新显色剂2—羧基—4—溴苯重氮氨基—4—苯基—2—噻唑与铂显色反应的研究

研究了新显色剂２－羧基－４－溴苯重氮氨基－４－苯基－２－噻唑与铂显色反应。在混合表面活性剂ＴｒｉｔｏｎＸ－１００和ＳＤＳ存在下，于ｐＨ７．０的磷酸盐缓冲介质中，铂（Ⅳ）与该试剂形成１∶２的红色配合物，其最大吸收波长位于５１０ｎｍ处，表观摩尔吸光系数ε＝５．９×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，铂量在０．０１～２．０ｍｇ／２５Ｌ范围内符合比尔定律，用于催化剂中铂的测定，结果满意。     

2-吡啶重氮氨基偶氮苯与镉(Ⅱ)的显色反应及其应用

报道了一种新型的三氮烯类偶氮染料的合成方法及其与Ｃｄ（Ⅱ）的显色的反应。在Ｔｒｉｔｏｎ Ｘ－１００存在下的弱碱性介质中，该试剂与镉形成 ４： ｌ的红色络合物，最大吸收波长位于５３０ ｎｍ处；表观摩尔吸光系数为 １．９２ ×ｌ０５ Ｌ·ｍｏｌ－１· ｃｍ－１；镉含量在 ０－ ０，５ ｍｇ／Ｌ范围内遵守比耳定律。直接应用于废水中微量镉的测定，结果令人满意。     

安替比林基重氮基—2,4—二硝基苯及其与镉的显色反应

合成了安替比林基重氮氨基－２，４－二硝基苯（ＡＰＤＮＢＴ）新试剂，并首先研究了它的分析性质及其与镉的显色反应。在ＴｒｉｔｏｎＸ－１００存在下，试剂的两级质子离解常数的ｐＫａ值分别是０．８和１０．８；在ｐＨ＝１０．２～１２．０的Ｂ－Ｒ缓冲溶液中，试剂与镉生成１：２的黄色配合物，呈褪色反应，吸光度差值最大的波长为５４０ｎｍ，其表观摩尔吸光系数为１．５２×１０＾５Ｌ／（ｍｏｌ．ｃｍ），线性范围每２５ｍＬ     

2—（5—溴—2—吡啶偶氮）—5—二甲氨基苯胺与铂（Ⅳ）显色反应及其应用

１引言目前，已有多种杂环偶氮类试剂测定铂的报道，但其在显色灵敏度等方面大多还不理想。本文系统研究了２－（５－溴－２－吡啶偶氮）－５－二甲氨基苯胺（５－Ｂｒ－ＰＡＤＭＡ）与Ｐｔ（Ⅳ）的显色反应，结果表明，在ｐＨ４．０～６．０的酸度范围内，在加热条件下铂（Ⅳ）与试剂形成紫红色络合物。该络合物在１．６ｍｏｌ／Ｌ高氯酸溶液中转变为另一型体绿蓝色络合物，表观摩尔吸光系数ε＝８．３×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，大多数常见金属离子及Ａｕ３＋、Ａｇ＋等贵金属离子在一定范围内对测定无干扰。在ＥＤＴＡ存在下，可…     

镉—碘化物—吖啶红高灵敏显色反应及其分析应用

基于在稀磷酸溶液中，镉（Ⅱ）与碘化物和吖啶红（ＡＤＲ）的离了缔合反应，发展了一种高灵敏测定镉的分光光度法。当以试剂空白作参比，离子缔合物的最大吸收波长位于５８０ｎｍ处，摩尔吸光系数达５．６ × １０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ｃｄ（Ⅱ）在０～８０ μｇ／Ｌ的浓度范围内符合比尔定律，方法有较好的选择性，可用于某些样品中痕量镉的测定。     

甲氧基苯并噻唑重氮氨基偶氮苯的合成及与镉的显色反应

合成了新显色试剂６－甲氧基苯并噻唑重氮氨偶氮苯，并研究了在ＴｒｉｔｏｎＸ－１００存在下与镉的显色反应。镉与试剂在ＰＨ１０．０－１１．０缓冲溶液中形成１：１的稳定紫红色络合物，其λｍａｘ＝５２８ｎｍ；ε＝２．４４＊１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。     

镉—双硫腙—CTMAB显色体系的研究及应用

研究了阳离子表面活性剂ＣＴＭＡＢ存在下，镉与双硫腙显色反应的条件及配合物的组成，在０．１６ｍｏｌ／Ｌ的ＮａＯＨ介质中，镉与双硫腙形成一红色配合物，该配合物的λｍａｘ＝５４０ｎｍ，ε５４０＝８．８９×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１镉与双硫腙的配合比为１：３，镉量在０～２５μｇ／２５ｍＬ范围内符合比尔定律，方法用于水样中镉的测定，获得满意结果。     

酚—次氯酸盐直接显色法测定血氨

报道了酚－次氯酸盐直接显色法测定血氨。结果表明，显色反应在ｐＨ１１．０￣１１．６范围内吸光度大、稳定且干扰小。有色化合物最大吸收波长位于６３５ｎｍ，表观魔鬼洋吸光系数为１．８３×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，血氮浓度在０￣１２００μｍｏｌ／Ｌ范围内符合比耳定律，检测下限为４．８μｍｏｌ／Ｌ。采用两种碱浓度不同的次氯酸盐溶液分别测定标准和血液样品，保持了显色溶液酸度一致性，因而提高了血氨测定     

新显色剂—6硝基—苯并噻唑重氮氨基偶氮苯与汞的显色反应及其应用研究

研究了新显色试剂６－硝基－苯并噻唑重氮氨基偶氮苯与Ｈｇ（Ⅱ）的显色反应。在乳化剂ＯＰ存在下，于ｐＨ１０．０的缓冲溶液中，Ｈｇ（Ⅱ）与显色剂形成１：２的稳定红色络合物。络合物的λｍａｘ＝５１５ｎｍ，其表观摩尔吸光系数为１．５３×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，Ｈｇ（Ⅱ）含量在０￣５μｇ／１０ｍＬ范围符合比尔定律，样品分析结果令人满意。     

安替比林基重氮氨基-2,4-二硝基苯与银(Ⅰ)的显色反应及其应用

本文报道了安替比林基重氮氨基－２，４－二硝基苯（ＡＰＤＮＢＴ）与银（Ⅰ）的显色反应．在吐温－８０存在下，ｐＨ＝９．０～１０．０的范围内，试剂与银（Ⅰ）形成２∶１的配合物；配合物对试剂的最大吸收在４８５ｎｍ处，ε为７．２×１０４Ｌ－１·ｍｏｌ·ｃｍ－１；提出了消除阳离子干燥的银镜分离法；方法用于测定合成试样及照相显影液中银的含量，回收率为９６～１０３％，相对标准偏差小于２．０％．     

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.