Synthesis of 1-methyl-2-fluoro-4,5-dicyanoimidazole was done by halogen exchange between 1-methyl-2-bromo-4,5-dicyanoimidazole and potassium fluoride. Halogen exchange between 1-methyl-2-bromo-4,5-dicyanoimidazole and lithium chloride in N-methylpyrrolidinone at 150 degrees C yielded 1-methyl-2-chloro-4,5-dicyanoimidazole, and additional heating to 210 degrees C resulted in the demethylation to yield 2-chloro-4,5-dicyanoimidazole. Thermolyses of the 2-halo-4,5-dicyanoimidazole derivatives (F, Cl) and 1-iodo-2-halo-4,5-dicyanoimidazole derivatives (Cl, Br, I) between 100 and 290 degrees C were found to yield Tris(imidazo)[1,2-a:1,2-c:1,2-e]-1,3,5-triazine-2,3,5,6,8,9-hexacarbonitrile, or HTT, with (C(5)N(4))(3) composition. HTT has been characterized and purified and the crystal structure obtained. Thermolysis of HTT at 490-500 degrees C gives a material with C/N = 1.020. The thermal properties of HTT and its decomposition products show thermal stability to 350 degrees C.
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http://dx.doi.org/10.1021/jo960828x | DOI Listing |
Phys Chem Chem Phys
January 2025
Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Valladolid, Spain.
This article reports a theoretical study on the halogen exchange reactions YX + CHO → Y + XCHO (with Y = F, Cl, Br; X = Cl, Br, I) carried out at a high level of accuracy using coupled-cluster based methodologies including CCSD(T)-F12, CCSD(T)/CBS and CCSDT(Q). Most of the reactions are exothermic at room temperature, with the exception of the reactions FI + CHO → F + ICHO and ClI + CHO → Cl + ICHO. Exothermicity follows two concurrent trends established by the strength of the bonds being cleaved and formed: Y = F < Cl < Br (X-Y bond strength) and X = Cl > Br > I (C-X bond strength).
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States.
Although alkyl alcohols and aryl chlorides are the two most abundant substrate pools for cross-electrophile coupling, methods to couple them remain limited. Herein we demonstrate a simple procedure for the in situ deoxychlorination of alcohols followed by XEC with aryl chlorides. A broad substrate scope can be achieved by tuning the rate of the reaction via halide exchange.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Freie Universität Berlin: Freie Universitat Berlin, Institut für Chemie und Biochemie, GERMANY.
Herein, we present the first easy-to-access synthesis of the perfluorotrityl cation (15F+) with commercial GaCl3 and the further functionalization of the para-fluorine atoms of 15F+ via halodefluorination using trimethylsilyl halides TMSX (X = Cl, Br). This gives access to equally reactive perhalogenated trityl derivatives (p-3Cl12F+ and p-3Br12F+), which can be handled at room temperature. The impact of the para-exchange on the electronic structure is determined by NMR and UV-Vis spectroscopy.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Jilin Province Key Lab of Green Chemistry and Process, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, Jilin, 130022, China.
A modular approach was developed for the first catalytic asymmetric total syntheses of naturally occurring C terpene quinone methides and their non-natural stereoisomers, which feature the presence of an unprecedented spiro[4.4]nonane-containing 6-6-6-5-5-3 hexacyclic skeleton. Resting on a chiral phosphinamide-catalyzed enantioselective reduction of 2,2-disubstituted cyclohexane-1,3-dione, a concise route for the synthesis of enantioenriched 6-6 bicyclic fragment was developed.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Solid State Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic.
The most commonly used homogeneous catalyst for fatty acid esterification is a corrosive sulphuric acid. However, this requires costly investment in non-corrosive equipment, presents a safety risk, is time consuming, and increases effluent generation. In this study, inorganic 3D heteroborane cluster strong acids are employed for the first time as homogeneous catalysts.
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