- Fluorination of aromatic compounds with N-fluorobenzenesulfonimide under solvent-free conditions
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Reactions of N-fluorobenzenesulfonimide with methylbenzenes, phenols, and phenol ethers were studied under solvent-free conditions. The rate constant ratio for the reactions with mesitylene and durene indicates polar mechanism of the process. Solvent-free fluorination of aromatic compounds with N-fluorobenzenesulfonimide in some cases is more selective than reactions with other N-F reagents in a solvent.
- Andreev,Borodkin,Shubin
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scheme or table
p. 1468 - 1473
(2010/03/24)
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- Novel process for generating useful electrophiles from common anions using Selectfluor fluorination agent
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In the present work, the electrophile equivalents C1+, Br+, SCN+, and NO2+ are generated from their respective sodium, potassium, and in some cases ammonium salts (M+X-) by reaction with Selectfluor electrophilic fluorination agent in acetonitrile solution at room temperature. These generated electrophilic species subsequently react in situ with a variety of aromatic substrates containing one or more substituent groups including H, F, C1, CH3, COOH, C(O)CH3, NO2, and OR′ and NR′R″ where R′ and R″ are H or CH3. The resulting substitution products are, in most cases, isolable as pure compounds in high yield. Variations in the process include the use of other anions, electrophilic fluorination agents, and solvents.
- Syvret, Robert G.,Butt, Kathleen M.,Nguyen, Tung P.,Bulleck, Victoria L.,Rieth, Ryan D.
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p. 4487 - 4493
(2007/10/03)
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- First application of ionic liquids in electrophilic fluorination of arenes; Selectfluor (F-TEDA-BF4) for "green" fluorination
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The NF fluorinating agent F-TEDA-BF4 dication salt (Selectfluor) 1 dissolves in imidazolium-based ionic liquids [emim][OTf] 7, [emim][BF4] 8, [bmim][PF6] 9 and [bmim][BF4] 10 (assisted by sonication), providing a convenient medium for fluorination of arenes under essentially acid-free conditions in a simple set-up (no volatile solvent; simple extraction of the aromatics without aqueous work-up), from which the ionic liquid can be easily recycled and reused. Comparative studies in [emim][OTf] 7 with anisole as substrate show that 1 is superior to NFTh-BF4 (Accufluor) 2 and that the N-fluoropyridinium salt NFPy-B2F7 4 is least effective. The scope of the reaction has been surveyed. Substrate selectivity (k mesitylene: k durene = 10) measured in competitive experiments in 7 is clearly indicative of a conventional polar mechanism. Substrate selectivity measured without the ionic liquid in MeCN solvent is also indicative of a polar mechanism but exhibits lower magnitude (k mesitylene: kdurene = 6). Addition of dicyclohexano-24-crown-8 to the fluorination reaction mixture (1 and anisole) in 7 reduced the conversion but did not change the isomer distribution. AM1 minimization was used to model the complexation of 1 with this crown. With reactive aromatics optimal fluorination yields in ionic liquids (using 1 equivalent of the NF reagent) are around 50% (higher for naphthalene). A key control experiment suggests that the free base (produced upon transfer-fluorination) could complex to unreacted 1 (generating a bulky dimer complex which may be ineffective for fluorine transfer) in competition to N-protonation.
- Laali, Kenneth K.,Borodkin, Gennady I.
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p. 953 - 957
(2007/10/03)
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- Elemental fluorine Part 12. Fluorination of 1,4-disubstituted aromatic compounds
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Direct fluorination of a series of 1,4-disubstituted benzene derivatives in acid reaction media at convenient temperature leads, in many cases, to selectively fluorinated aromatic products in preparatively useful conversions and yields.
- Chambers, Richard D.,Hutchinson, John,Sparrowhawk, Matthew E.,Sandford, Graham,Moilliet, John S.,Thomson, Julie
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p. 169 - 173
(2007/10/03)
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- Fluorination process
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According to the present invention there is provided a process for the selective introduction of one or more fluorine atoms into a disubstituted aromatic compound in an acid medium with fluorine gas characterized in that the acid medium has a dielectric constant of at least 20 and a pH of less than 3. The present process provides a cost effective means of selectively introducing one or more fluorine atoms into an aromatic compound in good overall yield.
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- Synthesis and evaluation of the anti-mammary tumor activity and of the estrogenic side effects of platinum(II) complexes
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The synthesis and structural characterization of mammary tumor-inhibiting, diastereomeric platinum(II) complexes with 2,6-Cl2, 2F, 6-Cl, 2-Cl, 6-F and 2,6-F2 substituents (1-PtSO4 to 4-PtSO4) are describ
- Gust, R,Schoenenberger, H
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p. 103 - 115
(2007/10/02)
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- Dihydropyridine derivatives, processes for their preparation and pharmaceutical compositions thereof
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There are described compounds of Formula I, in which R1, R2, R3 and R4 are as defined in the specification,R5 is alkyl optionally interrupted by an amide group and optionally substituted by halogen or by a carboxy or a heterocyclic group,X is -O-, -NR-, -S(O)m1, or a bond,Z is hydrogen or together with R forms a bond,R is hydrogen, alkyl or together with Z forms a bond,R6 is a 5 or 6 membered unsaturated nitrogen containing heterocyclic ring, optionally fused to a phenyl ring and optionally substituted by one or more of oxo, hydroxy, alkyl, -(CH2)n1NH2, alkoxy, phenyl or -COOH,and when X is -NR- or -S(O)m1-, R6 may in addition be hydrogen or a group -CH2CH2NH2, -CH2CH2-het. or NHC(=NH)NH2,when X is -O-, R6 may also be a group -NH2, -C(=O) (CH2)nNH2, -CH2CH2NR14R15 or CH2CH2OCH2CH2NR14R15,when X is -NR-, -S(O)m1-, or a bond, R6 may also be hydrogen or a group -C(=NR12)NHR13,R13 and R14 may be hydrogen or alkyl,R12 is hydrogen, alkylcarbonyl, nitrile or hydroxy,R15 is hydrogen or a group R11,m and m1 are each 0, 1 or 2,n is 0 or 1,n1 is an integer from 0 to 6, and pharmaceutically acceptable salts, esters, amides, analogues and protected derivatives thereof.
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