生化TAM自由基与白蛋白能自发结合,有望用于蛋白构效关系研究;同时也提示将TAM自由基酯基衍生物用于活体成像或自旋标记物时应考虑其与蛋白相互作用的影响.     

邻菲咯啉合铜配合物与牛血清白蛋白的相互作用

利用荧光光谱法研究了两种配合物,[Cu（phen）（L-Phe）（H2O）]ClO4（1）（L-Phe为L-苯丙氨酸根）和[Cu（phen）（Gly）（H2O）]ClO4·2．5H2O（2）（Cly为甘氨酸根）,与牛血清白蛋白（BSA）的相互作用。结果表明,牛血清白蛋白的荧光强度随着配合物浓度的增大而逐渐降低,配合物（2）与BSA的结合常数大于配合物（1）与BSA的结合常数,牛血清白蛋白对配合物的结合位点数为1,荧光猝灭作用机理为静态猝灭．     

胡椒碱与牛血清白蛋白的作用及Cu2+、Fe3+影响的研究

采用荧光光谱及紫外光谱法研究了胡椒碱与牛血清白蛋白（bovine serum albumin,BSA）的相互作用。实验结果表明：胡椒碱与BSA形成基态复合物从而猝灭BSA的内源性荧光,猝灭原因主要为静态猝灭和非辐射能量转移作用。胡椒碱对BSA的猝灭速率常数Kq为7．31×10^12 L·mol^-1·s^-1（25℃）和7．20×10^12 L·mol^-1·s^-1（37℃）,胡椒碱与BSA的结合常数K为1．02×10^7 L·mol^-1（25℃）和1．11×10^7 L·mol^-1（37℃）,结合位点数n为1．45（25℃）和1．46（37℃）。根据Ftirster偶极-偶极非辐射能量转移理论问题得到结合距离r为3．28nm（25℃）和3．30nm（37℃）。通过热力学参数的计算,确定胡椒碱与牛血清白蛋白的相互作用是一个熵增加和吉布斯自由能降低的自发过程,主要作用力为疏水作用力。同步荧光光谱表明,胡椒碱与BSA的相互作用没有引起BSA构象的变化。讨论了共存金属离子Cu^2＋、Fe^3＋对胡椒碱与BSA相互作用的影响。     

可可碱与牛血清白蛋白作用光谱特性的研究

本文应用荧光光谱法研究了可可碱（TB）与牛血清白蛋白（BSA）相互作用的光谱特性。测定了18℃、30℃、40℃温度下的结合常数KA分别为1．68×10^4、1．58×10^4、1．45×10^4L／mol,结合位点数咒分别为1．04、1．03、1．03。实验结果表明：TB对BSA内源荧光的猝灭机理主要为静态猝灭;热力学参数探讨其相互作用机理,TB主要以静电力与BSA相互作用;研究了TB对BSA构象的影响,BSA的荧光主要源于色氨酸残基。同时研究了Cu^2＋存在下TB与BSA的相互作用。     

A Comparison Study on the Interaction of Sunset Yellow and β-Carotene with Bovine Serum Albumin

在模拟生理pH条件（pH=7．4）下,采用多种光谱法研究日落黄和β-胡萝卜素与BSA的相互作用,并比较两者与BSA相互作用过程的差异性．通过荧光光谱法和紫外吸收光谱法确定了日落黄和β-胡萝卜素对牛血清白蛋白的荧光猝灭机制,采用Stern—Volmer、双对数方程和热力学公式求出相互作用的猝灭常数、结合常数配、结合位点数月和作用力类型．结果表明：日落黄和β-胡萝卜素对BSA的猝灭属于静态猝灭,两者与BSA的民都达到10^5L／mol,结合位点数均为1,日落黄与BSA的作用力以静电引力为主,而β-胡萝卜素则是通过氢键和范德华力与BSA作用．通过红外光谱法和圆二色谱法研究了二者对BSA构象的影响,结果表明,日落黄与BSA作用的过程中,会引起BSA二级结构的改变,而β-胡萝卜素则对BSA的构象基本不产生影响．     

光谱法研究吡嗪酰胺与牛血清白蛋白的相互作用

用光谱法研究了抗结核药吡嗪酰胺(Pyrazinamide,PZA)与牛血清白蛋白(bovine serum albumin,BSA)的相互作用,初步探讨了PZA对BSA的猝灭机理为静态猝灭,并用荧光猝灭法测定了作用的位点数n和结合常数K。根据不同温度下的热力学常数确定了PZA与BSA之间的作用力主要是氢键和范德华力作用。根据Forster非辐射能量转移原理,测定了实验条件下PZA与BSA相互结合时,能量授体-受体的结合距离。并用同步荧光和紫外光谱法研究了PZA对BSA构象的影响。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.