Selective hydrodechlorination of fluorinated arylamines

Селиванова, Г. А.; Gurskaya, Larisa Yu.; Покровский, Л. М.; Kollegov, V. F.; Shteingarts, V. D.

doi:10.1016/j.jfluchem.2004.06.006

Cited by 15 publications

(7 citation statements)

References 26 publications

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“…The preparation of 10c by hydrodechlorination of 2,4 diamino 1 chloro 3,5,6 trifluorobenzene by treat ment with Zn 0 in aqueous NH 3 was documented. 26 Ac cording to a publication, 6 compound 10c is also formed in a mixture with other products upon the reaction of chloropentafluorobenzene with aqueous NH 3 in a steel autoclave at 200 °C.…”

Section: Methodsmentioning

confidence: 80%

Selective mono-and diamination of polyfluorinated benzenes and pyridines with liquid ammonia

et al. 2007

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Amination of pentafluoropyridine, 2,3,5,6 tetrafluoropyridine, 4 chlorotetrafluoropyridine, 3,5 dichlorotrifluoropyridine, octafluorotoluene, α,α,α,2,3,5,6 heptafluorotoluene, deca fluoro m xylene, decafluorobiphenyl, hexafluorobenzene, and pentafluorobenzene with liquid ammonia was investigated. Bis aminodefluorination temperatures for the majority of sub strates were shown to exceed significantly the corresponding temperatures of monoamino defluorination. The optimal conditions for selective preparation of mono and diamino polyfluoro(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. N. N. Vorozhtsov´s school made a considerable con tribution to the chemistry of polyfluoroaromatic com pounds: methods for the synthesis 1 and functionali zation 2,3a of base polyfluoroarenes were developed. Cur rently many polyfluoroarene derivatives are demanded for high tech processes and materials. In particular, diamino and dihydroxy(poly)fluoroarenes serve as struc tural blocks in the synthesis of polyimides used in fiber optic and thin film light guides, nanofilters, and mem branes, dielectric coatings, liquid crystalline displays, op tical diodes, laser media, etc. 4 Polyfluorinated amines of the benzene and pyridine series are used in the synthesis of biologically active compounds. 5It is known 6 that aminodehalogenation of arenes in aqueous ammonia, which is usually carried out in steel autoclaves at high temperatures (up to 250 °C), is often accompanied by competing transformations of arenes such as hydroxy and/or hydrodehalogenation involving water and the autoclave material. The version of the method of polyfluoroarene amination developed in this study im plies the use of liquid ammonia as both the reagent and the reaction medium. The possibility of aminodefluorina tion of some polyfluoroarenes with enhanced electrophi licity in liquid ammonia has been demonstrated previ ously. 7 The efficiency of liquid ammonia as a medium for aromatic nucleophilic substitution has been described in a review. 8 Note that the temperatures suitable for the work with liquid ammonia are limited by the range from -70 to 120 °C (m.p. -78 °C, critical point 133 °C). 9 It follows from analysis of published data that arene amino dehalogenation in liquid ammonia has a higher rate than that in aqueous ammonia; therefore, the processes are carried out at relatively low temperatures and the side reactions are minimized.The purpose of this study was to elucidate the condi tions for mono and diamination of polyfluorinated ben zene and pyridine derivatives in liquid ammonia, which are optimal as regards the selectivity and product yield, to develop simple and practically feasible techniques for separation of mixtures of amino compounds, and to syn thesize new high purity polyfluoroaromatic diamines de manded in high tech applic...

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Section: Methodsmentioning

confidence: 80%

Selective mono-and diamination of polyfluorinated benzenes and pyridines with liquid ammonia

et al. 2007

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“…Unlike perfluoroarylamines, their chlorine-containing analogues upon the action of zinc in aqueous ammonia undergo hydrodehalogenation very easily but with removal of chlorine (Scheme 15) [24].…”

Section: Experimental Data and Synthetic Applicationsmentioning

confidence: 99%

“…HOMO's of the pentafluoroacetanilide RA and the corresponding RA scomplex (the MO images are simplified by omitting the minor lobes associated with the fluorine atoms and the acetamido group). [24] S N Ar model. However, as zinc cations accumulate in the reaction medium, prevailing becomes ortho-hydrodefluorination, having been explained on the basis of the assumption of formation of a chelate complex of a zinc cation with a substrate.…”

Section: Mechanismmentioning

confidence: 99%

“…This allows believing that in going from arylamines, containing only fluorine, to their chloropolyfluoro analogues, the nature is changed of the MO accepting an electron. In case of a Cl-containing substrate an electron comes, obviously, directly on a s*-MO of the C-Cl bond to be synchronously cleaved, rather than on a p*-MO, which is strongly influenced by the amino group p-donating effect blocking hydrodehalogenation [24]. However, in case the energies of the MOs involved into hydrodefluorination and hydrodechlorination are obviously close, these two types of hydrodehalogenation can compete (Scheme 19) [7,8].…”

Section: Mechanismmentioning

confidence: 99%

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Recent advances in practice and theory of polyfluoroarene hydrodehalogenation

Shteingarts

2007

Journal of Fluorine Chemistry

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“…8,9 Thanks to this, the area of quinolines and their functional derivatives polyfluorinated on a benzene ring has been opened for intensive elaboration. [9][10][11][12][13] We believed this methodology is possible to apply to N-acetyl derivatives of perfluoronaphthylamines for preparing their less fluorinated analogues unsubstituted ortho to an amino group as potential building blocks for polyfluoronaphthoazaheterocycles, some of which also can be highly biologically active (for example, by analogy with mono-and difluorobenzoquinolines 14 ).…”

Section: Introductionmentioning

confidence: 99%

Hydrodefluorination of N-acetylheptafluoro-2-naphthylamine by zinc in aqueous ammonia: synthetic outcomes and mechanistic considerations

Reshetov¹,

Селиванова²,

Politanskaya³

et al. 2011

Arkivoc

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Dedicated to Professor Usein M Dzhemilev on the occasion of his 65th birthday AbstractReduction of the N-acetyl derivatives of heptafluoro-2-naphthylamine and its less fluorinated analogues by zinc in aqueous NH 3 has been investigated as a possible general and concise route to partially fluorinated N-(2-naphthyl)acetamides and, accordingly, 2-naphthylamines inaccessible by other ways. Quantum chemical calculations and CV measurement results have been used to discuss and justify the suggested reaction mechanism including two competing routes: fragmentation of a substrate radical anion and its complex with a zinc cation.

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Selective hydrodechlorination of fluorinated arylamines

Cited by 15 publications

References 26 publications

Selective mono-and diamination of polyfluorinated benzenes and pyridines with liquid ammonia

Selective mono-and diamination of polyfluorinated benzenes and pyridines with liquid ammonia

Recent advances in practice and theory of polyfluoroarene hydrodehalogenation

Hydrodefluorination of N-acetylheptafluoro-2-naphthylamine by zinc in aqueous ammonia: synthetic outcomes and mechanistic considerations

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