氯霉素在Pt/GC离子注入修饰电极上的伏安行为及其测定

氯霉素在浓度为０．１ ｍ ｏｌ／Ｌ 的ＮａＯＨ 溶液中,Ｐｔ／ＧＣ 离子注入修饰电极上有一还原峰,峰电位为 － ０．８０ Ｖ（ｖｓ．ＳＣＥ）,氯霉素的浓度在 １．０×１０－ ５～１．０×１０－ ３ ｍ ｏｌ／Ｌ 范围内与峰电流成正比。检出限为５．０×１０－ ６ ｍ ｏｌ／Ｌ。已用于氯霉素眼药水的测定。用线性扫描和循环伏安法研究体系的性质。实验表明,是注入的Ｐｔ催化了氯霉素的还原;体系属准可逆过程。     

托美汀的吸附伏安法研究

在０．２ｍｏｌ／Ｌ ＮＨ３－ＮＨ４Ｃｌ底液中，托美汀在悬汞电极上有一灵敏的还原峰。峰电位为Ｅｐｃ＝－１．４８Ｖ，该峰具有明显的吸附性，峰电流ｉｐｃ与ＴＯＬ浓度在４．０×１０＾－９－７．０×１０＾－７ｍｏｌ／Ｌ范围内呈线性关系；检出限为５．０×１０＾－１０ｍｏｌ／ｌ，用该法测定了片剂ＴＯＬ的含量，结果良好。     

锡(Ⅳ)-没食子酸-钒(Ⅳ)体系极谱吸附催化波的研究

在ｐＨ ２．３ 的氯乙酸盐缓冲液中，Ｓｎ（Ⅳ）－没食子酸（ＧＡ）－Ｖ（Ⅳ）体系产生一灵敏的吸附平行催化波，峰电位为－ ０．５０ Ｖ（ｖｓ．ＳＣＥ），二次导数峰高与锡浓度在６．７×１０－ １０～１．７×１０－ ６ ｍ ｏｌ／Ｌ 范围内呈良好线性关系，检测限达３×１０－ １０ ｍ ｏｌ／Ｌ。本文用循环伏安法等电化学方法研究了催化波的性质及电极反应机理。方法已成功地应用于罐头食品中微量锡的测定，结果满意。     

多菌灵在玻碳电极上的伏安行为及其应用

应用循环伏安法、微分脉冲伏安法对多菌灵在破碳电极上的电化学行为及其测定进行了研究。在ｐＨ＝９．０的２ｍｏｌ／Ｌ ＮＨ３－ＮＨ４Ｃｌ底液中，对其进行循环伏安扫描，发现于０．６１Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）产生一灵敏的氧化峰。微分脉冲伏安法殉菌灵的检测限为４×１０＾－８ｍｏｌ／Ｌ。多菌灵的浓度在５．０×１０＾－７￣１．０×１０＾－５ｍｏｌ／Ｌ间与微分脉冲伏安峰电流呈线性关系（ｒ＝０．９９４２）。对于１×     

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可溶性硅

本文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￣（－３）ｍ０ｌ／Ｌ（ＮＨ＿４）＿６ＭＯ＿７Ｏ＿（２４）－６．８×１０￣（－２）ｍｏｌ／ＬＮａ＿３Ｃｉｔ－０．４８ｍｏｌ／ＬＮＨＯ＿３体系中，硅浓度在８．３×１０￣（－７）～１．７×１０￣（－３）ｍｏｌ／Ｌ范围内与峰电流呈良好线性关系，检测限为８．０×１０￣（－７）ｍｏｌ／Ｌ。对可溶性硅（以ＳｉＯ＿２计）为２４５．０５ｍｇ／Ｌ的黑液，稀释１０倍后，取２．００ｍＬ平行测定９次，ＲＳＤ为０．５８％，加标回收率在９７．３％～１０４．４％间。     

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     

铊(Ⅰ)-碘化钾-向红菲啰啉络合吸附波的研究

在Ｎａ２Ｂ４Ｏ７－ＮａＯＨ 介质（ｐＨ １０．８）中,可获得灵敏的铊（Ⅰ）－碘化钾－向红菲口罗啉极谱络合吸附还原波,其二阶导数波灵敏度高、波形好,峰电位在－ ０．５８ Ｖ 处（ｖｓ．ＳＣＥ）。波高与铊（Ⅰ）浓度在２．０×１０－ ８～９．０×１０－ ７ ｍ ｏｌ·Ｌ－ １范围内呈线性关系, 检出限１．０×１０－ １０ ｍ ｏｌ·Ｌ－ １。本法用于测定工厂废水中的痕量铊,结果满意。本文还对极谱波的性质和机理进行了研究。     

脑益嗪的吸附伏安特性及其测定

在ｐＨ２．３的ＫＣｌ－ＨＣｌ底液中，脑益嗪在汞电极上有一还原峰。其导数峰电位为－１．４７Ｖ（ＳＣＥ）；线性范围１．０×１０＾－７～１．０×１０＾－６ｍｏｌ／Ｌ；最低检测限为１．０×１０＾－７ｍｏｌ／Ｌ。用多种电化学手段证明，脑益嗪的还原属于反应物弱吸附的不同逆过程。该法用于样品中脑益嗪含量的测定，结果令人满意。     

阿霉素的吸附伏安法研究

阿霉素在０．１ｍｏｌ／Ｌ ＨＡｃ－ＮａＡｃ底液，富集电位－０．２０Ｖ，富集时间１２０ｓ，扫速１００ｍＶ／ｓ等条件下，于悬汞电极上产生一灵敏的吸附伏安还原峰，峰电位为－０．４５ＢＶ，峰电流与ＡＤＭ浓度为１．０×１０１０＾－９－４．０×１０＾－７ｍｏｌ／Ｌ范围内呈线性关系，检测限可达５．０×１０＾－１０ｍｏｌ／Ｌ。     

线性扫描示波极谱法测定抗癌药物紫杉醇

抗癌药物紫杉醇在０．２ｍｏｌ／Ｌ ＮＨ３－ＮＨ３－ＮＨ４Ｃｌ中,采用单扫示波极说法进行测定,形成一良好的还原峰,峰电位Ｅｐ＝－１．４５Ｖ（ｖｓ．ＳＣＥ）。峰电流与紫杉醇的浓度在１．０×１０＾－７￣８．０×１０＾－６ｍｏｌ／ｌ之间呈线性关系;检测限为５．０×１０＾－８ｍｏｌ／Ｌ,并将此方法应用于样品测定。用线性扫描和循环伏安法研究体系的性质,结果表明,紫杉醇的电极过程属于具有吸附性的准可逆过程。     

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.