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Reverdito Ana María García Mariano Hernán Salerno Alejandra Locani Oscar Alberto Perillo Isabel Amalia 《平面色谱法杂志一现代薄层色谱法》2007,20(3):227-230
JPC – Journal of Planar Chromatography – Modern TLC - When the components of a reaction mixture cannot be quantified by UV-visible spectrophotometry, because the λmax values of... 相似文献
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Ana M. Reverdito Liliana Orelli Mnica Dalmaso Isabel Perillo Beatriz M. Fernndez 《Journal of heterocyclic chemistry》1991,28(2):273-281
Reaction of 1,2-diaryl-3-methyl-1,4,5,6-tetrahydropyrimidinium iodides 1a-i with alkaline solutions afforded N-aroyl-N-aryl-N'-methyltrimethylenediamines 2a-i . Compounds 2 are stable under acid conditions but in neutral or alkaline media spontaneously rearrange giving N-aroyl-N'-aryl-N-methyltrimethylenediamines 3a-i . Treating compounds 3 with concentrated acids reverse reaction takes place. Kinetic studies were performed on this intramolecular N → N' aroyl transfer over the Ho-pH range -0.9 to 2.30. Compounds 3 undergo acyl transfer to give 2 by a mechanism which involves a change in the rate determining step from formation to acid-catalysed decomposition of a six-membered heterocyclic intermediate on going from Ho to pH values. The existence of maxima in the pH rate profile allow to determine apparent pKa values of the hexahydropyrimidine intermediates which gave good correlation with the Swain F substituent constants. Stability of these heterocycles was also predicted by determination of thermodinamic parameters. Comparisons are made with the behaviour of five-membered heterocyclic intermediates (imidazolidine derivatives) which were studied in an earlier paper. 相似文献
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Beatriz M. Ferndez Ana M. Reverdito Samuel Lamdan 《Journal of heterocyclic chemistry》1981,18(5):933-937
Rate constants (kobs) of hydrolysis in boiling alkaline ethanolic solution for six 1-aryl-2-phenyl-2-imidazolines were determined. The influence of substituents in the phenyl group at N-1 upon rate of hydrolysis was studied. When the imidazoline ring is considered to be a substituent of the benzene ring at N-1, a good correlation with the Hammett equation is found. It was observed that reaction rates were enhanced by electron-releasing phenyl substituents of N-1 and reduced by electron-withdrawing groups, providing a change in the mechanism of the reaction in the first case that was not observed in the second. Agreement with the Hammett equation allowed comparison between experimental and “calculated” rate constants which are nearly equal. An equation relating the rate constants with the ionization constants of imidazolinium ions is given. 相似文献
4.
Beatriz M. Fernndez Ana M. Reverdito Guillermo A. Paolucci Isabel A. Perillo 《Journal of heterocyclic chemistry》1987,24(6):1717-1724
Reaction of l-alkyl-2,3-diarylimidazolinium iodides 1a-i with alkaline solutions afforded N'-alkyl-N-aroyl-N-arylethylenediamines 2a-i. Compounds 2 are stable under acid conditions but in neutral or alkaline media rearrange giving N-alkyl-N-aroyl-N-arylethylenediamines 3a-i. Treating compounds 3 with concentrated acids reverse reaction 3 → 2 takes place. Kinetic studies were performed on this intramolecular N → N' aroyl transfer over the Ho-pH range ?0.9 to 2.30. Compounds 3 undergo acyl transfer to give 2 by a mechanism which involves a change in the rate determining step from formation to catalysed decomposition of a heterocyclic intermediate I 2+ on going from Ho to pH values. The existence of maxima in the pH rate profile allowed to determine apparent pKa values of the imidazolidine intermediates which gave good correlation with Hammett sigma values. Stability of these heterocycles was also predicted by determination of thermodynamic parameters. 相似文献
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Shmidt MS Reverdito AM Kremenchuzky L Perillo IA Blanco MM 《Molecules (Basel, Switzerland)》2008,13(4):831-840
We present herein the results of microwave promoted N-alkylations of isatin (1)with different alkyl, benzyl and functionalized alkyl halides. Reactions were carried out under different conditions, always employing methodologies compatible with MW assisted chemistry. Generation of isatin anion employing diverse bases and solvents or using the preformed isatin sodium salt was tested. The best results were achieved using K(2)CO(3) or Cs(2)CO(3) and a few drops of N,N-dimethylformamide or N-methyl-2-pyrrolidinone. These reactions present noteworthy advantages over those carried out employing conventional heating. 相似文献
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Beatriz M. Fernndez Ana M. Reverdito Isabel A. Perillo Samuel Lamdan 《Journal of heterocyclic chemistry》1983,20(6):1585-1588
Rate constants (kobs) of hydrolysis in sulfuric acid-water mixtures at 100° for five 1-aryl-2-phenyl-2-imidazolines were determined. The influence of substituents in the phenyl group at N-1 upon the rate of hydrolysis was studied. When the imidazoline ring is considered to be a substituent of the benzene ring at N-1, a good correlation with the Hammett equation is found. In opposition to the behavior in alkaline media it was observed that reaction rates were enhanced by electron-withdrawing phenyl substituents and reduced by electron-releasing groups providing, similarly, a change in the mechanism of the reaction in the second case that was not observed in the first. Agreement with the Hammett equation allowed comparison between experimental and “calculated” rate constants which are fairly close. An equation relating the rate constants with the pKa values of the imidazolinium ions is given. 相似文献
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