青霉素 V钾的二次微分简易示波伏安法测定

利用青霉素 V钾在 pH=7的 KH2PO4-Na2HPO4缓冲溶液中产生切口的示波特性 , 提出了一种药片中青霉素 V钾的测定方法 - - 二次微分简易示波伏安法 ; 校正曲线的线性范围为 2.0× 10-5～ 2.0× 10-4 mol/L, 检出限为 8× 10-6 mol/L; 对 7.0× 10-5 mol/L青霉素 V钾 8次测定结果的相对标准偏差为 1.6% ; 实验结果表明该法具有分析速度快、仪器装置简单以及药片中的淀粉等物质不干扰测定的优点 .     

ZrC-桑色素络合物在碳糊电极上的二次导数吸附伏安法测定Zr的研究

研究了Zr 桑色素络合物在碳糊电极正电位区的吸附伏安行为 ,并利用其在 0 .74V处的二次导数吸附氧化峰电流与Zr(Ⅳ )浓度为 6 .0× 10 -9～ 2 .0× 10 -6mol/L呈线性而测定Zr;检出限为 3.0× 10 -9mol/L(S/N =3)。最佳测定条件为 :2 .0mol/LHCl、1.0× 10 -5mol/L桑色素 ;富集电位为 0V(vs .SCE) ;扫描速度为2 5 0mV/s。该法不需萃取分离 ,可直接用于岩石样品中Zr的测定 ,结果满意     

血红蛋白模拟过氧化物酶催化反应体系的极谱分析

用极谱分析法研究了血红蛋白催化H2O2氧化邻苯二胺(OPD)的反应体系.血红蛋白具有类似过氧化物酶的功能,它能够催化OPD-H2O2的反应生成一种具有电化学活性的产物,该产物在滴汞电极上-0.64V(vs.SCE)产生一个峰形良好的极谱还原峰.优化了血红蛋白的催化反应条件和催化反应产物的极谱测定条件 在最佳条件下,该体系可用于血红蛋白含量的测定,线性范围为2.0×10-9～2.0×10-7mol/L,检测限为1.0×10-9mol/L;也可用于痕量H2O2的测定,线性范围为1.0×10-6～2.0×10-4mol/L,检测限为1.0×10-6mol/L.     

四种阴离子的毛细管电泳电导检测(英文)

 采用柠檬酸 柠檬酸钠作为缓冲体系 ,使用负高压 ,对Cl-,NO3 -,HCO3 -和H2 PO4 -等 4种常见阴离子进行了分离检测 ,研究了缓冲剂的种类、浓度、pH值及操作电压对分离的影响。在选定的条件下 ,4种离子的定量线性范围 :Cl-5 0× 10 -5mol/L～ 2 5× 10 -3 mol/L ,NO3 -6 0× 10 -5mol/L～ 2 0× 10 -3 mol/L ,HCO3 -5 0× 10 -6mol/L～ 2 0× 10 -4 mol/L ,H2 PO4 -6 0× 10 -5mol/L～ 1 0× 10 -3 mol/L ;检出限 :Cl-1 5× 10 -5mol/L ,NO3 -3 0×10 -5mol/L ,HCO3 -1 0× 10 -6mol/L ,H2 PO4 -2 0× 10 -5mol/L ;峰面积的RSD (n =6 ) :Cl-3 1% ,     

苯巴比妥的二次微分简易示波伏安法测定

利用苯巴比妥的示波特性 ,分别建立了在0.2mol/LKOH和1.0×10-4mol/LCd2 +-0.1mol/L硼砂底液中直接和间接测定苯巴比妥的二次微分简易示波伏安法 ;直接测定和间接测定的线性范围分别为1.0×10 -5mol/L～1.0×10 -4mol/L和4.0×10 -6mol/L～8.0×10 -5mol/L ;检出限分别为8×10 -6mol/L和2×10 -6mol/L;在直接测定中 ,对6.000×10 -5mol/L苯巴比妥进行10次测定的RSD为4.5 % ;间接测定中 ,对2.000×10 -5mol/L苯巴比妥进行10次测定的RSD为2.6 % ;这一研究表明对于一些在示波分析中灵敏度不高或本身没有示波活性的药物 ,可以利用其与金属离子生成沉淀的方法间接测定 ,从而提高药物测定的灵敏度、拓宽示波分析应用领域     

头孢哌酮钠的直接和间接示波测定

在pH4.2HAc -NaAc缓冲溶液中 ,头孢哌酮钠在示波图阴极支 -1.48V(vsSCE)处产生一个灵敏切口 ;而在0.2mol/LNaOH底液中 ,头孢哌酮钠与 β_环糊精(β_CD)形成包结物使 β_CD在示波图上产生的切口变浅。根据这些示波特性 ,建立了测定头孢哌酮钠注射剂中头孢哌酮钠含量的直接和间接二次微分简易示波伏安法。实验结果表明 :直接测定头孢哌酮钠的线性范围为1.2×10 -5～2.2×10 -4mol/L ,检出限为6.0×10 -6mol/L ,对3.000×10 -5mol/L进行5次测定的RSD为2.1 % ;而间接测定的线性范围为2.0×10 -6～9.0×10 -5mol/L ,检出限8.0×10 -7mol/L ,对2.500×10 -6mol/L进行5次测定的RSD为2.7 %。与直接法相比较 ,间接测定头孢哌酮钠的检出限更低而线性范围更宽     

二次微分简易示波伏安法用于葛根素测定

根据在 0 .1 mol/ L Na OH溶液中 ,葛根素在二次微分简易示波伏安图阴极支-0 .95V ( vs.SCE)产生一灵敏峰的示波特性 ,建立了二次微分简易示波伏安法测定药品中葛根素含量的新方法。线性范围为 2 .5× 1 0 - 6～ 3 .5× 1 0 - 5mol/ L,相关系数为 0 .9985,检出限为 1× 1 0 - 6mol/ L,对 9.0× 1 0 - 6mol/ L葛根素进行 5次测定的RSD为 1 .5%。利用该法测定中药葛根及心可舒片剂中葛根素的回收率分别为 1 0 0 .2 %和 96.9%。     

铋B-芦丁体系的微分吸附计时电位法研究

提出一种测定痕量铋的微分吸附计时电位法。利用悬汞电极作工作电极 ,置富集电位于 0 .10V ,在0 .0 15mol/LHAc 0 0 0 5mol/LNaAc 7.5× 10 -7mol/L芦丁的底液中 ,测定铋 的线性范围为 1.0× 10 -10 ～7 5× 10 -8mol/L ,检出限为 5× 10 -11mol/L。探讨了影响方法灵敏度的主要因素 ,研究了电极过程。利用此法测定了中草药样品中的铋含量 ,结果满意。     

四磺基锰酞菁作为过氧化物模拟酶在过氧化氢化学发光测定中的应用

以四磺基锰酞菁 (MnTSPc)作为过氧化物模拟酶催化H2 O2 与鲁米诺的化学发光反应 ,建立了测定环境样品中H2 O2 的化学发光分析新方法。该法的线性范围为 4 .0× 10 - 8～ 2 .0× 10 - 5mol L ;检出限为 6 .8×10 - 9mol L ;对 1.0× 10 - 6 mol L的H2 O2 进行连续 10次平行测定 ,相对标准偏差为 2 .4 %。用本法对天然雨水进行了分析测定 ,结果良好。     

磷钼杂多酸光度法测定吲哚乙酸

研究了吲哚乙酸与磷钼杂多酸在浓度为 0 .0 3 mol/L的硫酸介质中发生氧化还原反应 ,形成的还原产物 (钼蓝 )在 NH3-NH4Cl缓冲溶液 (p H8.4)中最大吸收波长为 314 nm,表观摩尔吸光系数 ε值为 3.5 4× 10 4L· mol-1·cm-1 ,吲哚乙酸含量在 5 .0× 10 -7～ 5 .0× 10 -5 mol/L范围内符合比尔定律 ,检出限为 1.0× 10 -7mol/L,对 2 .0 0× 10 -5 mol/L吲哚乙酸测定 10次的相对标准偏差为 6 .42 % ,加标回收率为 94.2 %～ 10 0 .1%     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.