荷移反应用于氨苄青霉素的测定

研究了氨苄青霉素与对苯醌的荷移反应，确定了反应条件。在ＰＨ４．４－５．０的醋酸－醋酸钠缓冲溶液中形成１：１络合物，其λｍａｘ＝４７２ｎｍ。氨苄青霉素三水合物浓度在１０－１２５ｍｇ／Ｌ范围地线性关系；当浓度为５０ｍｇ／Ｌ时相对标准偏１．８％；表观摩尔吸光系数为２．６４×１０＾３Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。应用拟定的方法测定药物制剂含量，结果与药典方法一致。回收率在９６％以上。     

α,α‘—联吡啶光度法测定微量钌

研究了钌与α，α‘－联吡啶配位反应。在ｐＨ４．６的ＨＡｃ－ＮａＡｃ缓冲溶液和ＮＨ２ＯＨ．ＨＣ存在下，在沸水浴中加热近５ｍｉｎ，钌与α，α’－联吡啶反应形成了１：３配合物，在４５６ｎｍ表观摩尔吸光系数为１．１×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。钌的比尔定律范围０－７０μｇ／２５ｍＬ，方法已被用于氯碱厂阳极泥中钌含量的测定。     

微乳液介质—1—（2—吡啶偶氮）—2—萘酚光度法测定汽油中环烷酸铁的含量

本研究了微乳液为介质时，铁与１－（２－吡啶偶氮）－２－萘酚（ＰＡＮ）的显色反应。选择７３０ｎｍ处为测定波长，ε为１．４×１０＾４Ｌ．ｍｏｌ＾－＾１．ｃｍ＾－＾１，铁量在０－５０μｇ／２５ｍｌ范围内符合比耳定律，该法适用于汽油中环烷酸铁的测定。     

头孢氨苄与苯醌类试剂的荷移反应

本研究了头孢氨苄与对苯醌和四氯苯醌的荷移反应，实验指出，头孢氨苄与对苯醌反应是在乙醇介质中进行，与四氯苯醌反应则在硼砂缓冲液中进行，两种络合物λｍａｘ值分别是４８７ｎｍ和３４６ｎｍ；表观摩尔吸光系统分别是１．３７×１０＾３和１．０２×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾０１；比尔定律线性范围分别是１０－１６０ｍｇ／Ｌ和３－３０ｍｇ／Ｌ，其组成比均是１：１，应用拟定的方法测定头孢氨苄制剂含量，结果与标     

偶合反应流动注射化学发光测定锆的研究

基于Ｚｒ置换Ｃｏ－ＮＴＡ配合物中的Ｃｏ（Ⅱ）和Ｃｏ（Ⅱ）催化过氧化氢氧化鲁米诺产生化学发光的反应，建立了偶合反应流动注射化学发光测定锆的新方法。方法的线性范围为１×１０＾－１０－１×１０＾－７ｇ．ｍｌ＾－１，检出限为３×１０＾－１１ｇ．ｍｌ＾－１，方法用于地矿术中锆的测定，结果满意。     

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。     

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。     

流动注射化学发光法测定甲氨蝶呤

研究了甲醛增强高锰酸钾与甲氨蝶呤的化学发光反应，由此建立了一种测定甲氨蝶呤的流动性注射化学发光分析法，方法的检出限为３．４×１０＾－９ｇ／ｍＬ，相对标准偏差为１．１％（２．０×１０＾－６ｇ／ｍＬ甲氨蝶呤，ｎ＝１１）线性范围为１．０×１０＾－８～１．０×１０＾－５ｇ／ｍＬ。该法已用于甲氨蝶呤针剂及片剂中甲氨蝶呤含量的测定。     

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。     

铝与溴代二甲氨基苯基荧光酮的多元配合物的光度研究

本文研究了在表面活性剂存在性，铝与溴代二甲氨基苯基荧光酮的显色反应。在弱酸性介质中，Ａｌ＾３＋ＢＤＭＡＦ－ＣＴＭＡＢ三元配合物在水浴加热至７０℃－８０℃时形成，其最大吸收波长为５７７ｎｍ，Ａｌ＾３＋：ＢＤＭＡＦ＝１：２，表观摩尔吸光系数为１．３４×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，表观稳定常数为７．４×１０＾５。在ＰＨ９．５－１０．５的氨性缓冲介质中，Ａｌ＾３＋－Ｆ＾－－ＢＤＭＡＦ－非离子表面     

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.     

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 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.