1—（2—苯并噻唑）—3—（4—偶氮苯基）—三氮烯与汞的显色反应研究及…

研究了新试剂１－（２－苯并噻唑）－３－（４－偶氮苯基）－三氮烯（ＢＴＰＡＰＴ）与汞的显色反应，在Ｔｗｅｅｎ－８０存在下，ｐＨ为１１．２０时，Ｈｇ（Ⅱ）与试剂生成红色的１：１配合物，最大吸收峰位于５１０ｎｍ，表现摩尔吸光系数为１．１０×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１线性范围０－１４μｇ／２５ｍＬ，建立了可用于饮用水，生活用水和工业废水汞含量测定的方法。     

安替比林基重氮氨基—2,4—二硝基苯与汞（Ⅱ）的显色反应及其应用

本研究了试剂安替比林基重氮氨基－２４－二硝基苯（ＡＰＤＮＢＴ）与汞的显色反应，在Ｔｗｅｅｎ－８０存在下和ｐＨ＝１０．２～１２．３的缓冲溶液中，ＡＰＤＮＢＴ与汞生成黄色络合物，其络合比为Ｈｇ∶ＡＰＤＮＢＴ＝１∶２，建立了以４４５ｎｍ为参比波长，５３８ｎｍ为测量波长的双波长分光光度法，其表观摩尔吸光系数为２．１×１０＾５Ｌ·ｍｏｌ＾－１·ｃｍ＾－１，线性范围是０     

喹啉基重氮氨基偶氮苯的合成及其与汞显色反应的研究

报道了新三氮烯类显色剂喹啉基重氮基偶氨苯的合成,性质及共与汞的显色反应。在ＰＨ９．５的硼砂－氢氧化钠缓冲介质中,有乳化剂ＯＰ存在下,该试剂与汞生成２：１的橙红色配合物,最大吸收波长在５２０ｎｍ处,表观摩尔吸光系数为１．５３＊１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１汞量在０－２０μｇ／２５ｍＬ范围内遵守比尔定律。     

新试剂3,3‘—二甲基联苯重氮氨基—4—苯基—2—噻唑分光光度法测定？…

研究了新试剂３,３’－二甲基联苯重氮氮基－４－苯基－２－噻唑（ＤＭＰＤＰＡＰＴ）在表面活性剂Ｎ－氨代十六烷基吡啶存在下,与汞（Ⅱ）显色反应的适宜条件。在ＰＨ７．２－９．２范围内,汞（Ⅱ）与ＤＭＤＰＤＡＰＴ形成２：２紫红色配合物,其最大吸收波长为５６０ｎｍ,配合物的表观摩尔吸光系数ε＝９．０１＊１０＾４Ｌ．ｍｏｌ＾－１。ｃｍ＾－１。汞（Ⅱ）浓度在０－１２μｇ／２５ｍＬ范围内符合比尔定律。此法已用于水     

米托蒽醌的吸附行为及其吸附伏安测定法研究

本文研究了米托蒽醌在悬汞电极上的吸附行为，在此基础上建立了米托蒽醌的吸附伏安测定方法。在ｐＨ为２．２的Ｂ．Ｒ缓冲体系中，米托蒽醌浓度在１．１×１０＾－６ｍｏｌ／Ｌ～１．１×１０＾－９ｍｏｌ／Ｌ范围内，浓度与电流呈线性，检出限可达５．５×１０＾－１０ｍｏｌ／Ｌ。若在盐酸－柠檬酸钠（ｐＨ为１．２５）缓冲体系中，检出限可低至１．１×１０＾－１１２ｍｏｌ／Ｌ。方法可用于尿样或血样中米托蒽醌的测定。     

2—[2‘—（4’—甲基—苯并噻唑）偶氮]—5—二甲氨基苯甲酸与钯（Ⅱ）显色反应…

合成了新试剂２－［２＇－（４＇－甲基－苯并噻唑）偶氮］－５－二甲氨基苯甲酸，并研究了其与钯（Ⅱ）的显色反应。实验表明，在５０％乙醇介质中，该试剂与钯（Ⅱ）反应生成１：１络合物，其最大吸收波长为６９８ｎｍ，表观摩尔吸光系数为５．８３×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。     

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。     

新显色剂2—（5—硝基—2—吡啶偶氮）—5—二甲所苯胺与钯显色反应的研究及其…

用新合成的偶氮试剂２－（５－硝基－２－吡啶偶氮）－５－二甲氨基苯胺研究了光度法测定钯的反应条件。结果表明，在０．４５－１．２ｍｏｌ／Ｌ盐酸介质中，钯与试剂形成稳定的蓝色配合物，其最大吸收波长位于６２１ｎｍ处，表观摩尔吸收系数为９．４×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，配合成的组成为Ｐｄ：５－ＮＯ２－ＰＡＤＭＡ＝１：２，钯浓度在０－１０μｇ／１０ｍＬ范围内符合比尔定律。本方法是目前测定钯的高灵敏     

阴离子表面活性剂—溴化十二烷基二甲基苄基铵—溴百里酚蓝显色反应…

本文研究了溴化十二烷基二甲基苄铵－溴百里酚蓝与阴离子表面活性剂显色反应的适宜条件结果表明，在ｐＨ７．４～８．２范围内阴离子表面活性剂与题示试剂形成１：２：１的绿色离子缔合物，其最大吸收峰位于６１４ｎｍ处。表观摩尔吸光系数分别为ε＾ＳＤＢＳ６１４＝３．９９×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１；ε＾ＳＤＳ６１４＝３．７０×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，ε＾ＳＬＳ６１４＝１．７１×１０＾４Ｌ．     

7—（对甲酰基苯偶氮）—8—羟基喹啉—5—磺酸的合成及其双波长分光光度…

７－（对甲酰基苯偶氮）－８－羟基喹啉－５－磺酸是一新显色剂，该试剂在微碱性介质中（ｐＨ＝７．５）与镓形成黄色络合物，络合物λｍａｘ＝３９２ｎｍ，摩尔吸光系数ε３９２＝２．２４×１０＾４Ｌ．ｍｃｌ＾－１．ｃｍ＾－１，同时在５００ｎｍ呈现负峰，用双峰双波长法测定镓ε３９２－５００＝６．８９×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，灵敏度是单波长法的三倍多，线性范围０～２．０×１０＾－６ｍｏｌ／Ｌ。用拟定     

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.     

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.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Catalyst free,visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes

An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C₆₀ and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C₆₀, followed by SET from the amine to the triplet excited state of C₆₀. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C₆₀ radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared.     

Highly efficient and stereoselective cycloaddition of nitrones to indolyl- and pyrrolylacrylates

The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities.     

Transition metal-free direct amination of benzoxazoles using formamides as nitrogen sources

A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields.     

l-Proline-catalyzed five-component domino reaction leading to multifunctionalized 1,2,3,4-tetrahydropyridines

Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl₃-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction.     

Exploring the scope of the Gewald reaction: Expansion to a four-component process

An efficient four-component reaction was developed to take advantage of the reactivity of the 2-aminothiophene-3-carbonitrile functionality, which is obtained during the classical three-component Gewald reaction. Various α-methylene bearing ketones were reacted with malononitrile, elemental sulfur, and aryl/heteroarylnitrile derivatives in t-BuOH/NaOH to afford 2-arylthieno[2,3-d]pyrimidin-4-amines in high yields. Preliminary studies revealed the photophysical properties of the products and their potential for use as metal sensors.