The C3-selective homodimerization of quinoxalinones is described. A C3-sp carbanion species generated through deprotonation of quinoxalinone using potassium -butoxide (KOBu) transfers an electron (single electron transfer mechanism) to a second quinoxalinone, affording a radical-anion intermediate. The radical scavenging and electron paramagnetic resonance (EPR) experiments support the plausible radical reaction pathway. A mild reaction temperature and a short reaction time were attained under cost-effective conditions, which reveal the amenability of this protocol to pharmaceutical and chemical industries.
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http://dx.doi.org/10.1039/d2cc02636h | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
Pulsed dipolar electron paramagnetic resonance (PD-EPR) measurement is a powerful technique for characterizing the interactions and conformational changes of biomolecules. The extraction of these distance restraints from PD-EPR experiments relies on manipulation of spin-spin pairs. The orthogonal spin labeling approach offers unique advantages by providing multiple distances between different spin-spin pairs.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
East China Normal University, School of Chemistry and Molecular Engineering, 3663 N. Zhongshan Rd., 200062, Shanghai, CHINA.
We present a novel electrochemical dicarboxylation of epoxides with CO2, characterized by the cleavage of two C-O single bonds. Not only are vinyl epoxides viable, but cyclic carbonates also serve as effective substrates, facilitating the synthesis of E-configured adipic and octanedioic acids with high chemo-, regio-, and stereoselectivity. The synthetic practicality is further highlighted by the diverse functionalizations of the resulting multifunctional diacids.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Physics, University of Liverpool, Oxford Street, Liverpool, L69 7ZE, UK.
Topological semimetals have recently garnered widespread interest in the quantum materials research community due to their symmetry-protected surface states with dissipationless transport which have potential applications in next-generation low-power electronic devices. One such material, [Formula: see text], exhibits Dirac nodal arcs and although the topological properties of single crystals have been investigated, there have been no reports in crystalline thin film geometry. We examined the growth of [Formula: see text] heterostructures on a range of single crystals by optimizing the electron beam evaporation of Pt and Sn and studied the effect of vacuum thermal annealing on phase and crystallinity.
View Article and Find Full Text PDFSci Rep
December 2024
INCI-UPR3212-CNRS, 8 Allée du Général Rouvillois, 67000, Strasbourg, France.
Mutations in the gene ABCA4 coding for photoreceptor-specific ATP-binding cassette subfamily A member 4, are responsible for Stargardts Disease type 1 (STGD1), the most common form of inherited macular degeneration. STGD1 typically declares early in life and leads to severe visual handicap. Abca4 gene-deletion mouse models of STGD1 accumulate lipofuscin, a hallmark of the disease, but unlike the human disease show no or only moderate structural changes and no functional decline.
View Article and Find Full Text PDFCell Death Discov
December 2024
Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain (UCLouvain), Brussels, Belgium.
Hypoxic tumors are radioresistant stemming from the fact that oxygen promotes reactive oxygen species (ROS) propagation after water radiolysis and stabilizes irradiation-induced DNA damage. Therefore, an attractive strategy to radiosensitize solid tumors is to increase tumor oxygenation at the time of irradiation, ideally above a partial pressure of 10 mm-Hg at which full radiosensitization can be reached. Historically, the many attempts to increase vascular O delivery have had limited efficacy, but mathematical models predicted that inhibiting cancer cell respiration would be more effective.
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