无机偶合反应化学发光分析 Ⅱ.H_2O_2-Na_2S_2O_3-鲁米诺体系测定痕量钼

本文将钼催化过氧化氢氧化硫代硫酸钠的反应与鲁米诺-H_2O_2化学发光反应相偶合,建立了痕量钼的无机偶合反应化学发光分析法。此方法的检出限是1.2×10~(-10)g/ml钼,相对标准偏差为2.7％(对5×10~(-9)g/ml钼11次测定),工作曲线的线性范围为1×10~(-9)～1×10~(-3)g/ml。此法巴成功地用于天然水中痕量钼的测定。     

还原剂与鲁米诺化学发光反应的研究(Ⅱ)——钒(Ⅱ)-鲁米诺化学发光反应

Fe(Ⅱ)和Ti(Ⅲ)与鲁米诺的化学发光反应已有报道,我们发现,Cr(Ⅱ)、Mo(Ⅲ)、W(Ⅲ)、U(Ⅲ)、CN~-、SO_3~(2-)、抗坏血酸等一大类还原剂均可与鲁米诺溶液作用产生化学发光,本文利用Jones还原柱产生V(Ⅱ),首次研究了V(Ⅱ)与鲁米诺的化学发光反应,在此基础上建立了钒的流动注射化学发光分析法,方法的检出限是8×10~(-11)g/mL钒,线性范围是4×10~(-10)～1×10~(-5)g/mL钒。测定的相对标准偏差小于2％,考察了20余种常见离子对测定的干扰情况,方法已用于水样中痕量钒的测定,初步探讨了发光反应的机理。     

偶合反应流动注射化学发光法测定镓

基于Ga(Ⅲ )置换Fe EDTA络合物中Fe 和Fe Luminol O2 产生化学发光的反应 ,建立了置换偶合反应流动注射化学发光测定痕量镓的新方法。方法线性范围为 1.4× 10 - 7～ 1.4× 10 - 5g mL ;检出限为 3×10 - 8g mL ;对 5× 10 - 6 g mL镓标准溶液进行 11次平行测定 ,相对标准偏差为 2 .6 %。方法用于中草药中痕量镓的测定 ,结果满意     

以盐酸肼还原天青I催化光度法测定痕量钼

基于天青Ⅰ与盐酸肼氧化还原反应钼的催化活性,拟定了测定痕量钼新的动力学方法。本法钼的检测限为6×10~(-4)μg/ml,可测定浓度范围为1×10~(-3)～9×10~(-1)μg Mo/ml。本法可用于井水、温泉水和废水中钼的测定。     

铬(Ⅲ)催化鲁米诺-过氧化氢体系化学发光反应的研究

痕量铬的液相化学发光分析法以灵敏度高、线性范围宽、仪器设备简单、操作方便快速而见长于铬的其它分析方法。鲁米诺-过氧化氢体系已用于水样和生物样品中痕量铬的化学发光测定。本文在自己设计的仪器上系统地研究了铬(Ⅲ)催化这一体系的化学发光反应,找到了反应的最佳条件,提高了测定的灵敏度,检测极限由6.8×10~(-12)g/ml降低到1.5×10~(-12)g/ml,     

利用H_2O_2-KI-鲁米诺体系化学发光法测定痕量钼

钼(Ⅵ)可以催化H_2O_2氧化I~-的反应,生成的I_2在碱性水溶液中能氧化鲁米诺而产生化学发光,本文将这两个反应结合起来,建立了铝的化学发光分析法,方法有较高的灵敏度,检出限为6×10~(-10)g/cm~3Mo,测定的相对标准偏差小于6％,工作曲线的线性范围是1×10~(-9)～1×10~(-7)g/cm~3Mo,用EDTA作掩蔽剂,排除了大多数金属离子的干扰,方法有较好的选择性,应用此法对一些粮食样品中的痕量钼进行了测定,结果比较满意。     

流动注射-邻菲啰啉协同催化化学发光法测定痕量的铜

本文拟订了邻菲啰啉-CTMAB-H_2O_2-Co(Ⅱ)-Cu(Ⅱ)协同催化化学发光体系流动注射测定痕量Cu(Ⅱ)的新方法。方法的检出限为8×10~(-12)g/ml Cu(Ⅱ),线性范围为1×10~(-10)-4×10~(-8)g/ml Cu(Ⅱ),相对标准偏差为0.9％分析速度为160样/小时。本法用于头发和水样中Cu(Ⅱ)的测定取得了满意的结果。     

水及血液中痕量铜的化学发光分析

本文采用自制仪器对鲁米诺-氰化钾-铜(Ⅱ)化学发光体系进行了系统研究,选定了测铜的最佳条件。该体系以铜(Ⅱ)作为氧化剂直接氧化鲁米诺产生λ_(max)为425nm的闪烁化学发光。测铜的线性范围为2×10~(-10)—6×10~(-7)/ml,检测下限为9×10~(-l2)g/ml,对10~(-10)g/ml铜(Ⅱ)测定的变异系数为4.6％。采用焦磷酸钠作为掩蔽剂可消除常见共存离子的干扰。此法用于水及人体全血中痕量铜的测定,结果均比较满意。     

钨(Ⅵ)-钼(Ⅵ)-鲁米诺化学发光反应测定钨

本文研究以钨(Ⅵ)形成钨钼杂多酸与鲁米诺反应,产生化学发光测定钨的方法及条件。在pH1.6静置溶液,钨钼杂多酸迅速形成,具有很高的氧化活性。测定钨的灵敏度达到0.084ng/ml,钨浓度从1×10~(-10)～1×10~(-5)g/ml范围内具有线性关系。通过巯基棉分离富集,用于天然水及岩矿样品中痕量钨的测定,均获得满意结果。     

偶合反应流动注射化学发光法测定汞

基于Hg(Ⅱ)置换Fe(Ⅱ)-DETA配合物中的Fe(Ⅱ)和Fe(Ⅱ)-鲁米诺-溶解氧产生化学发光的反应,建立了置换偶合反应,流动注射化学发光测定痕量汞的新方法.方法线性范围为1×10~(-7)～1×10~(-5)g·ml~(-1)相对标准偏差为3.5%(n=11,C=1×10~(-6)g·ml~(-1)),检出限为3×10~(-8)g·ml~(-1),方法用于工业废水中汞的测定,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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.