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61.
Ingrid F. Zattoni Lais D. Guanaes Letícia B. Cerqueira Roberto Pontarolo Diogo R.B. Ducatti M. Eugênia R. Duarte Miguel D. Noseda Angela C.L.B. Trindade Alan G. Gonçalves 《Tetrahedron letters》2019,60(40):151129
We have evaluated four 1,4-dihydropyridines (DHPs 1a, 1b, 1c and 1d) as reducing agents, which presented free (hydrogenated) or phenyl-substituted N-1 and C-4 positions of the DHP ring. Reactions combining each of the DHP and different amounts of BF3OEt2 were evaluated for the reduction of imine 2a (N-benzylideneaniline). DHP simultaneously substituted at N-1 and C-4 (1a), and DHP substituted at C-4 (1b) gave lower yields for reduction of 2a in comparison with DHPs 1c and 1d (both unsubstituted at the C-4 position). By evaluating the amount of added BF3OEt2 to the reaction mixture, we have found that DHP 1c (substituted at N-1) provided its best yield for amine 3a (82%) when associated with stoichiometric amounts BF3OEt2, while DHP 1d (N-1- and C-4-unsubstituted derivative) was more effective (90% yield) with catalytic quantities of the Lewis acid. The reaction system using DHP 1c under stoichiometric BF3OEt2 could also be successfully applied with additional imine examples and under reductive amination conditions. 相似文献
62.
de Lima Melchiades Gabriela Angeli Valéria Weiss Colombo Mariana Koester Letícia Scherer 《Journal of Thermal Analysis and Calorimetry》2020,142(3):1249-1260
Journal of Thermal Analysis and Calorimetry - Compatibility is an important step in pre-formulation studies during the development of solid dosage forms. In the present study, we used thermal... 相似文献
63.
Franciele Queiroz Ames Lívia Bracht Francielle Sato Lidiane Vizioli de Castro-Hoshino Bruno Ambrósio da Rocha Letícia Aparecida de Oliveira 《Natural product research》2020,34(16):2341-2345
Abstract Fish oil (FO) is a natural source of omega-3 fatty acids, with well-established beneficial effects in inflammatory diseases when FO is orally administered. This study investigated the effects of a topically applied FO preparation (FOP) on phenol-induced ear edema and evaluated the percutaneous penetration of FOP in ear tissue. After applying phenol, groups of mice received FOP on the ear. After 1?h, ear tissue was collected to determine the percent inhibition of edema, myeloperoxidase activity, and to perform photoacoustic spectroscopy (PAS). Treatment with FOP did not reduce edema, but reduced myeloperoxidase activity. The FOP decreased the area of bands that characterize inflamed tissue and penetrated into the tissue. These results indicated an inhibitory effect of FOP on leukocyte recruitment in phenol-induced ear edema. These data support the applicability of PAS as a non-destructive method for evaluating the inflammatory response, percutaneous penetration and antiinflammatory activity of compounds. 相似文献
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Soraia I. Falcão Miguel Vilas-Boas Letícia M. Estevinho Cristina Barros Maria R. M. Domingues Susana M. Cardoso 《Analytical and bioanalytical chemistry》2010,396(2):887-897
In this study, an ethanolic extract from Portuguese propolis was prepared, fractionated by high-performance liquid chromatography,
and the identification of the phenolic compounds was done by electrospray mass spectrometry in the negative mode. This technical
approach allowed the identification of 37 phenolic compounds, which included not only the typical phenolic acids and flavonoids
found in propolis from temperate zones but also several compounds in which its occurrence have never been referred to in the
literature. Four of the novel phenolic compounds were methylated and/or esterified or hydroxylated derivatives of common poplar
flavonoids, although six peculiar derivatives of pinocembrin/pinobanksin, containing a phenylpropanoic acid derivative moiety
in their structure, were also identified. Furthermore, the Portuguese propolis sample was shown to contain a p-coumaric ester derivative dimer. 相似文献
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67.
Letícia Vieira Jodar Fabrício Aparecido Santos Valtencir Zucolotto Bruno Campos Janegitz 《Journal of Solid State Electrochemistry》2018,22(5):1431-1438
A stable conducting film for sensing using reduced graphene oxide (RGO), gold nanoparticles (GNPs), and potato starch (PS) is proposed. The characterization of the nanomaterials was obtained by ultraviolet and visible spectroscopy, dynamic light scattering, zeta potential, Fourier transform infrared spectroscopy, atomic force microscopy, and cyclic voltammetry. The voltammetric behavior of the RGO-GNPs-PS/GCE electrodes was studied in the presence of estriol and the results showed a high anodic peak current at 0.64 V. Under optimal conditions, an analytical curve was obtained, in which the anodic peak estriol was linear in the range from 1.5 to 22 μmol L?1, with a detection limit of 0.48 μmol L?1. The modified electrodes were applied for determination of estriol in environmental and biological samples. The proposed electrode was used for estriol determination in water and urine samples, which presented a recovery range from 92.1 to 106%, showing that RGO-GNPs-PS/GCE is a viable alternative for the detection of estriol and can be attractive for several electrochemical applications. 相似文献
68.
Letícia Caramori Cefali Daniele Cristina Barbosa de Oliveira Cristina Maria Franzini Janaína Artem Ataíde Patrícia Moriel Priscila Gava Mazzola 《Journal of Dispersion Science and Technology》2018,39(8):1149-1152
The aim of the present study was to carry out stability tests and in vitro sun protection factor (SPF) evaluations of formulations containing free or microencapsulated chemical sun filters to improve their use. To this end, three formulations were developed and subjected to stability studies. The most stable formulation was chosen as a vehicle for free and microencapsulated chemical sun filters, and subjected to further stability studies and in vitro SPF assays. The SPF values were approximately 12 and 11 for formulations containing free and encapsulated sun filters, respectively, and both types were stable under stress. Chemical sun filters can be microencapsulated, which may aid in generating innovative sunscreen formulations. 相似文献
69.
Letícia R. Teixeira Rubén D. Sinisterra Rafael P. Vieira Maria Carolina Doretto Heloisa Beraldo 《Journal of inclusion phenomena and macrocyclic chemistry》2003,47(1-2):77-82
Aryl semicarbazones can be considered a novel class of compounds presenting anticonvulsant activity. In order to improve the efficiency and bioavailability of benzaldehyde semicarbazone (BS) we used the host–guest strategy and β-cyclodextrin (β-CD) to prepare a BS/β-CD 1:1 inclusion compound, which was characterized by thermal analyses (TG, DTG, DSC), XRD powder pattern diffraction analyses, infrared data and 1H, 13C, 2D-ROESY NMR and 1H relaxation times. The BS/β-CD inclusion compound was tested in rats using the maximum electroshock (MES) screen. The minimum dose necessary to produce anticonvulsant activity decreased from 100 mg/Kg (ip or vo) for the free semicarbazone to 25 mg/Kg/vo (75%) and 15 mg/Kg/ip (85%), indicating that the host–guest strategy that uses β-CD and BS is very effective and could be successfully employed in the preparation of pharmaceutical formulationof anticonvulsants. 相似文献
70.