用新试剂2[—5‘—氟—2’—砷酸基苯）偶氮]—1,8—二羟基—3,6—萘二磺酸荧光法

研究了试剂２－」５’－氟－２’－－砷酸基苯）偶氮「－１，８－二羟基－３，６－萘二磺酸与硼的荧光性能。硼与试剂形成１：２的强荧光配合物，其λｅｘ／λｅｍ＝２３４ｎｍ／３８０ｎｍ，Ｂ（Ⅲ）含量在０－３６０μｇ／Ｌ范围内呈良好线性关系，检测限为２．０６μｇ／Ｌ，据此建立了测定微量硼的新方法。     

用新荧光试剂7—（2,4—二羟基—5—羧基苯偶氮）—8—羟基喹啉—5—磺酸？…

研究了新荧光试剂７－（２，４－二羟基－５－羧基苯偶氮）－８－羟基喹啉－５－磺酸（ＤＨＣＢＡＱＳ）与镁形成配合物的荧光性能，在ｐＨ９．０的硼砂缓冲介质中，试剂与镁形成１：１配合物，其λｅｘ／λｃｍ＝３５８ｎｍ／５０２ｎｍ。镁（Ⅱ）含量在０￣４８０μｇ／Ｌ范围内呈良好线性关系，检测限为３．７μｇ／Ｌ，据此建立测定痕量镁的新方法，并应用于矿样及血清中痕量镁（Ⅱ）的测定，结果满意。     

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。     

用新荧光试剂7-(2,4-二羟基-5-羧基苯偶氮)-8-羟基喹啉-5-磺酸荧光法测定镁

研究了新荧光试剂７－（２，４－二羟基－５－羧基苯偶氮）－８－羟基喹啉－５－磺酸（ＤＨＣＢＡＱＳ）与镁形成配合物的荧光性能，在ｐＨ９０的硼砂缓冲介质中，试剂与镁形成１∶１配合物，其λｅｘ／λｅｍ＝３５８ｎｍ／５０２ｎｍ。镁（Ⅱ）含量在０～４８０μｇ／Ｌ范围内呈良好线性关系，检测限为３７μｇ／Ｌ，据此建立测定痕量镁的新方法，并应用于矿样及血清中痕量镁（Ⅱ）的测定，结果满意。     

用新试剂2-[(5’-氟-2’-砷酸基苯)偶氮]-1,8-二羟基-3,6-萘二磺酸荧光法测定硼

研究了试剂２－［（５’－氟２’－砷酸基苯）偶氮］－１，８－二羟基－３，６－萘二磺酸与硼的荧光性能．硼与试剂形成１：２的强荧光配合物，其λｅｘ／λｅｍ＝２３４ ｎｍ／３８０ ｎｍ， Ｂ（Ⅱ）含量在 ０～３６０μｇ／Ｌ范围内呈良好线性关系，检测限为２．０６μｇ／Ｌ，据此建立了测定微量硼的新方法。该方法应用于茶叶、铝合金及粮食等样品中微量硼的测定，结果满意．     

荧光法测定硼的研究

研究了新试剂２－［（５′－甲基－２′－胂酸茯苯）偶氮］－１，８二羟基－３，６－萘二磺到与硼的荧光性能。在ｐＨ６．７的磷酸氢二钠－磷酸二氢钾缓冲介质中，硼与试剂形成１：２的强荧光配合物，其λｅｘ／λｅｍ＝２３５ｎｍ／３６７ｎｍ，Ｂ（Ⅲ）含量在０￣２００μｇ／Ｌ范围内呈良好线性关系，检测限为０．６２９μｇ／Ｌ，建立了测定微量硼的新方法。该方法应用于茶叶及淀粉等亲品中微量硼的测定，结果满意。     

钪—水杨醛苯甲酰腙高灵敏度荧光反应及其应用

研究了水杨醛苯甲酰腙（ＳＡＢＨ）与钪荧光反应新体系的最佳条件。在ｐＨ＝６．４乙醇／水（６．２：３．８）溶液介质中，形成络合物的组成比１：３（钪、试剂），λｅｘ／λｅｍ＝３８５ｎｍ／４５５ｎｍ，建立钪荧光分析法的线性范围为０￣１００μｇ／Ｌ；相对标准偏差１．５％；检出下限为０．０２５μｇ／Ｌ。考察了３０种共存离子的干扰情况，方法成功用于地质中样中痕量钪的测定。     

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。     

水杨醛缩—5—碘—5—氨基喹啉的合成及荧光光度法测定煤渣中痕量镓的研究

报道了新息夫碱试剂水杨醛缩－５－碘－５－氨基喹啉（ＳＡＩＡＱ）的合成。用元素分析、红外光谱法确定了其结构。测定了ＳＡＩＡＱ的酸度常数Ｋａ１＝２．４０×１０＾－４，Ｋａ２＝２．９８×１０＾－９。在ｐＨ３．５０￣５．００范围内ＳＡＩＡＱ与Ｇａ＾３＋形成稳定的荧光螯合物，且在λｅｘ／λｅｍ＝４２８ｎｍ／５４０ｎｍ产生强烈荧光。其荧光强度与Ｇａ＾３＋的浓度在１．５μｇ／Ｌ￣２６０μｇ／Ｌ范围内呈线性关系，     

水杨醛缩-5-碘-8-氨基喹啉的合成及荧光光度法测定煤渣中痕量镓的研究

报道了新息夫碱试剂水杨醛缩－５－碘－８－氨基喹啉（ＳＡＩＡＱ）的合成。用元素分析、红外光谱法确定了其结构。测定了ＳＡＩＡＱ的酸度常数Ｋａ１＝２．４０×１０－４，Ｋａ２＝２．９８×１０－９。在ｐＨ３．５０～５．００范围内ＳＡＩＡＱ与Ｇａ３＋形成稳定的荧光螯合物，且在λｅｘ／λｅｍ＝４２８ｎｍ／５４０ｎｍ产生强烈荧光。其荧光强度与Ｇａ３＋的浓度在１．５μｇ／Ｌ～２６０μｇ／Ｌ范围内呈线性关系，检出限１．５μｇ／Ｌ，考察了共存离子的影响，选择性高。已应用于煤渣中痕量镓的分析。     

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.