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Amide isotope labeling is a crucial tool in drug discovery and development. However, current methods label the desired peptide bond in a multi-step fashion. This study presents novel strategies for amide isotope exchange through transamidation and amide metathesis. By optimizing reaction conditions and exploring substrate scope, we achieved direct labeling of both amine and carbonyl moieties. These findings pave the way for more sustainable isotope labeling technologies. Furthermore, preliminary examples of isotope-containing waste recycling demonstrate a crucial step towards a greener future for isotope chemistry.
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http://dx.doi.org/10.1039/d5sc02566d | DOI Listing |
J Labelled Comp Radiopharm
September 2025
National Key Laboratory for the Development and Utilization of Forest Food Resources, Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, Jiangsu, China.
Carbon-11 (C)-labeled radiotracers are invaluable tools in positron emission tomography (PET), enabling real-time visualization of biochemical processes with high sensitivity and specificity. Among the various C synthons, cyclotron-produced [C]CO is a fundamental precursor, though its direct incorporation into complex molecules has traditionally been limited by its low reactivity, gaseous form, and short half-life. Recent advances in [C]CO fixation chemistry through both nonphotocatalytic and photocatalytic methods have significantly expanded its utility in the synthesis of structurally diverse compounds, including carboxylic acids, carbonates, carbamates, amides, and ureas.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
The C-H functionalization of arenes mediated by well-defined bis(phosphine)-supported organometallic iron(III) complexes is described. One-electron oxidation of -(depe)Fe(CH) (depe = 1,2-bis(diethylphosphino)ethane) generated the corresponding isolable iron(III) dimethyl derivative that was unstable toward Fe-CH homolysis. Oxidation of the corresponding iron(II) bis(aryl) complex -(depe)Fe(tolyl) resulted in rapid reductive elimination of the biaryl with formation of iron(I).
View Article and Find Full Text PDFMetab Brain Dis
September 2025
Department of Pharmaceutical Sciences, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, 79106, USA.
Acetaminophen is widely recognized for its safety as a pain reliever and fever reducer at recommended doses. However, in addition to the well-known hepatotoxic and nephrotoxic effects at overdoses recent animal studies in rats have raised the possibility that acetaminophen at a high dose of 500 mg/kg may lead to acute impairment of the blood-brain barrier (BBB). Because species differences in hepatic and renal toxicity of acetaminophen are present, we assessed here the effect of moderate and severe overdoses of acetaminophen (300 mg/kg and 600 mg/kg, respectively) after intraperitoneal administration in mice on BBB permeability.
View Article and Find Full Text PDFJ Chem Phys
September 2025
College of General Education, Chung-Ang University, Seoul 06973, South Korea.
Isotope-edited infrared (IR) spectroscopy is a powerful tool for probing site-specific structures and dynamics within proteins. However, the interpretation is often complicated by spectral congestion and environmental heterogeneity. In this study, vibrational exciton models combined with molecular dynamics simulations are employed to examine the frequency distributions and IR spectra of isotope-labeled local modes (ILMs) in parallel coiled-coil dimers.
View Article and Find Full Text PDFIn Vivo
August 2025
Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Background/aim: Refractory differentiated thyroid carcinoma (DTC) and anaplastic thyroid carcinoma (ATC) are associated with poor prognoses. Molecularly targeted agents such as lenvatinib are expected to significantly improve outcomes. However, data from real-world settings remain limited.
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