Enantioselective amination of 4-substituted pyrazolones catalyzed by oxindole-containing thioureas and by a recyclable linear-polymer-supported analogue in a continuous flow process

Producción CientíficaA highly efficient organocatalytic amination of 4-substituted pyrazolones with azodicarboxylates mediated by a novel quinine-derived thiourea with a 3,3-diaryl-oxindole scaffold is reported. This synthetic method furnished 4-amino-5-pyrazolones in high yields and with excellent enantioselectivities (up to 97:3 er) at room temperature in short reaction times. Moreover, a linear-polymer-supported bifunctional thiourea, synthesized by reacting a bifunctional aromatic monomer (biphenyl) with isatin in superacidic media and further derivatization, was proven to be also an efficient heterogeneous organocatalyst for this α-amination reaction. The practical value of this process was demonstrated by the use of the immobilized catalyst in recycling experiments, maintaining the activity without additional reactivation, and in flow processes, allowing the synthesis of 4-amino-pyrazolone derivatives in a gram scale with high yield and enantioselectivity.Agencia Estatal de Investigación- FEDER-UE (PID2020-118547GB-I00)Junta de Castilla y León (VA224P20

Commentary: Attentional control and the self: The Self-Attention Network (SAN)

The Self-Attention Network (SAN) model (Humphreys & Sui, 2015) is a recent neurocognitive model to account for self-biases in the allocation of attention. It emerges from psychological, neuropsychological, and neuroimaging evidence on three phenomena: own-name effects, own-face effects, and self-biases in associative matching. Specifically, it posits that our responses to self-related stimuli are differentially subserved by a network comprising three nodes: (i) a general-purpose top-down attentional control network which involves the dorsolateral prefrontal cortex and the intra-parietal sulcus; (ii) a self-representation hub located in the ventromedial prefrontal cortex (vmPFC), and (iii) a bottom-up orientating mechanism which depends on the posterior superior temporal sulcus (pSTS). Accordingly, attentional shifts upon hearing our own name or seeing our own face would rely on interactions among such nodes, mimicking perceptual-saliency effects and determining emergent behavior.Though attractive, this proposal features two major caveats. First, the evidence for own-name effects is inconsistent and undermined by psycholinguistic confounds. Second, the node proposed to subserve self-specific information lacks neurofunctional specificity. Here we discuss both issues and advance relevant methodological recommendations.Fil: García, Adolfo Martín. Universidad Nacional de Cuyo. Facultad de Educación Elemental y Especial; Argentina. Universidad Diego Portales; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; ArgentinaFil: Huepe, David. Universidad Diego Portales; ChileFil: Martínez Pernía, David. Universidad Diego Portales; ChileFil: Morales, Juan P.. Universidad Diego Portales; ChileFil: Huepe, Daniela. Universidad Diego Portales; ChileFil: Hurtado, Esteban. Universidad Diego Portales; ChileFil: Calvo Garbarino, Noelia Belén. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Ibanez Barassi, Agustin Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Universidad Nacional de Cuyo. Facultad de Educación Elemental y Especial; Argentina. Universidad Diego Portales; Chile. Centre of Excellence in Cognition and its Disorders; Australi

Porous organic polymers containing active metal centers for Suzuki–Miyaura heterocoupling reactions

Producción CientíficaA new generation of confined palladium(II) catalysts covalently attached inside of porous organic polymers (POPs) has been attained. The synthetic approach employed was straightforward, and there was no prerequisite for making any modification of the precursor polymer. First, POP-based catalytic supports were obtained by reacting one symmetric trifunctional aromatic monomer (1,3,5-triphenylbenzene) with two ketones having electron-withdrawing groups (4,5-diazafluoren-9-one, DAFO, and isatin) in superacidic media. The homopolymers and copolymers were made using stoichiometric ratios between the functional groups, and they were obtained with quantitative yields after the optimization of reaction conditions. Moreover, the number of chelating groups (bipyridine moieties) available to bind Pd(II) ions to the catalyst supports was modified using different DAFO/isatin ratios. The resulting amorphous polymers and copolymers showed high thermal stability, above 500 °C, and moderate–high specific surface areas (from 760 to 935 m2 g–1), with high microporosity contribution (from 64 to 77%). Next, POP-supported Pd(II) catalysts were obtained by simple immersion of the catalyst supports in a palladium(II) acetate solution, observing that the metal content was similar to that theoretically expected according to the amount of bipyridine groups present. The catalytic activity of these heterogeneous catalysts was explored for the synthesis of biphenyl and terphenyl compounds, via the Suzuki–Miyaura cross-coupling reaction using a green solvent (ethanol/water), low palladium loads, and aerobic conditions. The findings showed excellent catalytic activity with quantitative product yields. Additionally, the recyclability of the catalysts, by simply washing it with ethanol, was excellent, with a sp2–sp2 coupling yield higher than 95% after five cycles of use. Finally, the feasibility of these catalysts to be employed in tangible organic reactions was assessed. Thus, the synthesis of a bulky compound, 4,4′-dimethoxy-5′-tert-butyl-m-terphenylene, which is a precursor of a thermal rearrangement monomer, was scaled-up to 2 g, with high conversion and 96% yield of the pure product.Agencia Estatal de Investigación (projects PID2019-109403RB-C22, MAT2016-76413-C2-R2, CTQ2017-89217- P and MAT2016-76413-C2-R1)Junta de Castilla y León (project VA038G18

Pyrrolidine-based catalytic microporous polymers in sustainable C=N and C=C bond formation via iminium and enamine activation

Producción CientíficaA new set of catalytic materials having a pyrrolidine moiety confined in microporous organic polymer networks (POPs) has been attained. These catalytic polymers have been prepared by a straightforward synthesis starting from microporous polymer networks made from isatin (or a mixture of isatin and trifluoroacetophenone) and 1,3,5-triphenylbenzene. The polymers efficiently catalyzed the formation of nitrones under very mild and sustainable conditions using green solvents through an iminium ion activation mechanism. The reactions are scalable, and polymers are easily recycled. Special attention has been paid to understanding all the factors that could affect the efficiency of the confined catalysts. The electronic and conformational characteristics of the pyrrolidine moiety attached to the porous polymers, as well as other features that could affect the transport through the network, such as molecular volume and shape of reactants and products, and even hydrophilic or hydrophobic properties, have been systematically evaluated. In addition, the heterogeneous polymers are also useful in Cdouble bondC bond formation through both iminium ion and enamine activation.Gobierno de España (Agencia Estatal de Investigación) - (Projects CTQ2016-78779-R, PID2019-109403RB-C22, RTI2018-096328-B-I00, CTQ2017-89217-P and PID2020-118547GBI00)Junta de Castilla y León, Unión Europea y Fondo Europeo de Desarrollo Regional (FEDER) - (Project VA224P20)

Polymer materials derived from the SEAr reaction for gas separation applications

Producción CientíficaA set of linear polymers were synthesized utilizing an electrophilic aromatic substitution reaction (SEAr) between biphenyl and ketone containing electron-withdrawing groups (isatin, IS; N-methylisatin, MeIS; and 4,5-diazafluoren-9-one, DF). Optimization of the polycondensation reaction was made to obtain high molecular weight products when using DF, which has not previously been used for linear polymer synthesis. Due to the absence of chemically labile units, these polymers exhibited excellent chemical and thermal stability. Linear SEAr polymers were blended with porous polymer networks derived from IS and MeIS, and both neat/mixed materials were tested as membranes for gas separation. The gas separation properties of both pristine polymers and mixed matrix membranes were good, showing some polymer membrane CO2 permeability values higher than 200 barrer

Hepatitis C virus intrinsic molecular determinants may contribute to the development of cholestatic hepatitis after liver transplantation

Cholestatic hepatitis C (CHC) is a severe form of hepatitis C virus (HCV) infection recurrence that leads to high graft loss rates early after liver transplantation (LT). To investigate the pathogenic mechanisms of CHC, we analysed HCV quasispecies in CHC patients compared to a control group (mild hepatitis C recurrence) by deep pyrosequencing. At the time of LT, NS5B quasispecies complexity was similar between the two groups but, after LT, it decreased more sharply in CHC patients than in the control group. Interestingly, the major variant before LT propagated efficiently and remained as the dominant sequence after LT in 62% of CHC patients versus 11% of controls (P=0.031). Sequence analysis of the complete nonstructural region in a limited number of patients revealed a potential 12 aa signature specific to the CHC group. These data suggest that intrinsic molecular determinants in the circulating HCV quasispecies may provide a fitness advantage, contributing to the development of CHC

Efficacy of Robot-Assisted Gait Therapy Compared to Conventional Therapy or Treadmill Training in Children with Cerebral Palsy: A Systematic Review with Meta-Analysis

Background: Motor, gait and balance disorders reduce functional capabilities for activities of daily living in children with cerebral palsy (CP). Robot-assisted gait therapy (RAGT) is being used to complement conventional therapy (CT) or treadmill therapy (TT) in CP rehabilitation. The aim of this systematic review is to assess the effect of RAGT on gait, balance and functional independence in CP children, in comparison to CT or TT. Methods: We have conducted a systematic review with meta-analysis. A search in PubMed Medline, Web of Science, Scopus, CINAHL, PEDro and SciELO has been conducted for articles published until October 2022. Controlled clinical trials (CCT), in which RAGT was compared to TT or CT and assessed gait speed, step and stride length, width step, walking distance, cadence, standing ability, walking, running and jumping ability, gross motor function and functional independence in children with CP, have been included. Methodological quality was assessed with the PEDro scale and the pooled effect was calculated with Cohen’s Standardized Mean Difference (SMD) and its 95% Confidence Interval (95% CI). Results: A total of 15 CCTs have been included, providing data from 413 participants, with an averaged methodological quality of 5.73 ± 1.1 points in PEDro. The main findings of this review are that RAGT shows better results than CT in the post-intervention assessment for gait speed (SMD 0.56; 95% CI 0.03 to 1.1), walking distance (SMD 2; 95% CI 0.36 to 3.65) and walking, running and jumping ability (SMD 0.63; 95% CI 0.12 to 1.14). Conclusions: This study shows that the effect of RAGT is superior to CT on gait speed, walking distance and walking, running and jumping ability in post-intervention, although no differences were found between RAGT and TT or CT for the remaining variables