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An unprecedented intramolecular acylation of unactivated pyridines via multiple C(sp/sp)-H functionalizations of a methyl, hydroxymethyl, or aldehyde group has been developed providing a general access to all four azafluorenones. The application of this protocol is further demonstrated to the synthesis of azafluorenone related fused nitrogen heterocycles and fluorenones. In addition, design and synthesis of a novel fluorene based organic emitter for potential use in organic light emitting devices (OLEDs) is also reported.
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http://dx.doi.org/10.1021/acs.joc.6b02065 | DOI Listing |
Int J Mol Sci
August 2025
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. Ferrocarril San Rafael Atlixco 186, Col. Leyes de Reforma 1A Sección, Iztapalapa, Ciudad de México C.P. 09310, Mexico.
A one-pot synthetic methodology that combines an Ugi-Zhu three-component reaction (UZ-3CR) with a cascade sequence (intermolecular Diels-Alder cycloaddition/intramolecular -acylation/decarboxylation/dehydration) using microwave-heating conditions, ytterbium (III) triflate (Yb(OTf)) as the catalyst, and chlorobenzene (for the first time in a multi-component reaction (MCR)) as the solvent, was developed to synthesize twelve new fluorinated-pyrrolo[3,4-]pyridin-5-ones containing a 4-amino-7-chloroquinoline moiety, yielding 50-77% in 95 min per product, with associated atom economies around 88%, also per product. Additionally, by in vitro tests, compounds and were found to effectively stop early SARS-CoV-2 replication, IC = 6.74 µM and 5.
View Article and Find Full Text PDFAdv Mater
August 2025
Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
Blue-emitting multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters with high photoluminescence quantum yield (PLQY), high robustness with short-lived emission lifetime is particularly desired for the development of organic light-emitting diodes (OLEDs). In this study, a series of MR-TADF molecules featuring fused boron/nitrogen (B/N) and C ═ O/N frameworks is reported. These emitters namely BNO, BNDO, and BNTO are systematically designed and synthesized to investigate the impact of molecular rigidity or planarity toward their excited-state dynamics through stepwise intramolecular electrophilic acylation reactions.
View Article and Find Full Text PDFInt J Biol Macromol
August 2025
College of Food Science and Engineering, Northwest A&F University, Yangling 712100, PR China. Electronic address:
Green, biodegradable, and renewable cellulose is a promising candidate for developing sustainable materials. This work prepared highly acetylated cellulose via electron beam irradiation pretreatment followed by acetylation. The degree of acetylation peaked at an acetic anhydride concentration of 5.
View Article and Find Full Text PDFOrg Lett
July 2025
Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan, R.O.C.
We report an efficient catalytic protocol for the intramolecular Wittig reaction enabled by the P/P redox cycle, starting from Ts-containing electron-deficient olefin (EDO) precursors, leading to EDOs that are traditionally inaccessible. This reaction proceeds through a cascade sequence involving the generated EDO from EDO precursor/phospha-Michael addition/-acylation/intramolecular Wittig reaction. This strategy exhibits broad substrate scope, high chemoselectivity, and excellent functional group tolerance.
View Article and Find Full Text PDFAcc Chem Res
August 2025
Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China.
ConspectusSince Heilbronner proposed cyclacenes as hypothetical molecules in 1954, zigzag hydrocarbon belts and their heteroatom-doped analogs have captivated chemists and materials scientists with their aesthetically appealing structures, intriguing properties, and potential applications. Except for the work reported in the late 1980s and early 1990s by Stoddart, who employed iterative Diels-Alder reactions to construct such belts, the field has remained dormant for decades. This stagnation is primarily due to the lack of synthetic methods.
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