银微盘电极上头孢氨苄降解产物的伏安行为及其应用

基于头孢氨苄降解产物中含有巯基，能与Ａｇ＾＋生成难溶化合物的特性，在银微盘电极上研究了ＣＥＸ降解产物的伏安行为，探讨了电极反应的机理。运用示差脉冲溶出伏安法，在０．１ｍｏｌ／Ｌ ＨＡｃ－ＮａＡｃ介质中，ＣＥＸ降解产物的还原峰电流与ＣＥＸ浓度于８．０×１０＾－８－７．０×１０＾－６ｍｏｌ／Ｌ范围内呈良好线性关系；检测限为１．０×１０＾０８ｍｏｌ／Ｌ；测定了头孢氨苄胶囊中ＣＥＸ含量为９２．０％，与药典     

一种测定微量碘离子的简便偶合化学发光法

报道了在含Ｉ＾－的Ａｓ箩丹明Ｂ混合溶液中直接注射Ｃｅ＾４－，通过记录化学发光持续时间对微量Ｉ＾－进行定量的偶合化学发光法。检出限为６．０×１０＾－８ｍｏｌ／Ｌ，线性响应的浓度范围为１．０×１０＾－７－１．０×１０＾－５ｍｏｌ／Ｌ。该法简便易行，所受的干扰小，用于加碘食盐，酱油及实际水样中微量Ｉ＾－的测定，结果满意。     

头孢噻肟钠的降解及其产物伏安行为的研究

头孢噻肟钠在ＮａＯＨ溶液中降解后，于０．１ｍｏｌ／ＬＮａＯＨ中得一灵敏的吸附伏安原峰，Ｅｐ＝－０．７８Ｖ（νｓＡｇ／ＡｇＣｌ），ｉｐ与头孢噻肟钠浓度在１．０×１０＾－＾９－１．０×１０＾－＾８，１．０×１０＾－＾８－１．０×１０＾－＾７，１．０×１０＾－＾７－１．０×１０＾－＾６ｍｏｌ／Ｌ范围内呈线性关系，检出限为５．０×１０＾－＾１＾０ｍｏｌ／Ｌ。用多种电化学手段研究其降解产物的伏安行为，测定了     

鸟嘌呤—铜配合物在汞电极表面上的电吸附性的研究

在０．０２ｍｏｌ／Ｌ ＮａＨＣＯ３－０．０５ｍｏｌ／Ｌａ２ＳＯ４介质中、用极谱法和伏安法研究表明,铜－乌嘌呤配合物在汞电极表面上的吸附服从Ｌａｎｇｍｕｉｒ吸附,测得其饱和吸附量Γｍ＝１．１×１０＾－１０ｍｏｌ／ｃｍ＾２,吸附系数β＝４．７×１０＾４,吸咐自由能△Ｇ°＝－３６．６ｋＪ／ｍｏｌ。在８×１０＾－６ｍｏｌ／Ｌ Ｃｕ＾２＋离子存在下,可用示差脉冲阴极吸附溶出法测定８×１０＾－１０～１×１０＾     

依诺沙星在混合粘合剂碳糊电极上的电化学特性

制备了混合粘合剂碳糊电极。在０．０１５ｍｏｌ／Ｌ，磷酸－０．１０ｍｏｌ／ＬＫＣｌ溶液中，依诺沙星在该电极上于－１．２６Ｖ处产生一灵敏的阴极溶出伏安峰。在－０．９０Ｖ富集９０ｓ后，依诺沙星的线性范围为３．１×１０＾－７－１．２×１０＾－５ｍｏｌ／Ｌ，检测下限为９．４２×１０＾－８ｍｏｌ／Ｌ，所提出的方法用于尿液和血清中依诺沙星测定，回收率在９６％－１０３％之间。     

乳酸环丙沙星单扫描示波极谱法研究

研究了乳酸环丙沙星的极谱伏安行为，在ｐＨ＝８．３的０．０２ｍｏｌ／Ｌ，ＮＨ４Ｃｌ－ＮＨ３．Ｈ２Ｏ底液中，乳酸环丙沙星能产生１个灵敏的还原峰，峰电位为－１．６１Ｖ，其导数峰高与浓度在３．９×１０＾－８～１．８×１０＾－６ｍｏｌ／Ｌ和１．８×１０＾６～１．１×１０＾－５ｍｏｌ／Ｌ范围内呈现良好的线性关系，相关系数ｒ＝０．９９９７，检测下限为２．５×１０＾－８ｍｏｌ／Ｌ，用于乳酸环丙沙星注射液的测定，相     

锑—铜—茜素络合剂体系极谱行为的研究

在１．０ｍｏｌ／Ｌ甲酸－甲酸钠－０．０３ｍｏｌ／Ｌ邻苯二甲酸氢钾混合底液（ｐＨ３．５）中，锑－茜素络合剂（ＡＬＣ）络合物在单扫示波极谱上于一０．５３Ｖ（ｖｓ．ＳＣＥ）产生一极谱波，加入１．６×１０＾－３ｍｏｌ／ＬＣｕ（Ⅱ）后，灵敏度有较大提高，峰电流与锑浓度在２．０×１０＾－８～３．０×１０＾－６ｍｏｌ／Ｌ范围内呈线性关系，检测限达１．０×１０＾－８ｍｏｌ／Ｌ，研究了电极反应机理，方法应用于铜合金     

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。     

丙酸睾丸素的吸附阴极溶出伏安法研究

在ｐＨ为６．０的Ｂ－Ｒ缓冲溶液中，丙酸睾丸素于电位－１．４Ｖ（ｖｓ．ＳＣＥ）左右处出现一个灵敏的附阴溶出峰。经５ｍｉｎ富集后，阴极溶出峰电流与浓度在１．３８×１０＾－＾８－７．３×１０＾－＾８ｍｏｌ／Ｌ范围内成线笥关系，该方法用于注射液中丙酸睾丸素含量测定，回收率８０％－８６％。检测下限为４．１×１０＾－＾９ｍｏｌ／Ｌ。     

硅钼杂多阴离子薄膜修饰电极线性扫描伏安法测定黑液中要溶性硅

本报导了以玻碳电极为基体的１∶１２硅钼杂多阴离子薄膜化学修，铈电极的制备及其电化学特性。并应用于导数伏安法测定。在４．０×１０＾－３ｍｏｌ／Ｌ９ＮＨ４）６Ｍｏ７Ｏ２４－６６．８×１０＾－２ｍｏｌ／ＬＮａ３Ｃｉｔ－０．４８ｍｏｌ／Ｌ ＮＨＯ３体系中，硅浓度在８．３×１０＾－７～１．７×１０＾－３ｍｏｌ／Ｌ。对可溶性硅（以ＳｉＯ２计）为２４５．０５ｍｇ／Ｌ的黑液，稀释１０倍后，取２．００ｍＬ平行测定     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.