Interaction of polyfluoroaromatic compounds with o-aminophenol. The Smiles rearrangement in the polyfluoroaromatic series

The reactions of polyfluoroaromatic compounds containing an electron-attracting substituent other than fluorine in the aromatic ring with o-aminophenol proceed at the amino or hydroxy group and lead to the corresponding hydroxydiarylamines (in neutral media) or aminodiaryl ethers (in alkaline media). The latter compounds, unlike 2,3,4,5,6-pentafluoro- 2'-aminodiphenyl ether, are transformed in dimethylformamide (DMFA) to isomeric polyfluoro-2-hydroxydiarylamines (the Smiles rearrangement). The increased electron-attracting capacity of substituent leads to the decreased activation energy and increased rearrangement rate constants.     

Phosphorylation of polyfluoroaromatic compounds

Conclusions Polyfluoroaromatic compounds react with Na dimethyl and diethyl phosphites and diethyl thiophosphite in the Michaelis-Becker reaction with formation of the corresponding methyl and ethyl polyfluoroarylphosphonates and thiophosphonates.For Communication 2, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 867–869, April, 1981.     

Homolytic reactions of polyfluoroaromatic compounds Part VIII. The decomposition of benzoyl peroxide in hexafluorobenzene

The decomposition of benzoyl peroxide in hexafluorobenzene proceeds by a spontaneous first-order process accompanied by an induced decomposition showing 1.5-order dependence upon the concentration of the peroxide. The induced decomposition is associated with the formation of 2,2′,3,4,5,6-hexafluorobiphenyl and benzoic acid. 2,3,4,5,6-Pentafluorobiphenyl is the main product at all concentrations of peroxide; small amounts of other compounds are formed, together with a high-boiling residue probably containing isomeric dodecafluorotetrahydroquaterphenyls. The mechanism is discussed.     

Vibrational spectra of polyfluoroaromatic compounds containing the azomethine group

Conclusions The replacement of hydrogen atoms of the benzene rings in aromatic azomethines is accompanied by changes in the state of the nitrogen atom and the C=N bond. This is expressed in a shift of the signals in the NMR spectra and in a change in band intensities for the stretching vibrations of multiple bonds in the Raman spectra, but it does not affect the positions of these bands.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 568–575, March, 1984.     

Homolytic reactions of polyfluoroaromatic compounds Part VII. Products and relative rates of phenylation of pentafluorobenzene,bromopentafluorobenzene and octafluorotoluene with benzoyl peroxide

Competitive rates of arylation of the title compounds were measured using hexafluorobenzene as reference. The results suggest that the species responsible for intermolecular discrimination and those responsible for intramolecular selection are not the same. The significance of this observation is discussed.     

Reaction of triethyl phosphite with polyfluoroaromatic compounds that contain activated fluorine atoms

Conclusions Polyfluoroaromatic compounds that contain activated fluorine atoms enter into the Arbuzov reaction with triethyl phosphite to give the corresponding diethyl esters of arylphosphonic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2839–2840, December, 1977.     

Hydrogenolysis of heptafluoro- and hexafluoroisopropyl groups in polyfluoroaromatic compounds

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2158–2159, September, 1991.     

Homolytic reactions of polyfluoroaromatic compounds. X. Biphenylyl radicals in the thermolysis of aroyl peroxides in polyfluoroaromatic solvents

The thermolyses of a number of aroyl peroxides in hexafluorobenzene, and of benzoyl peroxide in octafluorotoluene, gave the corresponding biaryls which were isolated by steam distillation. Mass spectrometry of the residues showed evidence of biphenylyl radicals arising from the arylation of the peroxides themselves or, possibly, of the derived aroic acids. Terphenyls, and the corresponding σ-intermediate radicals, could be found, and the relative molecular masses of the latter components showed that subsequent arylation of the main binuclear products was not the main source of terphenyls.     

Homolytic reactions of polyfluoroaromatic compounds V. The reaction of pentafluorophenyl radicals with fluorobenzene

The arylation of fluorobenzene with pentafluorophenyl radicals obtained by the reaction of the corresponding aniline with pentyl nitrite is described. The reaction involves attact at the 2t?-,3t?-and 4t?-positions. The composition of the mixture and the nature of its components were determined by ¹⁹F NMR spectroscopy and were confirmed by gas-liquid chromatography.     

Fluorinated tropylium ions in the mass spectra of some polyfluoroaromatic compounds

The most prominent ion in the mass spectra of C₆F₅CH₂X (X ? H, Br, CH:CH₂, COCl, and CH₂C₆F₅) is C₇F₅H₂⁺, formulated as the pentafluorotropylium cation. This ion is also found, in an amount comparable to the parent ion, in the spectrum of (C₆F₅)₂CH₂. The heptafluorotropylium cation is found similarly in the spectrum of C₆F₅CF₃. The mass spectra of (C₆F₅)₂CHBr and [(C₆H₅)₂CH]₂ exhibit an ion C₁₃F₁₀H⁺ as the base peak, which is probably a pentafluorophenylpentafluorotropylium cation. The alcohol (C₆F₅)₂CHOH shows loss of C₆F₅, followed by 2H, as a major breakdown pathway. The mode of formation, and the subsequent fragmentation, of the major ions in these spectra, are discussed.     

Reaction of polyfluoroaromatic compounds with electrophilic agents in the presence of tris(dialkylamino)phosphines

A method was developed for the replacement of chlorine, bromine, and iodine in halopolyfluoroaromatic compounds by hydrogen under the action of P(NEt₂)₃ and a proton donor.     

Carbon-13 spin–lattice relaxation in some polyfluoroaromatic compounds

Carbon-13 chemical shifts, spin-lattice relaxation times and nuclear Overhauser enhancement factors are reported for five polyfluoroaromatic compounds at 28°C. In all cases the relaxation of the fluorine bearing carbon is predominantly dipolar. Effective correlation times are smaller than those of the analogous benzene derivatives by a factor of 3–4, in qualitative agreement with predictions from the Stokes–Einstein diffusion theory. The T₁ values for the para-carbon of monosubstituted fluorobenzenes is clearly shorter than the T₁ values for the ortho- and meta-carbons. This phenomenon was traced to anisotropic tumbling, and D∥ and D⊥ diffusion coefficients were computed using Woessner's equations for molecules assumed to behave like symmetric rotors about their C₂ in-plane principal symmetry axis. Equal tumbling ratios, D∥/D⊥, were found in this way for toluene and perfluorotoluene.     

Reactions of polyfluoroaromatic compounds with electrophilic agents in the presence of tris(dialkylamino)phosphines

When reacted with P(NEt₂)₃ and a proton donor, pentafluoropyridine, 3-chlorotetrafluoropyridine, pentafluorobenzonitrile, and octafluorotoluene yield products of replacement of the fluorine atom by hydrogen at position 4. This process is accompanied by the side reaction of aminodefluorination. In the case of 3-H-heptafluorotoluene and octafluoronaphthalene, aminodefluorination is the main reaction. Reactions of perfluoro-4-isopropyltoluene, 4-H-heptafluorotoluene, and 4-methylheptafluorotoluene do not occur under the above-mentioned conditions. For Part 7, see Ref. I. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1498–1500, August, 1997.     

Polyfluoreoethers from 1,1,5,5-tetrahydryl-F-1,5-pentanediol and polyfluoroaromatic and polyfluoroheteroaromatic compounds

The use of the Williamson reaction to prepare polyfluoroethers, [OArOCH₂(CF₂)₃CH₂]_n from 1,1,5,5-tetrahydryl-F-1,5-pentanediol and polyfluoroaromatic and polyfluoroheteroaromatic compounds was investigated. Fluorine NMR spectroscopy was used to determine the structures of the resultant polymers. F-Biphenyl and 1,5-bis(F-2-pyridyloxy)-1,1,5,5-tetrahydryl-F-pentane (BPFP) afforded the polymers where Ar is 4,4′-C₆F₄C₆F₄ and respectively. The polymer prepared from F-pyridine differed from that obtained from BPFP in that it had an irregular structure and contained 2,4′- as well as 2,2′ - and 4,4′-linked rings. F-Benzene, 4-(1,1-dihydryl-F-butoxy)-F-pyridine, and F-pyrimidine each gave materials having copolymer structures. The inherent viscosities of the polymers depended on the polyfluorocyclic compound used and ranged from 0.05 to 0.2 dl/g. The heterocyclic polymers were elastomeric. The polymers from F-pyridine and BPFP had the lowest glass transition temperatures (～?10°C), and started to lose weight (by thermogravimetry) at ～300°C in oxygen and at ～350°C in nitrogen.