噻吩甲酰三氟丙酮的电化学性质及应用

在 0 .5mol/LHCl和 0 .2g/L的明胶溶液中 ,利用线性扫描极谱法测定噻吩甲酰三氟丙酮 (简称TTA) ,发现有一还原峰 ,其峰电位是 - 1 .0 0V (vs.SCE)。峰电流与TTA浓度在 2 .5× 1 0 - 5mol/L～ 2 .0× 1 0 - 3mol/L之间存在线性关系 (r=0 .9986) ,检测下限为 1 .0× 1 0 - 5mol/L。利用单扫描极谱法和循环伏安法对极谱峰的电化学性质进行了研究     

锌(Ⅱ)-茜素紫络合物的极谱行为及应用

用线性扫描示波极谱法研究了锌 ( ) -茜素紫络合物的伏安行为 ,发现在含有 0 .1 mol/L KCl,p H=9.96的 Britton- Robinson缓冲溶液中锌 ( ) -茜素紫络合物产生一灵敏的极谱吸附波 ,其峰电位为 - 1 .2 7V( vs.SCE) ,峰电流与锌 ( )的浓度在 8× 1 0 - 8～ 2× 1 0 - 6 mol/L的范围内呈线性关系 ,检出限为 5× 1 0 - 8mol/L。研究了电极反应机理 ,并用建立的方法成功地测定了发样中的锌     

氟苯尼考的极谱法研究

应用循环伏安法、线性扫描伏安法和控制电位电解库仑法对氟苯尼考的电化学行为进行了研究。在0 .2mol/LNaOH NaH2 PO4(pH =7.6 )缓冲液中 ,对其进行扫描 ,发现于 - 0 .886V (vs.SCE)处产生一灵敏的还原峰 ,其峰电流与氟苯尼考的浓度在 1.0× 10 -5～ 7.0× 10 -4mol/L范围内呈良好的线性关系 (r =0 .9994 ) ;检出限为 1.0× 10 -6mol/L。对 1.0× 10 -4mol/L氟苯尼考溶液进行 10次平行实验 ,RSD为 0 .3%。实验结果表明 :氟苯尼考在极谱电极上有吸附性质 ;求得了电极反应的电子转移数为 2 ;研究了电极反应机理     

铅-茜素紫-邻菲罗啉体系的极谱行为及其应用

用线性扫描示波极谱法研究了 Pb( ) -茜素紫 -邻菲罗啉体系的伏安行为 ,发现在含有 0 .1 mol/L KCl,p H 4.70的 HAc- Na Ac缓冲溶液中 Pb( ) -茜素紫 -邻菲罗啉体系产生一灵敏的极谱吸附波 ,其峰电位为 - 0 .56V( vs.SCE) ,峰电流与铅 ( )的浓度在 8× 1 0 - 8～ 2× 1 0 - 6 mol/L范围内呈线性关系 ,检出限为 5× 1 0 - 8mol/L;研究了电极反应机理 ,并用建立的方法测定了皮蛋中的铅含量。     

泼尼松的示波极谱测定及其电化学行为

基于泼尼松产生的极谱还原波 ,提出了测定泼尼松的单扫描示波极谱法。在0 .1 2 mol/ L HAc-0 .0 8mol/ L Na Ac ( p H 4.6)的缓冲溶液中 ,泼尼松于 -1 .1 3 V处产生一极谱还原波。二阶导数峰电流与其浓度在 2 .4× 1 0 - 6～ 1 .6× 1 0 - 5mol/ L范围内有良好的线性关系 ( r=0 .9991 ,n=8) ,检出限为 8.0× 1 0 - 7mol/ L。测定了片剂中泼尼松的含量。讨论了泼尼松的电化学行为     

吡柔比星的伏安行为及其应用

吡柔比星在 0 .1 mol/L HAc- Na Ac缓冲溶液 (p H4.3)中 ,出现一灵敏的示波极谱导数还原峰 ,峰电位为 - 0 .39V(vs.SCE) ,峰电流与吡柔比星浓度在 2 .0× 1 0 -7～ 4.0× 1 0 -6mol/L范围内成正比。检出限为 1 .0× 1 0 -8mol/L。用于病人尿样的测定。用线性扫描和循环伏安法研究体系的性质。体系属具有吸附性的可逆过程。     

钴/玻碳离子注入修饰电极伏安法测定呋喃妥因的研究

呋喃妥因 (NFT)在 0 .1mol/LHAc NaAc (pH 4 .0 )溶液中于钴 /玻碳 (Co/GC)离子注入修饰电极上产生一灵敏的伏安还原峰 ,峰电位为 - 0 .2 6V(vs.Ag/AgCl) ,峰电流与NFT浓度在 6 .0× 10 -8～ 5 .0× 10 -6mol/L范围内呈线性关系 (r =0 .9987) ,检出限为 1.0× 10 -8mol/L。用线性扫描伏安法和循环伏安法研究了NFT的伏安行为、吸附特性和电极反应机理。测定了电子转移数 (n =4 )、转移系数 (α =0 .5 8)和参与反应的质子数 (X =4 )等电化学参数。结果表明该电极过程为一具有吸附性的不可逆过程。该法用于片剂中NFT含量的测定 ,得到满意的结果。用标准加入法测得该法的回收率为 94 .0 %～ 98.5 %。     

西维来司他的极谱伏安法研究

应用循环伏安法(CV)、线性扫描伏安法(LSV)、控制电位电解库仑法(BE)对西维来司他的电化学行为进行了研究。在0.2mol/LHAc-NaAc(pH=5.6)缓冲液中,对其进行扫描,发现于-1.29V(vs.SCE)处产生一灵敏的还原峰,其峰电流与西维来司他的浓度在1×10-5~2×10-4mol/L范围内呈良好的线性关系(r=0.9976);检出限为2.0×10-6mol/L。对5.0×10-5mol/L西维来司他溶液进行12次平行实验,RSD为0·56%。实验结果表明,西维来司他在极谱电极上有吸附性质,并为此求得了电极反应的电子转移数为4,同时对电极反应机理进行了研究。     

抗癌药长春新碱及其与微管蛋白相互作用的电化学研究

在 0 0 5mol/LTris,0 15mol/LNaCl溶液中 ,用吸附伏安法研究长春新碱 (VCR) ,其峰电位在 -1 68V (vs .Ag/AgCl) ,峰电流与 1 0× 10 -8～ 2 0× 10 -7mol/LVCR浓度成正比 ,检测限为 7 0× 10 -9mol/L .用常规脉冲极谱法、线性扫描和循环伏安法等研究该体系的电化学行为 .实验表明 ,电极还原过程为具有吸附特征的不可逆过程 .VCR的吸附符合Frumkin吸附等温式 .也研究了VCR与微管蛋白的相互作用 .实验表明 ,VCR与微管蛋白形成一电活性的结合物 ,这一结合物具有吸附性 ,且还原过程也为不可逆过程     

单扫示波极谱法测定氧氟沙星

在 0 .1 5mol/L HAc- Na Ac( p H 3.64)中 ,采用单扫示波极谱法测定氧氟沙星 ,得到一良好的还原峰 ,峰电位 Ep=- 1 .45V( vs.SCE)。峰电流 IP与氧氟沙星的浓度在 3.0× 1 0 - 7～ 6.2× 1 0 - 6 mol/L范围内呈线性关系 ,相关系数 r=0 .9983,检出限为 7.0× 1 0 - 8mol/L。此法已用于片剂的测定。用线性扫描和循环伏安法研究了体系性质 ,结果表明 ,氧氟沙星的电极过程为具有吸附性的不可逆过程。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

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.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.