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Synthetic Methods for High-Energy Organofluorine Compounds
Published in Mark J. Mezger, Kay J. Tindle, Michelle Pantoya, Lori J. Groven, Dilhan M. Kalyon, Energetic Materials, 2017
Finally nitrolysis of the nosylamide groups in 20 using a mixture of nitric acid and triflic acid gave HNFX in 65% yield (Figure 1.7).12 The use of the 1:1 mixture of nitric acid and concentrated sulfuric acid as the nitrating agent brings about the conversion of 20 to HNFX in relatively poor yield (16%) and requires higher temperatures (70°C) for the reaction to proceed. On the other hand, nitration of 20 using nitric acid in the superacidic system consisting of a mixture of fluorosulfuric acid (FSO3H) and antimony pentafluoride (SbF5) had no extra advantage, because even though the nitrolysis of the first nosylamide group was rapid and was complete in one hour at room temperature, the subsequent step proved to be much slower and has no obvious advantage over the N-nitration in triflic acid; under the stronger superacidic conditions, in the presence of fluorosulfuric acid and antimony pentafluoride, the highly reactive, superelectrophilic protonitronium cation is reversibly formed (NO2H2+), which brings about further electrophilic nitration of the p-nitrobenzenesulfonyl (Nosyl) group to give the corresponding 2,4-dinitrobenzeneslfonyl derivative. Thus formed 2,4-dinitrobenzenesulfonyl derivative is much less reactive (but comparable with nitration in triflic acid) toward further desulfonylative N-nitration to give HNFX.
Polysaccharides
Published in Stanislaw Penczek, H. R. Kricheldorf, A. Le Borgne, N. Spassky, T. Uryu, P. Klosinski, Models of Biopolymers by Ring-Opening Polymerization, 2018
Polymerization of 2-ABG was carried out with Lewis acids and their complexes as catalyst, and the results are shown in Table 6. Although the cationic polymerization of 2-ABG with 10 to 20 mol% PF5 or BF3·OEt2 with respect to the monomer does not give a polymer, oligomers with M¯n of 1000 to 2000 (DPn¯=3to6) can be obtained in low yields with antimony pentafluoride as catalyst but not with PF5-C6H5COF. As a result, the C-2 azide group causes a remarkable decrease in the polymerizability. Two factors might be considered for this reason. One is the complexation of Lewis acid PF5 with the azido group at C-2, which has been confirmed by measuring 31P NMR spectrum of the polymerization system. Another is possibly an intramolecular interaction of the azido group with the electron-deficient C-1 carbon atom at the propagating chain end. This is ascribed to the electron-releasing character of the azido group, indicated by the 13C NMR spectrum.
Review. Inverse coordination. Organic nitrogen heterocycles as coordination centers. A survey of molecular topologies and systematization. Part 2. Six-membered rings
Published in Journal of Coordination Chemistry, 2019
Inverse coordination complexes with coordinatively unsaturated inorganic molecules such as mercury diiodide (6) [9], gallium trichloride (7) [10], and antimony pentafluoride (8) [11] attached to the pyrazine heterocycle, are shown in Scheme 2.