Organic electrochemistry: Synthesis and functionalization of β-lactams in the twenty-first century

Organic electrochemistry is a technique that allows for the heterogeneous redox reactions avoiding both the use of stoichiometric amounts of redox reagents and the resulting formation of stoichiometric by-pro- ducts. In fact, the redox reagent in these reactions is the electron, which is naturally eco-friendly and pro- duces no side compounds. It is therefore quite obvious that electrochemistry can be classified as a “green” tech- nology. The use of this methodology in the synthesis of β-lactams is not a novelty, but the growing interest in this class of biologically active compounds, due to the dis- covery of new fields of application (after a moment of decrease in interest due to antibiotic resistance) has been a stimulus for the search for more efficient electro- chemical ways to synthesize and transform β-lactams. Thus, this review deals with the twenty-first-century applications of electroorganic technique to the chemistry of β-lactams, by analyzing first the syntheses classified by the type of reactions (cyclization, cycloaddition, etc.) and then by manipulating the β-lactam structure, using it as a synthon. Lastly, the importance of this technique is demonstrated by a study of a pilot plant scale reduction of a cephalosporanic acid derivative to a commercially important antibiotic

Reaction of Electrogenerated Cyanomethyl Anion with Cyclohexylisocyanate: Synthesis of N-(cyclohexylcarbamoyl) acetamide. An Unexpected Product

The contamination with water of the cathodic ACN-Et4NBF4 solution gave us the opportunity to investigate alkyl isocyanate reactivity toward electrogenerated anions. The cathodic reduction of a ACN-Et4NBF4 solution led to the formation of both hydroxide and cyanomethyl anions. The reaction of the catholyte with cyclohexylisocyanate led to the exclusive formation of acetamidated product, with no traces of cyanomethylated one. On the contrary, when reacting with benzaldehyde only the cyanomethylated was isolated. Considering that the acetamidated product of benzaldehyde is reported to be unstable (thus its formation cannot be excluded), various experiments were carried out in order to understand the anomalous reactivity of cyclohexylisocyanate. Moreover, computational analysis allowed to state the higher stability of acetamidated product with respect to the cyanomethylated one. The possibility of a concerted reaction, instead of acetamide anion formation prior to the reaction, is still an open question

An insight into the reactivity of the electrogenerated radical cation of caffeine

Controlled potential electrolyses of caffeine (CAF) were carried out at a Pt electrode in undried acetonitrile (ACN) and ACN-H2O and the products of the anodic oxidation were analyzed by HPLC-PDA-ESI-MS/MS. A higher current efficiency occurred in ACN-H2O, but an analogous chromatographic outline was found in both media, evidencing a reactive pathway of the electrogenerated radical cation CAF•+ with water, added or in trace, as nucleophile. No dimeric forms were evidenced, excluding any coupling reactions. Neither was 1,3,7-trimethyluric acid found, reported in the literature as the main oxidative route for CAF in water. Four main chromatographic peaks were evidenced, assigned to four proposed structures on the base of chromatographic and spectral data: a 4,5-diol derivative and an oxazolidin-2-one derivative were assigned as principal oxidation products, supporting a mechanism proposed in a previous work for the primary anodic oxidation of the methylxanthines olefinic C4 = C 5 bond. Two highly polar degradation products were also tentatively assigned, that seemed generating along two different pathways, one opening the imidazolic moiety and another one opening the purinic one

Impact of dealcoholization by osmotic distillation on metabolic profile, phenolic content, and antioxidant capacity of low alcoholic craft beers with different malt compositions

Beer antioxidants originate mainly from malts, classified as colored, caramel, and roasted, according to the malting process. This study aimed to characterize, in terms of phenolic antioxidants, three types of Pale Ale craft beers brewed using increasing percentage of dark malt (0, 5, and 15% Caraamber malt, called PA100, PA95, PA85, respectively) and to evaluate the impact of dealcoholization by osmotic distillation (OD) on the same antioxidants. All the alcoholic (PA, 6.2-6.8 vol %) and low alcoholic (LA-PA, 1 vol %) beers were analyzed by HPLC-ESI-MS/MS, total phenolic content (TPC), and antioxidant activity (AA): similar phenolic profiles were evidenced and 43 compounds identified or tentatively identified. Some differences were found among PA100, PA95, and PA85: PA85 was richer in free phenolic compounds (10.55 mg/L) and had a higher TPC (463.7 GAE mg/L) and AA (852.1 TE mg/L). LA-PA beers showed the same phenolic profile and similar TPC and AA compared to PA beers; however, there were some differences regarding LA-PA85 (5.91 mg/L). Dealcoholization by OD seemed to weakly affect the phenolic fraction. ESI-MS/MS infusion experiments evidenced oligosaccharides, small organic acids, and amino acids, whose presence was confirmed and quantitated by NMR: besides ethanol and other alcohols, weak to strong loss of low-molecular-weight metabolites was evidenced in LA-PA beers

Phytochemical analysis and In vitro antileukemic activity of alkaloid-enriched extracts from Vinca sardoa (Stearn) Pignatti

Vinca sardoa (Stearn) Pignatti, known as Sardinian periwinkle, is widely diffused in Sardinia (Italy). This species contains indole alkaloids, which are known to have a great variety of biological activities. This study investigated the antileukemic activity against a B lymphoblast cell line (SUP-B15) of V. sardoa alkaloid-rich extracts obtained from plants grown in Italy, in Iglesias (Sardinia) and Rome (Latium). All the extracts showed a good capacity to induce reductions in cell proliferation of up to 50% at the tested concentrations (1–15 g/mL). Moreover, none of the extracts showed cytotoxicity on normal cells at all the studied concentrations

Prevalence and predictor factors of respiratory impairment in a large cohort of patients with Myotonic Dystrophy type 1 (DM1): A retrospective, cross sectional study

Introduction: Respiratory complications are relevant in DM1, leading to a significantly increased morbidity and mortality risk in these patients; however, so far only few studies concerning respiratory function have been conducted in DM1 patients. We report a retrospective, multicenter, cross sectional study on a large cohort of DM1 patients widely characterized in the phenotype, to assess prevalence and identify predictors of restrictive respiratory syndrome. Methods: 268 DM1 subjects aged >18 years, who had recently performed spirometric tests were included; restrictive syndrome was diagnosed if forced vital capacity (FVC) <80% of predicted. This cut-off was used for statistical univariate and multivariate analysis. Results: 51.9% patients showed a restrictive syndrome, and half of them had indication to non-invasive ventilation (NIV), yet only 50% resulted compliant to NIV. CTG expansion size in leukocytes, clinical muscle severity, most functional parameters of respiratory muscle involvement, presence of cardiac conduction disturbances, pacemaker (PMK), exertion dyspnea, obstructive sleep apnea, and indication and compliance to NIV were all significantly associated with restrictive syndrome at the univariate analysis; in the multivariate model only the first two factors resulted independent predictors. Discussion: A high prevalence of restrictive syndrome in our DM1 cohort, mainly due to respiratory muscles weakness, was observed and documented; the severity of muscle impairment and the CTG expansion size confirmed to be independent predictors of respiratory restriction. Our data suggest that optimization of respiratory therapeutic management, particularly regarding launching of NIV, might help to reduce the rate of deaths due to respiratory complications in DM1

Desafíos y potencialidades del trabajo conjunto en territorio: reflexiones sobre el quehacer arqueológico y etnobiológico

El objetivo de esta ponencia es reflexionar acerca del quehacer arqueológico/etnobiológico en el marco de la realización de dos proyectos de extensión en el Partido de Punta Indio. Para ello, se presentan diversas experiencias de investigación/extensión realizadas de manera interdisciplinaria por el Laboratorio de Análisis Cerámico (LAC), el Laboratorio de Etnobotánica y Botánica Aplicada (LEBA), ambos pertenecientes a la Facultad de Ciencias Naturales y Museo (UNLP), y la comunidad de Punta del Indio (partido de Punta Indio, Buenos Aires, Argentina). El primero de los proyectos se denominó “Todas las voces del parque. Construcción participativa del patrimonio natural-cultural del Ecocentro del Parque Costero del Sur (Partido de Punta Indio, Buenos Aires)”, y fue acreditado y financiado por la Universidad Nacional de La Plata mediante su Convocatoria Ordinaria 2016 y desarrollado durante el 2017 y parte del 2018. Dicho proyecto buscó propiciar la participación comunitaria y la valoración del patrimonio natural-cultural de la Reserva de Biosfera Parque Costero del Sur (PCS), con el fin de plasmar múltiples voces en la generación colectiva de un guión museográfico para un Centro de Interpretación y el acondicionamiento de un Sendero de Interpretación. A partir del trabajo realizado en este proyecto, la visualización de un conjunto de problemáticas locales y la apertura del Centro Comunitario de Extensión Universitaria en los partidos de Magdalena y Punta Indio, el mismo equipo interdisciplinario decidió presentar en la Convocatoria Específica 2019 un nuevo proyecto denominado “De yuyos, plantas y saberes. Convivencias e intercambios en el Parque Costero del Sur”. Su objetivo es visibilizar y discutir las distintas valoraciones del patrimonio tangible e intangible vinculado al entorno vegetal por parte de los pobladores del PCS, a partir de la implementación de espacios de encuentro e intercambio de saberes. Las actividades propuestas para este proyecto se reformularon y adaptaron a la virtualidad debido a las condiciones que generó la pandemia, logrando en este contexto mantener y desarrollar diálogos e intercambios con la comunidad. A partir de la realización de los proyectos nos interesa reflexionar sobre los desafíos y potencialidades del trabajo conjunto con los pobladores del PCS. Estas experiencias nos permiten considerar que en los espacios de intercambio generados surgen nuevos conocimientos que pueden propiciar mejoras en la calidad de vida y la organización comunitaria, como también una nueva forma de hacer Extensión Universitaria en y desde el territorio.Universidad Nacional de La Plat

El conocimiento ambiental local en el ejercicio de la soberanía territorial y alimentaria : Saberes, paisaje e identidad en el Parque Costero del Sur (provincia de Buenos Aires)

Nuestro trabajo surge de considerar que la diversidad biológica y la diversidad cultural tienen una interdependencia evidente. El concepto central que manejaremos es el de diversidad biocultural, entendida como la diversidad de la vida en todas sus manifestaciones (biológica, cultural, lingüística) interrelacionadas en un complejo sistema socioecológico (Maffi, 2005). En este marco, las acciones humanas se expresan tanto en la selección de especies y variedades, como en la experimentación y ajuste de las mismas a las condiciones ambientales locales; por lo tanto, in fluyen de forma directa o indirecta sobre la biodiversidad. Estos aspectos, junto con otros en los cuales tienen lugar interacciones entre distintos agentes en las prácticas sociales cotidianas, generan un espacio particular, al que denominamos paisaje.Comisión de Defensa de la Soberanía (UNLP)Facultad de Ciencias Naturales y Muse

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations