Cathodic deprotonation of 5-substituted isoxazoles

The regularities of electroreduction of 5-substituted isoxazoles are studied by examining their cyclopropyl and phenyl derivatives. It is found that this process proceeds on a steel electrode according to the mechanism of direct cathodic deprotonation and is accompanied by the removal of a proton from the 3rd position of the isoxazole ring with the formation of a corresponding carbanion, which is readily isomerized to enolate anion of an open type. The same mechanism is realized also in the electroreduction of 5-substituted isoxazoles on cathodes with a high overpotential of hydrogen evolution (C, Hg). An alternative process, namely, an indirect cathodic deprotonation of 5-substituted isoxazoles, can be realized with the use of MeOH or t-BuOH as the prebases.     

Electroreduction of primary nitramines on platinum in MeCN

Reduction of primary nitramines RNHNO₂ (R=Me, Et, Prⁱ, α-pyridyl) in anhydrous MeCN at a Pt cathode was studied by voltammetry and electrolysis. The process includes one-electron transfer and nitramine deprotonation to give the corresponding anions. The products ofN-alkylation of these anions can be obtained only when their potassium salts are used (but not tetrabutylammonium salts). This is due to the effects of ion association, which influence the dual reactivity of the anions under investigation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 82–85, January, 1999.     

Unnatural amino acids. 3. Aziridinyl ketones from esters and amides of aziridine-2-carboxylic acids

A series of N-substituted amides and esters of aziridine-2-carboxylic acids have been prepared and have been subjected to deprotonation with lithium diisopropylamide. The intermediate carbanions reacted more readily with the carbonyl groups of the substrates than with methyl iodide. So, in place of the expected amides or esters of methylaziridine-2-carboxylic acids, amides or esters of 2-aziridinylcarbonylaziridine-2-carboxylic acids were isolated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, 220–225, February, 2007.     

小麦根系中有机酸的离子色谱法分析研究

研究了离子交换和离子排斥法用于小麦根系中有机酸分析的色谱条件,首次建立了植物报系中有机酸的高子色谱分析方法。分别用Ｎａ＿２ＣＯ＿３／ＮａＨＣＯ＿３,Ｎａ＿２ＣＯ＿３／ＮａＯＨ和ＨＣｌ作离子交换和离子排斥分高的流动相,选用化学抑制型电导检测器。对样品中柠檬酸、苹果酸、丁二酸、反丁烯二酸、乙酸、草酸的检测限为Ｏ１～０．５μｇ／ｍＬ,相对标准偏差为１．７８％～２．９７％,样品加标回收率为１００±１０％。     

基于离子交换-电导检测法对酿酒葡萄中有机酸含量进行分析

建立了离子色谱法测定酿酒葡萄中乳酸、丙酸、苹果酸、酒石酸、草酸、柠檬酸、琥珀酸和抗坏血酸的方法。样品经提取、脱色、过滤后以自动淋洗液发生器生成的1.5~30 mmol/L KOH为淋洗液洗脱,抑制电导检测器检测。考察了共存非测定离子及相邻离子间的干扰,结果表明非测定无机离子对测定无干扰。8种有机酸在一定浓度范围内与其峰面积呈良好的线性关系,检出限为0.064~0.25 mg/L,加标回收率为89.5%~96.2%。该方法用于宁夏贺兰山东麓酿酒葡萄中8种有机酸分析,8种有机酸均被检出,以苹果酸和酒石酸含量最高,柠檬酸次之,其它酸含量均较低。酿酒葡萄为典型的酒石酸型水果。     

离子排斥色谱法分析有机酸和无机弱酸

用非抑制型电导检测的离子排斥色谱法,以对甲苯磺酸为淋洗液,研究了柠檬酸、苹果酸、抗坏血酸、乙醇酸、甲酸、乙酸、丙酸及氢氟酸和碳酸的色谱分离及定量检测条件。     

Novel synthesis of copper oxide on fabric samples by cathodic cage plasma deposition

The fabrics with copper or copper oxide deposition are of considerable interest because of exceptional antibacterial properties, which are useable in medical, textiles, and hygiene applications. Unfortunately, the conventional techniques take long processing time, complex equipment, and combination of several processing steps (nanoparticles synthesis and their deposition on fabrics). In this novel study, cathodic cage plasma deposition assisted with copper cathodic cage is used for the synthesis of the copper oxide on polyester and polyamide fabrics. For the enhancement of synthesis efficiency, the effect of cathodic cage lid thickness is also investigated. The samples are assessed by using scanning electron microscopy, elemental dispersive spectroscopy, and X‐ray photoelectron spectroscopy. It is found that using cathodic cage plasma deposition, fabrics can be successfully synthesized by the copper oxide with comparatively small treatment time, cost‐effectively, and environmentally friendly. Interestingly, cathodic cage plasma treatment is already proved to be working effectively on industrial scale; thus, it is predicted to be of noteworthy importance for fabrics processing on large‐scale garments manufacturing and hospitals.     

离子交换树脂在有机催化反应中的应用进展

总结了阳离子交换树脂催化剂和阴离子交换树脂催化剂分别在酯化、烷基化、醚化、缩合、异构化、环氧化等有机合成反应中的应用进展,评述了离子交换树脂催化剂的催化性能和可回收利用性,展望了未来离子交换树脂催化剂的开发和发展方向。     

Covalent Organic Frameworks: A Sustainable Photocatalyst toward Visible-Light-Accelerated C3 Arylation and Alkylation of Quinoxalin-2(1H)-ones

A practical and scalable protocol for visible-light-accelerated arylation and alkylation of quinoxalin-2(1H)-ones with hydrazines is reported. In this protocol, a hydrazone-based two-dimensional covalent organic frameworks (2D-COF-1) was employed as the heterogeneous photocatalyst (PC). Due to its excellent photocatalytic properties, good chemical stability and heterogeneous nature, the present method exhibits high efficiency, good functional group tolerance, easy scalability and remarkable catalyst reusability. More importantly, it provides an alternative way that allows rapid access to various C3 arylated or alkylated quinoxalin-2(1H)-ones in a greener and sustainable manner.     

有机酸在阴离子交换树脂上的保留行为及其机理

研究了有机酸在阴离子交换树脂上的保留行为。首次报道了有机酸在阴离子交换色谱过程中的“多峰现象”,即一种有机酸有两个或两个以上的色谱峰流出色谱柱。对这种“多峰现象”形成的机理进行了初步探讨,提出了有机酸离解后的不同价数阴离子在阴离子交换树脂上同时保留的机理。研究中还发现离解很弱的有机酸的保留行为不完全符合离子交换机理。     

Controllable and reversible proton transfer for inorganic cyanide visual sensing based on the deprotonation of azo-phenolic hydroxyl group

ABSTRACT

Methods for optical detection of inorganic cyanide based on the single molecule sensor with high selectivity and sensitivity have attracted increasing interest recently due to the high toxicity of cyanide ions. In this work, a visual sensor (S1) containing both imidazole NH and azo-phenolic OH was synthesised and characterised. The spectral experimental data indicated that protic aqueous solution facilitated enhancing the selectivity of cyanide ions with the nanomolar-level detection limit in semi-aqueous solution. The visual sensing mechanism arising from the deprotonation of azo-phenolic OH and the enhancement of intramolecular charge transfer could be clearly demonstrated by titration experiments of ¹H NMR, HR MS and energy changes between the HOMO?LUMO band gaps. Furthermore, the reversibility and reusability of S1 upon alternating addition of CN^? and H⁺ were studied.     

基于有机物电极的电化学能量存储与转化

由于高安全的特性,水系二次电池被认为是未来大型储能的有效解决方案之一. 然而,现有水系电池主要以含金属元素的无机化合物为电极活性材料,其在大型储能中的实际应用仍受到循环寿命、环境问题、原料成本或金属元素丰度的限制. 相较于无机电极材料,部分有机电极材料具有原料丰富、结构丰富、可持续及环境友好等优点. 此外,有机物材料分子内空间大,能够存储不同价态电荷,因此近年来被广泛关注. 本文综述了课题组近期在有机物电极方面的研究进展,内容聚焦含羰基有机物通过C=O/C-O-的可逆转化存储单价金属阳离子(Li⁺, Na⁺)、双价金属阳离子(Zn²⁺)、质子(H⁺)所涉及的电化学过程,及其在水系锂、钠离子电池、水系锌离子电池、质子电池以及分步电解水中的应用.     

Solid-phase synthesis and utilization of side-chain reactive unnatural amino acids

Alkylation of the benzophenone imine of glycine Wang resin with α,ω-dihaloalkanes yielded valuable reactive intermediates. These racemic ω-chloro or ω-bromo intermediates were converted to α-amino acids containing diverse side-chain functionalities (e.g. ω-chlorides, nitriles, and thioethers), proline and its ring homologs, and 1-aminocycloalkanecarboxylic acid derivatives.     

Stereospecificity of alkylation of phosphite anion in electrochemical version of the Michaelis-Becker reaction

Benzylation ofcis2-hydro-2-oxo-4-methyl-1,3,2-dioxaphosphorinane in the electro-chemical version of the Michaelis-Becker reaction occurs stereospecifically with retention of the stereochemistry of the hydrophosphoryl center and affords stereochemically pure 2-benzyl-2-oxo-4-methyl-1,3,2-dioxaphosphorinane (yield 60–70 %). The structure of this compound was determined by X-ray diffraction analysis. The mechanism of the process was discussed.Translated fromIzvestiya Akademii Nauk. Seriva Khimicheskaya, No. 2, pp. 444–446, February, 1996.     

烟草中9种有机酸的梯度离子色谱法测定研究

采用淋洗液自动发生一梯度离子色谱分离,电导检测法分离测定了烟草中的甲酸、乙酸、乳酸、丙酸、丁酸、苹果酸、丙二酸、草酸和柠檬酸,并研究了9种有机酸在阴离子交换色谱中的保留行为.以淋洗液自动发生器生成的KOH为淋洗液,样品经提取、过滤稀释后,在IonPac AS1l-HC阴离子交换色谱柱上分离,抑制电导检测器进行检测,一次...     

食品中有机酸的高效液相色谱分析法

对离子交换色谱法、离子排斥色谱法和反相高效液相色谱法分析食品中有机酸的特色和近几年的研究与应用状况作一综述。