Iron(III) Triflimide as a catalytic substitute for gold(I) in hydroaddition reactions to unsaturated carbon-carbon bonds

[EN] In this work it is shown that iron(III) and gold(I) triflimide efficiently catalyze the hydroaddition of a wide array of nucleophiles including water, alcohols, thiols, amines, alkynes, and alkenes to multiple CC bonds. The study of the catalytic activity and selectivity of iron(III), gold(I), and BrOnsted triflimides has unveiled that iron(III) triflimide [Fe(NTf2)3] is a robust catalyst under heating conditions, whereas gold(I) triflimide, even stabilized by PPh3, readily decomposes at 80 degrees C and releases triflimidic acid (HNTf2) that can catalyze the corresponding reaction, as shown by in situ 19F, 15N, and 31PNMR spectroscopy. The results presented here demonstrate that each of the two catalyst types has weaknesses and strengths and complement each other. Iron(III) triflimide can act as a substitute of gold(I) triflimide as a catalyst for hydroaddition reactions to unsaturated carbon-carbon bonds.The work has been supported by Consolider-Ingenio 2010 (proyecto MULTICAT). J.R.C.A. thanks MCIINN for the concession of a pre-doctoral FPU fellowship. A. L. P. thanks ITQ for financial support.Cabrero Antonino, JR.; Leyva Perez, A.; Corma Canós, A. (2013). Iron(III) Triflimide as a catalytic substitute for gold(I) in hydroaddition reactions to unsaturated carbon-carbon bonds. Chemistry - A European Journal. 19(26):8627-8633. https://doi.org/10.1002/chem.201300386S862786331926Brenzovich, W. E. (2012). Gold in der Totalsynthese: Alkine als Carbonylersatz. Angewandte Chemie, 124(36), 9063-9065. doi:10.1002/ange.201204598Brenzovich, W. E. (2012). Gold in Total Synthesis: Alkynes as Carbonyl Surrogates. Angewandte Chemie International Edition, 51(36), 8933-8935. doi:10.1002/anie.201204598Oliver-Meseguer, J., Cabrero-Antonino, J. 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Homogeneous Gold Catalysis Beyond Assumptions and Proposals-Characterized Intermediates. Angewandte Chemie International Edition, 49(31), 5232-5241. doi:10.1002/anie.200907078Beaumont, S. K., Kyriakou, G., & Lambert, R. M. (2010). Identity of the Active Site in Gold Nanoparticle-Catalyzed Sonogashira Coupling of Phenylacetylene and Iodobenzene. Journal of the American Chemical Society, 132(35), 12246-12248. doi:10.1021/ja1063179Marion, N., Ramón, R. S., & Nolan, S. P. (2009). [(NHC)AuI]-Catalyzed Acid-Free Alkyne Hydration at Part-per-Million Catalyst Loadings. Journal of the American Chemical Society, 131(2), 448-449. doi:10.1021/ja809403eGrirrane, A., Corma, A., & Garcia, H. (2008). Gold-Catalyzed Synthesis of Aromatic Azo Compounds from Anilines and Nitroaromatics. Science, 322(5908), 1661-1664. doi:10.1126/science.1166401Corma, A., & Garcia, H. (2008). Supported gold nanoparticles as catalysts for organic reactions. Chemical Society Reviews, 37(9), 2096. doi:10.1039/b707314nGonzález-Arellano, C., Abad, A., Corma, A., García, H., Iglesias, M., & Sánchez, F. (2007). Catalysis by Gold(I) and Gold(III): A Parallelism between Homo- and Heterogeneous Catalysts for Copper-Free Sonogashira Cross-Coupling Reactions. Angewandte Chemie, 119(9), 1558-1560. doi:10.1002/ange.200604746González-Arellano, C., Abad, A., Corma, A., García, H., Iglesias, M., & Sánchez, F. (2007). Catalysis by Gold(I) and Gold(III): A Parallelism between Homo- and Heterogeneous Catalysts for Copper-Free Sonogashira Cross-Coupling Reactions. Angewandte Chemie International Edition, 46(9), 1536-1538. doi:10.1002/anie.200604746Hashmi, A. S. K. (2007). Gold-Catalyzed Organic Reactions. Chemical Reviews, 107(7), 3180-3211. doi:10.1021/cr000436xWienhöfer, G., Westerhaus, F. A., Jagadeesh, R. V., Junge, K., Junge, H., & Beller, M. (2012). Selective iron-catalyzed transfer hydrogenation of terminal alkynes. 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Chemical Communications, 47(17), 4849. doi:10.1039/c0cc05733aZhou, S., Fleischer, S., Junge, K., Das, S., Addis, D., & Beller, M. (2010). Asymmetrische Synthese von Aminen: eine allgemeine und effiziente eisenkatalysierte enantioselektive Transferhydrierung von Iminen. Angewandte Chemie, 122(44), 8298-8302. doi:10.1002/ange.201002456Zhou, S., Fleischer, S., Junge, K., Das, S., Addis, D., & Beller, M. (2010). Enantioselective Synthesis of Amines: General, Efficient Iron-Catalyzed Asymmetric Transfer Hydrogenation of Imines. Angewandte Chemie International Edition, 49(44), 8121-8125. doi:10.1002/anie.201002456Cabrero-Antonino, J. R., Leyva-Pérez, A., & Corma, A. (2010). Iron-Catalysed Regio- and Stereoselective Head-to-Tail Dimerisation of Styrenes. Advanced Synthesis & Catalysis, 352(10), 1571-1576. doi:10.1002/adsc.201000096Zhou, S., Junge, K., Addis, D., Das, S., & Beller, M. (2009). A Convenient and General Iron-Catalyzed Reduction of Amides to Amines. 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Iron-Catalyzed Reactions in Organic Synthesis. Chemical Reviews, 104(12), 6217-6254. doi:10.1021/cr040664hFürstner, A., Leitner, A., Méndez, M., & Krause, H. (2002). Iron-Catalyzed Cross-Coupling Reactions. Journal of the American Chemical Society, 124(46), 13856-13863. doi:10.1021/ja027190tKischel, J., Jovel, I., Mertins, K., Zapf, A., & Beller, M. (2006). A Convenient FeCl3-Catalyzed Hydroarylation of Styrenes. Organic Letters, 8(1), 19-22. doi:10.1021/ol0523143Patil, N. T., Kavthe, R. D., & Shinde, V. S. (2012). Transition metal-catalyzed addition of C-, N- and O-nucleophiles to unactivated C–C multiple bonds. Tetrahedron, 68(39), 8079-8146. doi:10.1016/j.tet.2012.05.125Beller, M., Seayad, J., Tillack, A., & Jiao, H. (2004). Katalytische Markownikow- und Anti-Markownikow-Funktionalisierung von Alkenen und Alkinen. Angewandte Chemie, 116(26), 3448-3479. doi:10.1002/ange.200300616Beller, M., Seayad, J., Tillack, A., & Jiao, H. (2004). Catalytic Markovnikov and anti-Markovnikov Functionalization of Alkenes and Alkynes: Recent Developments and Trends. Angewandte Chemie International Edition, 43(26), 3368-3398. doi:10.1002/anie.200300616Hashmi, A. S. K. (2007). Homogeneous gold catalysis: The role of protons. Catalysis Today, 122(3-4), 211-214. doi:10.1016/j.cattod.2006.10.006Hashmi, A. S. K., Schwarz, L., Rubenbauer, P., & Blanco, M. C. (2006). The Condensation of Carbonyl Compounds with Electron-Rich Arenes: Mercury, Thallium, Gold or a Proton? Advanced Synthesis & Catalysis, 348(6), 705-708. doi:10.1002/adsc.200505464Williamson, K. S., & Yoon, T. P. (2012). Iron Catalyzed Asymmetric Oxyamination of Olefins. Journal of the American Chemical Society, 134(30), 12370-12373. doi:10.1021/ja3046684Hashmi, A. S. K., Braun, I., Nösel, P., Schädlich, J., Wieteck, M., Rudolph, M., & Rominger, F. (2012). Eine einfache Gold-katalysierte Synthese von Benzofulvenen -gem-diaurierte Spezies als «Instant-Dual-Activation»-Präkatalysatoren. Angewandte Chemie, 124(18), 4532-4536. doi:10.1002/ange.201109183Hashmi, A. S. K., Braun, I., Nösel, P., Schädlich, J., Wieteck, M., Rudolph, M., & Rominger, F. (2012). Simple Gold-Catalyzed Synthesis of Benzofulvenes-gem-Diaurated Species as «Instant Dual-Activation» Precatalysts. Angewandte Chemie International Edition, 51(18), 4456-4460. doi:10.1002/anie.201109183Antoniotti, S., Dalla, V., & Duñach, E. (2010). Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate - der Effekt eines stark delokalisierten Gegenions. Angewandte Chemie, 122(43), 8032-8060. doi:10.1002/ange.200906407Antoniotti, S., Dalla, V., & Duñach, E. (2010). Metal Triflimidates: Better than Metal Triflates as Catalysts in Organic Synthesis-The Effect of a Highly Delocalized Counteranion. Angewandte Chemie International Edition, 49(43), 7860-7888. doi:10.1002/anie.200906407Ricard, L., & Gagosz, F. (2007). Synthesis and Reactivity of Air-Stable N-Heterocyclic Carbene Gold(I) Bis(trifluoromethanesulfonyl)imidate Complexes. Organometallics, 26(19), 4704-4707. doi:10.1021/om7006002Dang, T. T., Boeck, F., & Hintermann, L. (2011). Hidden Brønsted Acid Catalysis: Pathways of Accidental or Deliberate Generation of Triflic Acid from Metal Triflates. The Journal of Organic Chemistry, 76(22), 9353-9361. doi:10.1021/jo201631xTaylor, J. G., Adrio, L. A., & Hii, K. K. (Mimi). (2010). Hydroamination reactions by metal triflates: Brønsted acid vs. metal catalysis? Dalton Trans., 39(5), 1171-1175. doi:10.1039/b918970jKovács, G., Lledós, A., & Ujaque, G. (2010). Mechanistic Comparison of Acid- and Gold(I)-Catalyzed Nucleophilic Addition Reactions to Olefins. Organometallics, 29(22), 5919-5926. doi:10.1021/om1007192Li, Z., Zhang, J., Brouwer, C., Yang, C.-G., Reich, N. W., & He, C. (2006). Brønsted Acid Catalyzed Addition of Phenols, Carboxylic Acids, and Tosylamides to Simple Olefins. Organic Letters, 8(19), 4175-4178. doi:10.1021/ol0610035(s. f.). doi:10.1021/ol061174Wabnitz, T. C., Yu, J.-Q., & Spencer, J. B. (2004). Evidence That Protons Can Be the Active Catalysts in Lewis Acid Mediated Hetero-Michael Addition Reactions. Chemistry - A European Journal, 10(2), 484-493. doi:10.1002/chem.200305407Penzien, J., Su, R. Q., & Müller, T. E. (2002). The role of protons in hydroamination reactions involving homogeneous and heterogeneous catalysts. Journal of Molecular Catalysis A: Chemical, 182-183, 489-498. doi:10.1016/s1381-1169(01)00496-4Weïwer, M., Coulombel, L., & Duñach, E. (2006). Regioselective indium(iii) trifluoromethanesulfonate-catalyzed hydrothiolation of non-activated olefins. Chem. Commun., (3), 332-334. doi:10.1039/b513946eLeyva, A., & Corma, A. (2009). Isolable Gold(I) Complexes Having One Low-Coordinating Ligand as Catalysts for the Selective Hydration of Substituted Alkynes at Room Temperature without Acidic Promoters. The Journal of Organic Chemistry, 74(5), 2067-2074. doi:10.1021/jo802558eLeyva, A., & Corma, A. (2009). Reusable Gold(I) Catalysts with Unique Regioselectivity for Intermolecular Hydroamination of Alkynes. Advanced Synthesis & Catalysis, 351(17), 2876-2886. doi:10.1002/adsc.200900491Arvai, R., Toulgoat, F., Langlois, B. R., Sanchez, J.-Y., & Médebielle, M. (2009). A simple access to metallic or onium bistrifluoromethanesulfonimide salts. Tetrahedron, 65(27), 5361-5368. doi:10.1016/j.tet.2009.04.068Hashmi, A. S. K., Blanco, M. C., Fischer, D., & Bats, J. W. (2006). Gold Catalysis: Evidence for the In-situ Reduction of Gold(III) During the Cyclization of Allenyl Carbinols. European Journal of Organic Chemistry, 2006(6), 1387-1389. doi:10.1002/ejoc.200600009Morita, N., & Krause, N. (2006). 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Global shifts, theoretical shifts: changing geographies of religion

10.1177/0309132510362602Progress in Human Geography346755-77

Performance studies of the final prototype for the CASTOR forward calorimeter at the CMS experiment

We present performance results of the final prototype for the CASTOR quartz-tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, the uniformity, as well as the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with $E=$ 10--200 GeV electrons, $E=$ 20--350 GeV pions, and $E=$ 50, 150 GeV muons in beam tests carried out at CERN/SPS in 2007

Adaptive Copy Number Evolution in Malaria Parasites

Copy number polymorphism (CNP) is ubiquitous in eukaryotic genomes, but the degree to which this reflects the action of positive selection is poorly understood. The first gene in the Plasmodium folate biosynthesis pathway, GTP-cyclohydrolase I (gch1), shows extensive CNP. We provide compelling evidence that gch1 CNP is an adaptive consequence of selection by antifolate drugs, which target enzymes downstream in this pathway. (1) We compared gch1 CNP in parasites from Thailand (strong historical antifolate selection) with those from neighboring Laos (weak antifolate selection). Two percent of chromosomes had amplified copy number in Laos, while 72% carried multiple (2–11) copies in Thailand, and differentiation exceeded that observed at 73 synonymous SNPs. (2) We found five amplicon types containing one to greater than six genes and spanning 1 to >11 kb, consistent with parallel evolution and strong selection for this gene amplification. gch1 was the only gene occurring in all amplicons suggesting that this locus is the target of selection. (3) We observed reduced microsatellite variation and increased linkage disequilibrium (LD) in a 900-kb region flanking gch1 in parasites from Thailand, consistent with rapid recent spread of chromosomes carrying multiple copies of gch1. (4) We found that parasites bearing dhfr-164L, which causes high-level resistance to antifolate drugs, carry significantly (p = 0.00003) higher copy numbers of gch1 than parasites bearing 164I, indicating functional association between genes located on different chromosomes but linked in the same biochemical pathway. These results demonstrate that CNP at gch1 is adaptive and the associations with dhfr-164L strongly suggest a compensatory function. More generally, these data demonstrate how selection affects multiple enzymes in a single biochemical pathway, and suggest that investigation of structural variation may provide a fast-track to locating genes underlying adaptation

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding. Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124. Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98). Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Roof Material Mapping: Application Over Liège Using Open-Source Object-Based Supervised Classification Algorithms

info:eu-repo/semantics/nonPublishe

La structure d'aliments modèles, contrôlée par le procédé, permet de moduler les cinétiques de digestion en condition in vitro

Introduction et but de l’étude Il a été largement montré que le régime alimentaire avait un potentiel de modulation du microbiote intestinal de l’hôte. Toutefois, les liens entre alimentation, microbiote et santé restent complexes. Nous disposons aujourd’hui des connaissances et méthodes nécessaires pour réaliser des études fonctionnelles et de dynamique du microbiote en lien étroit avec l’aliment et sa déconstruction dans le tube digestif et ceci afin de tendre vers des stratégies de management nutritionnel de l’écologie intestinale. C’est dans ce contexte qu’une stratégie de conception d’aliment modèle a été mise en place afin de moduler les cinétiques de mises à disposition des nutriments. Les aliments modèles choisis sont des matrices lipo-protéiques qui représentent un grand nombre d’aliments composant notre alimentation. Matériel et méthodes Sur la base des connaissances de la littérature, une stratégie de conception des aliments a été mise en place. Celle-ci visait des conditions de coalescence variables en condition gastrique, via la structuration de l’interface, mais également via la structuration de la phase continue de l’émulsion. Ainsi les deux aliments formulés étaient composés de 10 % d’huile de colza et de 15 % de protéines de lactosérum. L’un était une émulsion liquide constituée de gouttelettes de taille moyenne (~1 μm) stabilisés par les protéines. L’autre était un gel obtenu après traitement thermique d’une émulsion à larges gouttelettes (~20 μm). Les deux aliments ont été ensuite digérés selon le protocole standardisé proposé par Minekus et al. 2014. Résultats et Analyse statistique Des différences très significatives entre les deux aliments ont été observées, aussi bien sur la lipolyse que sur la protéolyse. Ainsi l’émulsion liquide, reste relativement stable au cours de la phase gastrique (pas de phénomènes marqués de coalescence) et présente une cinétique de lipolyse plus rapide que l’aliment de type gel. De même, la dénaturation des protéines de l’aliment gélifié associé à de grandes tailles de gouttelettes d’huile conduit à une protéolyse et une lipolyse ralenties. Afin de dissocier la lipolyse de la protéolyse des aliments modèles sans matière grasse ont été préparés et leur cinétiques de digestion in vitro comparées aux aliments avec matière grasse. Conclusion Nous avons pu formuler des aliments modèles de composition identique mais présentant des structures très différentes et parfaitement maîtrisées en jouant sur les paramètre physiques de contrôle des procédés (pression, vitesse d’homogénéisation et température). Ces deux aliments modèles ont permis de quantifier en condition de digestion in vitro l’impact de la structure sur les cinétiques de digestion des nutriments. Ces résultats seront confrontés prochainement dans des conditions in vivo (étude animale sur rat) qui permettra d’évaluer l’impact des cinétiques de digestion et des digestibilités sur des marqueurs physiologiques du métabolisme et du comportement ainsi que sur l’expression et la structuration du microbiote intestinal