An amino-linked nitrogen heterocyclic carbene (amino-NHC), 1-tBu, has been shown to mediate carbon-carbon coupling through the direct C-H functionalization of benzene and pyridine in the absence of a metal catalyst. Using EPR, the first spectroscopic evidence corroborating the single electron transfer mechanism for the metal-free carbon-carbon coupling manifold, as reported by others, is introduced.
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http://dx.doi.org/10.1039/c2cc32519e | DOI Listing |
Organometallics
January 2025
Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77842, United States.
Protolysis of AlMe or AlEt with 2-diisopropylphosphinopyrrole () resulted in alane/bis(phosphine) pincer ligands containing two flanking phosphines and a central Al-Me (), Al-Et () unit. Reactions of with [(COD)MI] (COD = 1,5-cyclooctadiene; M = Rh or Ir) in the presence of pyridine produced pincer complexes ( and ) with M supported by the PAlP tridentate ligand, and pyridine, methyl, and iodide as monodentate ligands for Al or M. The analogous reaction of with [(COD)MI] and pyridine resulted in the formation of the analogous compounds and with hydride in place of methyl.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Organic Chemistry, University of Debrecen Egyetem Square 1 Debrecen 4032 Hungary
Domino Knoevenagel-cyclization reactions of styrene substrates, containing an -(-formyl)aryl subunit, were carried out with -substituted 2-cyanoacetamides to prepare tetrahydro-4-pyrano[3,4-]quinolone and hexahydrobenzo[]phenanthridine derivatives by competing IMHDA and IMSDA cyclization, respectively. The diastereoselective IMHDA step with α,β-unsaturated amide, thioamide, ester and ketone subunits as a heterodiene produced condensed chiral tetrahydropyran or thiopyran derivatives, which in the case of Meldrum's acid were reacted further with amine nucleophiles in a multistep domino sequence. In order to simplify the benzene-condensed tricyclic core of the targets and get access to hexahydro-1-pyrano[3,4-]pyridine derivatives, a truncated substrate was reacted with cyclic and acyclic active methylene reagents in diastereoselective Knoevenagel-IMHDA reactions to prepare novel condensed heterocyclic scaffolds.
View Article and Find Full Text PDFJ Mol Model
January 2025
School of Chemical and Environmental Engineering, China University of Mining and Technology-Beijing, Haidian District, Ding No.11 Xueyuan Road, Beijing, 100083, People's Republic of China.
Context: Understanding the structural characteristics of coal at the molecular level is fundamental for its effective utilization. To explore the molecular structure characteristic, the long-flame coal from Daliuta (DLT), coking coal from Yaoqiao (YQ), and anthracite from Taixi (TX) were investigated using various techniques such as elemental analysis, Fourier transform infrared spectroscopy, solid-state C nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy. Based on the structural parameters, the coal molecular model was constructed and optimized.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Organic and Analytical Chemistry (ICOA UMR 7311), CNRS, University of Orleans, F-45067 Orléans, France.
The emergence of RNA viruses driven by global population growth and international trade highlights the urgent need for effective antiviral agents that can inhibit viral replication. Nucleoside analogs, which mimic natural nucleotides, have shown promise in targeting RNA-dependent RNA polymerases (RdRps). Starting from protected 5-iodouridine, we report the synthesis of -substituted-(1,3-diyne)-uridines nucleosides and their phosphoramidate prodrugs.
View Article and Find Full Text PDFChem Sci
December 2024
Department of Chemistry and Biochemistry, University of California, San Diego La Jolla California 92093 USA
Metal-organic frameworks (MOFs) can be prepared from oligomeric organic ligands to prepare materials referred to as oligoMOFs. Studies of oligoMOFs are relatively limited, with most existing reports focused on fundamental structure-property relationships. In this report, functional groups, such as terminal alkynes and pyridine groups, are installed on the tether between 1,4-benzene dicarboxylic acid (Hbdc) groups of the dimer ligands.
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