- Decarbethoxylative Arylation Employing Arynes: A Metal-Free Pathway to Arylfluoroamides
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An efficient, metal-free decarbethoxylative arylation protocol for the synthesis of α-aryl-α-fluoroamides from fluoromalonamates, under ambient reaction conditions using aryne as an electrophilic arylating agent, is reported. This decarbethoxylative arylation proceeds under mild conditions and provides a practical and effective entry to a wide range of α-aryl-α-fluoroacetamides. Interestingly, the use of the tert-butyl ester of fluoromalonamate prevented the otherwise rapid decarboxylation step, affording the arylated fluoromalonamate in moderate yield.
- Gupta, Ekta,Kant, Ruchir,Mohanan, Kishor
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p. 6016 - 6019
(2017/11/10)
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- Nucleophilic (Radio)Fluorination of α-Diazocarbonyl Compounds Enabled by Copper-Catalyzed H-F Insertion
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The copper-catalyzed H-F insertion into α-diazocarbonyl compounds is described using potassium fluoride (KF) and hexafluoroisopropanol. Access to complex α-fluorocarbonyl derivatives is achieved under mild conditions, and the method is readily adapted to
- Gray, Erin E.,Nielsen, Matthew K.,Choquette, Kimberly A.,Kalow, Julia A.,Graham, Thomas J. A.,Doyle, Abigail G.
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supporting information
p. 10802 - 10805
(2016/09/09)
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- A diastereoselective Mannich-type reaction of α-fluorinated carboxylate esters: Synthesis of β-amino acids containing α-quaternary fluorinated carbon centers
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We report a diastereoselective Mannich-type reaction of α-alkyl, α-aryl, and α-vinyl fluoroacetates with N-tert-butylsulfinyl imines. This method provides a powerful means to access a broad range of highly functionalized β-amino acids containing α-fluorinated quaternary stereogenic carbon centers. We also show that the stereochemical outcome of the present reaction is highly dependent on the steric and electronic properties of the fluorocarbon nucleophiles. This protocol uses readily available starting materials, tolerates a variety of functional groups, and is operationally simple.
- Li, Xiang,Li, Ya,Shang, Huaqi
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supporting information
p. 6457 - 6462
(2016/07/15)
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- Diversity-oriented approach to CF3CHF-, CF3CFBr-, CF3CF2-, (CF3)2CH-, and CF3(SCF3)CH-substituted arenes from 1-(Diazo-2,2,2-trifluoroethyl)arenes
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Arenes substituted with perfluoroalkyl groups are attractive targets for drug and agrochemical development. Exploiting the carbenic character of donor/acceptor diazo compounds, a diversity-oriented synthesis of perfluoroalkylated arenes, for late stage fluorofunctionalization, is described. The reaction of 1-(diazo-2,2,2-trifluoroethyl)arenes with HF, F/Br, F2, CF3H, and CF3SH sources give direct access to a variety of perfluoroalkyl-substituted arenes presenting with incremental fluorine content. The value of this approach is also demonstrated for radiochemistry and positron emission tomography with the [18F]-labeling of CF3CHF-, CF3CBrF-, and CF3CF2-arenes from [18F]fluoride.
- Emer, Enrico,Twilton, Jack,Tredwell, Matthew,Calderwood, Samuel,Collier, Thomas Lee,Ligault, Benot,Taillefer, Marc,Gouverneur, Vronique
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supporting information
p. 6004 - 6007
(2015/01/09)
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- Use of Task-Specific Ionic liquid for selective electrocatalytic fluorination
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[Chemical equation presented] Highly selective indirect anodic fluorination of organic compounds was successfully carried out for the first time by using a task-specific ionic liquid of iodoarene as a mediator in ionic liquid hydrogen fluoride salts.
- Sawamura, Takahiro,Kuribayashi, Shunsuke,Lnagi, Shinsuke,Fuchigami, Toshio
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supporting information; experimental part
p. 644 - 646
(2010/07/03)
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- Design of reaction media for nucleophilic substitution reactions by using a catalytic amount of an amphiphilic imidazolium salt in water
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Molecules of an amphiphilic imidazolium salt assemble in water to form a hydrophobic membrane including an interface consisting of ammonium species. Such an interface works as a reaction medium like an ionic liquid. We used the medium for nucleophilic substitution reactions between alkyl halides and anionic nucleophiles. This procedure allowed the reactions to proceed efficiently in water without any organic solvent.
- Asano, Keisuke,Matsubara, Seijiro
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experimental part
p. 989 - 1002
(2010/10/19)
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- The effect of substituents and operating conditions on the electrochemical fluorination of alkyl phenylacetates in Et3N·4HF medium
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Selective electrochemical fluorination of alkyl phenylacetates (Ph-CH2-COOR, where R is methyl, ethyl, n-propyl, n-butyl, i-propyl and sec-butyl) under galvanostatic conditions were reported in Et3N·4HF medium. Preparative electrolysis experiments were carried out both in pre-electrolysed dry Et3N·4HF and the same electrolyte medium without pre-electrolysis. Very little hydrolysed fluorinated products were obtained in pre-electrolysed medium where as significant quantities of hydrolysed products leading to fluorinated phenylacetic acid were obtained from Et3N·4HF without pre-electrolysis. Under optimum experimental conditions up to 87% selectivity of monofluoro ester could be achieved. Difluoro alkyl phenylacetate, monofluoro and difluoro phenylacetic acids were the other predominant side products obtained. The hydrolysis appears to be initiated by tautomeric transformation of proton after the initial electro oxidative formation of the cation radical. 19F as well as 1H NMR spectroscopy have been employed to identify the minor constituents formed during the electro oxidative process.
- Ilayaraja,Manivel,Velayutham,Noel
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p. 185 - 192
(2008/09/17)
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- SUBSTITUTED HYDROXYETHYL AMINE COMPOUNDS AS BETA-SECRETASE MODULATORS AND METHODS OF USE
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The present invention comprises a new class of compounds useful for the modulation of Beta-secretase enzyme activity and for the treatment of Beta-secretase mediated diseases, including Alzheimer's disease (AD) and related conditions. In one embodiment, the compounds have a general Formula I or Formula II wherein RIa, RIb, RIc, B, R3, R4, R5 and W of Formula I, and RIa, RIb, RIc, R2, R2a, R3, R4, R5, R6, Al, A2, A3, A4, W, X, Z, m and n of Formula II are defined herein.
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Page/Page column 148
(2009/01/20)
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- N-ALKYL-AZACYCLOALKYL NMDA/NR2B ANTAGONISTS
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Compounds represented by Formula (I): and/or pharmaceutically acceptable salts, individual enantiomers and stereoisomers thereof, are effective as NMDA/NR2B antagonists useful for treating conditions such as pain, Parkinson’s disease, Alzheimer’s disease, epilepsy, depression, anxiety, ischemic brain injury including stroke.
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Page/Page column 46
(2008/06/13)
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- Synthesis of α-fluorocarboxylates from the corresponding acids using acetyl hypofluorite
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α-Fluorocarboxylic esters and acids were synthesized in good yields. The corresponding esters and acids were converted to their ketene acetals, and these enol derivatives reacted with AcOF made directly from fluorine. This route circumvents the problems associated with nucleophilic fluorinations such as various eliminations and rearrangements. α- and β-branched carboxylic acid derivatives that cannot be directly fluorinated gave by this electrophilic fluorination the corresponding α-fluoro derivatives in good yield. Both the fluorination reaction and the preparation of AcOF are fast and suitable for [18]F incorporation into acids and esters needed for working with PET. α-Fluoroibuprofen (20) and methyl 2-fluoro-3,3,3-triphenylpropionate (32) are two examples of this general reaction.
- Rozen,Hagooly,Harduf
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p. 7464 - 7468
(2007/10/03)
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- Influence of a 2-fluoro substituent on diastereoselectivity in the 1,3-dipolar cycloadditions of nitrones
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It is clear that the role of 1,2-asymmetric induction on the 1,3-dipolar cycloaddition of nitrones is influenced by the presence of a fluorine atom at the C-2 position. 2-Fluoro nitrones, synthesized by three different methods, have been subjected to the intermolecular 1,3-dipolar cycloaddition with ethyl vinyl ether. The stereostructures of isoxazolidines formed were determined by their conversion into 2,7-dioxa-6-azabicyclo[3.2.1]octanes. The diastereoselectivity of 2-fluoro nitrones was the reverse of that of the corresponding 2-hydro nitrones. This fact supports that the conformation with relief from the dipole repulsion between the fluorine atom and the oxygen atom of the nitrone is a preferred one for 2-fluoro nitrones, while the corresponding 2-hydro nitrones adopt the conformation with the least 1,3-allylic strain.
- Ihara, Masataka,Tanaka, Yuko,Takahashi, Nobuyuki,Tokunaga, Yuji,Fukumoto, Keiichiro
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p. 3043 - 3052
(2007/10/03)
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- Synthesis of 2-fluoro- acids, esters, and amides from α-dicyanoepoxides
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The opening of α-dicyanoepoxides by pyridine polyhydrofluoride yields polymerisable 2-fluorocyanoformyls which may be kept intact when diluated in dichloromethane or ether. These intermediates react with nucleophiles such as water, methanol or amines to give respectively 2-fluoroacids, esters or amides.
- Amanetoullah, A. Ould,Chaabouni,Baklouti
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p. 1155 - 1161
(2007/10/03)
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- Effect of fluorine substitution of α-and β-hydrogen atoms in ethyl phenylacetate and phenylpropionate on their stereoselective hydrolysis by cultured cancer cells
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(±)-Ethyl 2-fluoro-2-phenylacetate was stereoselectively hydrolyzed by cultured cells of several rat cancer cell lines to give the carboxylic acid rich in the R enantiomer. The stereoselectivity increased for (±)-ethyl 2-fluoro-2-phenylpropionate (2b) with all present cell lines and for (±)-ethyl 2-phenyl-3,3,3-trifluoropropionate (3b) with rat hepatoma McA-RH7777 cell line. The stereoselectivity was different for the different cell lines, as McA-RH7777 cells preferred (R)-2b in contrast with the preference towards (S)-2b by other cells such as ras oncogene-transformed rat liver Anr4 cells. These stereoselectivities were different from those for non-fluorinated (±)-ethyl 2-phenylpropionate. Thus fluorine atoms are recognized by ester hydrolases of cancer cells, and fluorine substitution on the acyl group will be useful for making ester-type anticancer prodrugs more specific to cancer cells.
- Yamazaki, Yoshimitsu,Yusa, Shiro,Kageyama, Yu-Ichi,Tsue, Hirohito,Hirao, Ken-Ichi,Okuno, Hiroaki
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p. 167 - 171
(2007/10/03)
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- Selective, Electrophilic Fluorinations Using N-Fluoro-o-benzenedisulfonimide
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The synthesis of N-fluoro-o-benzenedisulfonimide (NFOBS, 2) and its use as an "electrophilic" fluorinating reagent with nucleophilic substrates is described and compared with that of N-fluorobenzenesulfonimide (NFSi, 3).NFOBS (2) is prepared in three steps in 81percent overall yield from commercially available o-benzenedisulfonic acid (4) and involves treatment of o-benzenedisulfonimide (6) with dilute fluorine (10percent F2/N2).Reaction of 2 with metal enolates, silyl enol ethers, and 1,3-dicarbonyl compounds affords the corresponding α-fluoro compounds in yields up to 95percent, with good control of mono- and difluorination.Fluorination of ortho-metalated aromatic compounds was achieved in modest to good yields (10-80percent).While the reactivities of 2 and 3 are similar, better yields were observed with the former reagent in the fluorination of metal enolates, Grignard and lithium reagents, while 3 gave better results with the ortho-lithiated aromatic substrates.The available evidence suggests an SN2-type mechanism for the fluorination of nucleophilic substrates by these reagents.
- Davis, Franklin A.,Han, Wei,Murphy, Christopher K.
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p. 4730 - 4737
(2007/10/02)
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- SELECTIVE MONO- AND DIFLUORINATION OF ENOLATES
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The selective transformation of enolates into mono- and difluorinated carbonyl compounds can be performed in a one-pot procedure using N-F-sultam 1.The yields and the selectivity of the fluorination strongly depend on the counterion of the enolate and the acidity of the protons α to the carbonyl group.
- Differding, Edmond,Rueegg, Gabriela M.,Lang, Robert W.
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p. 1779 - 1782
(2007/10/02)
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The reaction of phenyltetrafluorophosphorane with secondary or tertiary α- or β -hydroxy esters, ketones, nitriles, ethers and nitro derivatives has been investigated. The formation of the alkoxyfluorophosphorane 3 has been established in several cases. G
- Costa,Boutin,Riess
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p. 3793 - 3797
(2007/10/06)
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