8 documents found, page 1 of 1
Síntese de 2-( 2- piridil) quinolinas promovida por micro- ondas e suas ativida...
Borel, Carmindo R.; Barbosa, Luiz C. A.; Maltha, Célia R. A.; Fernandes, Sergio A.; Santos, Larissa B.; Takahashi, Jacqueline A.In this work a series of 2-(2- pyridyl)quinolines were prepared via a Povarov reaction between anilines, 2-pyridinocarbadehyde and ethyl vinyl ether under microwaves heating conditions. The optimized conditions herein reported allowed the preparation of several pyridylquinolines in yields in the range of 30-83%, some of them not previously accessible by this multicomponent process. The reported methodology has ...
Comparison of GC and HPLC for quantification of organic acids in two jaboticaba...
Jham, Gulab N.; Fernandes, Sergio A.; Garcia, Clerverson F.; Palmquist, DebraGas chromatography (GC) with trimethylsilyl derivative formation was compared to high-performance liquid chromatography (HPLC) for quantification of organic acids (OAs) in two jaboticaba (Myrciaria) fruit (pulp and pericarp) varieties (Sabará and Açu Paulista). Succinic and citric acids were the major OAs found in all the samples analyzed. Besides being much more tedious, the results obtained with GC were signi...
Potencial da palha de cana-de-açúcar para produção de etanol
Santos, Fernando A.; Queiróz, José H. de; Colodette, Jorge L.; Fernandes, Sergio A.; Guimarães, Valéria M.; Rezende, Sebastião T.Sugarcane straw biomass accounts for 1/3 of the energy potential of sugarcane and represents a rich source of sugars. Studies have been intensified for the use of this biomass along with bagasse for the production of cellulosic ethanol. Development of this technological path will allow for taking full advantage of sugarcane, increasing ethanol production without expanding the area cultivated. However, in order ...
p-Sulfonic acid calixarenes as efficient and reusable organocatalysts for the s...
Silva, Daniel L. da; Fernandes, Sergio A.; Sabino, Adão A.; Fátima, Ângelo deA new and efficient methodology is proposed for obtaining 3,4-dihydropyrimidin-2(1H)-ones/-thiones through Biginelli reactions. It is based on the use of less than the stoichiometric amount of p-sulfonic acid calixarenes as organocatalysts. A number of aromatic aldehydes as well as urea or thiourea can be employed for successfully synthesizing the corresponding Biginelli adducts. The described methodology is de...
p-Sulfonic acid calix[n]arenes as organocatalysts for the transesterification r...
Liberto, Natália A.; Almeida, Camila G.; Souza, Isabella F.; Silva, Márcio J. da; Fernandes, Sergio A.; Hyaric, Mireille LeThe catalytic activity of p-sulfonic acid calix[4]arene was studied in the transesterification reactions of Passiflora seed oil with methanol or ethanol. Calix[n]arenes are highly versatile organocatalysts and conversion rates >98 % were obtained for the transformation of Passiflora seed oil to its methyl or ethyl esters after 5 h of reaction in the presence of p-sulfonic acid calix[4]arene (3.52 mol % in ethan...
Experimental and theoretical NMR determination of isoniazid and sodium p-sulfon...
Teixeira, Milena G.; Assis, João V. de; Soares, Cássia G. P.; Lopes, Juliana F.; Carvalho, Guilherme S. L.; Lourenço, Maria C. S.; Almeida, Mauro V. deIn this work the inclusion complex formation of isoniazid with sodium p-sulfonatocalix[n]arenes is reported aiming to improve the physicochemical and biopharmaceutical properties of isoniazid a first line antibuberculosis drug. The architectures of the complexes were proposed according to NMR data Job plot indicating details on the insertion of the isoniazid in the calix[n]arenes cavities. DFT theoretical NMR c...
Benzocaine complexation with p-sulfonic acid calix[n]arene: experimental (1 H-N...
Arantes, Lucas M.; Varejão, Eduardo V. V.; Pelizzaro-Rocha, Karin J.; Cereda, Cíntia M. S.; Paula, Eneida de; Lourenço, Maicon P.; Duarte, Hélio A.The aim of this work was to study the interaction between the local anesthetic benzocaine and p-sulfonic acid calix[n]arenes using NMR and theoretical calculations and to assess the effects of complexation on cytotoxicity of benzocaine. The architectures of the complexes were proposed according to (1) H NMR data (Job plot, binding constants, and ROESY) indicating details on the insertion of benzocaine in the ca...
Theoretical investigation on the molecular inclusion process of prilocaine into...
Sousa, Sara M.R. de; Fernandes, Sergio A.; Almeida, Wagner B. De; Guimarães, Luciana; Abranches, Paula A.S.; Varejão, Eduardo V.V.The present letter reports, for the first time, results from a theoretical analysis of the inclusion process involving the prilocaine into the p-sulfonic acid calix[6]arene. Structure and stabilization energies were calculated, in both gas and aqueous phases, using a sequential methodology based on semiempirical and Density Functional Theory (DFT) calculations. From the results, a qualitative structure property...