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1.
It has been shown by UV-spectroscopy in solvents of varying polarity that heteroaromatic N-oxides form molecular complexes of n, π -type with tetracyanoethylene. As time passes they convert into ionized form. The convertion rate increases parallel to donor basicity, solvent polarity and temperature. The formation of equimolar and trimolar complexes has been proved according to the UV-spectroscopic and dipole moment data. Stability constants have been calculated. 相似文献
2.
E. M. Koldasheva Yu. V. Geletii V. V. Yanilkin V. V. Strelets 《Russian Chemical Bulletin》1990,39(5):886-890
The primary products of electrooxidation of heteroaromatic N-oxides are the corresponding cation-radicals. The redox properties of N-oxides, and also the stability of the cation-radicals generated from them, are determined by the number of N atoms and N-oxide groups in the heterocyclic ring and also by the nature of the substituents. Using phenazine di-N-oxide as an example, it was shown that the generation of the cation radical induces the oxidation of cyclohexane into cyclohexanol and cyclohexanone and is accompanied by deoxygenation of the di-N-oxide into a mono-N-oxide. The oxidation of cyclohexane proceeds by two paths, in one of which molecular oxygen participates, while in the second path an oxygen transfer probably takes place from the di-N-oxide cation radical to cyclohexane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 994–999, May, 1990.The authors wish to express their gratitude to A. E. Shilov for his participation in the discussion of the results, and also to R. E. Lokhov and A. V. Ryzhakov for providing samples of a series of N-oxides. 相似文献
3.
《Chemical physics letters》1986,128(3):319-322
The photoreaction of systems containing N-oxides and amines has been studied by ESR. The lowest triplet state of the heteroaromatic N-oxide combines with triethylamine to form an exciplex. Oxygen transfer and α-cleavage of the N-C bond in the amine part of the exciplex gave diethyl nitroxide. 相似文献
4.
Kinetic manometric studies indicate that the first step in the thermal decomposition of a number of N-oxides is the formation of a cyclic activated complex. There is a correlation between the thermal stability of the compounds studied in the liquid phase and the charge on the oxygen atom of the N-oxide group calculated by the MPDP method. Autocatalysis of gas evolution from halogenopyridine N-oxides is explained by hydrogen halide autocatalysis. The limit of thermal stability for N-oxides is likely to be no greater than 270°C.Biisk Lyceum, Altai Region, Biisk 659302. Kazan' State Technological University, Kazan' 420015. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1573–1576, November, 1995. Original article submitted October 20, 1995. 相似文献
5.
Sha Peng Yan-Xi Song Jun-Yi He Shan-Shan Tang Jia-Xi Tan Zhong Cao Ying-Wu Lin Wei-Min He 《中国化学快报》1990,30(12):2287-2290
An eco-friendly protocol for the synthesis of various 2-sulfonyl quinolines/pyridines through sulfonylation of heteroaromatic N-oxides with sodium sulfinates in water under metal-and oxidant-free conditions has been developed. The high reaction efficiency, operational simplicity, short reaction time, air-and moisture-insensitive conditions and remarkable functional group compatibility make the developed protocol very attractive for the preparation of 2-sulfonyl N-heteroaromatic compounds. 相似文献
6.
Oxidation of 5-phenyl-1,2,3,4-thiatriazole (1) with peroxytrifluoroacetic acid yields 5-phenyl-1,2,3,4-thiatriazole-3-oxide (2) a representative of a new class of heteroaromatic N-oxides. The structure is based on the mass spectral fragmentation of 2 and the isotope labelled with 15N at position 2. IR and ESCA measurements are consistent with this assignment. The thermal, photochemical, and chemical properties of the oxide are discussed. 相似文献
7.
Heaney F Lawless E Mahon M McArdle P Cunningham D 《Organic & biomolecular chemistry》2006,4(12):2408-2416
The reaction between the heteroaromatic N-oxides 1a, 1b and 1c with dimethyl acetylenedicarboxylate or methyl propiolate furnishes 1,3-benzodiazepines, the products of ring transformations of primarily formed cycloadducts. The structures of 8a and 10a have been confirmed by X-ray crystallographic analysis. The aldonitrone 1c also reacts with N-methylmaleimide and with phenyl vinyl sulfone to furnish the first examples of primary cycloaddition products from quinazoline 3-oxides. 相似文献
8.
Azine N-oxides undergo highly regioselective metalation with TMPZnCl·LiCl under mild conditions. A palladium-catalyzed Negishi cross-coupling reaction of the resulting organozinc species with heteroaromatic bromides provides heterobiaryls specifically oxidized at one nitrogen position in up to 95% yield. 相似文献
9.
Pignataro L Benaglia M Annunziata R Cinquini M Cozzi F 《The Journal of organic chemistry》2006,71(4):1458-1463
A series of structurally simple pyridine N-oxides have readily been assembled from inexpensive amino acids and tested as organocatalysts in the allylation of aldehydes with allyl(trichloro)silane to afford homoallylic alcohols. (S)-proline-based catalysts afforded the products derived from aromatic aldehydes in fair to good yields and in up to 84% enantiomeric excess (ee). The allylation of heteroaromatic, unsaturated, and aliphatic aldehydes was less satisfactory. By running the reaction in the presence of achiral and chiral additives and structurally different catalysts, we collected some insights into the relationship between the stereochemical outcome and the catalyst's structural features. Even if the ee's obtained are inferior to the best values observed with other catalysts, this work concurs to show that structurally simple pyridine N-oxides can also promote the allylation reaction with satisfactory stereocontrol. 相似文献
10.
Summary This title pyridine N-oxides have been prepared and their copper(II) complexes isolated as perchlorate, tetrafluoroborate and nitrate salts. The ligands coordinatevia both the pyridine N-oxide oxygen and the amine nitrogen to give bis(ligand) complexes for the perchlorate and tetrafluoroborate salts. The nitrate solids have [CuL(NO3)2] stoichiometry with monodentate nitrato-ligands. The spectral properties of these complexes are compared to those of N-alkyl-and N,N-dialkyl2-picolinamine N-oxides as well as other 2-substituted pyridine N-oxides.NATO Fellow on leave from Istanbul Medical Faculty, Istanbul University. 相似文献
11.
A summary is given for the data on 1,3-dipolar cycloaddition reactions of aromatic N-oxides, which are convenient one-step methods for the synthesis of several heterocyclic compounds. Special attention was given to N-oxides as possible ambident donors in the formation of molecular complexes with dipolarophiles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 579–591, May, 1992 相似文献
12.
Summary. Various heteroaromatic N-oxides were efficiently deoxygenated to the corresponding bases under mild conditions using formamidinesulfinic
acid (thiourea S,S-dioxide).
Received March 24, 2000. Accepted April 18, 2000 相似文献
13.
Wen Xin Wu Hu Cheng Liu Dr. Wei Jun Jin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(2):e202103336
Rapid capture of 129I with high volatility and toxicity in the environment has attracted much attention. Herein we reported a firstly synthesized nonporous material: pyridine N-oxides (NTPO and ATPO) as iodine adsorbent. Both of NTPO and ATPO exhibit remarkable performance on the adsorption of iodine in aqueous solution, vapor state and organic solvents. Upon the capture of iodine, pyridine N-oxides were transformed to binary cocrystals combined with the pyridine N-oxides and iodine which is driven by halogen bond between iodine and oxygen atoms. Moreover, pyridine N-oxides shows high chemical, thermal and moisture stability. 相似文献
14.
A. R. Gataulina G. A. Kutyrev A. F. Maksimov A. -M. P. Ernandes M. P. Kutyreva 《Russian Journal of General Chemistry》2018,88(11):2300-2306
Hyperbranched polyesters containing terminal p-toluenesulfonylamido and diethoxyphosphorylamido groups have been synthesized, and their complexes with copper(II) and cobalt(II) ions have been prepared. The thermal stability of the ligands and their metal complexes has been studied by differential scanning calorimetry. 相似文献
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17.
1-苯基-3-甲基-七氟丁酰吡唑酮-5(PMHFP)及邻菲咯啉(phen)希土混配配合物的合成及性质研究 总被引:1,自引:1,他引:1
本文在乙醇中合成了PMHFP及phen与希土离子的三元配合物Ln(PMHFP)3·phen(Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y).通过化学分析,元素分析及电导分析确定了配合物的组成;研究了配合物的紫外、红光光谱;借助于差热-热重分析仪研究了所有配合物的挥发性质,测定了它们各自的起始挥发温度,探讨了用于希土分析的可能性. 相似文献
18.
V. P. Andreev Ya. P. Nizhnik S. G. Tunina B. Z. Belashev 《Chemistry of Heterocyclic Compounds》2002,38(5):553-559
Thirteen new molecular complexes of pyridine and quinoline N-oxides with CuCl2 and ZnCl2 of composition 1:1 and 2:1 have been obtained and characterized. Their structure depends on the constitution of the ligand, the nature of the metal, and the reactant ratio at complex formation. 相似文献
19.
H. A. El-Boraey F. A. El-Saied S. A. Aly 《Journal of Thermal Analysis and Calorimetry》2009,96(2):599-606
UO2(VI), Sn(IV), Th(IV) and Li(I) complexes of 4-azomalononitrile antipyrine (L) have been isolated and characterized based on
IR spectra, 1H NMR, elemental analyses, molar conductance and thermal analysis (DTA/TG). The study revealed that the ligand behaves as
a neutral bidentate one and coordination takes place via the carbonyl atom of pyrazolone ring >C=O and the azomethine nitrogen
>C=N. The thermal stability of the metal complexes were investigated by thermogravimetry (TG), differential thermal analysis
(DTA) techniques and infrared spectra, and correlated to their structure. The thermal study revealed that Th(IV) complexes
show lower thermal stability than both UO2(VI) and Sn(IV) complexes. 相似文献
20.
The thermal behaviours of the Ti(II), Mn(II), Fe(II), Ni(II), Cu(II) and Zn(II) complexes of triethanolamine were studied by means of thermogravimetry, differential thermogravimetry, differential thermal analysis infrared spectrophotometry and elemental analysis. The sequence of thermal stability of the metal complexes, determined by using the initial decomposition temperature, was found to be Ti(II)?Mn(II)>Fe(II)>Ni(II)>Zn(II)>Cu(II). Some of the kinetic parameters, such as the activation energy and order of reaction for the initial decomposition reaction, were calculated and the relationship between the thermal stability and the chemical structure of the complexes is discussed. 相似文献