过氧化氢歧化酶模拟酶的合成及催化性质的研究——meso-四(4-磺基苯)卟啉-锰(MnTPPS_4)作为模拟酶的研究

锰和meso-四(4-磺基苯)卟啉的螯合物MnTPPS_4可以作为过氧化氢歧化酶的模拟酶催化H_2O_2分解。本文首次探索将该模拟酶应用于生物传感器方面的可行性。在25℃、pH8.0条件下,模拟酶电极对1.0×10~(-3)～7.0×10~(-3)mol/L浓度范围的H_2O_2的响应呈线性。相关系数为0.9964。该电极的重现性,回收率良好,具有一定的抗干扰能力。这为进一步将该模拟酶代替天然酶应用于生物传感器奠定基础。     

过氧化物酶模拟酶催化荧光反应的研究(Ⅰ)——MnTPPS_4-HVA-H_2O_2体系

首次研究了meso-四(4-磺基苯)卟啉和锰的络合物(MnTPPS_4)作为过氧化物酶模拟酶对高香草酸(HVA)和H_2O_2荧光反应的催化作用,拟订了用模拟酶测定痕量H_2O_2和葡萄糖的荧光测定方法,并对模拟酶和天然酶的性能进行了比较。用MnTPPS_4测定H_2O_2和葡萄糖的灵敏度分别可以达到8.5×10~(-8)mol/L的H_2O_2和0.5μgmL~(-1)的葡萄糖。     

锆基金属有机框架纳米酶用于电化学检测过氧化氢的研究

以具有拟过氧化物酶活性的新型含锆金属有机框架(Zr-MOF)为修饰材料,以全氟聚苯乙烯磺酸溶液(Nafion)为稳定剂,使用滴涂法将材料修饰在玻碳电极(GCE)表面,制备用于过氧化氢(H_2O_2)检测的无酶电化学传感器(Nafion/Zr-MOF/GCE)。采用循环伏安法和计时电流法研究H_2O_2在修饰电极上的电化学行为,结果表明:该修饰电极对H_2O_2具有良好的电催化活性,可以明显增强H_2O_2的检测电流值,在浓度为1～45 mmol/L的范围内呈现出良好的线性关系,检出限为0.1 mmol/L。该电化学传感器成功应用于牙膏中H_2O_2含量的测定。     

基于偶氮化反应构筑无酶无试剂型H_2O_2传感器研究

近年来,人们在临床诊断、化学医药、环境保护等领域对H_2O_2的测定展开了广泛研究.电化学方法测定H_2O_2具有方法简便、灵敏度高等优点.发展无酶无试剂型H_2O_2传感器是重要的研究方向之一.新型无酶无试剂H_2O_2生物传感器的构筑过程如图1所示.以自组装共价键合法,4-氨基苯硫酚(4-ATP)自组装在Au电极表面后进行偶氮化反应,通过偶联反应实现硫堇Th的共价固定.     

基于偶氮化反应构筑无酶无试剂型过氧化氢传感器的研究

近年来,人们在临床诊断、化学医药、环境保护等领域对过氧化氢的测定开展了广泛研究~([1]).电化学方法测定H_2O_2具有方法简便、灵敏度高等优点.发展无酶无试剂型H_2O_2传感器是重要的研究方向之一~([2,3]).利用偶氮4-氨基苯硫酚(ATP)膜具有强的导电性,偶氮基可与硫堇(Th)进行偶联反应,从而在电极表面实现Th的共价固定,建立了新型无酶无试剂H_2O_2生物传感器.     

基于PAC修饰的氧化石墨烯负载纳米Pt构建新型三维过氧化氢电化学传感器

为构建一种新的无酶电化学生物传感器并将其用于细胞中释放的H_2O_2的有效检测,将聚二烯丙基二甲基氯化铵(PAC)修饰的氧化石墨烯(GO)和纳米Pt通过物理吸附和电化学沉积H_2PtCl_6共同负载于玻碳电极上,成功制备了Pt/PAC-GO/GCE生物传感器。扫描电镜表明纳米Pt能很好地负载于PAC-GO表面。Pt/PAC-GO/GCE生物传感器对H_2O_2具有较宽的线性范围(0.04～3.6μmol/L及4.4～28.6μmol/L)及较高的电流响应(检出限为0.01μmol/L)。此外,该生物传感器具有较强的抗干扰能力,已成功用于活细胞H_2O_2的检测,有望用于医学诊断。     

基于贵金属纳米颗粒构建无酶过氧化氢电化学传感器的研究

采用一步电化学沉积方法分别将三种常用贵金属纳米颗粒(Au,Ag,Pt)负载于工作电极上,构建了基于纳米薄膜的过氧化氢(H_2O_2)无酶电化学传感器。通过扫描电子显微镜(SEM)表征证明三种金属纳米颗粒成功修饰在玻碳电极(GCE)表面。通过比较三种金属纳米颗粒检测H_2O_2的能力,发现Ag纳米粒子具有更优异的催化活性。进一步研究扫描速率和检测电压对Ag/GCE催化性能的影响。电化学实验结果表明,该修饰电极显示出优异的H_2O_2催化活性以及在优化条件下可以达到0.01～23mmol·L~(-1)的线性范围,检出限为3.3μmol·L~(-1),并将该传感器用于检测吐温80中残留H_2O_2,为吐温80的质量检查提供了一种简单快捷的方法。     

基于生物活性PEDOT负载血红蛋白的H_2O_2生物传感器

H_2O_2检测的灵敏度和精确性非常重要,因为H_2O_2不仅是一些高选择性酶的副产物,而且是食物、药物、临床、工业、环境分析和众多其它领域的重要中间体.因此,建造高灵敏度高精确性的H_2O_2生物传感器具有广泛的市场前景.     

金纳米簇增强的化学发光反应及在葡萄糖检测中的应用

金纳米簇(Au NCs)具有拟过氧化物酶活性,能催化鲁米诺(Luminol)与H_2O_2反应,产生增强的化学发光信号。不同于其它纳米微粒催化的Luminol-H_2O_2化学发光反应,Au NCs催化得到的是慢化学发光信号,且其信号能在10min内保持稳定。基于此反应,本文发展了简单、方便的化学发光测定H_2O_2的新方法。在优化的实验条件下,测定H_2O_2的检测限为10μmol/L。将此方法应用于葡萄糖的检测,其线性范围为10~1 000μmol/L,检测限为10μmol/L。目前一些重要的生物分子,如尿酸和乳酸等均能与相关酶反应生成H_2O_2,本方法也能进一步拓宽至这些生物分子的检测。     

基于HRP-H_2O_2-OPDA发光体系的流感病毒H1N1酶联免疫传感器

制备了一种基于HRP-H_2O_2-OPDA发光体系的流感病毒H1N1酶联免疫传感器。利用流感病毒H1N1表面的HA(血球凝集素)蛋白与糖蛋白能有效结合的特性,选择辣根过氧化物酶(HRP)作为生物标记物直接标记在流感病毒的表面,HRP能有效催化H_2O_2-邻苯二胺(OPDA)体系产生灵敏的显色反应和荧光效应。实验对HRP孵化时间、H_2O_2-OPDA催化反应时间等参数进行了优化。结果表明,该酶联免疫传感器对流感病毒H1N1检测的动态响应范围为0.0001~0.5μg/m L,检出限为50 pg/m L(3σ)。其他亚型病毒和干扰蛋白对该传感器的干扰较小,表现出良好的选择性。所构建的方法可为其它流感病毒及其它抗原的检测提供参考。     

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.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.