单扫描极谱法测定注射液及血清中维生素K1

建立了维生素K1的极谱测定方法.在0.05 mol·L-1 NH4Cl-NH3(pH 8.58)缓冲溶液中,维生素K1可产生一极谱还原峰,峰电位Ep为-0.39 V ;其二阶微分峰峰电流ip″与维生素K1的浓度在1.1×10-7 ～2.2×10-5 mol·L-1范围内呈线性关系,相关系数r=0.998 6(n= 9 );方法的检出限为4.0×10-8 mol·L-1.13次平行测定2.2×10-5 mol·L-1维生素K1还原波二阶导数峰峰电流ip″的相对标准偏差(RSD)为1.83%.本法可直接用于注射液及血清中维生素K1含量的测定.     

吡虫清催化极谱波的研究

在浓度为 0 .2 mol· L- 1Na OH+ 0 .2 mol· L- 1H3BO3+ 0 .2 mol· L- 1KCl( p H=1 0 .0 )的底液中 ,吡虫清在单扫描示波极谱上有一灵敏的催化氢波 ,极谱波的峰电位于 - 1 .5 9V( vs.SCE)附近 ,该峰具有一定的吸附性。吡虫清的浓度在 7.0×1 0 - 5～ 7.0× 1 0 - 4mol· L- 1范围内与峰电流成线性关系。本文对吡虫清极谱波的性质和电极过程进行了详细的探讨     

催化氢波-单扫描示波极谱法测定克拉霉素

建立一种灵敏快速测定克拉霉素的新方法。在 0. 24 mol·L-1 KH2PO4 Na2HPO4(pH 6.81)支持电解质中,克拉霉素于-1.57 V(vs.SCE)处产生一催化氢波,其二阶导数峰峰电流与克拉霉素浓度在2.0×10-6~ 1.6×10-4mol·L-1范围内呈线性关系(r=0.999 4,n=8),检出限为1.0×10-6 mol·L-1。10 次测定 1. 0×10-5 mol·L-1 克拉霉素峰电流相对标准偏差为1 8%,回收率在98.3%~100.6%之间。该方法可用于药剂中克拉霉素的测定。     

线性扫描极谱法测定微量肉桂酸

在 1mol·L-1HOAc NaOAc介质中 (pH =3.6 ) ,肉桂酸有一还原峰 ,其峰电位为 - 1.4 7V(vs.SCE)。峰电流与肉桂酸浓度在 2 .0× 10 -5～ 8.0× 10 -4 mol·L-1之间呈线性关系 (r =0 .9989) ,检出限为 1.0× 10 -5mol·L-1。该法应用于肉桂酸含量的测定 ,结果满意 ,并对肉桂酸的电化学性质进行了研究     

锑(Ⅲ)-钛铁试剂-溴化十六烷基三甲胺体系极谱络合吸附波研究

在 0 .0 4mol·L- 1磷酸中 ,锑 (Ⅲ ) 钛铁试剂 (Tiron) 溴化十六烷基三甲胺体系产生灵敏的极谱络合吸附波。峰电位为 - 0 .4 4V(vs .SCE) ,二阶导数峰高与锑 (Ⅲ )浓度在 8.2× 10 - 10 ～ 2 .0× 10 - 6mol·L- 1范围内呈线性关系 ,检出限达 4× 10 - 10 mol·L- 1。研究了极谱波的性质及电极反应机理。方法应用于三氧化二砷及铜合金中微量锑的直接测定 ,结果满意     

二次微分简易示波伏安法直接测定酒样中半胱氨酸

在 0 .2mol·L- 1NaOH支持电解质溶液中 ,半胱氨酸在二次微分简易示波伏安图阴极支- 0 .4 9V(vs .SCE)处产生一灵敏的峰 ,研究了半胱氨酸在此底液中的示波伏安行为 ,并据上述示波特性建立了二次微分简易示波伏安法直接测定酒中半胱氨酸含量的新方法。校正曲线的线性范围为 3.0× 10 - 6 ～ 5 .0× 10 - 5mol·L- 1,相关系数为 0 .9995 ,检出限为 1× 10 - 6 mol·L- 1,对 1.0×10 - 5mol·L- 1半胱氨酸进行 6次测定的RSD为 1.8%。利用此法测定了啤酒、黄酒及加饭酒中半胱氨酸的含量 ,样品的回收率分别为 94 .2 %、10 1.6 %和 10 2 .2 %。方法具有仪器装置简单、经济 ,方法简便快速、无需通氮除氧以及对样品进行前处理的优点     

胆红素的伏安特性及其微分脉冲伏安法测定

建立中成药中胆红素定量测定的微分脉冲伏安法。在多种介质中研究胆红素在玻碳电极上的电化学行为 ,全面优化条件后 ,采用标准加入法对中成药中胆红素进行测定 ,并通过与药典中标准方法对照和干扰实验及回收率实验对本方法进行评价。在 0 .2mol·L-1HAc NaAc 5 0 %EtOH和 1 1 5mol·L-1KH2 PO4 Na2 HPO4 溶液中 ,峰电流与胆红素浓度分别在 6.2 5× 1 0 -7～ 1 .0 0× 1 0 -5mol·L-1(r=0 .9976)和 5 .0 0× 1 0 -8～ 3.0 0× 1 0 -6mol·L-1(r=0 .9939)范围内呈良好的线性关系 ,检测下限分别为 5 .0× 1 0 -8mol·L-1和 5 .0× 1 0 -9mol·L-1。众生丸和牛黄解毒片中胆红素的质量分数分别为 0 .0 86%和 0 .1 0 9% ,RSD分别为 3 4%和 3.0 % ,回收率为 96.6%～ 1 0 4 .1 % ,其结果与药典中标准方法测定结果基本一致。     

钴-锌试剂络合吸附伏安法测定中草药中钴

研究了测定痕量钴的一种灵敏的吸附伏安法 ,利用钴和锌试剂络合物在悬汞电极上的吸附性 ,有效地提高了分析的灵敏度。在 0 .0 0 5mol·L-1NH3 和 0 .0 6mol·L-1NH4Cl及 2 .5× 1 0 -6mol·L-1锌试剂底液条件下 ,该体系 1 .5 ,2 .5阶微分吸附伏安法测定钴的线性范围为 1× 1 0 -10 ～ 1× 1 0 -7mol·L-1,用 2 .5阶微分吸附伏安法 ,富集 3min的检出限为 5× 1 0 -11mol·L-1。用此法直接测定了中草药中痕量钴     

β-环糊精-二次微分简易示波伏安法测定苯巴比妥

在NaOH底液中 ,β 环糊精能够产生灵敏切口 ,且该切口深度随苯巴比妥 β 环糊精包结物量的增加而变浅。根据 β 环糊精的示波特性 ,建立了用二次微分简易示波伏安法间接测定苯巴比妥注射液中苯巴比妥含量的新方法。苯巴比妥的浓度在 2 .5× 10 - 6 ～ 4 .5× 10 - 5mol·L- 1范围内的回归方程为h(V) =4 .5 5 9- 1.381× 10 4 c(mol·L- 1) ,相关系数为 - 0 .9976 ,检出限为 1.5×10 - 6 mol·L- 1。对于 2 .5× 10 - 5mol·L- 1苯巴比妥 5次测定的相对标准偏差为 2 .7% ,回收率为10 2 .1%。与高效液相色谱和其他方法相比 ,此法具仪器简单、简便快速、无需通氮除氧等特点     

溶出伏安法对维生素K3的研究与测定

应用微分脉冲溶出伏安法(DPSV)对维生素K3在玻碳电极(GCE)上的电化学行为进行了研究.在氨水-NH4Cl(pH 9.0)底液中,对维生素K3进行循环伏安扫描,发现有一对良好的氧化还原峰出现,对电极反应机理进行了探讨.阴极溶出伏安峰电流与其浓度在2.0×10-6～1.0×10-4mol·L-1范围内呈线性关系(r=0.998 5),检出限为4.0×10-7mol·L-1.对于1.0×10-5mol·L-1的维生素K3,平行7次测定结果的RSD为1.15%.应用此方法对亚硫酸氢钠甲萘醌注射液进行了测定,方法的回收率为97.3%～102.5%.     

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.