催化还原褪色光度法测定粉煤灰中微量铜

在ＰＨ５．０的ＨＡｃ－ＮａＡｃ缓冲休系中,痕量Ｃｕ（Ⅱ）催化抗坏血酸还原偶氮胭脂红Ｂ的褪色反应,褪色程度与Ｃｕ（Ⅱ）量在一定范围内线性相关。建立了测定痕量Ｃｕ（Ⅱ）的光度法,检出限为３．５＊１０＾－１１ｇ／ｍＬ,褪色程度与Ｃｕ（Ⅱ）量在０．０－２．０μｇ／Ｌ范围内符合比耳定律。本法结合Ｎ５３０－Ｎ５１０混合萃取剂萃取分离,测定了粉煤灰中的微量铜。     

催化光度法测定煤矸石中微量铜的研究

在乙酸－乙酸钠介质中痕量铜对抗坏血酸还原二溴对甲基偶氮羟（２－Ｂｒ－ｐＭＡＣ）褪色反应有催化作用,催化程度与Ｃｕ（Ⅱ）量线性相关。借此建立了测定痕量Ｃｕ（Ⅱ）的分光光度法。实验表明,有色溶液所最大吸收波长为５８６ｎｍ,方法检出限为０．０４８μｇ／Ｌ,Ｃｕ（Ⅱ）量在０￣０．８μｇ／５０ｍＬ范围内符合比耳定律,可用于测定煤矸石中的微量铜。     

锑（锡）—Ferron—Se（Ⅳ）络合吸附催化波研究及应用

在ｐＨ１．８的Ｈ２ＳＯ４－ＮａＡｃ缓冲溶液中，用单扫示波极谱法，Ｓｂ（Ⅲ）或者（Ｓｎ（Ⅳ）－７－碘－８－羟基喹啉－５－磺酸－Ｓｅ（Ⅳ）体系可产生灵敏的络合吸附催化波。锑、锡浓度分别在０．４～２００μｇ／Ｌ和０．８～１８０μｇ／Ｌ范围内与峰高呈线性关系，检测限分别为０．２μｇ／Ｌ和０．４μｇ／Ｌ，并用于工业废水，地下水和天然水中痕量锑和锡的测定，同时对电话性络合物的组成，极谱波的性质和电极过程机理也     

Cu(Ⅱ)KIO_4胭脂红-1,10-菲罗啉体系催化动力学光度法测定人发中痕量铜

基于ｐＨ６．５ 的Ｎａ２ＨＰＯ４ＮａＨ２ＰＯ４ 缓冲介质中铜离子对高碘酸钾氧化胭脂红褪色反应的催化作用,提出了催化动力学光度法测定痕量铜的新方法。研究了该方法的适宜反应条件,方法的检出限为１．１×１０－ ７ｇ／ＬＣｕ（Ⅱ）,表观摩尔系数ε＝ ７．８×１０５Ｌ·ｍ ｏｌ－ １·ｃｍ － １,线性范围为０～０．５μｇ／１０ｍ ＬＣｕ（Ⅱ）,方法已用于人发中痕量铜的测定     

萃取催化光度法测定痕量铜

研究了在ｐＨ５．５的弱酸性介质中,利用邻菲罗啉活化铜（Ⅱ）催化过氧化氢氧化邻氨基酚显色的指示反应,用萃取平衡控制反应时间,水相中邻氨基酚的浓度和反应程度,建立了萃取催化光度法测定痕量铜的新方法。方法的线性范围为０．０００５０￣０．１０ｍｇ／Ｌ,检测限为５．０×１０＾－７ｇ／Ｌ。用于水和粮食中痕量铜的测定,结果满意。     

新荧光试剂—3—邻甲苯基—5—（2‘—羧基苯偶氮）绕丹宁的荧光性质研究

本文报道新荧光试剂－３－邻甲苯基－５－（２’－羧基苯偶氮）绕丹宁（３ＯＭＲＡＣＰ）的荧光特性，建立了荧光分析测定铜的方法，在ｐＨ５．６时，３ＯＭＲＡＣＰ与铜（Ⅱ）形成螯合物，并在λｅｘ／λｅｍ＝３０８ｎｍ／４０５ｎｍ产生强烈荧光，其荧光强度与铜（Ⅱ）的浓度在０．１～４．０×１０＾－２μｇ／ｇ范围内呈线性关系，检测限达５×１０＾－４μｇ／ｇ。测定了人发中的痕量铜，结果满意。     

催化还原褪色光度法测定痕量铜的研究

本文在少量氯化钠存在下的磷酸－磷酸二氢钾缓冲溶液（ｐＨ＝２．７）中，以铜（Ⅱ）催化次磷酸钠还原罗丹明Ｂ褪色为指示反应，建立了痕量铜的动力学光度分析新方法，在沸水浴中加热反应１０ｍｉｎ，测定的线性范围在０～０．４０μｇ／２５ｍＬ铜（Ⅱ）回归方程为△Ａ＝１．９７５ｃ＋０．００３，相关系数为０．９９９９，以△Ａ＝０．０１计算得测定下限为０．００５μｇ／２５ｍＬ。方法应用于铅基合金，纯铅粉和标准镁合金中铜     

催化动力学分析法测定痕量铜

研究了在氨性介质中，Ｃｕ（Ⅱ）催化Ｈ２Ｏ２氧化噻嗪红Ｒ的退色反应，据此建立了催化动力学光度测定Ｃｕ（Ⅱ）的新方法，方法的线性范围为０．００５－０．５μｇ／２５ｍｌ。曾应用于水、猪肝和小麦粉标准物质中痕量铜的测定，获得满意结果。     

茚三酮缩7—氨基—8—羟基喹啉—5—磺酸催化荧光测定痕量钒（Ⅴ）及其…

合成了新型席夫碱类试剂茚三酮缩７－氨基－８－羟基喹啉－５－磺酸，建立了该剂催化荧光测定痕量钒的 新体系，反应在盐酸体系中进行，其λｅｘ／λｅｍ为３２５／４４８（ｎｍ），钒（Ⅴ）的量在０－４０．０μｇ／Ｌ、４０．０－１６０．０μｇ／Ｌ呈良好线性关系，检测下限为１．７μｇ／Ｌ，方法用于水样痕量钒的测定，结果令人 满意。     

荧光法测定环境水中的痕量砷

建立了测定环境水中痕量砷的荧光新方法,在ＰＨ６．５－７．５的缓冲介质中,利用２′,７′－二氯荧光素（ＤＣＦ）作为荧光试剂,激发波长λｅｘ＝５１０ｎｍ,发射波长λｅｍ＝５２８ｎｍ下,测定痕量砷,亚砷酸根浓度在０．２５－３．５０μｇ／２５ｍＬ范围内,相对荧光强度差值与亚砷酸根浓度呈线性关系,检测限为０．１６μｇ／２５ｍＬ,用于检测自来水和池塘水中的痕量砷,回收率为９５％－１０５％。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.     

Copper-catalyzed multicomponent reactions of 2-iodoanilines,benzylamines, and elemental sulfur toward 2-arylbenzothiazoles

A relatively cheap copper salt-catalyzed, three-component approach providing 2-arylbenzothiazoles in good to excellent yields from readily available 2-iodoanilines, benzylamines, and sulfur powder is reported. This methodology allows preparation of various classes of 2-arylbenzothiazoles and provides a general, reliable approach.