76 research outputs found
Imidazolium-urea Low Transition Temperature Mixtures for the UHP-promoted oxidation of boron compounds
Different carboxy-functionalized imidazolium salts have been considered as components of low transition temperature mixtures (LTTMs) in combination with urea. Among them, a novel LTTM based on 1-(methoxycarbonyl)methyl-3-methylimidazolium chloride and urea has been prepared and characterized by differential scanning calorimetry throughout its entire composition range. This LTTM has been employed for the oxidation of boron reagents using urea-hydrogen peroxide adduct (UHP) as the oxidizer, thus avoiding the use of aqueous H2O2, which is dangerous to handle. This metal-free protocol affords the corresponding alcohols in good to quantitative yields in up to 5 mmol scale without the need of further purification. The broad composition range of the LTTM allows for the reaction to be carried out up to three consecutive times with a single imidazolium salt loading offering remarkable sustainability with an E-factor of 7.9, which can be reduced to 3.2 by the threefold reuse of the system.This work was financially supported by the University of Alicante (VIGROB-316, UAUSTI20-16), the Spanish Ministerio de Ciencia, Innovación y Universidades (PGC2018-096616-B-I00), and the Generalitat Valenciana (AICO/2021/013). M.M. thanks the ISO (University of Alicante) for a predoctoral contract
Iron-Based Imidazolium Salt as Dual Lewis Acid and Redox Catalyst for the Aerobic Synthesis of Quinazolines
A low transition temperature mixture formed with 1-butyl-3-(methoxycarbonylmethyl)imidazolium chloride and iron(III) chloride has proven to be an efficient catalyst for the synthesis of quinazolines following a sequence of condensation-cyclization-oxidation reactions. The protocol is simple and effective for coupling 2-acylanilines and benzylamines to form nitrogen containing heterocycles with moderate to excellent yields (up to 93%), being possible to perform the reaction in preparative scale. The functionalized imidazolium salt is crucial for the activation of the reagents under solvent-free conditions, and the presence of iron in the catalyst mediates the oxidation step with atmospheric oxygen. These features make the presented procedure better, from an environmental point of view, than other processes previously described. For this comparison, different "green" metrics have been used, such as atom economy, stoichiometric factor, reaction mass efficiency, E-factor and EcoScale.This work was financially supported by the University of Alicante (VIGROB-316, UADIF20-106, UAUSTI21-15), the Spanish Ministerio de Ciencia, Innovación y Universidades (PGC2018-096616-B-I00), the Spanish Ministerio de Ciencia e Innovación (PID2021-127332NB-I00), and the Generalitat Valenciana (AICO/2021/013). M.M. thanks the ISO (University of Alicante) for a predoctoral contract
Nickel-Imidazolium Low Transition Temperature Mixtures with Lewis-Acidic Character
Low transition temperature mixtures (LTTMs) are a new generation of solvents that have found extensive application in organic synthesis. The interactions between the components often generate highly activated, catalytically active species, thus opening the possibility of using LTTMs as catalysts, rather than solvents. In this work, we introduce a nickel-based imidazolium LTTM, study its thermal behavior and explore its catalytic activity in the solvent-free allylation of heterocycles with allylic alcohols. This system is effective in this reaction, affording the corresponding products in excellent yield without the need for additional purifications, thus resulting in a very environmentally friendly protocol.This research was funded by Ministerio de Ciencia e Innovación (grant number PID2021-127332NB-I00), Generalitat Valenciana (grant numbers AICO/2021/013 and IDIFEDER/2021/013) and University of Alicante (grant numbers VIGROB-316, UAUSTI22-23, UADIF22-104)
Compulsive Social Behavior Emerges after Selective Ablation of Striatal Cholinergic Interneurons
The mechanisms underlying social dysfunction in neuropsychiatric conditions like obsessive-compulsive disorder (OCD) and Tourette syndrome (TS) remain uncertain. Dysfunctions in basal ganglia, including reduced number of striatal cholinergic interneurons (SCIN), have been involved in their pathophysiology. To explore the role of SCIN in relation to perseverative behaviors we characterized a new transgenic mouse model in which inducible ablation of SCIN is achieved with high efficiency in a cell-type and region specific manner. Mice were subjected to an extensive behavioral testing including assessment of social behaviors and corticostriatal functional connectivity was evaluated in vivo. Selective SCIN ablation leads to altered social interactions together with exacerbated spontaneously emitted repetitive behaviors. Lesioned mice showed normal motor coordination, balance, and general locomotion. Interestingly, only environmentally-driven, but not self-directed, repetitive behaviors are exacerbated in lesioned mice. Remarkably, in mice with SCIN ablation the normal pattern of social exploration is continuously replayed. The emerging pattern of social interactions is highly predictable and invariant across time. In vivo electrophysiological recordings indicate that SCIN ablation results in an increase of the functional connectivity between different cortical areas and the motor, but not associative, region of the striatum. Our results identify a role of SCIN in suppressing perseverative behaviors including social related ones. In sum, SCIN ablation in mice leads to exacerbated ritualistic-like behaviors that impact on social performance providing a link between SCIN dysfunction and social impairments present in psychiatric disorders.Fil: Martos Schott, Yanina Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Braz, Bárbara Yael. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Beccaria, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Murer, Mario Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Belforte, Juan Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; Argentin
1,3-Bis(3-carboxypropyl)-1H-imidazole
The use of γ-aminobutyric acid (GABA) as a starting material in a multicomponent reaction has resulted in the preparation of the zwitterionic 1,3-bis(3-carboxypropyl)imidazole (bcpim). The synthesis of this imidazole derivative in a one-pot procedure with stoichiometric amounts of the corresponding reagents (formaldehyde, glyoxal, and GABA in a 1:1:2 ratio) has resulted in a straightforward and effective methodology, meaning a significant improvement from a sustainable point of view.This research was funded by Ministerio de Ciencia, Innovación y Universidades (grant number PGC2018-096616-B-I00), Ministerio de Ciencia e Innovación (PID2021-127332NB-I00), Generalitat Valenciana (grant number AICO/2021/013), and the University of Alicante (grant number VIGROB-316)
DES-Type Interactions To Promote Solvent-Free and Metal-Free Reactions between Nitrogen-Containing Heterocycles and Allylic Alcohols
Nitrogen-containing heterocycles are of great interest to organic chemists since they are present in a wide array of bioactive molecules. The use of allylic alcohols to carry out the allylation of heterocycles has been described as a sustainable alternative for this type of functionalization. Among the plethora of methodologies described, the use of metals, solvents, or hazardous reagents is ubiquitous. The protocol described in this work has provided a solventless and metal-free alternative, being mediated by the easy-to-synthesise and reusable 1,3-bis(carboxymethyl)imidazolium chloride. The protocol has resulted compatible with several nitrogen-containing heterocycles (i.e. indole, pyrazole, triazole, tetrazole, carbazole, indazole, and benzotriazole) and allylic alcohols, providing the allylated-heterocycles with up to quantitative yield, being possible to perform the reaction in preparative scale.Based on various green metrics (atom economy, stoichiometric factor, reaction mass efficiency, materials recovery parameter, E-factor, and EcoScale), the overall greenness significance of the methodology has been established.This work was financially supported by the University of Alicante (VIGROB-316, UADIF20-106, UAUSTI21-15), the Spanish Ministerio de Ciencia, Innovación y Universidades (PGC2018-096616-B-I00), the Spanish Ministerio de Ciencia e Innovación (PID2021-127332NB-I00) and the Generalitat Valenciana (AICO/2021/013). MM thanks the ISO (University of Alicante) for a predoctoral contract
Hydrological changes around Los Tollos shallow lake (Cadiz-Seville, Spain) in the context of its restoration
Se realiza una descripción sintética de la hidrogeología de la masa de
agua subterránea (M.A.Sb.) de Lebrija (Sevilla-Cádiz), y en particular del sector
meridional de la misma donde se asienta la laguna de Los Tollos. El establecimiento
de una explotación minera de arcillas fibrosas en el entorno
de la laguna, así como las extracciones de aguas subterráneas para facilitar
las labores mineras y para el abastecimiento urbano y el uso agrícola, produjeron
impactos importantes sobre el funcionamiento hidrogeológico natural,
principalmente caídas en los niveles piezométricos y migración de
aguas salinas. La evolución hidrogeológica en el entorno de la laguna tras
el cese de las actividades impactantes, indica una recuperación general de
niveles en todos los subsistemas, y una tendencia a la igualación de los mismos.
Esta recuperación, aunque positiva, es aún insuficiente de cara a la restauración
ambiental que persigue el proyecto en que se enmarca este trabajoA brief description of the hydrogeology of the GroundWater Body (GWB)
of Lebrija (Cadiz-Seville) has been made, especially of its southern part,
where Los Tollos shallow lake is located.An open pit mine of fibrous clays in
the vicinity of the lake, as well as groundwater withdrawals to facilitate the
mining and supply for urban and agricultural use, produced significant impacts
on the natural hydrogeological functioning of the shallow lake. Such
impacts where mainly a general lowering of the water table in the area and
migration of saline water.The hydrogeological evolution of the area, after the
ending of the environmental pressures, shows both a general recovery in all
the aquifers of the GWB and a tendency for equilibrium. This recovery, although
positive, is still not enough to achieve a complete environmental
restoration of the lake,which is the main objective of the project in which this
work is frame
Photochemical Access to Substituted β-Lactams and β-Lactones via the Zimmerman-O\u27Connell-Griffin Rearrangement
A photomediated protocol giving facile access to substituted β-lactam and β-lactones is presented. The method realizes, for the first time, the use of the Zimmerman-O\u27Connell-Griffin (ZOG) rearrangement in [2 + 2] cycloaddition. Products are obtained in high yield with excellent diastereoselectivity under visible light irradiation and under mild reaction conditions
Lactic acid bacteria from artisanal tanneries: isolation and evaluation of acidifyng ability
The tanning process allows to transform animal skin in stable and non-putrescible products namely leather. This process consists in various steps such as washing skins, liming, depilation, lime removal by washing, purging and tanning. During purging, the skins are immersed in a cereal mix which is let to ferment for 12-24 h at room temperature (18ºC-37°C). After this period, the pH decreased to 4.5-5.0, a condition that is required for the final steps. Under these homemade working conditions, the cereal fermentation is quite variable and affects the quality of the leather. The objective of this study was to isolate lactic acid bacteria (LAB) from the fermented cereal mixture in artisanal tanneries and to evaluate in vitro the acidifying activity of the strains. This is the first step for the formulation of a starter culture for tanneries to normalize the process.Samples of fermented cereals were taken from a tannery located in San Pedro de Colalao, Tucumán, Argentina, and colonies were isolated in MRS agar medium. The primary identification of the isolates included Gram stain, microscopic observations and catalase reaction. Gram positive, catalase negative strains (23) were cultured in a CERELA medium formulated for the production of lactic ferment and incubated at 18°C and 37°C for 24 h. At intervals, pH and titratable acidity (TTA) were determined. In most samples, a prevalence of cocci (95%) respect to bacilli was observed. The total isolated strains (56), 23 strains were Gram (+) and catalase (negative) which were selected. At 37 °C, most strains (21) acidified the culture medium within the first 8-h reaching a final pH ≤ 5.0 and a TTA ≥100ºD. At 18 °C, all strains showed a lower growth; however, the decrease in pH was 4.5-5.0 and the acidity developed (100-140ºD) after 24 hours of fermentation were similar to values obtained at 37°C. The best acid-producer strains were identified as Enterococcus faecium CRL 1943 and Leuconostoc citreum CRL 1945 by phenotypic and genotypic techniques. Currently, studies are being conducted to formulate a lactic inoculant on the basis of these strains and their metabolites for artisanal tanning.Fil: Correa Deza, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Gerez, Carla Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Martos, Gladys Irma. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Nuñez, Martha Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Fiori, Mario. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Font, Graciela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaXI Congreso Argentino de Microbiología GeneralCórdobaArgentinaSociedad Argentina de Microbiología Genera
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