Valorization of Oleuropein via Tunable Acid-Promoted Methanolysis

The acid-promoted methanolysis of oleuropein was studied using a variety of homogeneous and heterogeneous acid catalysts. Exclusive cleavage of the acetal bond between the glucoside and the monoterpene subunits or further hydrolysis of the hydroxytyrosol ester and subsequent intramolecular rearrangement were observed upon identification of the most efficient catalyst and experimental conditions. Furthermore, selected conditions were tested using oleuropein under continuous flow and using a crude mixture extracted from olive leaves under batch. Formation of (−)-methyl elenolate was also observed in this study, which is a reported precursor for the synthesis of the antihypertensive drug (−)-ajmalicine.Centro de Investigación y Desarrollo en Ciencias Aplicada

Magnetic ionic plastic crystal: choline[FeCl4]

A novel organic ionic plastic crystal (OIPC) based on a quaternary ammonium cation and a tetrachloroferrate anion has been synthesized with the intention of combining the properties of the ionic plastic crystal and the magnetism originating from the iron incorporated in the anion. The thermal analysis of the obtained OIPC showed a solid?solid phase transition below room temperature and a high melting point above 220 1C, indicating their plastic crystalline behaviour over a wide temperature range, as well as thermal stability up to approximately 200 1C. The magnetization measurements show the presence of three-dimensional antiferromagnetic ordering below 4 K. The results from electrochemical characterization display a solid-state ionic conduction sufficiently high and stable (between 10 2.7 and 10 3.6 S cm 1 from 20 to 180 1C) for electrochemical applications

Solubility of carbon dioxide in ammonium based CO2-induced ionic liquids

The solubility of carbon dioxide in ionic liquids was measured in a new apparatus. The ionic liquids chosen have ammonium-based cations and show melting temperature decreases under CO2 pressure that range from low (25 K) to extremely high (120 K). The main purpose of this study was to check whether the solubility of the gas in each liquid could explain the previously reported wide differences in melting point depression (MPD). The results show there is no correlation between solubility and MPD

Incorporation of Resveratrol in Polymeric Nanogel for Improvement of Its Protective Effects on Cellular and Microsomal Oxidative Stress Models

Nanogels are attractive drug delivery systems that provide high loading capacity for drug molecules, improve their stability, and increase cellular uptake. Natural antioxidants, especially polyphenols such as resveratrol, are distinguished by low aqueous solubility, which hinders therapeutic activity. Thus, in the present study, resveratrol was incorporated into nanogel particles, aiming to improve its protective effects in vitro. The nanogel was prepared from natural substances via esterification of citric acid and pentane-1,2,5-triol. High encapsulation efficiency (94.5%) was achieved by applying the solvent evaporation method. Dynamic light scattering, atomic force microscopy, and transmission electron microscopy revealed that the resveratrol-loaded nanogel particles were spherical in shape with nanoscopic dimensions (220 nm). In vitro release tests showed that a complete release of resveratrol was achieved for 24 h, whereas at the same time the non-encapsulated drug was poorly dissolved. The protective effect of the encapsulated resveratrol against oxidative stress in fibroblast and neuroblastoma cells was significantly stronger compared to the non-encapsulated drug. Similarly, the protection in a model of iron/ascorbic acid-induced lipid peroxidation on rat liver and brain microsomes was higher with the encapsulated resveratrol. In conclusion, embedding resveratrol in this newly developed nanogel improved its biopharmaceutical properties and protective effects in oxidative stress models

Efficient Continuous Production of the Biofuel Additive 5-(t-Butoxymethyl) Furfural from 5-Hydroxymethylfurfural

The catalytic etherification of 5-hydroxymethylfurfural (HMF) with t-butanol to a biofuel additive 5-(t-butoxymethyl) furfural (t-BMF) is studied by screening 27 heterogeneous protic and/or Lewis acids. Preyssler heteropolyacid H14[NaP5W30O110] and Montmorillonite-based CLOI_CSP catalysts are identified as the most efficient ones, allowing the etherification to reach the t-BMF/HMF equilibrium faster ( 1:1), thus promoting minimum side reactions. Further optimization of the batch experimental conditions, namely catalyst loading, temperature, HMF concentration, time, t-BMF stability, and additives, allows the t-BMF/HMF equilibrium to be reached in less than 3 h with outstanding selectivity >95%. Under optimized conditions, CLOI_CSP is reused for four cycles without significant loss of efficiency. In addition, it exhibits high efficiency under flow conditions, allowing continuous production of t-BMF up to 0.7 g t-BMF g1 catalyst min1 at high concentrations of HMF.Fil: Pardo Cuervo, Oscar H.. Universidade de Lisboa; Portugal. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Simeonov, Svilen P.. Institute of Organic Chemistry with Centre of Phytochemistry Bulgarian Academy of Sciences; Bulgaria. Universidade de Lisboa; PortugalFil: Peixoto, Andreia F.. Universidad de Porto; PortugalFil: Popova, Margarita D.. Institute of Organic Chemistry with Centre of Phytochemistry Bulgarian Academy of Sciences; BulgariaFil: Lazarova, Hristina I.. Institute of Organic Chemistry with Centre of Phytochemistry Bulgarian Academy of Sciences; BulgariaFil: 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: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Freire, Cristina. Universidad de Porto; PortugalFil: Afonso, Carlos A. M.. Universidade de Lisboa; Portuga

Valorization of Oleuropein via Tunable Acid-Promoted Methanolysis

The acid-promoted methanolysis of oleuropein was studied using a variety of homogeneous and heterogeneous acid catalysts. Exclusive cleavage of the acetal bond between the glucoside and the monoterpene subunits or further hydrolysis of the hydroxytyrosol ester and subsequent intramolecular rearrangement were observed upon identification of the most efficient catalyst and experimental conditions. Furthermore, selected conditions were tested using oleuropein under continuous flow and using a crude mixture extracted from olive leaves under batch. Formation of (−)-methyl elenolate was also observed in this study, which is a reported precursor for the synthesis of the antihypertensive drug (−)-ajmalicine.Fil: Cavaca, Lídia A. S.. Universidade de Lisboa; PortugalFil: Rodrigues, Catarina A. B.. Universidade de Lisboa; PortugalFil: Simeonov, Svilen P.. Universidade de Lisboa; Portugal. Bulgarian Academy of Science; BulgariaFil: Gomes, Rafael F. A.. Universidade de Lisboa; PortugalFil: Coelho, Jaime A. S.. Universidade de Lisboa; PortugalFil: 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: Sathicq, Angel Gabriel. 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: Martínez, José J.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Afonso, Carlos A. M.. Universidad Pedagógica y Tecnológica de Colombia; Colombi