Metal-free solvent promoted oxidation of benzylic secondary amines to nitrones with H202

An environmentally benign protocol for the generation of nitrones from benzylic secondary amines via catalyst-free oxidation of secondary amines using H2O2 in MeOH or CH3CN is described. This methodology provides a selective access to a variety of C-aryl nitrones in yields of 60 to 93%. Several studies have been performed to shed light on the reaction mechanism and the role of the solventWe thank FEDER/Ministerio de Ciencia, Innovación y Universidades−Agencia Estatal de Investigación (Grant PGC2018-098660-B-I00) and CAPES (Finance Code 001), CNPq (310514/2018-5), FAPEMIG for financial suppor

Recent advances in organic reactions catalyzed by nickel

Nickel complexes have been widely used as catalysts in organic reactions. Their low price compared to Pd and Pt complexes, in addition to their high reactivity and affinity to ϖ systems; the possibility to access different oxidation states and the difficulty to undergo beta-hydride elimination are important features that have attracted the attention of chemists in recent decades. Furthermore, some drawbacks observed with Pd catalysis have been solved by Ni catalysis. These Ni based-catalysts have been used in different reaction manifolds to promote challenging transformations. Herein, recent work using nickel catalysts in different types of reactions, such as carbonylations, carboxylations, C-H activations and dual catalytic systems are described. Critical mechanistic investigations, as well as synthetic applications are also covered.

Old drawback on azlactone formation revealed by a combination of theoretical and experimental studies

New insights into the formation of azlactone heterocycles bearing different substituents are hereby presented. The sum of both kinetic and thermodynamic factors contributes for the formation of 2-alkyl or 2-aryl substituted azlactones, while the cyclization of 2-alcoxy azlactones is less favored. These results are in perfect accordance with experimental observations obtained by infrared (IR) and electrospray ionization mass spectrometry (ESI(+)-MS) of the crude reaction mixture.

Methods of preparation and biological activity of quinolinic acid and derivatives

In 1981 2,3-pyridine dicarboxylic acid (quinolinic acid) was discovery to be a selective agonist for the N-methyl -D-aspartic acid (NMDA) receptor. As a consequence it possesses neurotoxic activity resulting from overstimulation of the receptor. Quinolinic acid is implicated as an etiological factor in a range of neurodegenerative disease including AIDS related dementia, Huntington´s disease and Lyme disease. In the design of novel therapies to treat these diseases, some molecules have been identified as an important target. In this paper we described different methods to prepare quinolinic acid and derivatives.

Microwave-assisted multicomponent synthesis of julolidines using silica-supported calix[4]arene as heterogeneous catalyst

The application of immobilizing calixarene onto the surface of silica using a sol-gel method, as an efficient heterogeneous catalyst (CX4SO3HSi(n)) for multicomponent Povarov reaction has been described. Catalytic activity of the CX4SO3HSi(n) for the synthesis of julolidines under greener and environmentally benign conditions in simple and efficient method was explored. Notably, only 0.5 mol% of the catalyst is sufficient to catalyze the Povarov solvent-free reaction under microwave-assistance. Besides, this protocol allows the construction of four new C-C bonds and two C-N bonds in a single step. To the best of our knowledge, this consists the first silica support calix[4]arene as a heterogeneous catalyst for multicomponent synthesis of julolidines.Fil: Ferreira de Paiva, Walysson. Universidade Federal de Viçosa. Departamento de Química.; BrasilFil: Bastos Braga, Ingredy. Universidade Federal de Viçosa. Departamento de Química.; BrasilFil: de Assis, João Vitor. Universidade Federal de Viçosa. Departamento de Química.; BrasilFil: Bonilla Castañeda, Sandra Milena. Universidade Federal de Viçosa. Departamento de Química.; BrasilFil: Sathicq, Ángel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Palermo, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Romanelli, Gustavo Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Natalino, Ricardo. Universidade Federal de Viçosa. Departamento de Química.; BrasilFil: da Silva, Marcio José. Universidade Federal de Viçosa. Departamento de Química.; BrasilFil: Martins, Felipe Terra. Universidade Federal de Goiás; BrasilFil: de Carvalho, Gustavo Senra Gonçalves. Universidade Federal de Juiz de Fora; BrasilFil: Amarante, Giovanni Wilson. Universidade Federal de Juiz de Fora; BrasilFil: Fernandes, Sergio Antonio. Universidade Federal de Viçosa. Departamento de Química.; Brasi

Processo Para Produção De Aciloìnas E Processo Para Produção De Fármacos

PROCESSO PARA PRODUÇÃO DE ACLLOINAS E PROCESSO PARA PRODUÇÃO DE FÁRMACOS. Refere-se a presente invenção a um novo processo de obtenção de fármacos, em especial do agente antidepressivo bupropion, a partir da síntese da forma racêmica e/ou assimétrica de aciloinas a partir de adutos de Morita-Baylis-Hilman, possuindo potencial atividade biológica.BRPI0900158 (A2)C07C45/00A61K31/12A61K31/135A61P25/34C07C49/175C07C209/14BR2009PI00158C07C45/00A61K31/12A61K31/135A61P25/34C07C49/175C07C209/1

Screening method for determination of C18:1 trans fatty acids positional isomers in chocolate by 1H NMR and chemometrics

The regulations established worldwide, restricting trans fatty acids (TFA) from industrial origin in foods, encourage the development of rapid methods to verify the quality of food products. A simple and rapid procedure based on 1H NMR combined with multivariate calibration was developed to quantify C18:1 TFA isomers in chocolate fat. Thirty chocolate samples (milk, dark and white chocolates) were analyzed by 1H NMR, and also by a reference gas chromatographic method. Then, partial least squares regression was used for model development. The most important 1H NMR signals for the modeling comprised the 5.25–5.45 ppm region, corresponding to CH (double bonds and glycerol backbone), and the 1.94–1.99 ppm region, characteristic of CH2 allylic to trans double bonds. Good predictive qualities for all TFA isomers were obtained. Coefficient of correlation for prediction was 0.967 for C18:1 trans 6–8; 0.981 for C18:1 trans 9; 0.987 for C18:1 trans 10; 0.941 for C18:1 trans 11; 0.983 for C18:1 trans 12 and 0.977 for total TFA. This study demonstrates the potential of 1H NMR to be applied in food industries in order to perform TFA control analysis as well as to investigate food fraud.This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 and PDSE 88881187078/2018–01; Spanish Ministry of Economy and Competitiveness (AGL2016-75159-C2-2-R); CNPq (303355/2017–4, 424032/2018–0); Finep (CT-INFRA 01/2013-REF 0633/13); RQ-MG (CEX.RED- 00010–14), and INCTBio (FAPESP 2014/50867–3, CNPq 465389/2014–7).Peer reviewe

Lipid classification of fish oil omega-3 supplements by 1H NMR and multivariate analysis

The worldwide advent of concentrated supplements containing omega-3 fatty acids (FA) in the form of triacylglycerols (TAG) or ethyl esters (EE) has increased the interest in developing methods to classify these products. The quality control based on their lipid composition has become necessary since EE bioavailability has been proved to be lower when compared to the TAG. In this preliminary study, eight models based on 1H NMR and supervised discriminant analysis (PLS-DA/OPLS-DA) were applied to classify omega-3 fish oil in TAG or EE forms. The 4.0–4.5 ppm region was selected for modeling since it bracketed spectral features to discriminate TAG and EE. The non-supervised principal component analysis was employed to visually evaluate the distribution of samples and revealed a clear separation of TAG from EE marine oils along PC1. In addition, representative TAG and EE samples were 100 % correctly classified using any of the eight supervised models studied. The developed models resulted in high R2Y (≥ 0.977) and Q2 (≥ 0.953), and low root mean square error for prediction (≤ 0.009), which demonstrates the high potential of this rapid and straightforward procedure to evaluate the lipid form of supplements and mislabeling.We would like to acknowledge the Spanish Ministry of Economy and Competitiveness (AGL2016-75159-C2-2-R); CAPES (PDSE 88881187078/2018-01, PNPD 23071022702/2018-43); CNPq (303355/2017-4, 424032/2018-0) and INCTBio (Projects FAPESP 2014/50867-3 and CNPq 465389/2014-7) for the fellowships and financial support.Peer reviewe