Abstract: The ability of redox-active metal centers to weaken the bonds in associated ligands is well precedented, but has rarely been utilized as a mechanism of substrate activation in catalysis. The role of sulfamethoxazole desensitization is controversial as rates of hypersensitivity reactions are similar between desensitization and drug challenge. Catalytic Carbocation Generation Enabled by the Mesolytic Cleavage of Alkoxyamine Radical Cations, Qilei Zhu, Emily C. Gentry, Robert R. Knowles, Catalytic Carbocation Generation Enabled by the Mesolytic Cleavage of Alkoxyamine Radical Cations, Angew. 2016, 55, 9969–9973. Feedback. These results offer further support for the ability of non-covalent interactions to enforce stereoselectivity in reactions of transient and highly reactive open-shell intermediates. Cooperative photoredox and chiral hydrogen-bonding catalysis. DOI: 10.1039/C5SC03350K. Chem. DOI: 10.1021/ja5056774. We report a catalytic protocol for efficient additions of cyclic and acyclic secondary alkyl amines to a wide range of alkyl olefins with complete anti-Markovnikov regioselectivity. 2001;24(4):239-47. doi: 10.2165/00002018-200124040-00001. An enantioselective, radical-based method for the intramolecular hydroamination of alkenes with sulfonamides is reported. Chem. USA.gov. De nombreuses molécules sont actuellement disponibles, les principales étant le gliclazide, le glimepiride, le glipizide, et le glibenclamide. 2016, 6, 2894–2903. Antibiotic allergies in children and adults: from clinical symptoms to skin testing diagnosis. Drug Saf. Dirk J. Schild, Marcus W. Drover, Paul H. Oyala. 2020, 142, 5974–5979. Experimental procedures, spectral data, and optical purity determinations (PDF). 2003;26(3):187-95. doi: 10.2165/00002018-200326030-00004. Our lab aims to establish concerted PCET as a general platform for substrate activation, providing new solutions to significant and long-standing synthetic challenges in the areas of free radical chemistry, asymmetric catalysis, and organometallic chemistry. Photocatalysis: A step closer to the perfect synthesis. The central aim of these efforts has been to demonstrate the ability of PCET to homolytically activate a wide variety of common organic functional groups that are energetically inaccessible using known molecular H atom transfer catalysts. Florian Loose, Dian Wang, Lei Tian, Gregory D. Scholes, Robert R. Knowles and Paul J. Chirik Concepts for the thermodynamically challenging synthesis of weak N–H bonds by photoinduced proton coupled electron transfer are explored. Dérivés du para-amino-benzène sulfonamide Sur le plan biologique Propriétés antibactériennes Bactériostatiques Large spectre Activité antiparasitaire Présentant, surtout pour les composés les plus anciens, un certain risque néphrotoxique. Moreover, this transformation affords access to a broad range of structurally complex heterocycles from simple amide starting materials. When chiral proton donors are used, these successor H-bond complexes provide a basis for asymmetric induction in subsequent reactions of the ketyl radical. 2016, 374, 30. Author information: (1)Division of Allergy and Immunology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Tex. These reactions are proposed to proceed via N -centered radicals formed by proton-coupled electron transfer (PCET) activation of sulfonamide N–H bonds. Here we describe a catalytic bond-weakening protocol for conjugate amination wherein the strong N–H bonds in N-aryl amides (N–H bond dissociation free energies ∼100 kcal/mol) are destabilized by ∼33 kcal/mol upon by coordination to a reducing titanocene complex, enabling their abstraction by the weak H-atom acceptor TEMPO through a proton-coupled electron transfer process. | Intermolecular Anti-Markovnikov Hydroamination of Unactivated Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer, Qilei Zhu, David E. Graff, Robert R. Knowles, Intermolecular Anti-Markovnikov Hydroamination of Unactivated Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer, J. In this process, electron transfer between an excited state oxidant and a TEMPO‐derived alkoxyamine substrate gives rise to a radical cation with a remarkably weak C−O bond. Les sulfamides sont des para-amino-phenyl sulfonamides ; les sulfones sont des molécules du type di-amino-diphényl sulfones. http://pubs.acs.org/page/copyright/permissions.html. Abstract: The next century’s energy needs demand novel catalysts.