多供电子基苯胺类化合物的合成及其芳基五唑衍生物稳定性

合成了6个含多供电子基的苯胺类化合物,为合成更稳定的芳基五唑提供了原料。合成过程中,以CMC稳定的纳米铁颗粒为还原剂,以[DMFH]H2PO4为催化剂,还原芳香族硝基化合物,改进了铁粉还原产生大量废水、铁泥的缺点,使反应更加绿色环保;此外,还原以对氨基苯磺酸制得的偶氮化合物,合成得到所需的苯胺类化合物。并通过量子化学方法计算了芳基五唑衍生物分解所需的能量壁垒,以此为依据,比较了苯环上供电子基的数量及不同位置对芳基五唑化合物稳定性的影响。苯环上间、对位的供电子基有利于芳基五唑的稳定,供电子基在对位时对稳定性的影响要强于间位,邻位的供电子基增大了空间位阻,不利于芳基五唑的稳定。     

多供电子基苯胺类化合物的合成及其芳基五唑衍生物稳定性

合成了6个含多供电子基的苯胺类化合物,为合成更稳定的芳基五唑提供了原料。合成过程中,以CMC稳定的纳米铁颗粒为还原剂,以[DMFH]H2PO4为催化剂,还原芳香族硝基化合物,改进了铁粉还原产生大量废水、铁泥的缺点,使反应更加绿色环保;此外,还原以对氨基苯磺酸制得的偶氮化合物,合成得到所需的苯胺类化合物。并通过量子化学方法计算了芳基五唑衍生物分解所需的能量壁垒,以此为依据,比较了苯环上供电子基的数量及不同位置对芳基五唑化合物稳定性的影响。苯环上间、对位的供电子基有利于芳基五唑的稳定,供电子基在对位时对稳定性的影响要强于间位,邻位的供电子基增大了空间位阻,不利于芳基五唑的稳定。     

液质联用技术对芳硝基物还原制芳香羟胺反应的研究

采用高效液相色谱-电喷雾质谱联用技术对芳硝基化合物选择性还原制羟胺的反应液进行直接分析,并对组分的结构进行了归属。对于不同溶剂中铁氧化物催化水合肼还原邻二硝基苯为邻硝基苯基羟胺的反应,分析表明,质子溶剂有利于邻二硝基苯还原,相同实验条件下,异丙醇为溶剂的反应体系中原料邻二硝基苯转化率高;乙醚为溶剂的反应体系中产物邻硝基苯基羟胺的选择性高。对于面包酵母还原芳硝基化合物制芳香羟胺的反应,芳环上具有吸电子取代基时,有利于得到芳香羟胺,在实验所选的一系列芳硝基化合物中,对1,2-二氰基-4-硝基苯还原的羟胺选择性大于98%。     

邻硝基苯甲醛的合成方法综述

论文从不同的原料(邻硝基甲苯、邻硝基甲苯醇、邻硝基苯甲酸、邻硝基苯甲酰胺、邻硝基苯甲酰氯、苯甲醛、邻硝基苄氯、邻硝基乙苯)出发,对邻硝基苯甲醛的化学合成进行了综述,同时对电化学合成也作了简要介绍。     

邻硝基苯甲酸的电合成

报道了用铅电极电氧化Co2＋成为Co3＋的优选条件。生成的含Co3＋电解液在室温下即可将邻硝基甲苯氧化成邻硝基苯甲酸，产率达82．9％。     

邻硝基甲苯氧化制邻硝基苯甲酸

甲苯硝化得到的邻硝基甲苯(以下简称ONT)和对硝基甲苯(以下简称PNT)之比为56:40。也就是说以年产5000t对硝基甲苯计算,将联产7000t邻硝基甲苯。PNT的用量很大,因此如何有效地利用ONT氧化制邻硝基苯甲酸(以下简称ONBA)是平衡PNT生产的重要措施。因为ONBA用途也很广,可用于制取靛蓝和直接染料,还可经还原生成邻氨基苯甲酸,用于有机合成、药物、染料、香料的合成及用作润滑脂和润滑油中的抗氧化剂。     

氯化四-(对氯苯基)铁卟啉催化氧化邻硝基甲苯的表观动力学研究

研究了氯化四-(对氯苯基)铁卟啉T(p-Cl)PPFeCl催化氧化邻硝基甲苯的表观动力学.在确定邻硝基苯甲醛和邻硝基苯甲酸为主要产物的基础上,建立了连串反应模型和速度方程.根据不同温度条件下所测得的反应速率常数,确立了邻硝基甲苯氧化生成邻硝基苯甲醛的第一步反应为一级反应,且表观活化能为99.5 kJ/mol;而邻硝基苯甲醛氧化生成邻硝基苯甲酸的第二步反应为1/2级反应,且表观活化能为82.9 kJ/mol.通过比较两步反应的表观活化能和反应速率常数,发现升高温度有利于邻硝基苯甲醛的生成,且反应速率较快.     

邻硝基苯甲酸的电合成

报道了用铅电极电氧化Ｃｏ＾２＋成为Ｃｏ＾３＋的优选条件，生成的含Ｃｏ＾３＋电解液在室温下即可将邻硝基甲苯氧化邻硝基苯甲酸，产率达８２．９％。     

取代铁卟啉催化氧化邻硝基甲苯绿色合成邻硝基苯甲酸

研究了一种在乙醇水溶液中,以取代铁卟啉为仿生催化剂,催化氧气氧化邻硝基甲苯绿色合成邻硝基苯甲酸的新方法。考察了不同取代铁卟啉催化剂对反应活性和主产物选择性的影响,发现所有铁卟啉均有活性,且卟啉环外取代基从强给电子基（—OH）到吸电子基（—NO₂）变化时,其催化活性（原料转化率）变化不大,但对主产物的选择性影响却很明显,其中T(p-Cl)PPFeCl的催化活性和选择性均为最好,含最强给电子基（—OH）或最强吸电子基（—NO₂）的金属卟啉对主产物的选择性均最低。考察了溶剂中乙醇的体积分数对反应的影响,发现在乙醇浓度为80 % 时,产物的选择性最高。系统地考察了碱浓度、氧气压力、温度、时间、原料初始浓度等因素对反应的影响,找到了优化的工艺条件。发现以T(p-Cl)PPFeCl为催化剂,当乙醇浓度为80%、碱浓度为3. 75 mol·L^-1时,在2. 0 MPa、55℃条件下反应12 h,邻硝基甲苯的转化率达到79. 7%,邻硝基苯甲酸的选择性和收率分别可达95. 8% 和76. 3%。     

无溶剂球磨法合成γ-硝基酯化合物的研究

采用球磨法在无溶剂条件下用硝酸钙促进硝基烯烃与丙二酸酯发生迈克尔加成反应,从而合成γ-硝基酯化合物。该反应在频率为20 Hz下进行,30 min即可完全转化。硝基烯烃及其衍生物与丙二酸酯反应可得到产率80%以上的目标产物,尤其当硝基苯乙烯苯环上的邻位有两个吸电子基时,产率可达95%。     

Mechanism of the electroreduction of 1,1-dicyanoethylene derivatives

The electroreduction behaviour of some substituted 1,1-dicyanoethylene derivatives in acetonitrile was investigated. The mechanism for the electroreduction of different substituted compounds was proposed using the results of cyclic voltammetry, rotating disc voltammetry, dc and differential pulse polarography and controlled potential electrolysis experiments. The effect of the presence of protons on the mechanism was also elucidated. The products of large scale electrolysis experiments were identified by the aid of electroanalytical and chromatographic methods.     

碳化钨/碳纳米管纳米复合材料的制备及其对硝基苯的电催化活性

采用表面修饰技术和原位还原碳化技术制备了纳米碳化钨（WC）/碳纳米管（CNT）纳米复合材料,通过X射线衍射（XRD）、扫描电子显微镜（SEM）和热重-差热分析（TG-DTA）等手段对WC/CNT纳米复合材料的晶相组成、形态结构和热稳定性进行了表征,结果显示样品是由WC和CNT两相构成,纳米WC颗粒均匀地分散在碳纳米管上,粒径细小;在空气气氛中,WC/CNT纳米复合材料在470℃以下保持稳定。采用循环伏安法研究了WC/CNT纳米复合材料对硝基苯的电催化活性和电化学稳定性。结果表明,WC/CNT纳米复合材料对硝基苯的电催化活性优于纳米WC和CNT,且WC/CNT纳米复合材料在硝基苯电还原过程中保持良好的化学稳定性。     

五氧化二氮对一元取代苯的硝化研究

研究了五氧化二氮在惰性溶剂中对甲苯,氯苯及硝基苯进行的硝化反应。在甲苯的一段硝化产物中ｐ－ＭＮＴ的生成比例可提高５％以上,在氯苯的硝化产物中,ｏ－ＭＮＣＢ生成比例有明显提高,在硝基苯的硝化产物中,间二硝基苯的比例可高达９７％以上。,     

Electrochemical reduction of tetraphenylcyclopentadienones

The electroreduction behavior of tetraphenylcyclopentadienone (tetracyclone) and some of its m,m′-and p,p′-substituted derivatives in acetonitrile was investigated. The mechanism for the electroreduction of these compounds in the absence and in the presence of protons was proposed using the results of cyclic voltammetry and controlled potential electrolysis experiments. The effects of the substitution on the peak potentials and on the stability of the anion radicals are discussed.     

Quinone‐Fused Pyrazoles through 1,3‐Dipolar Cycloadditions: Synthesis of Tricyclic Scaffolds and in vitro Cytotoxic Activity Evaluation on Glioblastoma Cancer Cells

A novel and straightforward synthesis of highly substituted isoquinoline‐5,8‐dione fused tricyclic pyrazoles is reported. The key step of the synthetic sequence is a regioselective, Ag₂CO₃ promoted, 1,3‐dipolar cycloaddition of C‐heteroaryl‐N‐aryl nitrilimines and substituted isoquinoline‐5,8‐diones. The broad functional group tolerability and mild reaction conditions were found to be suitable for the preparation of a small library of compounds. These scaffolds were designed to interact with multiple biological residues, and two of them, after brief synthetic elaborations, were analyzed by molecular docking studies as potential anticancer drugs. In vitro studies confirmed the potent anticancer effects, showing promising IC₅₀ values as low as 2.5 μm against three different glioblastoma cell lines. Their cytotoxic activity was finally positively correlated to their ability to inhibit PI3K/mTOR kinases, which are responsible for the regulation of diverse cellular processes in human cancer cells.     

Palladium‐Catalyzed Regioselective γ‐Mono‐ and Diarylation of Acrylamide Derivatives with Aryl Halides

Palladium‐catalyzed direct mono‐ and diarylations involving C(sp³) H cleavage at the γ‐position of acrylamides are described. The monoarylation products can be obtained with ortho‐substituted aryl halides. Single crystal X‐ray diffraction has shown that the double bond has shifted towards the introduced aryl group to afford the γ‐arylated β,γ‐unsaturated amide products. A second arylation occurs when less sterically hindered aryl halides are employed. This chemistry offers a novel disconnection for the synthesis of γ‐arylated compounds.     

Intermediate products of electrochemical reduction of nitrofurans in aprotic media

Using polarographic and cyclic voltammetric techniques electrochemical reduction of 2-nitrofuran derivatives has been studied in DMF. The first stage of electroreduction has been found to lead to formation of anion radicals; the next stage leads either to formation of corresponding dianions or to substituted N-furylhydroxylamines, depending on the nature of the substituent and the medium. The latter are oxidized under cyclic voltammetric measurement conditions to substituted nitrosofurans. Effects of substituents in position 2 of 5-nitrofurans on half-wave potentials of the first and second stage of electroreduction have been quantitatively evaluated for these compounds using life (linearity of free energy) relationships. The effect of heteroatoms on one-electron reduction of nitroderivatives of furan, thiophene, selenophene and benzene have been subjected to comparative study.     

6种取代四苯基卟啉化合物的合成

以二甲苯为溶剂,氯乙酸为催化剂,硝基苯为氧化剂,由取代苯甲醛与吡咯发生缩合反应合成了6种取代四苯基卟啉化合物,并用紫外-可见光谱(UV-Vis)和红外光谱(IR)对所合成的产物进行了结构表征.考察了酸性催化剂和氧化剂对卟啉合成收率的影响,使卟啉收率得到了大幅提高,其中对位取代四苯基卟啉的合成收率＞45%,邻位取代四苯基...     

The relationship between the structure and electrocatalytic properties of TiO2 electrodes doped with CeO2

This paper describes the study of the preparation of Ti/Ti_1-xCe_xO₂ electrodes using the Pechini method and their application for the electroreduction of nitrobenzene in aqueous acid medium. The electrodes were studied using X-ray diffraction, and scanning electron microscopy and it was found that the electrocatalytic properties are influenced by the microstructure and morphology of the electrodes. All doped electrodes presented an enhanced performance for nitrobenzene electroreduction when compared to pure TiO₂. The Ti_0.995Ce_0.005O₂ electrode presented the best performance, with an increase of 58% in the aniline yield under galvanostatic electrolysis conditions.     

硝基苯在碳化钨/碳纳米管粉末微电极上的电化学行为

采用表面修饰和原位还原碳化技术制备了碳化钨（WC）/碳纳米管（CNT）纳米复合材料,并以其为电催化剂制成了WC/CNT纳米复合材料粉末微电极（WC/CNT-PME）。采用计时电流法、循环伏安法和原位红外反射光谱技术研究了酸性溶液中硝基苯在WC/CNT-PME上的电化学行为,讨论了扫描速率和温度对其电化学行为的影响。结果表明,WC/CNT纳米复合材料对硝基苯的电催化活性明显高于碳纳米管和纳米碳化钨;硝基苯在WC/CNT-PME上的还原反应是一受吸附控制的不可逆过程,其还原产物为对氨基苯酚。