Synthesis of Pyridines by Anodic Oxidation of 1,4-Dihydropyridines

Anodic oxidation of a series 1,4-dihydropyridines were performed in acetonitrile-tetrabutylammonium perchlorate electrolyte solution at platinum electrode using controlled potential electrolysis. On the bases of electroanalytical results the electrochemical oxidation mechanism of 1,4-dihydropyridines could be designed ECEC process. As a result of two-electron oxidation corresponding pyridines were obtained in yields ranging from 85%–92%. The advantages of electrochemical synthesis of pyridine derivatives are simple reaction condition, low cost and of high purity products.     

1,4-Diazabicyclo[2.2.2]octanes

1,4-Diazabicyclo[2.2.2]octane-2-carboxylic acid bis(methylbromide), which is readily converted with splitting out of hydrogen bromide to the corresponding quaternary betaine, was synthesized.     

An Efficient,Simple and Inexpensive Method for the Preparation of 1,4-Benzoquinone Monoketals via Anodic Oxidation of 1,4-Dimethoxybenzenes

Anodic oxidation of a series of 1-substituted-2,5-dimethoxybenzenes gives 2-substituted-1,1,4,4-tetramethoxycyclohexa-2,5-dienes in almost quantitative crude yield. Selective monohydrolysis of these bis-ketals is possible in many cases, and gives 3-substituted-4,4-dimethoxycyclohexa-2,5-dienones in good to excellent overall yield.     

1,4-Diazabicyclo[2.2.2]octanes (review)

The literature data and our own experimental data on the synthesis and physical and chemical properties of 1,4-diazabicyclo[2.2.2]octanes as compared with their 4-deaza analogs (quinuclidines) are correlated. Methods for the practical utilization of the diazabicyclic systems are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 723–738, June, 1976.     

1,4—二氢吡啶及其衍生物电化学反应机理的研究

研究了１１种１，４－二氢吡啶及其衍生物在乙腈溶剂中和铂盘电极上的电化学行为。实验结果表明：１，４－二氢吡啶及其衍生物在铂盘电极上的反应是受扩散和化学反应速率控制的两电子不可逆氧化过程，经连续两步失电子脱氢后形成相应的吡啶。用紫外吸收光谱电化学方法观测了电化学氧化过程。并与化学氧化产物的紫外光谱作了比较，证明１，４－二氢吡啶的电化学氧化产物与化学氧化产物一致。因此，电化学氧化是一种不需加化学试剂可使     

Synthesis of Dibenzocyclooctadienes by Anodic Oxidation

the use of electrochemical oxidation was applied to the synthesis of dibenzocyclooctadiene lactones related to steganacin skeleton. This reaction, performed with compounds 1 and 2, led to results comparable with the oxidation with RuTFA, TTFA and VOF₃.     

Anodic Oxidation of the N-cyanomethyloxazolidine system

The electrochemical oxidation of the N-cyanomethyloxazolidine system in acetonitrile at a platinum electrode afforded a radical cation which might follow either one of two pathways, according to the experimental conditions: the first, in the presence of chloride or bromide ions led to halogenated products, the second, in the presence of water, led to lactam/amide formation. The mechanistic pathway of both reactions is discussed.     

Oxidation of 1,4-dihydropyridines

The rate constants for the oxidation of 17 mono- and polynuclear 1,4-dihydropyridine derivatives with chloranil were determined. The constants obtained were compared with the results of fermentative and electrochemical oxidation.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 691–694, May, 1973.     

Anodic Oxidation of Ketone Allylhydrazones into the Corresponding Azines

Several ketone allylhydrazones were electrochemically oxidized in methanol in the presence of sodium methoxide and potassium iodide to afford the corresponding azines. The electro-oxidation involves formation of a new carbon–nitrogen double bond between an allylic carbon atom and the nitrogen atom of a hydrazone to afford a conjugated system. Optimal yields were obtained when 0.5 equivalents of sodium methoxide and a catalytic amount of potassium iodide were used as the supporting electrolyte at room temperature. Presumably, the electro-oxidation involves a two-electron oxidation process where the iodide ion functions as electron carrier.     

Anodic oxidation of mono- and disubstituted 1,4-dimethoxybenzenes

The electrochemical oxidation of mono- and disubstituted 1,4-dimethoxybenzene derivatives with zero, one, and two benzylic CH(2)X groups (X = OAc, Cl, OH) (5a-c and 6a-c) has been carried out by using both constant-current and controlled-potential techniques in methanol and in the presence of different electrolytes and working electrodes. Constant-current electrolysis in KOH-methanol solutions yielded mostly the corresponding 1,4-quinone derivatives from 5a-c and 6b, whereas the disubstituted 1,4-dimethoxybenzenes 6a,c underwent side-chain oxidation to form 2,5-dimethoxyterephthalaldehydes. Upon alteration of the medium from the commonly used basic KOH-methanol to neutral LiClO(4)-methanol, a new spectrum of products was achieved in most cases, involving novel coupling products from monosubstituted substrates and quinone derivatives from disubstituted ones. Controlled-potential oxidation at the glassy carbon anodes and in a neutral LiClO(4)-methanol medium led to more complex mixtures of products, namely, polymers and new coupling products from monosubstituted substrates and quinones and side-chain oxidation (or substitution) products from the disubstituted ones. Three new coupling products were isolated and characterized by X-ray measurements.     

Hydroxyanthraquinones Carminic Acid and Chrysazin Anodic Oxidation

The anodic oxidation of the hydroxyanthraquinones carminic acid (CA) and chrysazin (CR) was investigated. The oxidation of CA proceeds in a pH‐dependent cascade mechanism, concerning the hydroquinone, the catechol and the 3‐OH groups in the anthraquinone moiety. The oxidation of the hydroquinone following the catechol electron‐donating groups occurs first at low positive potentials, the 3‐OH group is oxidized irreversibly at a higher potential. The oxidation of CR is pH‐dependent and occurs in successive steps. Oxidation of the hydroquinone tautomer in the CR‐ring occurs first, and the symmetrical 1‐OH and 8‐OH groups are irreversibly oxidized at the same higher potential.     

一步阳极氧化法制备超亲水氧化铝

本文应用一步阳极氧化法在铝表面制作纳米粗糙结构的超亲水表面.考察控槽压、控电流及氧化时间对氧化铝表面超亲水性的影响.测试表明,控电流法更有利于制作超亲水表面,增大电流密度可缩短氧化时间,该法可制作稳定性好、机械强度高的超亲水氧化铝表面,富有潜在的应用价值.     

碱性介质中葡萄糖在铂电极上的阳极氧化

为了进一步探明葡萄糖在铂电极上的氧化机理,用循环伏安法(CV)在-0.9～0.4 V(相对于饱和甘汞参比电极)内研究了葡萄糖在铂电极上催化氧化行为,首次详细报道了葡萄糖在电化学氧化过程中的电位振荡现象,并用电流扫描法表征了葡萄糖的电位振荡情况.电流扫描结果表明,在较慢的电流扫描速度下,电极过程出现了明显的电位振荡.说明电极上产生了毒化中间物,电位振荡是由于毒化中间物在电极上的吸附和在高电位下氧化除去引起的.     

Anodic Oxidation of Copper in Concentrated Sulfuric Acid Solutions

Copper oxidation in 1–10 M sulfuric acid solutions is studied using cyclic voltammetry and x-ray diffraction methods. Copper passivation is shown to be caused by the formation of a resistive porous layer of copper(I) oxide via an electrochemical mechanism. The primary product of the electrode reaction is unstable and, depending on the acid concentration, either enters chemical reactions with electrolyte components or is oxidized electrochemically to give copper(II) oxide.     

阳极氧化法制备TiO2多孔薄膜

本文综述了制备TiO2薄膜的各种方法,详细介绍了阳极氧化法制备TiO2多孔膜的进展,在非含氟电解液体系中,对纯钛进行阳极氧化处理可制得表面呈无规则生长的多孔膜结构;在含氟电解液体系中,则可自组织形成高度有序的TiO2纳米管阵列,并指出阳极氧化法是可在常温低压下进行、操作工艺简单、薄膜性能稳定、再现性好的一种最具工业化应用潜力的制备方法。     

1,4-二氮杂二环[2.2.2]辛烷衍生物的卤代作用有效诱导介电相变

我们通过精确的分子设计,得到3种1,4-二氮杂二环[2.2.2]辛烷(Dabco)衍生物X-EtHDabco(EtDabco=N-乙基-1,4-二氮杂双环[2.2.2]辛烷,X=H、F、Cl).分别以3种Dabco衍生物、溴化锌为原料按一定配比反应,成功地合成了一系列新型有机-无机杂化相变材料(H-EtHDabco)[...