Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Arylation et vinylation de nucléophiles azotés, oxygénés et carbonés par le cuivre (étude du mécanisme et récentes avancées)

Cette thèse, portant sur les arylations de nucléophiles catalysées par le cuivre, avait deux objectifs principaux : mieux appréhender les phénomènes mis en jeu au cours du processus catalytique d une part, étendre le champ d application des systèmes catalytiques au cuivre d autre part. Les efforts réalisés pour mieux comprendre le mécanisme mis en jeu ont permis d avancer des arguments relativement solides en faveur d une espèce catalytiquement active au degré d oxydation +1, et de proposer un mécanisme en accord avec l ensemble des faits expérimentaux acquis au cours de l étude : la réaction pourrait procéder via un mécanisme par addition oxydante élimination réductrice, analogue à celui rencontré dans le cas du Pd(0) et du Ni(0), isoélectroniques du Cu(I). En outre, la contribution du solvant et du ligand au succès de la réaction a été mieux cernée et une rationalisation de l ensemble des résultats nous a conduits à identifier un certain nombre de propriétés que doit présenter le ligand pour conférer au cuivre une forte activité catalytique. Plusieurs informations acquises au cours de l étude mécanistique ont été exploitées pour développer de nouvelles réactions la méthode d arylation des phénols par les catalysées par le cuivre: bromures aromatiques mise au point opère dans les conditions les plus douces connues à ce jour, ce qui rend le procédé particulièrement compétitif dans l optique d un développement industriel. la méthode de cyanuration des bromures aromatiques proposée procède via la formation in situ des iodures aromatiques correspondants et présente deux innovations majeures: l'utilisation de la cyanhydrine de l acétone en tant que source de cyanure ainsi que l emploi de quantités catalytiques de ligand. Cette méthode pourrait constituer une alternative pour la synthèse industrielle de nitriles aromatiques. le champ d'application de nos systèmes catalytiques au cuivre a en outre pu être étendu à la vinylation d'une large gamme d hétérocycles azotés et de phénols par des bromures vinyliques : N-alcèn-1-ylazoles et alcèn-1-ylaryléthers sont obtenus dans des conditions douces par rapport aux autres voies d accès existantes.The two main objectives of the present work dealing with copper-catalyzed arylations of nucleophilic compounds, were a better understanding of the mechanism occurring in the course of the catalytic process and a broadening of the scope of our copper-based catalysts. Efforts to better understand the underlying mechanism allowed us to provide a large set of evidence supporting a catalytic species in the + 1 oxydation state and to propose a mechanism in agreement with the experimental data obtained during our studies: the reaction would proceed via an oxidative addition reductive elimination mechanism, comparable with that occurring in reactions catalyzed by Pd(0) and Ni(0), both isoelectronic of Cu(I). The different studies carried out allowed to better understand the relative contribution of the solvent and the ligang to the reaction. Rational analysis of our whole set of data suggested that the ligand must exhibit some properties which are necessary to confer a strong activity to copper. Some informations obtained from the mechanistic study allowed us to develop new The devised coupling reaction of phenol copper-catalyzed reactions: and aryl bromides operates in milder conditions, making the process particularly attractive for an application at the industrial scale. The proposed cyanation method of aryl bromides proceeds via the formation of the corresponding aryl iodides and involves two main innovations: the use of acetone cyanohydrin as cyanating agent in copper-mediated cyanations and the use of catalytic amounts of ligands. This method would be an alternative for the industrial synthesis of The scope of our copper-based systems has been aryl nitriles. extended to the vinylation of a wide range of nitrogen heterocycles and phenols by vinyl bromides: N-(1-alkenyl)-azoles and alkenyl aryl ethers derivatives can thus be obtained in milder conditions than those described in the literatureMONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Iron-copper co-catalyzed process for Carbon-Carbon or Carbon-Heteroatom bonding

The present invention relates to a process for creating a Carbon-Carbon bond (C-C) or a Carbon-Heteroatom bond (C HE) by reacting a compound carrying a leaving group with a nucleophilic compound carrying a carbon atom or a heteroatom (HE) that can substitute for the leaving group, creating a C-C or C-HE bond, wherein the reaction takes place in the presence of an effective quantity of a catalytic system comprising iron and copper

Terpyridine–Ru Complexes Noncovalently Supported on Cobalt Magnetic Nanoparticles for Nitroarene Transfer Hydrogenation

International audienceThis work reports the preparation and characterization of active and recyclable supported catalysts involving molecular Ru−terpyridine complexes and their ability to promote the transfer hydrogenation of nitroarenes in 2-propanol. The system proposed is based on the design of original pyrene-tagged terpyridine ligands, either monomeric "1 tpy " (one pyrene tag for one terpyridine) or multivalent "5 tpy " (one pyrene tag for five terpyridines), able to interact with the graphene surface of commercially available cobalt magnetic nanoparticles (MNPs) through π-stacking interactions. The existence of noncovalent interactions between the pyrene-tagged terpyridines and the MNP surface at 20°C was assessed by fluorescence spectroscopy for the first time in 2-propanol, an organic medium. Interestingly, 1 tpy and 5 tpy were shown to be released upon temperature increase (80°C) while the association was restored upon temperature decrease (20°C). The reversibility of this phenomenon enabled to reach high activities in nitroarene transfer hydrogenation for the corresponding Ru complexes (catalytic species are free in refluxing 2propanol) and high recyclabilities (noncovalent interactions are restored upon cooling). It is noteworthy that the multivalent ligand 5 tpy displaying, as expected, the higher terpyridine loading (0.15 mmol of tpy/g of MNPs vs 0.03 mmol for 1 tpy) also gave rise to the Ru catalyst with the best recyclability (8 consecutive cycles with no loss of activity against 5 cycles for the catalyst based on the monomeric ligand 1 tpy). In both cases, the ruthenium leaching was found to be low and the expected aniline met the requirements of the pharmaceutical industry (<10 ppm Ru) from the third run

A Novel and Efficient Iron-Copper Co-Catalyzed Arylation of Nitrogen Nuceophiles

International audienceIn summary, we have presented here a first and original example of a cooperative bimetallic catalysis [Fe]-[Cu] allowing the N-arylation of various nitrogen nucleophiles from differently substituted aryl halides (X = I, Br, Cl

Synthesis, Characterization, and Functionalization of Tetrafunctional Double-Decker Siloxanes

International audienceNovel tetravinyl- and tetraallyl-substituted closed double-decker siloxanes (DDSQs) were synthesized and characterized, and their structures were elucidated by X-ray crystallographic analysis. Moreover, it was shown that peripheral olefins could successfully undergo hydrosilylation quantitatively. Such tetrafunctionalizable DDSQs (DDSQ-Vinyl4 and DDSQ-Allyl4) thus constitute promising building blocks for more complex inorganic–organic hybrid materials.SynopsisNovel tetravinyl- and tetraallyl-substituted closed double-decker siloxanes (DDSQs) were synthesized and peripheral olefins shown to successfully undergo hydrosilylation quantitatively. Such tetrafunctionalizable DDSQs thus constitute promising building blocks for more complex inorganic−organic hybrid materials

PROCÉDÉ DE PRÉPARATION DE LIGANDS DE TYPE PHOSPHINES BUTADIÉNIQUES, LEURS COMPLEXES AVEC LE CUIVRE, ET LEURS APPLICATIONS EN CATALYSE

La présente invention concerne un procédé de préparation de ligands de type phosphines butadiéniques, leurs applications, notamment comme ligands de métaux catalytiques utilisés dans les réactions de formation de liaisons carbone-carbone et cabone-hétéroatome

Well-defined cyclic silanol derivatives

International audienceCyclic silanol derivatives (CSDs), possessing siloxane rings consisting of T-unit silicon and oxygen atoms, are considered efficient precursors for the preparation of function materials in various application fields

UTILISATION DE COMPLEXES CUIVRE/PHOSPHINES CYCLOVINYLIQUES COMME CATALYSEURS D'ARYLATION

La présente invention concerne l'utilisation de composés de type phosphines cyclovinyliques sous forme de complexes avec le cuivre, comme catalyseurs de réactions de formation de liaisons carbone-carbone et cabone-hétéroatome. La présente invention concerne également les complexes du cuivre avec au moins une phosphine cyclovinylique, ainsi que le procédé de création de liaison carbone-carbone ou carbone-hétéroatome catalysé par un complexe cuivre/phosphine cyclovinylique