Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cS Ar) rather than classical, two-step, S Ar mechanisms. Whereas traditional S Ar reactions require substantial activation of the aromatic ring by electron-withdrawing substituents, such activating groups are not mandatory in the concerted pathways.
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http://dx.doi.org/10.1002/anie.201902216 | DOI Listing |
J Hazard Mater
January 2025
State Key laboratory of Chemical Safety, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, PR China. Electronic address:
Fluorescent probes for in vivo hypochlorous acid (HClO) imaging often face challenges of low selectivity and high cytotoxicity, largely due to poor analyte recognition and water-insoluble aromatic skeletons. To address this, we synthesized fluorescein hydrazide by introducing a spiro-lactam unit into fluorescein, which offers high emission intensity and molar absorption. The five-membered heterocycle in fluorescein hydrazide is selectively disrupted by HClO, enhancing the conjugated system and electron delocalization of the fluorophore, resulting in highly sensitive fluorescence detection of HClO.
View Article and Find Full Text PDFAnal Chem
January 2025
Xinjiang Key Laboratory of Trace Chemical Substances Sensing, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830000, China.
The specific fluorescent detection of α-methyltryptamine (AMT) presents a great challenge because similar amine groups and benzene rings exist in a variety of amines. Here, we show the precise modulation of the electron-withdrawing strength of the π-conjugate bridge in aldehyde-containing Schiff base-based fluorescent probes for ultratrace AMT discrimination. It is found that different electron-withdrawing groups -CH, -CHN, and -CHBr as the π-conjugate bridge of the 2-dicyanomethylidene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF)-based probes can classify and identify organic amines with different amine nucleophilicities.
View Article and Find Full Text PDFCurr Med Chem
January 2025
Brazilian Nuclear Energy Commission, Nuclear Engineering Institute, Laboratory of Novel Radiopharmaceuticals and Nanoradiopharmacy, Rio de Janeiro, 21941906, Brazil.
This study discusses the chemical perspectives of the [18F]F-PSMA probe, a pivotal tool in prostate cancer imaging. [18F]Fluorine, a positron emitter with a half-life of 109.8 minutes, is produced in a cyclotron by bombarding [18O]-enriched targets with protons.
View Article and Find Full Text PDFNat Chem
January 2025
CCNU-uOttawa Joint Research Centre, Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China.
Nitroarenes are readily accessible bulk chemicals and can serve as versatile starting materials for a series of synthetic reactions. However, due to the inertness of the C-NO bond, the direct denitrative substitution reaction with unactivated nitroarenes remains challenging. Chemists rely on sequential reduction and diazotization followed by the Sandmeyer reaction or the nucleophilic aromatic substitution of activated nitroarenes to realize nitro group transformations.
View Article and Find Full Text PDFDalton Trans
January 2025
Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.
In this work, we show two synthetic routes to substitute the N position of mesoionic imines (MIIs). By Buchwald-Hartwig amination, 5-amino-1,2,3-triazoles can be arylated at the said position, showing the versatility of amino-triazoles as building blocks for MIIs. The reaction of MIIs with electrophiles (MeI, fluoro-arenes) highlights the nucleophilic nature of MIIs as even at room temperature aromatic C-F bonds can be activated with MIIs.
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