Ru(phen)3 2+-SDBS-KMnO4化学发光体系检测半胱氨酸的研究

在20mmol·L-1硫酸-1.2mmol.L-1十二烷基苯磺酸钠(SDBS)介质中,半胱氨酸可以增强三(1,10-菲咯啉)钌(Ⅱ)[Ru(phen)32+]-KMnO4化学发光体系的发光强度.基于此,建立了一种化学发光直接检测半胱氨酸的新方法.在优化的实验条件下,该方法的线性范围和检测限分别为2.5×10-2-2.0μg·mL-1和2.1×10-2μg·mL-1,对11份含半胱氨酸0.5μg·mL-1的溶液平行测定的相对标准偏差(R.S.D.)为5.3%.将其用于合成样品中半胱氨酸含量的测定,结果令人满意.并提出了可能的化学发光机理.     

Ru(phen)32+-SDBS-KMnO4化学发光体系检测还原型谷胱甘肽的研究

当硫酸介质中有阴离子表面活性剂十二烷基苯磺酸钠(SDBS)存在时,还原型谷胱甘肽(G-SH)可以增强三(1,10-菲咯啉)钌(Ⅱ)[Ru(phen)32+]-KMnO4化学发光体系的发光强度.基于此,建立了一种化学发光直接检测G-SH的新方法.在优化的实验条件下,该方法的线性范围和检出限分别为5.0×10-2～2.0μg·mL-1和3.5×10-2μg·mL,对1.0μg·mL-1的G-SH溶液平行测定11次的相对标准偏差(RSD)为5.8%.将其用于合成样品中G-SH含量的测定,结果满意.并提出了可能的化学发光机理.     

铕-伊文思蓝分光光度法测定新霉素及妥布霉素

在酸性条件下,铕(Ⅲ) 伊文思蓝(EB)与硫酸新霉素(NEO)或硫酸妥布霉素(TOB)反应生成三元蓝色离子缔合物。最大吸收波长位于668nm(NEO)和670nm(TOB);线性范围分别为0～15.5μg·mL-1(NEO)和0～15.0μg·mL-1(TOB);摩尔吸收光系数(ε)为1.19×105(NEO)和9.05×104(TOB)L·mol-1·cm-1;最大负吸收波长位于608nm,线性范围分别为0～16.5μg·mL-1(NEO)和0～16.0μg·mL-1(TOB),摩尔吸收光系数(ε)为1.54×105(NEO)和1.08×105(TOB)L·mol-1·cm-1。当用双波长叠加时,ε值为2.73×105(NEO)和2.00×105(TOB)L·mol-1·cm-1。该法已用于市售药物及尿液中新霉素和妥布霉素含量的测定,分析结果满意。     

基于I--N-氯代丁二酰亚胺-鲁米诺反应体系流动注射化学发光法测定白藜芦醇

基于在碱性介质中,白藜芦醇对I-增强N-氯代丁二酰亚胺-鲁米诺化学发光体系的阻抑作用,建立了测定白藜芦醇的流动注射化学发光分析新方法.优化了流动注射化学发光的分析条件和探讨了反应的可能机理.测定白藜芦醇的线性响应质量浓度范围为2.5×10-9～8.0×10-8g·mL-1,检出限为6.3×10-10g·mL-1,用5.0×10-8g·mL-1的白藜芦醇标准溶液进行11次测定,相对标准偏差(RSD)为2.2%.应用本法测定了虎杖、葡萄酒、葡萄皮样品中的白藜芦醇含量,结果满意.     

鲁米诺-过氧化氢化学发光体系测定利福平

基于鲁米诺在碱性条件下可以被H2O2氧化产生化学发光,利福平对此化学发光具有增敏作用这一现象,结合流动注射技术建立了一种直接测定利福平的流动注射化学发光新方法.该方法的线性范围在1.0×10-6～2.0×10-8g·mL-1,检出限为3.0×10-9g·mL-1,对5.0×10-7g·mL-1的利福平连续进行11次平行测定,其相对标准偏差为3.0%.该法已成功测定了利福平胶囊及眼药水中利福平的含量.     

Ru（phen）32＋-Ce（Ⅳ）化学发光体系检测吲哚乙酸的研究

基于吲哚乙酸(IAA)对三(1, 10-菲咯啉)钌(Ⅱ)[Ru(phen)2+3]-Ce(Ⅳ)化学发光体系的发光增强作用,建立了一种化学发光直接检测IAA的新方法.在优化的实验条件下,该方法的线性范围为5.0×10-3 ～2.0 μg·mL-1,检出限为2×10-3μg·mL-1 ;对含0.50 μg·mL-1IAA的溶液平行测定11次的相对标准偏差(RSD)为5.5%.方法用于合成样品中IAA含量的测定,结果满意.本文还对可能的化学发光机理进行了探讨.     

TI(Ⅰ)-Cr(Ⅵ)-碘化钾-鲁米诺体系化学发光法测定铊

利用了Tl(Ⅰ)对Cr(Ⅵ)氧化碘化钾反应的催化作用,以碘-鲁米诺化学发学反应指示反应的进程。建立了测定铊的化学发光新方法。线性范围为Tl(Ⅰ)0.001～1μg·ml~(-1),检出限为Tl(Ⅰ)0.0006μg·ml~(-1)。     

甲基橙-溴酸钾体系催化光度法测定微量甲醛

基于硫酸介质中甲醛对溴酸钾氧化甲基橙显著的促进作用,建立了催化光度法测定微量甲醛的方法。本方法线性范围为0.014～0.14μg·mL-1,检出限为0.0122μg·mL-1。对0.0554μg·mL-1甲醛8次平行测定的RSD为1.09%。方法用于检测水发海产品中甲醛的含量,结果和用标准方法乙酰丙酮比色法所测结果基本一致。     

谷氨酸流动注射化学发光法测定

在碱性介质中,谷氨酸对硫氰化钾 鲁米诺化学发光体系有增敏作用,建立了用硫氰化钾 鲁米诺 氨基酸体系测定谷氨酸的新方法。该法灵敏度高,操作简单、快速。用该方法测定谷氨酸的线性范围为0.01～1.0μg·ml-1,检出限可达0.01μg·ml-1,采样频率为190次·h-1,对5μg·ml-1的谷氨酸连续平行测量10次,RSD为1.2%。用该方法对皮革屑中酶法提取的谷氨酸含量进行了测定,并与氨基酸测定仪测定的结果进行了比较,结果满意。     

高效液相钴离子催化化学发光抑制法测定茶叶中的茶氨酸

 研究了用高效液相分离、抑制化学发光测定茶叶中茶氨酸的分析方法。该法采用YWG C18(10μm,250mm×5 0mmi d )柱,以0 01mol·L-1醋酸钠 醋酸缓冲液(pH5 5)为流动相,流速为0 8mL·min-1。对茶氨酸抑制Co2+催化鲁米诺(luminol)与过氧化氢(H2O2)化学发光反应的条件进行了优化:Co2+的质量浓度为2μg·L-1,鲁米诺浓度为0 25mmol·L-1,H2O2浓度为0 5mmol·L-1。在茶氨酸的质量浓度为0 2g·L-1～5 0g·L-1时,茶氨酸抑制化学发光产生负峰的相对峰面积Y(将实际峰面积缩小至万分之一)与其质量浓度X(kg·L-1)的线性回归方程为Y=33862X+1 0605(r=0 9983)。     

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.     

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.     

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.     

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.