- Highly reactive and regenerable fluorinating agent for oxidative fluorination of aromatics
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A newly synthesized copper aluminum fluoride of nominal composition CuAl2F8 exhibits excellent reactivity towards direct oxidative fluorination of aromatic compounds, as well as fluorodechlorination of chloroaromatics. The spent CuAl2F8 reagent can be regenerated by treatment with O2 and HF, and the fluorination process has been demonstrated to retain high conversions through 20 reaction cycles. The main advantages of this new process are safety, minimal waste, and potentially low cost.
- Janmanchi, Krishna Murthy,Dolbier Jr., William R.
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- NEW DEVELOPMENTS IN THE SYNTHESIS OF LOWER FLUORINATED PYRIDINES VIA DIAZOTIZATION-FLUORINATION OF AMINOPYRIDINES IN ANHYDROUS HYDROGEN FLUORIDE
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The isolation and stabilization of elusive 4-fluoropyridine as the hydrochloride salt (54percent yield) from fluorodediazoniation of 4-aminopyridine in anhydrous hydrogen fluoride (AHF) is described.Unlike the low yields (0-13percent) recently reported from the chlorodediazoniation of 2,6-diaminopyridine and 3-halo-2,6-diaminopyridine, fluorodediazoniation gave high yields (49-62percent) of the corresponding 2,6-difluoropyridines.In contrast, benzene analogs, i.e. m-phenylenediamine and 4-chloro-m-phenylenediamine, form only tars under similar fluorination conditions.Vicinal aminohalopyridines, e.g. 3-amino-2-chloropyridine and 2-amino-3,5-dichloropyridine give the corresponding fluorohalopyridine in 49-89percent yield.Again, the benzene analogs, i.e. o-chloroaniline and 2,4-dichloroaniline, resist fluorination.
- Boudakian, Max M.
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- Method for efficiently synthesizing fluorine-containing compound
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The invention discloses a method for efficiently synthesizing a fluorine-containing compound, and relates to the field of fluorine-containing compound synthesis. The method is a method for generating a corresponding fluorine atom substituted fluorine-containing compound by reacting aromatic chloride or activated chloride serving as a raw material with potassium fluoride under the action of a novel catalyst. The method disclosed by the invention has the advantages of good product selectivity, high efficiency, mild reaction conditions, simplicity and convenience in operation, convenience in application and the like.
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Paragraph 0074-0076
(2021/06/26)
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- PROCESS FOR FLUORINATING COMPOUNDS
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Disclosed are mild temperature (e.g., from 0 to 80°C) SNAr fluorinations of a variety of halide and sulfonate substituted aryl and heteroaryl substrates using NMe4F.
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Page/Page column 29; 33; 35
(2017/02/28)
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- Rhodium catalyzed, carbon-hydrogen bond directed hydrodefluorination of fluoroarenes
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[CpRhCl(μ-Cl)]2 is reported as a highly efficient and selective precatalyst for the hydrodefluorination of perfluoroarenes using a hydrocarbon-soluble aluminum dihydride as the terminal reductant. Reactions are directed to cleave a C-F bond adjacent to an existing C-H bond with high regioselectivity (98.5-99%). A heterobimetallic complex containing an extremely rare Al-H-Rh functional group has been isolated and shown to be catalytically competent.
- Ekkert, Olga,Strudley, Sebastian D. A.,Rozenfeld, Alisa,White, Andrew J. P.,Crimmin, Mark R.
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supporting information
p. 7027 - 7030
(2015/05/19)
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- Acyl azolium fluorides for room temperature nucleophilic aromatic fluorination of chloro- and nitroarenes
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The reaction of acid fluorides with N-heterocyclic carbenes (NHCs) produces anhydrous acyl azolium fluorides. With appropriate selection of acid fluoride and NHC, these salts can be used for the room temperature SNAr fluorination of a variety of aryl chlorides and nitroarenes.
- Ryan, Sarah J.,Schimler, Sydonie D.,Bland, Douglas C.,Sanford, Melanie S.
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supporting information
p. 1866 - 1869
(2015/04/27)
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- Anhydrous Tetramethylammonium Fluoride for Room-Temperature SNAr Fluorination
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This paper describes the room-temperature SNAr fluorination of aryl halides and nitroarenes using anhydrous tetramethylammonium fluoride (NMe4F). This reagent effectively converts aryl-X (X = Cl, Br, I, NO2, OTf) to aryl-F under mild conditions (often room temperature). Substrates for this reaction include electron-deficient heteroaromatics (22 examples) and arenes (5 examples). The relative rates of the reactions vary with X as well as with the structure of the substrate. However, in general, substrates bearing X = NO2 or Br react fastest. In all cases examined, the yields of these reactions are comparable to or better than those obtained with CsF at elevated temperatures (i.e., more traditional halex fluorination conditions). The reactions also afford comparable yields on scales ranging from 100 mg to 10 g. A cost analysis is presented, which shows that fluorination with NMe4F is generally more cost-effective than fluorination with CsF.
- Schimler, Sydonie D.,Ryan, Sarah J.,Bland, Douglas C.,Anderson, John E.,Sanford, Melanie S.
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p. 12137 - 12145
(2016/01/09)
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- Process for the Synthesis of Highly Active Binary Metal Fluoride as a Fluorinating Agent for Aromatics
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The subject invention relates to a process for the synthesis of highly active binary metal fluoride system for the fluorination of aromatic compounds. Fluorinated aromatic compounds are valuable synthons for the chemical synthesis of pharmaceutical drugs and novel polymers. Fluorobenzene is used to control carbon content in steel manufacturing, is an intermediate for pharmaceuticals, pesticides and other organic compounds. Fluorobenzene is typically produced by the reaction of aniline and sodium nitrite in the presence of hydrogen fluoride. The present invention relates to a process for the synthesis of highly active binary metal fluoride system consists of copper (II) fluoride and aluminum (III) fluoride for the fluorination of aromatic compounds in gas phase and recycling of the reagent, in situ, using O2 and HF.
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Page/Page column 5
(2010/02/17)
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- Room-temperature nucleophilic aromatic fluorination: Experimental and theoretical studies
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(Chemical Equation Presented) Taming the reagent: The use of anhydrous tetrabutylammonium fluoride (TBAFanh) in nucleophilic aromatic substitution reactions, including variants of the selective halogen-exchange and fluorodenitration processes (see scheme), was investigated. It was shown that TBAFanh permits these reactions to be performed under surprisingly mild conditions if it is used in relatively nonpolar media.
- Sun, Haoran,DiMagno, Stephen G.
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p. 2720 - 2725
(2007/10/03)
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- The structural proliferation of 2,6-difluoropyridine through organometallic intermediates
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Contrary to a literature claim, 2,6-difluoropyridine-3-carboxaldehyde can be readily prepared by consecutive treatment of 2,6-difluoropyridine with lithium diisopropylamide and N,N-dimethylformamide. Regioselective displacements of fluorine from the aldehyde by nucleophiles were carried out. To demonstrate the versatility of the organometallic approach, some two dozens of further 2,6-difluoropyridine derivatives were prepared applying a combination of modern organometallic methods such as site selective hydrogen/metal and halogen/metal permutations and deprotonation-triggered heavy halogen migrations. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Schlosser, Manfred,Rausis, Thierry
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p. 1018 - 1024
(2007/10/03)
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- Elemental fluorine. Part 10.1 Selective fluorination of pyridine, quinoline and quinoxaline derivatives with fluorine-iodine mixtures
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Selective fluorination of a range of pyridine and quinoline substrates to give corresponding 2-fluoro-derivatives can be readily achieved in high yield at room temperature using elemental fluorine-iodine mixtures. Reaction of fluorine with iodine forms, in situ, systems that function like sources of both iodonium and fluoride ions and fluorination of heterocyclic derivatives is suggested to proceed by fluoride ion attack on intermediate W-iodo-heterocyclic species. Quinoxaline derivatives react under similar conditions to give either the 2-fluoro- or 2,3-difluoro-quinoxaline derivatives depending on the ratio of fluorine passed through the solution. In related processes, pyridine can be alkoxylated upon reaction of an appropriate alcohol and fluorine.
- Chambers, Richard D.,Parsons, Mandy,Sandford, Graham,Skinner, Christopher J.,Atherton, Malcolm J.,Moilliet, John S.
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p. 803 - 810
(2007/10/03)
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- Preparation of 2-Fluoropyridines via Base-Induced Decomposition of N-Fluoropyridinium Salts
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N-Fluoropyridinium salts with either BF4-, SbF6-, or PF6- as a counteranion were treated with excess base such as triethylamine at room temperature to give 2-fluoropyridine in good yield.This method was succesfully applied to the preparation of 2-fluoropyridine derivatives possessing electron-donating or -withdrawing substituents using substituted N-fluoropyridinium tetrafluoroborates.Pyridine-F2 compounds produced through reactions of pyridines with molecular fluorine were also treated with base to give 2-fluoropyridines but in low yields.These reactions are considered to occur through a carbene mechanism as follows: a novel N-F-containing cyclic carbene (3), generated from the N-fluoropyridinium salts by 2-proton abstraction, reacts with fluorine atoms from counteranions such as BF4-, SbF6-, or PF6-, followed by elimination of F- from the N-F moiety, to yield 2-fluoropyridines.Previously reported findings in reactions of pyridines with molecular fluorine are explained on the basis of this mechanism.
- Umemoto, Teruo,Tomizawa, Ginjiro
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p. 1726 - 1731
(2007/10/02)
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- DIRECT FLUORINATION OF SUBSTITUTED PYRIDINES
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The direct fluorination of pyridines bearing alkyl, halogen, ester, or ketone functions has been employed to prepare the corresponding 2-fluoro-substituted pyridines.
- Puy, Michael Van Der
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p. 255 - 258
(2007/10/02)
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- FLUORINATIONS WITH POTASSIUM TETRAFLUOROCOBALTATE(III) PART VII. FURTHER INVESTIGATIONS ON THE FLUORINATION OF PYRIDINE
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The product from the fluorination of pyridine by KCoF4 at ca. 220 deg C contains eleven fluoropyridines, two fluoro-2-azahex-enes, three azahexadienes, and two fluoro-N-methylpyrrolidines, besides an azacyclohexa-1,3-diene.Four products were isolated from fluorination of pyridine by CoF3 at ca. 150 deg C, a 2-azahexene, two N-methylpyrrolidines, and 4H-nonafluoropiperidine.
- Coe, Paul L.,Holton, Andrew G.,Tatlow, John Colin
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p. 171 - 190
(2007/10/02)
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- FLUORINATIONS WITH COMPLEX METAL FLUORIDES. PART 6. FLUORINATION OF PYRIDINE AND RELATED COMPOUNDS WITH CAESIUM TETRAFLUOROCOBALTATE(III)
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Pyridine has been fluorinated over caesium tetrafluorocobaltate(III) (CsCo(III)F4) at 300-400 deg C to give a mixture of undecafluoro-N-methyl-pyrrolidine, bis(trifluoromethyl)amine, pentafluoropyridine and several polyfluoropyridines; the product composition depend to some extent on the geometry of the reactor.The fluorinations of pentafluoropyridine, piperidine and undecafluoropiperidine were also investigated.
- Plevey, Raymond G.,Rendell, Richard W.,Tatlow, John Colin
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p. 159 - 170
(2007/10/02)
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- Diazotization-fluorination in a medium of hydrogen fluoride-containing ammonium ions
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Process for diazotization-fluorination of aromatic or heterocyclic amines in a solution of hydrogen fluoride containing ammonium ions.
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- Process for making 2,6-difluoro pyridine
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It has been found that practical rates of formation of 2,6-difluoropyridine from 2,6-dichloropyridine and KF can be attained without resort to catalysts, high temperatures or large excesses of KF, if: A. dimethyl sulfoxide (DMSO) is employed as the reaction medium, B. the reaction mixture contains less than 0.015 grams of HF and 0.5 grams of K2 CO3 or KHCO3 per 100 grams of KF and less than 0.5 grams of water per 100 grams of DMSO, c. the difluoropyridine is distilled out as formed, and D. the reaction mixture is intensely stirred and kept at a temperature of 175°-192° C.
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