溶胶-凝胶基质修饰的镉离子选择性电极

一种以CdS为活性物质,用溶胶 凝胶技术制作的新型镉离子选择性电极。电极的斜率为29mV/decade,线性范围为1.0×10-1～6.0×10-5mol/L,检测下限为4.5×10-5mol/L,适宜的pH3.2～5.9,并对回收率进行了测定。     

聚氯乙烯膜依诺沙星选择电极的研制与应用

以盐酸依诺沙星与四苯硼酸盐生成的分子缔合物制成新型PVC膜依诺沙星选择电极,应用于依诺沙星药片的含量测定。在pH 2.2～6.5范围内,电极的能斯特响应范围为5.0×10~(-5)～1.0×10~(-2)mol/L,斜率为58.0mV/pc,检出限为4.2×10~(-6)mol/L。该电极响应速度快,重现性好。3次测定的平均回收率为97.5％,RSD为1.0％,结果与紫外分光光度法基本一致。     

盐酸普鲁卡因离子选择性电极的研制及应用

用盐酸普鲁卡因离子缔合物为电活性物质,以11邻苯二甲酸二正辛酯和邻苯二甲酸二正丁酯为增塑剂,研制成了以PVC为基质膜的盐酸普鲁卡因离子选择性电极.盐酸普鲁卡因浓度在1.0×10-4～2.5×10-2 mol/L范围内时,电极电位服从能斯特方程.响应斜率为56.6 mV/△PC,检测下限为3.16×10-5mol/L,对盐酸普鲁卡因的回收率为95.0%～105%,相对标准偏差为4.6%.本文还考察了电极的各种性质,测定了20种常见离子的选择性系数.方法巳用于实际样品中的盐酸普鲁卡因测定,与常规方法对照,相对误差为4.1%.     

盐酸曲马多离子选择性电极的研制与应用

介绍了盐酸曲马多离子选择性电极的制备,特性以及在药物分析方面的应用。综合考虑活性物质的含量和增塑剂种类及含量的影响,选择了以盐酸曲马多—四苯硼钠缔合物为活性物质,以DOP为增塑剂的电极体系。该电极在5×10-5～1×10-2mol/L范围内表现能斯特响应,斜率为57.1mV/pC,检测下限为1×10-5mol/L。电极对多种异质离子表现良好的选择性。运用电位法测定药物中的盐酸曲马多,回收率为94.9%～106.0%。     

5—羟色胺敏感膜电极的研究 Ⅰ.离子缔合型5—羟色胺膜电极的研制

5-羟色胺(5-HT)与许多疾病的发生和发展有关。应用正交试验,研究了离子缔合型5-HT敏感膜电极的最优化膜组成。筛选了由3种定域体,7种增塑剂组成的213个配方,选定了以四苯硼-5-HT离子缔合物为活性物、磷酸三(2-乙基己基)酯为增塑剂的涂碳PVC膜电极。电极各项性能良好,其线性范围为1.00×10~(-2)～1.58×10~(-5)mol/L,检测下限为4.17×10~(-6)mol/L,斜率为59.7mV/p5-HT。电极寿命超过39天,用混合溶液法测定了体液中可能存在的17种物质的选择性系数。已用该电极测定了牛血小板中的5-HT。     

一种评价离子选择性电极综合性能的新方法及其在盐酸强力霉素PVC膜选择性电极研制中的应用

以电极的响应斜率、响应线性、检出限和响应时间等参数 ,首次提出了一个评价离子选择性PVC膜电极综合性能的新方法———综合性能指数 (ICQ) ,应用ICQ 于以盐酸强力霉素 -四苯硼酸根为电活性物 ,以邻苯二甲酸二丁酯为增塑剂的盐酸强力霉素离子选择性电极的PVC膜成分优选 ;该电极在5.0×10-6～3.2×10-2mol/L范围内呈线性响应 ,斜率为54.5mV/pc,检出限为2.4×10 -6mol/L ;采用直接电位法测定药物片剂中的盐酸强力霉素的含量 ,方法的回收率为99.6%～100.1% ;研究发现 ,当溶液 pH>4时以盐酸强力霉素 -磷钨酸根离子缔合物为电活性物的盐酸强力霉素PVC膜电极呈现超_Nernst响应     

基于UV光固化聚合膜硫氰酸根离子选择性电极的研究

以二丙烯酸脂肪族尿烷酯低聚物为基本原料 ,碘化十二烷基三庚基铵为电活性物质 ,采用 UV光固化聚合成膜研制硫氰酸根离子电位敏感电极。对膜的成分进行了优化 ,优化后的膜与 PVC膜比较具有较高的机械强度和较强的附着力。电极对硫氰酸根离子响应的线性范围为 4.7× 1 0 - 6 ～ 1 .0× 1 0 - 1mol/L,检测下限为 1 .2×1 0 - 6 mol/L ,电极斜率 5 7.5± 1 .5 m V/decade,对常见阴离子电位选择性系数进行了测试 ,电极具有良好的选择性。将电极用于人体尿样中硫氰酸盐的测定 ,结果令人满意     

甲硫醇离子选择性电极的研制及其在甲胺磷残留量测定中的应用

本文以甲硫醇银及硫化银为电活性材料制得对甲硫醇离子有选择性响应的固态膜离子选择性电极。在pH为9.3的0.035mol/L Na_2B_4O_7-0.1mol/L NaOH-0.1mol/L Na_2SO_3介质中,电极的线性响应范围为5×10~(-6)～1×10~(-2)mol/L,响应斜率为58mV/pX。蔬菜中甲胺磷的残留量可以用乙酸乙酯或甲醇水溶液提取后,利用其在碱性条件下水解生成甲硫醇离子的特性用本电极测定,检测限2μg/g,设备简单,操作方便。     

W2O18/NPA修饰电极的研制及在抗坏血酸测定中的应用

研制了掺杂于l-萘胺聚合膜中的杂多酸W2Ol8／NPA化学修饰电极。在弱酸性介质中此电极对抗坏血酸有电位响应。测定了电极的电位选择性系数、响应时间等电化学参数。电极的线性响应范围为10-5～10-2mol·L-1。最佳pH值范围为1～6,检出下限为7×10-6mol·L-1。电极用于测定药剂中抗坏血酸的含量。     

聚氯乙烯膜普鲁卡因选择电极的研制与应用

研制了一种以普鲁卡因碘化物与碘化铋形成的缔合物为电活性物质的PVC(聚氯乙烯 )膜普鲁卡因选择电极 ,测定了普鲁卡因注射液的含量 ;电极的线性响应范围1.0×10 -1～6.3×10 -5mol/L,级差电位为45mV/pc ,检出限为3.4×10-5 mol/L ;该电极响应迅速 ,测定结果与药典法相符     

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.