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121.
A practical access to alkyl- and aryl-substituted (E)-2-(azidomethyl)alkenoates and related azido compounds from the corresponding allylic bromides in aqueous acetone is described. An alternative method to obtain the starting bromides based on heterogeneous catalysis under mild conditions was also investigated. 相似文献
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Mónica S. EstevãoLuísa C. Carvalho Luísa M. FerreiraEduarda Fernandes M. Manuel B. Marques 《Tetrahedron letters》2011,52(1):101-106
The electrochemical behavior of an indole library of compounds, including several tryptophan and tryptamine derivatives previously demonstrated to be active against several reactive oxygen species (ROS), was investigated. For this purpose, a voltammetry study was undertaken and the oxidation potential was correlated to the scavenging activity reported for the studied indoles. All the compounds showed an oxidation potential peak lower than that observed for indole (Epox = 1.035 V), but higher than that described for the antioxidant melatonin (Epox = 0.715 V). The electrochemical behavior showed a high correlation with the scavenging activity of peroxyl radical, for selected compounds. 相似文献
125.
Alvaro S. de Sousa Zanele Hlam Manuel A. Fernandes Helder M. Marques 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(4):o229-o232
The crystal structure of the title compound, C8H17NO2, consists of (R,R) and (S,S) enantiomeric pairs packed in adjacent double layers which are characterized by centrosymmetric hydrogen‐bonded dimers, generated via N—H...O and O—H...O interactions, respectively. Intermolecular interactions, related to acceptor and donor molecule chirality, link the achiral double layers into tubular columns, which consist of a staggered hydrophilic inner core surrounded by a hydrophobic cycloalkyl outer surface and extend in the [011] direction. 相似文献
126.
Christiane Fernandes James L. Wardell Janet M. S. Skakle 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):o499-o502
The molecule of 2-(hydroxymethyl)-1,3-propanediol, C4H10O3, lies across a mirror plane in space group P21/m, with disorder of both terminal hydroxyl H atoms. The molecules are linked by three O—H⋯O hydrogen bonds which combine to form sheets; in each O—H⋯O bond, the H atom resonates between the two O atoms. In the crystal structure of N,N′-bis[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]malonamide, C11H22N2O8, the molecule lies about a twofold axis and has four strong hydrogen bonds which form a mixture of chains and dimers; these combine to give a three-dimensional supramolecular framework. 相似文献
127.
L. Fernandes C. P. G. da Silva 《Journal of Radioanalytical and Nuclear Chemistry》1992,166(6):521-530
Thallium-201 was obtained by irradiating natural mercury with protons from IPEN's CV-28 Cyclotron. The chemical separation process chosen to separate thallium from mercury was an extraction chromatography technique. It consists on the passage of aqueous solutions (mobile phase), containing the elements that will be separated, through a glass column packed with an inert powder (support) saturated with the extractant (stationary phase). 相似文献
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Bruno Fernandes Ana C. Correia Fernanda Cosme Fernando M. Nunes 《Natural product research》2015,29(1):37-45
The purpose of this work was to study the volatile composition of vine leaves and vine leaf infusion prepared from vine leaves collected at 30 and 60 days after grape harvest of two Vitis vinifera L. species. Eighteen volatile compounds were identified by gas chromatography–mass spectrometry in vine leaves and in vine leaf infusions. It was observed that the volatile compounds present in vine leaves are dependent on the time of harvest, with benzaldehyde being the major volatile present in vine leaves collected at 30 days after harvesting. There are significant differences in the volatile composition of the leaves from the two grape cultivars, especially in the sample collected at 60 days after grape harvest. This is not reflected in the volatile composition of the vine leaf infusion made from this two cultivars, the more important being the harvesting date for the volatile profile of vine leaf infusion than the vine leaves grape cultivar. 相似文献
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