15 research outputs found

    Sulfur in asymmetric synthesis

    Get PDF
    This thesis is divided into three chapters. The first chapter is a review of the literature methods utilised to date in the synthesis of non-racemic chiral sulfoxides, including resolution, stereospecific nucleophilic substitution at sulfur, asymmetric oxidation and enzymatic methods Also, this first chapter introduces briefly the palladium-catalysed allylic nucleophilic substitution reaction. It covers the nature of different factors which can influence on the enantiomeric excess. The second section deals with our approaches to the synthesis of potentially chelating sulfoxides of high enantiomeric purity and their subsequent application, mainly in the process of palladium-catalysed allylic nucleophilic substitution reactions as chiral ligands, but also their application as chiral auxiliaries in the synthesis of chiral α-hydroxy or α-amino ketones. This second chapter also deals with the design of a new class of chiral ammo-sulfides as ligand in the palladium-catalysed allylic nucleophilic substitution reaction. The most successful ligand synthesised enantiomerically pure N-(1,1-dimethylethyl)-N-(1S,2S)-2-[(1,1-dimethylethyl)thio]-1-methyl-2-phenylethyl-N-methylamine was applied successfully to the palladium-catalysed allylic nucleophilic substitution reaction, furnishing the product in up to 89% ee. The third part of this thesis deals with the experimental procedures undertaken in this work

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

    Get PDF
    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/)

    The reductive cleavage of cyclic aminol ethers to N,N-dialkylaminoderivatives: Modifications to the Eschweiler-Clarke procedure

    No full text
    The reductive cleavage of cyclic aminol ethers to give N-alkylamino- derivatives in very high yields can be achieved using chlorotrimethylsilane in the presence of sodium cyanoborohydride: in the case of cyclic aminol ethers derived from formaldehyde the Eschweiler-Clarke reaction can be carried out in formic acid heated under reflux in the absence of formaldehyde

    High Risk of Anal and Rectal Cancer in Patients With Anal and/or Perianal Crohn’s Disease

    No full text
    International audienceBackground & AimsLittle is known about the magnitude of the risk of anal and rectal cancer in patients with anal and/or perineal Crohn’s disease. We aimed to assess the risk of anal and rectal cancer in patients with Crohn’s perianal disease followed up in the Cancers Et Surrisque AssociĂ© aux Maladies Inflammatoires Intestinales En France (CESAME) cohort.MethodsWe collected data from 19,486 patients with inflammatory bowel disease (IBD) enrolled in the observational CESAME study in France, from May 2004 through June 2005; 14.9% of participants had past or current anal and/or perianal Crohn’s disease. Subjects were followed up for a median time of 35 months (interquartile range, 29–40 mo). To identify risk factors for anal cancer in the total CESAME population, we performed a case-control study in which participants were matched for age and sex.ResultsAmong the total IBD population, 8 patients developed anal cancer and 14 patients developed rectal cancer. In the subgroup of 2911 patients with past or current anal and/or perianal Crohn’s lesions at cohort entry, 2 developed anal squamous-cell carcinoma, 3 developed perianal fistula–related adenocarcinoma, and 6 developed rectal cancer. The corresponding incidence rates were 0.26 per 1000 patient-years for anal squamous-cell carcinoma, 0.38 per 1000 patient-years for perianal fistula–related adenocarcinoma, and 0.77 per 1000 patient-years for rectal cancer. Among the 16,575 patients with ulcerative colitis or Crohn’s disease without anal or perianal lesions, the incidence rate of anal cancer was 0.08 per 1000 patient-years and of rectal cancer was 0.21 per 1000 patient-years. Among factors tested by univariate conditional regression (IBD subtype, disease duration, exposure to immune-suppressive therapy, presence of past or current anal and/or perianal lesions), the presence of past or current anal and/or perianal lesions at cohort entry was the only factor significantly associated with development of anal cancer (odds ratio, 11.2; 95% CI, 1.18-551.51; P = .03).ConclusionsIn an analysis of data from the CESAME cohort in France, patients with anal and/or perianal Crohn’s disease have a high risk of anal cancer, including perianal fistula–related cancer, and a high risk of rectal cancer

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

    No full text
    International audienc
    corecore