乙二醛双缩(2-羟基苯胺)(GBHA)在稀土离子分析中的应用

利用乙二醛双缩（2－羟基苯胺）（GBHA）对Ln^3 系离子进行分组分析，同时以GBHA为显色剂，用分光光度法分别测定了Ho^3 ,Yb^3 ,Er^3 ,Dy^3 和Tb^3五种离子，其检出限为10^-6mol/L，工作曲线线性范围为10^-5－－10^-3mol/L。     

Chemical species produced in the reaction between ethanedial (glyoxal) and 5-amino-1,10-phenanthroline and their iron(II) complexes: electrochemical studies and analytical applications

The cyclic voltammetric behavior of carbon paste electrodes modified by direct admixing with the products of the reactions between ethanedial (glyoxal) and 5-amino-1,10-phenanthroline at 100°C and that of their iron(II) complexes is reported. The ligand(s) produced in absence of iron(II) are able to complex iron(II) and copper(II) ions reversibly, but other ions such as nickel(II), cobalt(II), cadmium(II) and manganese(II), if complexed, show no electrochemical activity. Admixing with the products of the reaction in the presence of excess of iron(II) ion, because of high insolubility and fast electron exchange, produces surfaces useful for amperometric detection in continuous-flow systems. The voltammetric and amperometric behavior in the presence of HSO^?₃ ions is reported in order to illustrate this application.     

Chemical species produced in the reaction between ethanedial (glyoxal) and 5-amino-1,10-phenanthroline and their iron(II) complexes: preparation and some spectrometric studies

Chemical species obtained by reaction of 5-amino-1, 10-phenanthroline with ethanedial (glyoxal) are reported with regard to their preparation, chemical composition and spectrometric characterization (UV-visible, infrared and liquid secondary ion mass spectrometry). Products of the reaction are postulated to be a mixture of species with molecular weights of 339, 371,480 and 524 u. Chemical reactions leading to these products and possible structural formulas for each of these species are presented. The iron complexes of these ligands, because of their extremely low solubility in most solvents, find application as redox mediators when incorporated in carbon paste electrodes, particularly for sensing in continuous-flow systems.     

Facile synthesis of hydantoins and thiohydantoins in aqueous solution

A series of hydantoins and thiohydantoins have been synthesized in water at room temperature from urea (or N-methylurea, or thiourea) and simple aldehydes (as glyoxal, and its simple derivatives) in the presence of phosphoric anhydride. The reaction time is 10 min using an equimolar amount of P₄O₁₀ with respect to the other reagents, but the reaction occurs also, even if with longer reaction times, with very small amounts of P₄O₁₀.In addition, this method provides a clean and ‘green’ approach to hydantoins, compounds of great interest in biological and pharmacological fields.     

多波长线性回归-矩阵法同时测定乙二醛、乙醛酸、草酸的含量

根据实验得出的乙二醛、乙醛酸、草酸三组分混合物中各组分在特定波长下呈现出的良好的线性关系,建立起三组分质量浓度与混合吸光度的回归方程组,形成了多波长线性回归-矩阵法,实现了乙二醛氧化制备乙醛酸体系中反应产物乙二醛、乙醛酸、草酸含量的同时测定.研究结果表明:当乙二醛检测下限为1.024 mg/L时,回收率为94%~98%...     

Oxidation of glyoxal to glyoxylic acid by oxygen over V2O5/C catalyst

A novel vanadium oxide catalyst supported on active carbon was prepared by an incipient wetness impregnation method, and the precursor was obtained from oxalic acid aqueous solutions of NH4VO3. The catalyst was applied liquid phase oxidation of glyoxal to glyoxylic acid. It was found that V2O5/C catalyst exhibited obvious activity for glyoxal oxidation. Glyoxylic acid could be obtained without pH regulation during the reaction. By using this catalyst, the conversion of glyoxal and the yield of glyoxalic acid were 29.2% and 13.6%, respectively at 313 K and oxygen flow 0.1 L/rain after reaction for 10 h.     

乙二醛在Pd4团簇吸附、解离以及选择氧化

采用第一性原理密度泛函理论,我们研究了乙二醛在具有四面体结构的Pd4团簇上吸附、解离以及氧化反应历程.研究表明:乙二醛中C-H键是最容易断裂的,断裂后形成的HCOOC基团分别和O或OH反应形成乙醛酸,也就是说乙二醛经过脱氢,选择氧化形成产物乙醛酸.在整个反应过程中,所需要的能垒均小于11.53 Kcal/mol.我们的研究不仅有助于理解乙二醛氧化的反应机理,而且对于今后设计更好的乙二醛选择氧化催化剂有一定的帮助作用.     

A facile one-pot highly chemo- and regioselective synthesis of the novel heterocyclic system indolo[1,2-c]azolo[1,5-a]quinazoline-8,10-dione

A series of novel indolo[1,2-c]azolo[1,5-a]quinazoline-8,10-diones was obtained by a multi-component reaction between cyclic 1,3-diketones, α-aminoazoles, and glyoxal. The unexpected cyclization process was established by NMR spectroscopy and X-ray diffraction measurements.     

Mass Spectroscopy of the Antileukemic Drug MGBG and Related Bis(Amidinohydrazones) [‘Bis(Guanylhydrazones)’]

The first study on the mass spectroscopy of various bis(amidinohydrazones) is reported. The compounds studied included the investigational antileukemic drugs methylglyoxal bis(amidino-hydrazone) [‘methylglyoxal bis(guanylhydrazone)’, MGBG] and glyoxal bis(amidinohydrazone), as well as seven mono- and dialkylglyoxal analogs thereof. The results indicate that the free bases of these high-melting compounds are volatilized well enough to allow a facile detection of the molecular ions and to make mass spectroscopy of the underivatized compounds a suitable method for the verification of the identity of the substances. This result is of importance considering the development of novel analogs and derivatives. A compilation of electron-impact mass spectra is reported and possible fragmentation routes are outlined. The fragmentation of the various congeners appears to occur essentially similarly, the main paths involving breakage of the carbon-carbon single bond in the glyoxal moiety or breakage of either one of the nitrogen-nitrogen single bonds.     

A one-pot stereoselective synthesis of novel polyfunctionalized imidazolidines

A facile, one-pot stereoselective synthesis of novel trans-4,5-dihydroxy-2-aryl-1,3-bis(heteroaryl)imidazolidines is achieved by a cyclocondensation reaction of 2 equiv of heteroarylamines with benzaldehyde derivatives, in the presence of guanidinium chloride as a polyfunctional organocatalyst, with aqueous glyoxal to afford the title products. This general protocol provides a wide range of new polyfunctionalized imidazolidines in good to high yields.