- Catalyst-Free Hydrodefluorination of Perfluoroarenes with NaBH4
-
Presented is an economical means of removing fluorine from various highly fluorinated arenes using NaBH4. The procedure was adapted for different classes of perfluoroarenes. A novel isomer of an emerging class of organic dyes based on the carbazole phthalonitrile motif was succinctly synthesized in two steps from tetrafluorophthalonitrile, demonstrating the utility of the hydrodefluorination procedure. Initial exploration of the dye shows it to be photoactive and capable of facilitating contrathermodynamic styrenoid E/Z isomerization.
- Schoch, Timothy D.,Mondal, Mukulesh,Weaver, Jimmie D.
-
p. 1588 - 1593
(2021/03/03)
-
- Synthetic method of 2,3,5,6-tetrafluoroaniline
-
The invention relates to a synthetic method of aniline, in particular to a synthetic method of 2,3,5,6-tetrafluoroaniline. The synthetic method comprises the following steps: taking 2,3,4,5,6-pentafluorobenzonitrile as a raw material; carrying out ammonification on the 2,3,4,5,6-pentafluorobenzonitrile with ammonia water at first; carrying out aftertreatment to obtain an intermediate which is 4-amino-2,3,5,6-tetrafluoroaniline; adding 90% of sulfuric acid; and carrying out hydrolyzing and decarboxylation to generate the 2,3,5,6-tetrafluoroaniline. The ammonia water is an aminating agent, ethylacetate is used as a solvent, tetrabutylammonium hydrogen sulphate is used as a phase transfer catalyst, high-selection ammoniation is carried out at low temperature, thus, an isomer by-product whichis 2-amino-3,4,5,6- tetrafluorobenzonitrile generated by general ammoniation is avoided, the high-purity intermediate which is 4-amino-2,3,5,6-tetrafluoroaniline can be obtained directly, and the purity of the 4-amino-2,3,5,6-tetrafluoroaniline can be 99.5% or above.
- -
-
Paragraph 0024; 0026; 0027; 0029
(2018/04/27)
-
- Preparation method of polyfluoroaniline
-
The invention relates to a preparation method of polyfluoroaniline, according to the method, the polyfluoroaniline is prepared by a two-step common reaction from polyfluorobenzene as a raw material, the method has the characteristics of low reaction temperature, small pressure, low cost, and the like, is suitable for industrial production application, and is convenient for large-scale production;the polyfluoroaniline product obtained by the method has less impurities and high product purity.
- -
-
Paragraph 0058; 0059; 0060; 0061
(2018/08/03)
-
- General and efficient synthesis of polyfluorinated 2-aminotolans and 2-arylindoles
-
It was established here that cross-coupling of polyfluorinated 2-iodoanilines with arylacetylenes in MeCN in the presence catalytic amounts of Pd(PPh3)2Cl2, CuI and Et3N produces the corresponding 2-aminotolans although their yields are decreased from 98% to 40% with increasing fluorination of the substrates. It was shown that the 2-aminotolans with six or fewer fluorine atoms in their rings can be heterocyclised by heating in ethanol containing p-TSA to produce the corresponding polyfluorinated indoles. Cyclisation of tolans containing larger numbers of fluorine atoms in their rings proceeds most efficiently in the presence of KOH, resulting in 2-phenylindoles containing the current maximum of eight fluorine atoms.
- Politanskaya, Larisa V.,Shteingarts, Vitalij D.,Tretyakov, Evgeny V.
-
-
- Amino- and hydrodefluorination of polyfluoroaromatic amines with aqueous ammonia in a steel autoclave. Synthesis of highly pure tetrafluorophenylenediamines
-
The action of aqueous ammonia on liexafhiorobenzene in a steel autoclave at 180-220 °C yields a mixture of isomeric tet rafluorophenylenediamines and 2,4,5-trifhioroplienylene-1,3-diamine. The content of the hydrodefluorination product significantly depends on the reaction temperature and time. Tetrafluorophenylene-1,3-diamine undergoes hydrodefluorination with aqueous ammonia in a steel autoclave at 200 °C to give 2,4,5-trifluorophenylene-1,3- diamine; when the additives of NH4F and/or FeCl3 are present, 2,5-difluorophenylene-1,3-diamine is additionally formed. The hydrodefluorination products are not formed during bis-aminodefluorination of hexafluorobenzene with aqueous ammonia in a glass reactor or with anhydrous ammonia (in a mixture with aprotic solvent) in a steel autoclave.
- Kusov,Rodionov,Vaganova,Shundrina,Malykhin
-
p. 823 - 827
(2010/08/08)
-
- Selective mono-and diamination of polyfluorinated benzenes and pyridines with liquid ammonia
-
Amination of pentafluoropyridine, 2,3,5,6-tetrafluoropyridine, 4-chlorotetrafluoropyridine, 3,5-dichlorotrifluoropyridine, octafluorotoluene, α,α,α,2,3,5,6-heptafluorotoluene, decafluoro-m-xylene, decafluorobiphenyl, hexafluorobenzene, and pentafluorobenzene with liquid ammonia was investigated. Bis-aminodefluorination temperatures for the majority of substrates were shown to exceed significantly the corresponding temperatures of monoaminodefluorination. The optimal conditions for selective preparation of mono-and diaminopolyfluoro(het)arenes were elucidated. An efficient method for isolation of particular polyfluorophenylenediamines from product mixtures formed in nonselective reactions of pentafluorobenzene and hexafluorobenzene with aqueous ammonia based on complexation with a crown ether is proposed.
- Vaganova,Kusov,Rodionov,Shundrina,Malykhin
-
p. 2239 - 2246
(2008/09/20)
-
- Fluorinated 1,3λ4δ2,2,4-benzodithiadiazines - A synthetic, structural and theoretical study
-
The series of title compounds has been prepared through both electrophilic (C6HnF5-n-N=S=N-SiMe3 + SCl2) and nucleophilic (C6HF4_S-N=S=N-SiMe3 + CsF) intramolecular ortho-cyclisation reactions, and the former route seems to be the more effective. High regioselectivity of the ring-closing procedures is observed in both cases. The compounds were characterised by X-ray crystallography and multinuclear (1H, 13C, 15N and 19F) NMR spectroscopy. In accordance with GIAO calculations, 15N{1H} experiments and the effects observed on complete substitution of hydrogen by fluorine, the high-field signal in the 15N NMR spectra can be assigned to N-4 and the low-field signal to N-2. In the crystal, 5,6,7-trifluoro-(5) and 5,6,8-trifluoro-1,3λ4δ22,4- benzodithiadiazine (6) are planar, whereas the 6,8-difluoro derivative 3 is bent along the S1...N4 line by 8.3°. According to NICS calculations the heterocycle moiety in this compound class is antiaromatic while the carbocycle is aromatic. The fluorine substituents increase the aromaticity - and in some cases (especially when a fluorine atom is present in the 8-position) the antiaromaticity - of the corresponding rings. The ortho-fluoro-containing starting material C6HnF5-n-N=S=N-SiMe3 (n = 2: 10) cyclises to the fluorinated 2,1,3-benzothiadiazole 27 upon treatment with CsF instead of SCl2. For starting compound 6-HC6F4-S-N=S=N-SiMe3 (14) the planar (Z,E) configuration features a short intramolecular H...N contact, as evidenced by X-ray diffraction. Both the reaction pathways mentioned are also discussed. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2003.
- Makarov, Alexander Yu.,Bagryanskaya, Irina Yu.,Blockhuys, Frank,Van Alsenoy, Christian,Gatilov, Yuri V.,Knyazev, Vladimir V.,Maksimov, Alexander M.,Mikhalina, Tatiana V.,Platonov, Vyacheslav E.,Shakirov, Makhmut M.,Zibarev, Andrey V.
-
-
- Method for production of aromatic compounds
-
For the production of an aromatic compound by hydrolyzing and decarboxylating a corresponding aromatic cyano compound in the presence of an acidic substance, this invention provides a method for the production of the aromaic compound, characterized by car
- -
-
-
- Catalytic and noncatalytic ammonolysis of chloropentafluorobenzene
-
Ammonolysis of chloropentafluorobenzene both in the presence and in the absence of copper(I) salt results mainly in replacement of the para-and ortho-fluorine atoms with respect to chlorine rather than replacement of the chlorine atom. Ammonolysis of 4-chloro-2,3,5,6-tetrafluoroaniline and 2-chloro-3,4,5,6-tetrafluoroaniline in the absence of copper(I) salt yields exclusively the corresponding fluorine substitution products, whereas in the presence of copper(I) salt the chlorine atom is replaced. Successive ammonolysis of chloropentafluorobenzene in the presence of copper catalyst along these two paths was put into the basis of a new method for preparation of 2,3,5,6-tetrafluoro-1,4-phenylenediamine. * This study was financially supported by the Russian Foundation for Basic Research (project no. 99-03-33111), by the Ministry of Science and Technology of the Russian Federation (project no 9.3.01), and by the Ministry of Education of the Russian Federation (project no. 015.05.01.13).
- Selivanova,Pokrovskii,Shteingarts
-
p. 404 - 409
(2007/10/03)
-
