表面活性剂增敏铍试剂Ⅱ荧光法测定痕量锰

在碱性条件下，Ｍｎ（Ⅱ）与铍试剂Ⅱ形成１；２的荧光络合物，其荧光峰为λｅｘ＝λｅｍ＝３６７／４６７（ｎｍ），表面活性剂十二烷基苯磺酸钠对体系具有强烈增敏作用，基于此建立了痕量锰的测定方法。本文研究了测定的最佳条件，即０．０１％铍试剂Ⅱ４．０ｍＬ，０．１ｍｏｌ／ＬＮａＯＨ６．０ｍＬ，１％ＳＤＢＳ ４．０ｍＬ，反应温度为９０℃，时间１０ｍｉｎ，线性范围为０－１６０μｇ／Ｌ，回归方程Ｘ（μｇ／Ｌ）＝２．     

催化褪色光度法测定微量锰（Ⅱ）的研究

本文研究在硫酸介质中，锰（Ⅱ）催化ＥＤＴＡ还原重铬酸银，而使之褪色的新指示反应。确定了催化褪色反应动力学条件，锰（Ⅱ）的浓度在０－０．４μｇ／ｍｌ范围内，工作曲线呈良好的线性关系，检测限为０．０１１μｇ／ｍＬ，该方法用于天然水及污水中锰的测定，获得满意结果。     

单扫描极谱法连续测定人发中的微量元素锌铁锰铜

本提出在０．１５ｍｏｌ／Ｌ乙二胺－７．５×１０＾－３ｍｏｌ／Ｌ三乙醇胺－２．５×１０＾－２ｍｏｌ／Ｌ硫氰酸钾底液中单扫描极谱法测定锌、铁、锰，续加硫酸（０．３ｍｏｌ／Ｌ）测定铜的方法，峰电位分别为－１．４２Ｖ，－１．６３Ｖ，－１．７１Ｖ，－０．４８Ｖ（ｖｓ．ＳＣＥ），线性范围：０．０５～１．４μｇ／ｍＬＭｎ，０．０４～１μｇ／ｍＬＣｕ，最低检出浓度．０３，０．０５，０．０２，０．０４μｇ／ｍＬＭ     

高灵敏催化光度法测定痕量锰的研究

研究了在ＨＡｃ－ＮａＡｃ介质中，１，１０－邻菲口罗啉存在下，痕量Ｍｎ（Ⅱ）催化高碘酸钾氧化偶氮胂Ⅲ的褪色反应及动力学条件，建立了测定痕量锰的新方法。本法检出限为６．１５×１０－９ｇ／Ｌ，线性范围为０．２～３．２μｇ／Ｌ，已成功用于茶叶、花生、黄豆及中药材枸杞、灵芝中锰的测定。     

水扬基荧光酮－溴化十六烷基三甲胺荧光熄灭法测定茶叶中的微量锰

本文研究了锰（Ⅱ）－水杨基荧光酮－溴化十六烷基三甲。在０．２１～１．６μｇ／２５ｍＬ范围内具有线性关系。检测限为０．２１μｇ／２５ｍＬ。本法灵敏度高，用于测定多种茶叶中的微量锰，结果满意。     

萃取催化光度法测定痕量锰及其反应机理

研究了在弱酸性介质中，以氨三乙酸为活化剂，利用锰（Ⅱ）催化高碘酸钾氧化二苯卡巴肼的指示反应，用卒取平衡控制反应时间和水相中二苯卡巴肼的浓度及反应程度，建立了萃取催化光度法测定痕量锰的新方法。方法的线性范围为０．１０～５０μｇ／Ｌ；检出限为８．７ｘ－８ｇ／Ｌ。用于水、茶叶和粮食中痕量锰的测定，结果满意。探讨了反应机理，建立了动力学方程式。     

1-(2-噻唑偶氮)-2-萘酚螯合物反相高效液相色谱法分离测定铜(Ⅱ)、铁(Ⅱ)和镍(Ⅱ)

以１－（２－噻唑偶氮）－２－萘酚（ＴＡＮ）作柱前显色剂，于ＯＤＳ柱上，用内含０．１ｍｏｌ／ＬＬｉＣｌ，５×１０－６ｍｏｌ／Ｌ ＴＡＮ和ＨＡｃ－ＮＨ４Ａｃ缓冲溶液（ｐＨ ５．５）的甲醇－水溶液（８０：２０，Ｖ／Ｖ）作流动相，流速为０．６ｍＬ／ｍｉｎ，并以紫外－可见检测器于５９０ｎｍ处进行检测，发展了一种ＲＰ－ＨＰＬＣ法同时分离测定铜（Ⅱ）、铁（Ⅱ）、镍（Ⅱ）的方法，方法灵敏度高，对于铜、铁、镍的检测限分别为１μｇ／Ｌ， ２ μｇ／Ｌ和 ０．４ μｇ／Ｌ。用于实际样品测定，结果满意。     

水扬基荧光酮—溴化十六烷基三甲胺荧光熄灭法测定茶叶中的微量锰

本文研究了锰（Ⅱ）－水扬基荧光酮－溴化十六烷基三甲，在０．２１～１．６μｇ／ｍＬ范围内具有线性关系。检测限为０．２１μｇ／２５ｍＬ。本法灵敏度高，用于测定多种茶叶中的微量锰，结果满意。     

高碘酸钾-酸性品红-NTA-DDMAA体系催化光度法测定良量锰

报道了以氨三乙酸为活化剂，以Ｎ－十二烷基二甲基铵基乙酸（ＤＤＭＡＡ）为增敏剂，高碘酸钾氧化酸性品红催化光度法测定痕量锰的新方法，在ＤＤＭＡＡ存在下，灵敏度提高了７倍（Ｍｎ２＋量为１．２～２．４μｇ／Ｌ）和１４倍（Ｍｎ２＋量为２．４～５．２μｇ／Ｌ），相对标准偏差为２．０％，检出限为１．４×１０－７ｇ／Ｌ，可用于茶叶中锰的测定。     

钒（Ⅳ）—硫胺素荧光光度法的研究与应用

利用钒（Ⅳ）作为氧化剂将硫胺素氧化成硫胺荧,建立了一种测量痕量硫胺素的荧光分光光度法,并将该方法应用于药物中硫胺素的测定。该方法测定硫胺素的线性范围为０．８～２４０．０μｇ／Ｌ;检出限为０．４５μｇ／Ｌ;对于４０．０μｇ／Ｌ的硫胺素测定１０次,其相对标准偏差为１．５％。     

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.     

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%).     

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.     

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.     

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.     

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.