3.5次微分循环示波计时电位法测定铋的研究

本文将３。５次微分循环示波计时电位法应用于铋的示波特性的研究和合成样品中微量铋的测定。铋在０．１ｍｏｌ／Ｌ ＮａＯＨ支持电解质中，于示波图阴极支上产生一灵敏切口，灵敏度为２×１０＾－７ｍｏｌ／Ｌ，线性范围为４×１０＾－７－２×１０＾－６ｍｏｌ／Ｌ。     

3,3‘—四亚甲基—双—（1—苯基—5—吡啶酮—4—羟酸酯）极谱行为研究

ＴＰＰＣ在０．０８ｍｏｌ／ＬＣＨ３ＣＯＯＮａ和０．４ｍｏｌ／ＬＣＨ３ＣＯＯＨ（ＮａＡｃ－ＨＡｃ下同）底液条件下，在电位－１．５７Ｖ附近产生一尖锐的导数波，峰高在３．７×１０＾－６－５．６×１０＾－５ｍｏｌ／Ｌ范围内呈线性关系，同时，讨论了极谱波的性质及电极反应机理。     

葡萄糖脱氢酶微型生物传感器的研制及应用

以甲苯胺兰（ＴＢ）修饰碳糊微电极为基体，将葡萄糖脱氢酶（ＧＤＨ）用丝素蛋白膜固定于修饰微电极表面制成了生物传感器，在ｐＨ７．０的ＮａＯＨ－ＮａＨ２ＰＯ４缓冲溶液中，烟酰胺腺嘌呤二核苷酸（ＮＡＤ）的浓度为１．０４×１０＾－３ｍｏｌ／Ｌ的条件下，其响应电流与葡萄糖浓度在１．０×１０＾－４～３．２×１０＾－３ｍｏｌ／Ｌ范围内有良好线性关系，响应时间为２０ｓ；检测限为４．０×１０＾－５ｍｏｌ／Ｌ。该传感器     

铜（Ⅱ）锌（Ⅱ）—氟哌酸体系电化学行为及示波极谱法研究

铜（Ⅱ）和锌（Ⅱ）分别在０．１ｍｏｌ／ＬＫＨ２ＰＯ４－Ｎａ２ＨＰＯ４缓冲溶液（ｐＨ６．５）和０．２５ｍｏｌ／ＬＮＨ４Ｃｌ溶液中，与氟哌酸形成良好的络合吸附波，峰电位分别为－０．２６Ｖ和－１．２８Ｖ（ｖｓ．ＳＣＥ），络合比分别为１：３和１：２，峰电流与铜（Ⅱ）和锌（Ⅱ）的浓度均在４．０×１０＾－７～５．０×１０＾－６ｎｏｌ／Ｌ范围内呈线性关系，检测限分别为７．０×１０＾－８和５．０×１０＾－８ｍｏｌ     

氧氟沙星的单扫描示波极谱分析

报道了一种灵敏的氧氟沙星测定方法－一阶导数单扫示波极谱分析，同时研究了它的极谱波性质和电极反应机理，在ｐＨ６．０的ＫＨ２ＰＯ４－Ｎａ２ＨＰＯ４（ＰＢＳ）底液中，氧氟沙星产生一个灵敏的还原峰，Ｅｐ＝－１．５５Ｖ（ｖｓ．ＳＣＥ），其导数峰高与浓度在１．０×１０＾－５～４．６×１０＾－７ｍｏｌ／Ｌ范围内呈良好的线性关系，相关系数ｒ＝０．９９９６，检测下限为２．４×１０＾－７ｍｏｌ／Ｌ，可用于氧氟沙星片剂     

含有吸附络合物溶液的倒数示波计时电位法的应用

Ｐｂ（Ⅱ）在０．２％乙二胺－５×１０＾－３ｍｏｌ·Ｌ＾－１ＨＯｘ－０．３ｍｏｌ·Ｌ＾－１ＫＯＨ溶液中，有良好的全数示波图，其峰电位Ｅｐ＝－１．０５（ｖｓ．ＳＣＥ），峰高与Ｐｂ＾２＋溶度在４．０×１０＾－７～２．０×１０＾－５ｍｏｌ·Ｌ＾－１内成正比，检测下限可达２．０×１０＾－７ｍｏｌ·Ｌ＾－１。本实验采用倒数示波计时电位法对铝合金“Ａ”中铅进行了测定，并直接通过示波图，对络合物的吸附属于性进行了     

介体型乳酸脱氢酶生物传感器的研制及应用

本报道了能对丙酮酸产生良好响应的电流型乳酸脱氢酶生物传感器。该传感器以耐尔兰Ａ修饰浸石墨电极为基体电极，将酶直接固化在蚕丝蛋白膜上。在ＰＨ７．４的ＮａＨ２ＰＯ４－ＮａＯＨ介质中，当２．４×１０＾－４ｍｏｌ／Ｌ的辅酶Ｉ（ＮＡＤＨ）存在下，该传感器的响应电流与丙酮酸浓度在３．２×１０＾－５ｍｏｌ／Ｌ范围内有良好的线性关系。响应时间为６０ｓ．本讨论了影响传感器响应的各种因素，用此传感器测定了人血清中     

测定超氧化物歧化酶活性的一种新的极谱分析方法

报道一种测定超氧化物歧化酶活生的新极谱分析方法，在０．１２５ｍｏｌ／ＬＮＨ３．Ｈ２Ｏ－０．７５ＭＯＬ／ｌ ｎｈ４ｃＬ－２．５％，Ｎａ２ＳＯ３－０．５％，吐温－８０－的介质中，ＳＯＤ在－０．５２Ｖ处产生一氧极谱催化波。ＳＯＤ在１．０×１０＾３Ｕ／Ｌ－４．０×１０＾３Ｕ／Ｌ的活性含量范围内与催化电流呈线性关系，检出限为８．０×１０＾２Ｕ／Ｌ。     

土豆汁修饰碳糊电极测定色氨酸的研究

本提出了用于测定色氨酸的土豆汁修饰碳糊电极，该电极选择性好，能有效地消除酪氨酸的干扰，在ｐＨ＝７．４的ＮａＨ２ＰＯ４－ＮａＯＨ生理缓冲液中，电极响应与色氨酸在９．８×１０＾－６～９．８×１０＾－５ｍｏｌ／Ｌ的浓度范围内呈线性关系，最低检出限是１．５×１０＾－６ｍｏｌ／Ｌ．并详细讨论了电极抗干扰能力与测定条件的关系。用该电极测定了实际样品氨基酸注射液中色氨酸的含量，结果与标准值吻合。     

钼（Ⅵ）—7—（1—苯偶氮）—8—羟基喹啉—5—磺酸钠络合吸附研究及应用

在ｐＨ４．８的０．０１３ｍｏｌ／Ｌ的ＨＡｃ－ＮａＡｃ介质中,钼－７－（１－苯偶氮）－８－羟基喹啉－５－磺酸钠体系在滴汞电地－０．４６Ｖ电位处得到良好的吸附还原波,其二阶导数峰电流Ｉ＾ｎ,ｐ与Ｍｏ在２．５×１０＾－８－４．５×１０＾－７ｍｏｌ／Ｌ浓芳范围内呈良好的线性关系,检测限为１．２５×１０＾－８ｍｏｌ／ＬＭｏ（Ⅵ）,方法用于钢样中策量钼的测定,结果较好。     

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.     

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.