- A Selective Single Step Amidation of Polyfluoroarenes
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This chemistry establishes a method for the synthesis of per- and poly-fluoroaryl acid amides, utilizing nucleophilic aromatic substitution. Traditionally, such amides are constructed in a two-step process, namely, ammonolysis and then N-acylation. Herein, good yields of N-polyfluoroaryl acid amides were achieved in a single step under mild reaction conditions. Key to achieving optimal yields is the use of two equivalents of the nucleophile. In addition, the mechanism of the reaction is discussed which has implications for other related nucleophilic substitutions.
- Day, Jon,Despain, Megan,Hamilton, Matthew,Keen, Brockton,Noel, Alyssa M.,Weaver, Jimmie D.
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- Anilide Formation from Thioacids and Perfluoroaryl Azides
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A metal-free method for fast and clean anilide formation from perfluoroaryl azide and thioacid is presented. The reaction proved highly efficient, displaying fast kinetics, high yield, and good chemoselectivity. The transformation was compatible with various solvents and tolerant to a wide variety of functional groups, and it showed high performance in polar protic/aprotic media, including aqueous buffer systems. (Chemical Equation Presented).
- Xie, Sheng,Fukumoto, Ryo,Ramstr?m, Olof,Yan, Mingdi
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- Conformational analysis of N-aryl-N-(2-azulenyl)acetamides
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Aromatic amides bearing 2-azulenyl group on the amide nitrogen were synthesized and their structures were investigated. The π-electron density of the N-aryl group was found to influence the cis-trans conformational preferences of these compounds in solution. X-ray crystallography revealed that the plane of the 2-azulenyl ring has a strong tendency to lie coplanar with the amide plane when the azulene group is located on the same side as the amide oxygen atom.
- Ito, Ai,Amaki, Takamasa,Ishii, Ayako,Fukuda, Kazuo,Yamasaki, Ryu,Okamoto, Iwao
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supporting information
p. 3994 - 3998
(2018/10/02)
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- Interaction of polyfluorinated 2-chloroquinolines with ammonia
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We have studied the interaction of polyfluorinated (in the benzene moiety) 2-chloroquinolines with liquid and aqueous ammonia as an approach to the synthesis of halogen-containing aminoquinolines. 5,7-Difluoro-, 5,6,8-trifluoro-, and 5,7,8-trifluoro-2-chloroquinolines mostly form products of substitution of the Cl atom, whereas 5,7-difluoro-2,6-dichloroquinoline, 5,6,7,8-tetrafluoro-, and 6,7-difluoro-2-chloroquinolines yield products of substitution of an F atom at various positions. The replacement of liquid ammonia with aqueous causes an increase in the proportion of the products of aminodechlorination relative to the products of aminodefluorination. For 2-chloro-6,8-difluoroquinoline this replacement leads to 2-amino-6,8-difluoroquinoline as the main product instead of the 8-amino-derivative. Activation energy values estimated by DFT calculations for the reactions in question agree with the reaction regioselectivity observed experimentally.
- Skolyapova, Alexandrina D.,Selivanova, Galina A.,Tretyakov, Evgeny V.,Bogdanova, Tatjana F.,Shchegoleva, Lyudmila N.,Bagryanskaya, Irina Yu.,Gurskaya, Larisa Yu.,Shteingarts, Vitalij D.
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supporting information
p. 1219 - 1229
(2017/02/18)
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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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- Reaction of pentafluoroacetanilide with zinc catalyzed by nickel complexes
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The reaction of pentafluoroacetanilide hydrodefluorination under the action of zinc in the presence of catalytic amounts of complexes, generated in situ from nickel chloride and 2,2′-bipyridine or 1,10-phenanthroline, was studied. The influence of the sol
- Prikhodko,Adonin,Parmon
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p. 2304 - 2310
(2014/05/06)
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- A new approach to polyfluoroaromatic amines with an unsubstituted position ortho to the amino group
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N-acetyl derivatives of polyfluoroaromatic amines have been found to be highly selectively defluorinated by zinc in aqueous ammonia at the position ortho to the acetamido group thus affording a new approach to potential building blocks for the synthesis o
- Laev,Evtefeev,Shteingarts
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- ATTOGRAM-LEVEL DETECTION AND RELATIVE RESPONSE OF STRONG ELECTROPHORES BY GAS CHROMATOGRAPHY WITH ELECTRON CAPTURE DETECTION.
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The responses as peak areas of some divergent compounds, most of which are strong electron absorbers, are measured by gas chromatography with electron capture detection (GC-ECD). The most sensitive compounds are derivatized lodothyronines, which are essentially 20-fold more sensitive than lindane. N,N-Dipentafluorobenzoylpentafluoroaniline, a somewhat less sensitive but more volatile substance, was selected for determination of a detection limit. The value was 90 ag(1. 6 multiplied by 10** minus **1**9 mol), largely due to an anomalous increase in its response at the trace level. This increases the reported sensitivity of GC-ECD by 100-fold.
- Corkill,Joppich,Kuttab,Giese
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p. 481 - 485
(2007/10/02)
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