- Deoxofluorination of Aliphatic Carboxylic Acids: A Route to Trifluoromethyl-Substituted Derivatives
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A practical method for the synthesis of functionalized aliphatic trifluoromethyl-substituted derivatives from aliphatic acids is developed. The transformation proceeds with sulfur tetrafluoride in the presence of water as a key additive. Compared to previous methods, the reaction gives products with full retention of stereo- and absolute configuration of chiral centers.
- Bugera, Maksym,Trofymchuk, Serhii,Tarasenko, Karen,Zaporozhets, Olga,Pustovit, Yurii,Mykhailiuk, Pavel K.
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p. 16105 - 16115
(2019/12/24)
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- Design of fluorinated 5-HT4R antagonists: Influence of the basicity and lipophilicity toward the 5-HT4R binding affinities
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Analogues of potent 5-HT4R antagonists possessing a fluorinated N-alkyl chain have been synthesized in order to investigate the effect of the resulting change in basicity and lipophilicity on the affinity and selectivity profile. We demonstrate that for this series, the affinity is decreased with decreased basicity of the piperidine's nitrogen atom. In contrast, the resulting increase in lipophilicity has minimal impact on binding affinity and selectivity. 3,3,3-Trifluoropropyl and 4,4,4-trifluorobutyl derivatives 6d and 6e have shown to bind to the 5-HT4R while maintaining their pharmacological profile and selectivity toward other 5-HT receptors.
- Fontenelle, Clement Q.,Wang, Zhong,Fossey, Christine,Cailly, Thomas,Linclau, Bruno,Fabis, Frederic
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p. 7529 - 7538
(2013/11/19)
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- KrF laser induced telomerization of bromides with olefins. Part 1. Self-inhibition and kinetic analysis
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The chain reaction of several organic bromides with olefins was induced by a KrF laser. In all cases we found a self-inhibition, leading to a termination of first order in the radical concentration. There is indirect evidence that it is due to molecular bromine, accumulated during the reaction in spite of the presence of olefins. It has not been noticed previously. We show that kinetic analysis is easy also for pulsed excitation, and the example CF3Br + C2H4 is studied in detail. We found rate constants for CF3 + C2H4 → CF3C2H4 (7.2·109 cm3 mol-1 s-1; this is in between two previous values) and for CF3C2H4 + CF3Br → CF3C2H4Br + CF3(1.2·109 cm3 mol-1 s-1) as well as preliminary values for some other reactions.
- Linyang,Fuss,Kompa
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p. 867 - 874
(2007/10/02)
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- Structural Effects on the Transition States of Imine-Forming Eliminations in N-Substituted O-(Arylsulfonyl)hydroxylamines
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A series of amines with various alkyl and aryl substituents at C-1 were converted to the corresponding N-(arylsulfonoxy)amines, which served as precursors for base-promoted, imine-forming elimination.By varying the bases used to promote the elimination and by varying the leaving groups attached to nitrogen, the Broensted parameters β and βlgCH3 were determined.These were used to locate the transition state on the More O'Ferrall-Jencks energy surface for elimination.Substituents were found to influence the structure of the activated complex markedly.Resonance effects were most important, while inductive effects had little influence .
- Hoffman, Robert V.,Shankweiler, Jean M.
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p. 4019 - 4022
(2007/10/02)
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