Dissolution of metal salts in bis(trifluoromethylsulfonyl)imide-based ionic liquids: Studying the affinity of metal cations toward a "weakly coordinating" anion

Despite the weakly coordinating ability of the bis(trifluoromethylsulfonyl)imide anion ([Tf2N]-) the corresponding ionic liquids (ILs) are able to dissolve relevant amounts of metal salts having the same anion, M[Tf2N]x. To better understand the metal dissolution process we evaluated the interaction ability of a set of metal cations (Y(III), Al(III), Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Li(I), and Na(I)) toward the [Tf2N]- anion measuring the relative aptitude to give the corresponding anionic monocharged complex, [M(Tf2N)x+1]- using the ESI-MS technique. UV-vis and NMR measurements were carried out to verify the consistence between the liquid and the gas phase. Density functional theory calculations have been used to identify the metal-containing species and determine their relative stability. An interesting correlation between interaction ability and chemical properties (Lewis acidity) was found

Oxidative N-Heterocyclic Carbene Catalysis

N-Heterocyclic carbene (NHC) catalysis is a by now consolidated organocatalytic platform for a number of synthetic (asymmetric) transformations via diverse reaction modes/intermediates. In addition to the typical umpolung processes involving acyl anion/homoenolate equivalent species, implementation of protocols under oxidative conditions greatly expands the possibilities of this methodology. Oxidative NHC-catalysis allows for oxidative and oxygenative transformations through specific manipulations of Breslow-type species depending upon the oxidant used (external oxidant or O2/air), the derived NHC-bound intermediates paving the way to non-umpolung processes through activation of carbon atoms and heteroatoms. This review is intended to update the state of the art in oxidative NHC-catalyzed reactions that appeared in the literature from 2014 to present, with a strong focus to crucial intermediates and their mechanistic implications

Humin Formation on SBA-15-pr-SO3H Catalysts during the Alcoholysis of Furfuryl Alcohol to Ethyl Levulinate: Effect of Pore Size on Catalyst Stability, Transport, and Adsorption

Herein, the alcoholysis of furfuryl alcohol in a series of SBA-15-pr-SO3H catalysts with different pore sizes is reported. Elemental analysis and NMR relaxation/diffusion methods show that changes in pore size have a significant effect on catalyst activity and durability. In particular, the decrease in catalyst activity after catalyst reuse is mainly due to carbonaceous deposition, whereas leaching of sulfonic acid groups is not significant. This effect is more pronounced in the largest-pore-size catalyst C3, which rapidly deactivates after one reaction cycle, whereas catalysts with a relatively medium and small average pore size (named, respectively, C2 and C1) deactivate after two reaction cycles and to a lesser extent. CHNS elemental analysis showed that C1 and C3 experience a similar amount of carbonaceous deposition, suggesting that the increased reusability of the small-pore-size catalyst can be attributed to the presence of SO3H groups mostly present on the external surface, as corroborated by results on pore clogging obtained by NMR relaxation measurements. The increased reusability of the C2 catalyst is attributed to a lower amount of humin being formed and, at the same time, reduced pore clogging, which helps to maintain accessible the internal pore space

Development and internal validation of a multifactorial risk prediction model for gallbladder cancer in a high-incidence country

Since 2006, Chile has been implementing a gallbladder cancer (GBC) prevention program based on prophylactic cholecystectomy for gallstone patients aged 35 to 49 years. The effectiveness of this prevention program has not yet been comprehensively evaluated. We conducted a retrospective study of 473 Chilean GBC patients and 2137 population-based controls to develop and internally validate three GBC risk prediction models. The Baseline Model accounted for gallstones while adjusting for sex and birth year. Enhanced Model I also included the non-genetic risk factors: body mass index, educational level, Mapuche surnames, number of children and family history of GBC. Enhanced Model II further included Mapuche ancestry and the genotype for rs17209837. Multiple Cox regression was applied to assess the predictive performance, quantified by the area under the precision-recall curve (AUC-PRC) and the number of cholecystectomies needed (NCN) to prevent one case of GBC at age 70 years. The AUC-PRC for the Baseline Model (0.44%, 95%CI 0.42-0.46) increased by 0.22 (95%CI 0.15-0.29) when non-genetic factors were included, and by 0.25 (95%CI 0.20-0.30) when incorporating non-genetic and genetic factors. The overall NCN for Chileans with gallstones (115, 95%CI 104-131) decreased to 92 (95%CI 60-128) for Chileans with a higher risk than the median according to Enhanced Model I, and to 80 (95%CI 59-110) according to Enhanced Model II. In conclusion, age, sex and gallstones are strong risk factors for GBC, but consideration of other non-genetic factors and individual genotype data improves risk prediction and may optimize allocation of financial resources and surgical capacity.Fil: Boekstegers, Felix. Ruprecht Karls Universitat Heidelberg; AlemaniaFil: Scherer, Dominique. Ruprecht Karls Universitat Heidelberg; AlemaniaFil: Barahona Ponce, Carol. Ruprecht Karls Universitat Heidelberg; AlemaniaFil: Marcelain, Katherine. Universidad de Chile; ChileFil: Gárate Calderón, Valentina. Universidad de Chile; ChileFil: Waldenberger, Melanie. No especifíca;Fil: Morales, Erik. Universidad Católica de Maule; ChileFil: Rojas, Armando. Universidad Católica de Maule; ChileFil: Munoz, César. Universidad Católica de Maule; ChileFil: Retamales, Javier. Instituto Nacional del Cáncer; ChileFil: de Toro, Gonzalo. Universidad Austral de Chile; ChileFil: Barajas, Olga. Universidad de Chile; ChileFil: Rivera, María Teresa. Hospital del Salvador; ChileFil: Cortés, Analía. Hospital del Salvador; ChileFil: Loader, Denisse. Hospital Padre Hurtado; ChileFil: Saavedra, Javiera. Hospital Padre Hurtado; ChileFil: Gutiérrez, Lorena. Hospital San Juan de Dios; ChileFil: Ortega, Alejandro. Hospital Regional; ChileFil: Bertrán, Maria Enriqueta. Hospital Base de Valdivia; ChileFil: Bartolotti, Leonardo. Hospital Base de Valdivia; ChileFil: Gabler, Fernando. Hospital Clínico San Borja Arriarán; ChileFil: Campos, Mónica. Hospital Clínico San Borja Arriarán; ChileFil: Alvarado, Juan. Hospital Regional de Concepción - Dr. Guillermo Grant Benavente; ChileFil: Moisán, Fabricio. Hospital Regional de Concepción - Dr. Guillermo Grant Benavente; ChileFil: Spencer, Loreto. Hospital Regional de Concepción - Dr. Guillermo Grant Benavente; ChileFil: Nervi, Bruno. No especifíca;Fil: Carvajal Hausdorf, Daniel. Universidad del Desarrollo; ChileFil: Losada, Héctor. Universidad de La Frontera; ChileFil: Almau, Mauricio. Hospital de Rancagua; ChileFil: Fernández, Plinio. Hospital de Rancagua; ChileFil: Olloquequi, Jordi. Universidad de Barcelona; EspañaFil: Fuentes Guajardo, Macarena. Universidad de Tarapacá; ChileFil: Gonzalez-Jose, Rolando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; ArgentinaFil: Bortolini, Maria Cátira. Universidade Federal do Rio Grande do Sul; BrasilFil: Acuña Alonzo, Victor. No especifíca;Fil: Gallo, Carla. Universidad Peruana Cayetano Heredia; PerúFil: Ruiz-Linares, Andres. Colegio Universitario de Londres; Reino UnidoFil: Rothhammer, Francisco. Universidad de Tarapacá; ChileFil: Lorenzo Bermejo, Justo. Ruprecht Karls Universitat Heidelberg; Alemani

Mendelian Randomization Analysis of the Relationship Between Native American Ancestry and Gallbladder Cancer Risk

Background A strong association between the proportion of Native American ancestry and the risk of gallbladder cancer (GBC) has been reported in observational studies. Chileans show the highest incidence of GBC worldwide, and the Mapuche are the largest Native American people in Chile. We set out to investigate the causal association between Native American Mapuche ancestry and GBC risk, and the possible mediating effects of gallstone disease and body mass index (BMI) on this association. Methods Markers of Mapuche ancestry were selected based on the informativeness for assignment measure and then used as instrumental variables in two-sample mendelian randomization (MR) analyses and complementary sensitivity analyses. Result We found evidence of a causal effect of Mapuche ancestry on GBC risk (inverse variance-weighted (IVW) risk increase of 0.8% for every 1% increase in Mapuche ancestry proportion, 95% CI 0.4% to 1.2%, p = 6.6×10-5). Mapuche ancestry was also causally linked to gallstone disease (IVW risk increase of 3.6% per 1% increase in Mapuche proportion, 95% CI 3.1% to 4.0%, p = 1.0×10-59), suggesting a mediating effect of gallstones in the relationship between Mapuche ancestry and GBC. In contrast, the proportion of Mapuche ancestry showed a negative causal effect on BMI (IVW estimate -0.006 kg/m2 per 1% increase in Mapuche proportion, 95% CI -0.009 to -0.003, p = 4.4×10-5). Conclusions The results presented here may have significant implications for GBC prevention and are important for future admixture mapping studies. Given that the association between Mapuche ancestry and GBC risk previously noted in observational studies appears to be causal, primary and secondary prevention strategies that take into account the individual proportion of Mapuche ancestry could be particularly efficient

Isolation of a High-Valent “Oxo-like” Manganese Porphyrin Complex Obtained from NaOCl Oxidation

We report the isolation and characterization of a high-valent manganese porphyrin complex which epoxidizes styrene both catalytically and stoicheiometrically

Dissolution of Metal Salts in Bis-(trifluoromethylsulfonyl)imide Based Ionic Liquids: Studying the Affinity of Metal Cations towards a “Weakly Coordinating” Anion

Despite the weakly coordinating ability of the bis(trifluoromethylsulfonyl)imide anion ([Tf2N]-) the corresponding ionic liquids (ILs) are able to dissolve relevant amounts of metal salts having the same anion, M[Tf2N]x. To better understand the metal dissolution process we evaluated the interaction ability of a set of metal cations (Y(III), Al(III), Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Li(I), and Na(I)) toward the [Tf2N]- anion measuring the relative aptitude to give the corresponding anionic monocharged complex, [M(Tf2N)x+1]- using the ESI-MS technique. UV-vis and NMR measurements were carried out to verify the consistence between the liquid and the gas phase. Density functional theory calculations have been used to identify the metal-containing species and determine their relative stability. An interesting correlation between interaction ability and chemical properties (Lewis acidity) was found

Eco-friendly functionalization of carbon-carbon double bonds through epoxidation and cycloaddition reactions

Dottorato di Ricerca in: Methodologies for the development of molecules of pharmacological interest, Ciclo XXI,a.a. 2007-2008Università della Calabri