测定汽油中铅的KMnO4—Luminol化学发光体系

研究了KMnO4氧化鲁米诺(luminol)的化学发光反应过程,探讨了铅(Ⅱ)后续催化该化学发光反应的反应历程,建立了在最佳反应条件下利用该后续发光反应定量测试微量铅的方法;采用流动注射化学发光方法测定了汽油中铅含量,方法检出限达0.01mg/L,检测线性范围在1.0×10-7～5.0×10-4mol/L,对大量阴阳离子进行了干扰试验,结果表明方法有良好的选择性.     

流动注射化学发光法测定水样中痕量间苯二酚

基于在甲醛存在条件下,高锰酸钾在酸性介质中氧化间苯二酚而发生化学发光反应,建立了测定痕量的间苯二酚化学发光分析法.该法测定间苯二酚的线性范围为5.0×10-9～1.0×10-4mol/L,检出限为3.0×10-9mol/L,相对标准偏差为3.5%(1.0×10-6mol/L间苯二酚,n=11).该法应用于测定水样中加入的间苯二酚,结果令人满意.     

测定化探样品中痕量钒的流动注射光泽精化学发光法

用配有Jones还原器的流动注射系统,研究了光泽精与钒(Ⅱ)的化学发光反应,并建立了钒的流动注射化学发光分析法。该法线性范围为1×10-6～1×10-2 g/L ,检出限为3×10-7 g/L,相对标准偏差为2.0 %(1×10-4 g/L,n=11),相关系数在0.9988以上。已用于化探样品中痕量钒的测定,结果令人满意。     

顺序注射化学发光法测定药物中的抗坏血酸

基于在酸性介质中KMnO4氧化抗坏血酸产生化学发光反应,HCHO的存在能使发光强度增强的原理,建立了顺序注射技术与化学发光分析联用测定痕量抗坏血酸的新方法。对进样顺序、体积、流速和浓度各因素进行了优化,在150μL进样体积下,方法的线性范围为1.0×10-9~2.0×10-6mol/L,检出限(3σ)为5.0×10-10mol/L,方法的相对标准偏差为1.3%(1.0×10-7mol/L,n=11)。采样频率为80样/h。应用该法测定维生素C针剂和片剂中的抗坏血酸,结果与标准方法一致。     

鲁米诺-[铁氰化钾-亚铁氰化钾]-酚磺乙胺化学发光体系

实验发现 ,酚磺乙胺与鲁米诺在碱性溶液中可产生弱的化学发光 ,铁氰化钾和亚铁氰化钾的存在对该化学发光反应具有很强的催化作用。基于此 ,建立了基于鲁米诺 铁氰化钾 /亚铁氰化钾 酚磺乙胺体系测定酚磺乙胺的流动注射化学发光新方法。酚磺乙胺浓度在 4 .0× 10 -6～ 1.0× 10 -4g/L范围内与化学发光强度具有线性关系。该方法的检出限为 1× 10 -6g/L ,相对标准偏差为 1.4 % (2 .0× 10 -5g/L酚磺乙胺溶液 ,n =11)。该方法用于止血敏注射液中酚磺乙胺的含量测定 ,结果令人满意。同时 ,还对可能的化学发光反应机理进行了初步探讨     

高锰酸钾-甲醛-尿酸化学发光体系的研究

在甲醛存在下,高锰酸钾与尿酸能够发生化学发光反应,产生很强的化学发光。据此采用流动注射技术,建立了一种利用高锰酸钾甲醛尿酸化学发光体系测定尿酸的化学发光分析法。方法的检出限为6×10-6 g/L;相对标准偏差为1. 8% (4. 0×10-4 g/L尿酸,n=11 );线性范围为2. 0×10-5 ~5. 0×10-3g/L。本法用于人体尿液中尿酸的测定,结果令人满意。并探讨了反应机理。     

锰(Ⅳ)-安乃近-甲醛化学发光体系的研究

实验发现锰(Ⅳ)氧化安乃近可以产生弱的化学发光,甲醛对这一化学发光反应有较强的增敏作用。据此建立了测定安乃近的流动注射化学发光分析法。在最优化的条件下,测定安乃近的线性范围为6 0×10-7～1 0×10-5mol/L,检出限为2×10-7mol/L安乃近。对1.0×10-6mol/L安乃近进行11次测定,相对标准偏差为3.4%。该方法已应用于针剂中安乃近的测定,其结果与药典方法测得值一致。     

锰(Ⅳ)-抗坏血酸-甲醛化学发光体系的研究

实验观察到锰(Ⅳ)氧化抗坏血酸可以产生弱的化学发光,甲醛对这一化学发光反应有较强的增敏作用,据此建立了测定抗坏血酸的流动注射化学发光分析法.方法的检出限为2×10-8 mol/L抗坏血酸;线性响应范围为6.0×10-8～2.0×10-5mol/L.对1.0×10-6mol/L的抗坏血酸进行11次测定,相对标准偏差为2.3%.该方法已成功应用于维生素C针剂和片剂中抗坏血酸含量的测定,结果与药典方法测得值一致.     

甲酸存在下 N-四氢苯并噻唑亚胺希夫碱的化学发光

新合成的N(2-四氢苯并噻唑)-2-羟基苯甲亚胺希夫碱与酸性高锰酸钾反应产生微弱的化学发光,甲酸的存在有显著的增敏作用。报道了其荧光光谱、化学发光光谱、紫外可见吸收光谱和化学发光动力学曲线,并建立了流动注射化学发光测定噻唑类希夫碱的方法。该法线性范围为1.0×10-7～8.0×10-5mol/L,检测限为5.0×10-8mol/L,对1.0×10-6mol/L噻唑类希夫碱11次平行测定的相对标准偏差为1.7％。     

毛细管电泳-间接化学发光法检测染发剂中苯二酚异构体和苯酚

根据某些酚类化合物在碱性条件下具有能猝灭鲁米诺-铁氰化钾体系化学发光信号的特性,建立了毛细管电泳-间接化学发光分离检测苯二酚异构体和苯酚的新方法.电泳缓冲溶液选用7.5 mmol/L Na2B4O7-2.5 mmol/L Na2HPO4.在优化的化学发光和电泳条件下,对苯二酚、间苯二酚、邻苯二酚和苯酚在10 min内可直接实现分离,其检出限(S/N=3)分别为2.9×10-8 mol/L、3.7×10-7 mol/L、8.4×10-8 mol/L和4.4×10-6 mol/L;相对标准偏差(RSD)为2.5%～4.8%(n=5).通过对不同染发剂实际样品进行分离分析研究,证明该方法可以用于实际染发剂样品的分析测定,结果令人满意.     

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.     

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.     

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.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

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.