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1.
The reduction of pyrazine, quinoxaline and triazine derivatives by titanium(III) chloride leads to di- or tetrahydrogenated compounds. High yields of tetrahydro compounds are also obtained through the reduction of quinoxalinium salts. These results are compared with those obtained by electrochemical reduction. 相似文献
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Kim JW Koike T Kotani M Yamaguchi K Mizuno N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(13):4104-4109
Reduction of allylic alcohols can be promoted efficiently by the supported ruthenium catalyst Ru(OH)x/Al2O3. Various allylic alcohols were converted to saturated alcohols in excellent yields by using 2-propanol without any additives. This Ru(OH)x/Al2O3-catalyzed reduction of a dienol proceeds only at the allylic double bond to afford the corresponding enol, and chemoselective isomerization and reduction can be realized under similar conditions. The catalysis is truly heterogeneous and the high catalytic performance can be maintained during at least three recycles of the Ru(OH)x/Al2O3 catalyst. The transformation of allylic alcohols to saturated alcohols consists of three sequential reactions: oxidation of allylic alcohols to alpha,beta-unsaturated carbonyl compounds; reduction of alpha,beta-unsaturated carbonyl compounds to saturated carbonyl compounds; and reduction of saturated carbonyl compounds to saturated alcohols. 相似文献
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We wish to report the preparation of new bisheterocyclic compounds derived from resoreinol. We tried to sue methods during this investigation which would be selective and afford only tricyclic linear compounds. The starting material was resorcinol or the monomethylether of resorcinol. By reaction with chloroacetonitrile, acrylonitrile or ethyl chlorobutanoate, we obtained the intermediate compounds which were then cyclized by reaction with sodium acetate or polyphosphoric acid; either a catalytic reduction or treatment with zinc in presence of hydrochloric acid furnished the heterocyclic base. Another condensation followed by a cyclization and a reduction gave the desired compounds. 相似文献
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Qi Xun SHI Rong Wen LU Zhu Xia ZHANG De Feng ZHAO State Key Laboratory of Fine Chemicals Dalian University of Technology Dalian 《中国化学快报》2006,(4)
Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron(III) oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst. 相似文献
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Two random reduction procedures (NH2NH2/H2O2 and NH2NH2/O2) were compared and conditions optimized for the reduction of two synthetic pheromone compounds (9Z,11E)-9,11-tetradecadienyl acetate and (9Z,12E)-9,12-tetradecadienyl acetate on a 300 microg scale at 60 degrees C. The relative amounts of the four products (completely reduced acetate, unreacted diene acetate and two monoene acetates), characterized by gas chromatography (GC) from the reaction mixture, depended on the reaction conditions. The reduction was straightforward without any detectable undesired side products. The reaction yields were reproducible with both the reducing reagents. The optimized reduction conditions thus established were utilized to reduce seven synthetic compounds (four diene and three triene acetates) on a micro scale (5 microg). In all cases, expected compounds were identified by GC-MS. After reduction, two methods were used to locate the position of double bonds in the partially reduced compounds. In the first method, the products from the above seven compounds were isolated by extraction with hexane and reacted with dimethyl disulfide to give the DMDS adducts. In the second method ("one-pot"), the reduced compounds were not isolated but instead, the solvents were evaporated and the DMDS derivatives formed. In both cases, determination of the position of the double bonds was possible by GC-MS analyses. The complete procedure (reduction and DMDS derivative formation) could be carried out on a 100 ng scale. Although neither of the partial reduction methods offered significant advantages over the other, partial reduction with NH2NH2/H2O2 was more convenient and hence should be the method of choice, together with DMDS derivative formation to locate double bonds in pheromones. In addition, a new procedure is described using ND2ND2/H2O2 and DMDS derivative formation capable of distinguishing between the double bond positions in (Z)-9-tetradecenyl acetate and (9Z,12E)-9,12-tetradecadienyl acetate (1:1 mixture). 相似文献
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Shalygina O. D. Anisimova O. S. Vinograd L. Kh. Suvorov N. N. 《Chemistry of Heterocyclic Compounds》1975,11(6):693-695
The nature of the products of reduction of nitro compounds of the indole series containing a polysulfide chain depends on the length of the latter. In mono- and disulfides only the nitro groups are reduced, and diamino monosulfides and diamino disulfides are formed. In the reduction of the dinitro trisulfide the chain is cleaved and an amino thiol is formed. The reduction of acetylthionitro compounds is accompanied by migration of the S-N bond, as a result of which an acetamido thiol is formed. 相似文献
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Aguilera-Venegas B Olea-Azar C Norambuena E Arán VJ Mendizábal F Lapier M Maya JD Kemmerling U López-Muñoz R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(3):1004-1012
Electrochemical and ESR studies were carried out in this work with the aim of characterizing the reduction mechanisms of 4-substituted and 1,4-disubstituted 7-nitroquinoxalin-2-ones by means of cyclic voltammetry in DMSO as aprotic solvent. Two reduction mechanisms were found for these compounds: the first, for compounds bearing a labile hydrogen by following a self-protonation mechanism (ECE steps), and the second, for compounds without labile hydrogen, based on a purely electrochemical reduction mechanism (typical of nitroheterocycles). The electrochemical results were corroborated using ESR spectroscopy allowing us to propose the hyperfine splitting pattern of the nitro-radical, which was later corroborated by the ESR simulation spectra. All these compounds were assayed as growth inhibitors against Trypanosoma cruzi: first, on the non-proliferative (and infective) form of the parasite (trypomastigote stage), and then, the ones that displayed activity, were assayed on the non-infective form (epimastigote stage). Thus, we found four new compounds highly active against T. cruzi. Finally, molecular modeling studies suggest the inhibition of the trypanothione reductase like one of the possible mechanisms involved in the trypanocidal action. 相似文献
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元素化学是无机化学教学的重要组成部分。通过实验的方法研究元素及其无机化合物的性质和反应规律,可以使传统的描述性教学成为易于形象理解和深入掌握的立体化教学。本实验包含简单无机化合物的合成制备以及运用程序升温还原技术(TPR)考查所制备的材料的氧化还原性质两部分内容。程序升温还原方法可以非常直观地反映出样品的还原过程,并可以给出样品还原能力强弱(峰的位置,用于定性考查)、还原物种种类和数目(峰的数目、强弱,用于定量考查),以及各组分之间的相互作用的信息。程序升温还原技术操作简便、易实行,可在高校化学实验教学中推广使用。 相似文献
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Osina M. A. Bogdanovskaya V. A. Tarasevich M. R. Yusipovich A. I. 《Russian Journal of Electrochemistry》2004,40(8):802-812
Electrochemical reactions of peroxide compounds (hydrogen peroxide and peracetic and perbenzoic acids) on an electrode of pyrocarbon with immobilized horseradish peroxidase (HRP) are studied. The immobilization of HRP is performed in the composition of a composite with Nafion whose structure is studied by a method of scanning tunneling microscopy. The proposed composite material provides for a high catalytic activity and stability of enzyme in the reaction of reduction of peroxide compounds. It is shown that the electrocatalytic reduction of the studied compounds on the electrode with the peroxidase–Nafion composite proceeds in conditions of direct bioelectrocatalysis. The effect of the solution pH and the concentration of substrates on the electrocatalytic activity of HRP in the composition of the composite is studied. On the basis of the obtained results a possible mechanism of the electrocatalytic reduction of peroxide compounds in the presence of HRP is suggested. The rate of a bioelectrocatalytic process is defined by the nature and concentration of the substrate as well as by the electrode potential and the solution pH. 相似文献
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The reduction of a variety of carbonyl compounds was efficiently carried out with NaBH4/DOWEX(R)50WX4 system. The reactions were performed to give the corresponding alcohols derivatives in perfect yields in THF at room temperature. Reduction of acyloins and a‐diketones by this reducing system produced efficiently the corresponding vicinal diols. Also, the reduction of aldehydes over ketones has been accomplished successfully by this system. Regioselectivity of this system was also investigated with exclusive 1,2‐reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields. 相似文献
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Mahmoud M. M. Ramiz Wael A. El‐Sayed Ezzat Hagag Adel A.‐H. Abdel‐Rahman 《Journal of heterocyclic chemistry》2011,48(5):1028-1038
A number of N‐substituted pyrimidine glycosides were synthesized by coupling reaction of the pyrimidine base with acetobromosugars followed by deprotection. The synthesized compounds were tested for their antiviral activity against Hepatitis B Virus (HBV). Plaque reduction infectivity assay was used to determine virus count reduction as a result of treatment with tested compounds which showed moderate to high anti viral activities. J. Heterocyclic Chem., (2011). 相似文献
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From 9H-amino [l]benzopyranno-as-triazines 2 and 3 , [l]ben-zopyranno[4,3-e] or [3,4-e]pyrimido[l,2-b]-as-triazinones have been prepared by reaction with β-ketoesters. Chemical reduction of the compounds gives tetrahydro derivatives. By electrochemical reduction the dihydro compounds 14 and 15 were from-ed. The same dihydro derivatives were obtained with Grignard reagents. 相似文献
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The partial reduction of electron-deficient pyridines is described herein. Mono- and disubstituted pyridines can be transformed into functionalized dihydropyridines using either Birch reduction conditions or sodium/naphthalene in THF. The compounds formed by these high-yielding reductive alkylation protocols have potential as synthetic intermediates, and we have shown that bicyclo compounds containing 6,5, 6,6, and 6,7 ring systems can be prepared in one step via a base-promoted cylization. 相似文献
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Synthesis, spectroscopic and electrochemical property of an unsymmetrical porphyrin and its Zn compound 总被引:1,自引:0,他引:1
Chang Fu Zhuang Yu Jing Zhang Ai Qing Xia Wen Hui Lian Yun Fang Wang Ping Zhang Tong Shun Shi 《中国化学快报》2010,21(7):769-773
<正>In this article,a new 5-(p-maleicaminophenyl)-10,15,20-triphenylporphyrin(H_2P) and relative zinc compound(ZnP) were synthesized and characterized by means of elemental analyses,UV-vis,IR,MS and ~1H NMR spectroscopies.Furthermore,we have investigated the fluorescence spectroscopy of these compounds.The oxidation and reduction properties of the compounds were studied by the cyclic voltarnmetry,the oxidation-reduction potentials were obtained. 相似文献
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Reddy PM Prasad AV Rohini R Ravinder V 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(3):704-712
Efficient catalytic method for the reduction of pralidoxime to its amine derivative by macrocyclic Ni(II) compounds has been developed. Ten macrocyclic Schiff base Ni(II) compounds were synthesized via non-template synthesis by treating the corresponding macrocycles with nickel chloride in 1:1 ratio. The resulting compounds were characterized by elemental, IR, (1)H NMR, (13)C NMR, mass, electronic spectra, conductance, magnetic, thermal studies and their structures have been proposed. These compounds were used as catalysts for the reduction of pralidoxime to its amino derivative. The reduced pralidoxime was also characterized by spectral analysis and catalytic cycle has been established. The reduced product was determined spectrophotometrically by treating with ninhydrin reagent and the percent yields were found to be in the range of 75.12-82.36%. 相似文献
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Procedures are described for the determination of organic compounds with iodine trichloride under Andrews's titration conditions. Samples are directly titrated with iodine trichloride or first reacted with an excess of iodine monochloride, with subsequent titration of the iodine formed. The direct titration is done initially in feebly acid medium, then the acidity is raised (biotin, methionine, cystine and thiomersal). Pre-oxidation with iodine monochloride is used if the organic compound reacts slowly [tryptophan and arsenic(III) compounds] or is determined in bicarbonate medium (hydroxylamine and thiosemicarbazide). The ferrocyanide formed by the reduction of ferricyanide (by thiourea and allylthiourea) can also be titrated. Arsenic(V) compounds are determined after reduction to arsenic(III), and iodine in organic compounds is converted into iodide by alkaline fusion into iodide and the iodide titrated. 相似文献