排序方式: 共有15条查询结果,搜索用时 296 毫秒
1.
Marcos A. P. Martins Adilson P. Sinhorin Clarissa P. Frizzo Lilian Buriol Elisandra Scapin Nilo Zanatta Helio G. Bonacorso 《Journal of heterocyclic chemistry》2013,50(1):71-77
5‐Bromo[5,5‐dibromo]‐1,1,1‐trihalo‐4‐methoxy‐3‐penten[hexen]‐2‐ones are explored as precursors to the synthesis of 3‐ethoxymethyl‐5‐trifluoromethyl‐1H‐pyrazoles from a cyclocondensation reaction with hydrazine monohydrate in ethanol. 3‐Ethoxymethyl‐carboxyethyl ester pyrazoles were formed as a result of a substitution reaction of bromine and chlorine by ethanol. The dibrominated precursor furnished 3‐acetal‐pyrazole that was easily hydrolyzed to formyl group. In addition, brominated precursors were used in a nucleophilic substitution reaction with sodium azide to synthesize the 3‐azidomethyl‐5‐ethoxycarbonyl‐1H‐pyrazole from the reaction with hydrazine monohydrate. These products were submitted to a cycloaddition reaction with phenyl acetylene furnishing the 3‐[4(5)‐phenyl‐1,2,3‐triazolyl]5‐ ethoxycarbonyl‐1H‐pyrazoles and to reduction conditions resulting in 3‐aminomethyl‐1H‐pyrazole‐5‐carboxyethyl ester. The products were obtained by a simple methodology and in moderate to good yields. 相似文献
2.
Del Sordo Filho Giovanni Torrecilha Jefferson Koyaishi Scapin Marcos Antônio Oliveira Sonia Maria Barros da Silva Paulo Sergio Cardoso 《Journal of Radioanalytical and Nuclear Chemistry》2021,329(1):61-70
Journal of Radioanalytical and Nuclear Chemistry - This study has evaluated chemical, radiological composition and determined the cation exchange capacity (CEC) for three commercially available... 相似文献
3.
The c-Jun terminal kinases (JNKs) are members of the mitogen-activated protein (MAP) kinase family and regulate signal transduction in response to environmental stress. Activation of JNK3, a neuronal-specific isoform, has been associated with neurological damage, and as such, JNK3 may represent an attractive target for the treatment of neurological disorders. The MAP kinases share between 50% and 80% sequence identity. In order to obtain efficacious and safe compounds, it is necessary to address the issues of potency and selectivity. We report here four crystal structures of JNK3 in complex with three different classes of inhibitors. These structures provide a clear picture of the interactions that each class of compound made with the kinase. Knowledge of the atomic interactions involved in these diverse binding modes provides a platform for structure-guided modification of these compounds, or the de novo design of novel inhibitors that could satisfy the need for potency and selectivity. 相似文献
4.
Marcos A. Scapin Vera L. R. Salvador Marycel E. B. Cotrim Maria A. F. Pires Ivone M. Sato 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(3):807-811
Uranium silicide (U3Si2), 20% 235U enriched powder, is an intermetallic compound used as nuclear fuel material, which is the state-of-the-art among nuclear fuel materials used in modern research reactors. It is produced by IPEN and used as nuclear fuel of the IEA-R1 reactor (IPEN/CNEN, São Paulo, Brazil); U3Si2 has 92.3 wt% Utotal and 7.7 wt% Si. The qualification of this material requires chemical and physical tests such as Si and Utotal content, isotope ratio, impurities, density, specific surface area and particle size determination. The Si and Utotal were determined by gravimetric and volumetric procedures. Usually, these classical methods require a long time for analyses and are expensive. The objective of this study was to establish a fast and efficient analytical method to meet ISO/IEC 17025:2005 requirements in the Si and Utotal determination. The X-ray fluorescence techniques (XRF) were chosen to allow a direct and non-destructive analysis, what is the main advantage compared to other instrumental techniques, since previous chemical treatments are not necessary. In this study, the performance of the wavelength dispersive (WDXRF) and energy dispersive (EDXRF) X-ray fluorescence techniques was evaluated. Furthermore, two different sample preparation procedures, plain powdered and pressed powdered, were evaluated. Statistical tools were used to evaluate the results and a comparison between these results and the conventional methods was done. 相似文献
5.
6.
7.
Ivone M. Sato Luiz A. T. Pereira Marcos A. Scapin Marycel B. Cotrim Cristiano S. Mucsi Jesualdo L. Rossi Luis G. Martinez 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(2):283-288
Brazilian nuclear power reactor (PWR type) use, as nuclear fuel, sintered UO2 pellets with Zircaloy cladding. The cladding material has to present high mechanical strength and corrosion resistance, which are related to the material chemical composition and microstructural characteristics. Zircaloy machining scraps were remelted using VAR process, resulting in a billet, and its elemental composition was determined. The major elements Zr, Sn, Fe, Cr and Ni were determined by EDXRFS; Hf and contaminants were determined by WDXRFS. The chemical analysis did not show changes in the alloy elemental composition, except for Fe and Cr, which their out-off content can be attributed to contamination from steel scraps. The found Cu contamination may be related to the contact of the melted Zircaloy droplets with copper crucible. The billet microstructure was evaluated using optical and scanning electron microscopy and showed the typical zirconium alloy microstructures (needle and plates) resulting from the high cooling rate and thermal gradients, present during the solidification. 相似文献
8.
Elisandra Rigo André E. Polloni Daniela Remonatto Francieli Arbter Silvana Menoncin J. Vladimir Oliveira Débora de Oliveira Helen Treichel Susana J. Kalil Jorge L. Ninow Marco Di Luccio 《Applied biochemistry and biotechnology》2010,162(7):1881-1888
The main objective of this work was the isolation and screening of microorganisms with potential for producing lipases for the synthesis of fatty esters as well as evaluating the specificity of the enzymes produced, using different alcohols (methanol, ethanol, n-propanol, and butanol) and fatty acids (oleic and lauric acids) as substrates. Promising biocatalysts for organic synthesis were obtained in this work. The isolated strains 69F and 161Y showed ability to efficiently catalyze the reaction for production of n-propyl oleate. Other strains can also be considered of potential interest, as 74F, 111Y, and 186Y. The future development of production using different substrates could result in cheap crude lipase of high importance to industrial applicability. 相似文献
9.
Marcos A.P. Martins Marcos V.M. Teixeira Elisandra Scapin Claudio M.P. Pereira Helio G. Bonacorso Yao-Feng Yuan 《Tetrahedron letters》2004,45(49):8991-8994
One-pot condensation of ethyl trichloroacetoacetate 1 with p-substituted aromatic aldehydes (Ph, 4-Me-C6H4, 4-Cl-C6H4, 4-MeO-C6H4) or furfural, and urea or thiourea catalyzed by indium(III) bromide affords eight trichloromethylated tetrahydropyrimidinones, in high yields. 相似文献
10.
M.A. Scapin C. Duarte M.H.O. Sampa I.M. Sato 《Radiation Physics and Chemistry》2007,76(11-12):1899-1902
The recycling process of the used mineral oils has been gaining a very important gap in the context of environmental protection. Among mineral oils from petroleum, the lubricating oils are not entirely consumed during their use; therefore, it is necessary to apply a treatment for recuperation seeking their reuse. Moreover, the environmental legislation of countries does not allow their discard in any type of soils, rivers, lakes, oceans or sewerage systems.The conventional treatment has shown certain difficulties in the recuperation process for used oils. The ionizing radiation process is renowned in the industrial effluents treatments due to its high efficiency in the degradation of organic compounds and in the removal of metals by the action of OH, H and eaq radicals.In this work, used automotive lubricating oil was treated by the ionizing radiation process for metal removal and degradation of organic compounds. The samples were irradiated with 100 and 200 kGy irradiation doses. Determination of the elements Mg, Al, P, S, Cl, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Mo, Nb, Cd, Sn, Ba, Bi and Pb, before and after the irradiation, was done by X-ray fluorescence technique and the organic profile was obtained by infrared spectroscopy. 相似文献