- Studies on the synthesis of fluorinated Schiff bases; biological activity of resulting (E)-N-benzylidene-2,3,5,6-tetrafluoropyridin-4-amine and 4-amino-2-ethoxy-3,5,6-trifluoropyridine
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The present work is aimed mainly to synthesize new fluorinated compounds and their biological significance against tested bacteria and fungus. Thus, the 4-amino-2-ethoxy-3,5,6-trifluoropyridine 4 was synthesized by the reaction of 4-amino 2,3,5,6-tetraflu
- Raache, Imane,Sekhri, Lakhdar,Tabchouche, Ahmed
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- MECHANISM FOR REACTIONS OF HALOGENATED COMPOUNDS. PART 4. ACTIVATING INFLUENCES OF RING-NITROGEN AND TRIFLUOROMETHYL IN NUCLEOPHILIC AROMATIC SUBSTITUTION
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Rate constants have been measured for the reactions of ammonia with various fluorinated pyridines and diazines in aqueous dioxan at 25 deg C.From the results the activating effects of ring-nitrogen (relative to C-H) and of trifluoromethyl (relative to -H)
- Chambers, R. D.,Martin, P. A.,Waterhouse, J. S.,Williams, D. L. H.,Anderson, B.
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- Reactions of polyfluoropyridines with bidentate nucleophiles: Attempts to prepare deazapurine analogues
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Reactions of pentafluoropyridine with guanidine, thiourea and urea with the hope of preparing derivatives which may be cyclised to polyfluorodeazapurines are described The reactions with urea and thiourea produced, somewhat unexpectedly, bis-(2,3,5,6-tetrafluoro-4-pyridyl)amine and bis-(2,3,5,6-tetrafluoro-4-pyridyl)sulfide, respectively, the structure of the amine was confirmed by X-ray crystallography. The product from the guanidine reaction was the expected 4-substituted tetrafluoropyridine derivative. Attempts to cyclise the latter are described and a rationalisation to explain the unexpected melamine derivatives which were produced is given.
- Coe, Paul L.,Rees, Anthony J.,Whittaker, Jane
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- STUDIES IN AZIDE CHEMISTRY. PART 12. ONE-POT CONVERSION OF 4-AZIDOTETRAFLUOROPYRIDINE TO 1,3,4-TRIFLUORO-7,9-DIMETHYL-11H-PYRIDOBENZODIAZEPINE
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Thermolysis of 4-azidotetrafluoropyridine in the presence of an excess of mesidine at 170 deg C yields tetrafluoro-4-(2,4,6-trimethylphenylazo)-pyridine, which undergoes intramolecular dehydrofluorination in situ to provide 1,3,4-trifluoro-7,9-dimethyl-11H-pyridobenzodiazepine.
- Banks, Ronald E.,Madany, Ismail M.
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- Reductive defluorination of polyfluoroarenes by zinc in aqueous ammonia
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Aqueous ammonia has been found to be a good and versatile medium for the reductive defluorination of polyfluoroarenes by zinc. Upon the reduction of pentafluorobenzoic acid, 2,3,4,5,6-pentafluorobenzyl alcohol, pentafluoropyridine and heptafluoro-2-naphthoic acid individual products derived from the removal of one fluorine atom have been obtained.
- Laev, Sergey S.,Shteingarts, Vitalij D.
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- N-Halogeno compounds. Part 16. Perfluoro-[N-fluoro-N-(4-pyridyl)acetamide] - A new site-selective electrophilic fluorinating agent
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Perfluoro-[N-fluoro-N-(4-pyridyl)acetamide] (2), prepared via direct fluorination of the sodium salt (4) of perfluoro-[N-(4-pyridyl)-acetamide], readily fluorinates diethyl sodio(phenyl)malonate [→PhCF(CO2Et)2], 1-morpholinocyclohexene(→2-fluorocyclohexanone), anisole (→2-and 4-FC6H4OMe), and phenol (→2-and 4-FC6H4OH) under mild conditions. The sodium salt precursor (4) of this side-chain N-F reagent (2) is easily made from pentafluoropyridine via the trifluoroacetylation of its 4-amino derivative or, more directly, by treating it with two equivalents of the monosodium salt of trifluoroacetamide.
- Banks,Besheesh,Tsiliopoulos
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- Hydrogen Bond Directed Photocatalytic Hydrodefluorination: Overcoming Electronic Control
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The photocatalytic C-F functionalization of highly fluorinated arenes is a powerful method for accessing functionalized multifluorinated arenes. The decisive step in the determining regioselectivity in fluorine functionalization is fluoride fragmentation from the radical anion of the multifluorinated arene. To date, the availability of regioisomers has been dictated by the innate electronics of the fluorinated arene, limiting the synthetic utility of the chemistry. This study investigates the remarkable ability of a strategically located hydrogen bond to transcend the normal regioselectivity of the C-F functionalization event. A significant rate acceleration is additionally observed for hydrodefluorination of fluorines that can undergo intramolecular hydrogen bonds that form 5-8-membered cycles with moderately acidic N-H's. The hydrogen bond is expected to facilitate the fragmentation not only by bending the C-F bond of the radical anion out of planarity but also by increasing the exothermicity of the fluoride extrusion step through protonation of the naked fluoride. Finally, the synthetic utility of the method is demonstrated in an expedited synthesis of the trifluorinated α-phenyl acetic acid derivative required for the commercial synthesis of Januvia, an antidiabetic drug. This represents the first synthesis of a commercially important multifluorinated arene via a defluorination strategy and is significantly shorter than the current strategy.
- Khaled, Mohammad B.,El Mokadem, Roukaya K.,Weaver, Jimmie D.
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supporting information
p. 13092 - 13101
(2017/09/26)
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- Photocatalytic hydrodefluorination: Facile access to partially fluorinated aromatics
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Polyfluorinated aromatics are essential to materials science as well as the pharmaceutical and agrochemical industries and yet are often difficult to access. This Communication describes a photocatalytic hydrodefluorination approach which begins with easily accessible perfluoroarenes and selectively reduces the C-F bonds. The method allows facile access to a number of partially fluorinated arenes and takes place with unprecedented catalytic activity using a safe and inexpensive amine as the reductant.
- Senaweera, Sameera M.,Singh, Anuradha,Weaver, Jimmie D.
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supporting information
p. 3002 - 3005
(2014/03/21)
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- Radical ipso-substitution of a carbon-fluorine bond leading to fluoro-7-azaindolines and fluoro-7-azaindoles
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Rare examples of a synthetically useful radical ipso-substitution of a carbon-fluorine bond are reported, leading to highly functionalized 5,6-difluoro-7-azaindolines. An unexpected hydrogen atom translocation and fragmentation with loss of molecular nitrogen and formation of a nitrile were observed in the case of an N-benzyl-tetrazole derivative.
- Liu, Zhibo,Qin, Ling,Zard, Samir Z.
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supporting information
p. 2704 - 2707
(2014/06/09)
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- Imidazopyridine and pyrimidinopyridine systems from perfluorinated pyridine derivatives
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Annelation of pentafluoropyridine via an intramolecular nucleophilic aromatic substitution process with benzamidine gave an imidazopyridine system in high yield in a two step process whilst alkyl amidines gave 4-aminotetrafluoropyridine by a competing eli
- Cartwright, Matthew W.,Sandford, Graham,Bousbaa, Jamaal,Yufit, Dmitrii S.,Howard, Judith A.K.,Christopher, John A.,Miller, David D.
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p. 7027 - 7035
(2008/02/05)
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- Reactions of arylthiazylamides with internal and external fluoro electrophiles - Formation of products with unusual structures
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The heteroatom reactivity of the title anions [as (Me2N)3S+ and Cs+ salts] toward both internal and external fluoro electrophiles has been investigated. The intramolecular nucleophilic cyclization of [ArNSN]- (as the cesium salts) bearing at least one ortho fluorine afforded 2,1,3-benzothiadiazoles (e.g. 2a,b), whereas intermolecular condensation with polyfluorinated pyridine and naphthalene afforded Ar-N=S=N-R with R = 4-PyF (4) and R = 2-NpF (8). Further interaction of [ArNSN]- with 4 or 8 proceeded with the transfer of NSN units resulting in (ArN=)2S (5) and [RNSN]-, followed by decomposition (R = 4-PyF) to 4-PyFNH2 (6) or intramolecular cyclization (R = 2-NpF) to the polyfluorinated thiadiazole 9. The compounds of types 4, 5, 8, and 9 have been characterized by single-crystal X-ray diffraction as having both Z,E and Z,Z configurations [8 and 9 as molecular complexes with C10F8 and (Ph-N=)2S (5e), respectively, featuring π-stacking interactions of the arene-polyfluoroarene type]. Besides normal aryl-polyfluoroaryl interactions, the 8·C10F8 complex also displays unusual polyfluoroaryl-polyfluoroaryl π-stacking.
- Lork, Enno,Mews, Ruediger,Shakirov, Makhmut M.,Watson, Paul G.,Zibarev, Andrey V.
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p. 2123 - 2134
(2007/10/03)
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- Reactions of polyfluoroarenes with hexamethyldisilazane and with 1,1,1-trimethyl-N,N-bis(trimethylsilyl)stannaneamine in the presence of caesium fluoride
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Hexamethyldisilazane and 1,1,1-trimethyl-N,N-bis(trimethylsilyl)stannaneamine aminate pentafluoropyridine, octafluorotoluene, pentafluorobenzonitrile, pentafluoronitrobenzene and pentafluorobenzene sulphonyl fluoride in the presence of caesium fluoride with formation of the corresponding perfluorinated aryl amines (ArNH2), diarylamines (Ar2NH) and triarylamines (Ar3N) (where the amine functions are in positions 4 relative to the arene substituent). - Keywords: Polyfluoroarenes; Hexamethyldisilazane; Caesium fluoride; Silylated amines
- Miller, Alexey O.,Furin, Georgii G.
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p. 169 - 172
(2007/10/03)
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- EQUILIBRIUM NH ACIDITY OF 4-SUBSTITUTED 1-AMINOANTHRAQUINONES IN DIMETHYL SULFOXIDE
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The equilibrium acidity of 1-amino-4-R-anthraquinones (R = CH3O, H, Cl, Br, NO2) was determined by transmetallation in DMSO (the Na+ cation, 25 deg C).A linear correlation was established between the pK values of the 4-substituted 1-aminoanthraquinones and the ?p- constants of the substituents R.The conduction of the electronic effect of the substituents R is stronger in the aminoanthraquinones than in the anilines and is closer to the naphthylamines.A linear relation is observed between the conduction of the electronic effect of the substituent and the square of the coefficient in the HOMO for the carbon atom at the point of addiion of the substituent in the series of anions of NH acids of various structure types.The increase in the NH acidity with change in the structure type of the NH acid is not necessarily accompanied by a decrease in the conduction of the electronic effect of the substituents.
- Os'kina, I. A.,Vlasov, V. M.,Terekhova, M. I.,Petrov, E. S.
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p. 2041 - 2044
(2007/10/02)
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- REACTION OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN LIQUID AMMONIA. X. AMINATION OF POLYFLUORINATED AROMATIC COMPOUNDS CONTAINING ELECTRON-WITHDRAWING SUBSTITUENTS
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It was shown for the case of 2,4-difluoro-, 2,4,6-trifluoro-, and pentafluoronitrobenzenes that both liquid ammonia and sodium amide in liquid ammonia are effective reagents for aminodefluorination with respect to the fluorine derivatives of nitrobenzene.The observed tendency for the ortho-orientation with respect to the nitro group to change to para-orientation with increase in the number of fluorine atoms is more clearly defined for sodium amide than for liquid ammonia as nucleophile on account, clearly, of the stabilization of the transition state of ortho-substitution in the latter case by an intramolcular hydrogen bond.
- Selivanova, G. A.,Chuikova, T. V.,Shtark, A. A.,Shteingarts, V. D.
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p. 2267 - 2272
(2007/10/02)
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- MECHANISMS FOR REACTIONS OF HALOGENATED COMPOUNDS. PART 6. INVESTIGATIONS INTO THE ACTIVATING EFFECT OF ORTHO-FLUORINE IN NUCLEOPHILIC AROMATIC SUBSTITUTION
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Separate activating effects for ortho- and meta- fluorine, on nucleophilic aromatic substitution, are determinated for pyrimidine and pyridine systems.Comparisons confirm the importance of ion-dipole interactions for activation by ortho-fluorine.The effects of ortho-fluorine on anionic ?-complexes are also discussed.
- Chambers, Richard D.,Seabury, Mark J.,Williams, D. Lyn H.,Hughes, Nigel
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p. 255 - 258
(2007/10/02)
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- FLUOROCARBON DERIVATIVES OF NITROGEN. PART 16. SYNTHESIS OF SOME UNSYMMETRICAL AROMATIC AZO-COMPOUNDS via DIAZOTISATION OF FLUORINATED ARYL- AND N-HETEROARYL-AMINES IN HYDROFLUORIC OR SULPHURIC ACID
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Coupling reactions of the type ArFN2+ + ArH -> ArFN=NAr + H+ have been accomplished between fluorinated arenediazonium ions selected from the benzenic, pyridinic and pyrimidinic classes F = C6F5, 4-CF3C6F4, 4-C5F4N, 4-C5F3N.Cl-3, 4-C5F2N.Cl2-3,5, 2-C5F3N.CF(CF3)2-4, 4-C4F3N2> and one or more aromatic compounds activated towards electrophilic attack (ArH = 1,3,5-Me3C6H3, 1,3,5-Et3C6H3, MeOC6H5, Me2NC6H5, and naphth-2-ol).The diazonium ions were generated by addition of solid sodium nitrite to solutions of the amines ArFNH2 in anhydrous hydrogen fluoride, 80percent hydrofluoric acid, or 98 percent sulphuric acid mixed with glacial aceticacid and propionic acid.This work has established that perfluorinated arenediazonium ions rank amongst the most electrophilic species of their general class.
- Alty, Adam C.,Banks, Ronald E.,Thompson, A. Ronald,Vellis, Haralambos S.,Fishwick Brian R.
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p. 147 - 170
(2007/10/02)
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- N-(POLYFLUOROARYL)-HIDROXYLAMINES. SYNTHESIS AND PROPERTIES
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Fluorine-containing N-arylhydroxylamines have been obtained by the reaction of hydroxylamine or its N- and O-derivatives on polyfluorinated benzenes and pentafluoropyridine.The influence of fluorine atoms on the reactivity of hydroxylamino group has been investigated.The reaction of N-polyflouroarylhydroxylamines with aldehydes has been shown not to occur, whereas their reaction with nitrosobenzenes leads to azoxybenzenes and with Lewis acids leads to corresponding nitrosobenzenes, azoxybenzenes and anilines.The action of acids on 2,3,5,6-tetrafluorophenylhydroxylamine leads to the acid-catalyzed rearrangement of the latter into 4-amino-2,3,5,6-tetrafluorophenol.C,N-Diarylnitrones have been obtained by the oxidation with MnO2 of fluorine-containing arylhydroxylamines possessing the CH-fragment in an α-position.
- Miller, A.O.,Furin, G. G.
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p. 247 - 272
(2007/10/02)
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- 4-amino-3-halo-2-pyridinone nucleoside and nucleotide compounds
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4-Amino-3-halo-1-β-D-ribofuranosyl-2-(1H)-pyridinone, 4-amino-3-halo-1-(2-deoxy-β-D-pentofuranosyl)-2(1H)-pyridinone, and nucleosides and 4-amino-3-halo-1-(2-deoxy-2,2-difluoroβ-D-pentofuranosyl)-2(1H)-pyridinone nucleosides and nucleotides are useful as antiviral agents and possess in vivo activity against the L1210 murine leukemia cell line.
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