653-39-4Relevant academic research and scientific papers
Some Comments on a Recently Proposed Method of Determining Chlormequat Residues by Derivatization With Pentafluorothiophenol
Mortimer, Richard D.,Weber, Dorcas F.
, p. 31 - 36 (1994)
A recent publication concerning the analysis of residues of the herbicide chloromequat in cotton seed by gas chromatography contains a significant error. A derivative prepared by reacting pentafluorothiophenol with chlormequat is actually produced by the reaction of the initial product of demethylation of chlormequat with a second molecule of pentafluorothiophenol. As the derivative in not derived from the chlormequat backbone, the method is not specific to chlormequat and could be misleading to an analyst using it or adapting it to other produce.
The organocatalytic synthesis of perfluorophenylsulfides: Via the thiolation of trimethyl(perfluorophenyl)silanes and thiosulfonates
Cai, Zhihua,Du, Guangfen,He, Lin,Lin, Muze,Luo, Jinyun,Wu, Leifang
supporting information, p. 9237 - 9241 (2021/11/13)
The organic superbase t-Bu-P4-catalyzed direct thiolation of trimethyl(perfluorophenyl)silanes and thiosulfonates was developed. Yields of perfluorophenylsulfides of up to 97% under catalysis of 5 mol% t-Bu-P4 were achieved. This method was shown to provide an efficient way to construct the perfluorophenyl-sulfur bond under mild metal-free reaction conditions. This journal is
Mild C?F Activation in Perfluorinated Arenes through Photosensitized Insertion of Isonitriles at 350 nm
Weidlich, Frauke,Esumi, Naoto,Chen, Dongyang,Mück-Lichtenfeld, Christian,Zysman-Colman, Eli,Studer, Armido
supporting information, p. 376 - 383 (2019/11/19)
Fluorinated compounds have become important in the fields of agrochemical industry, pharmaceutical chemistry and materials sciences. Accordingly, various methods for their preparation have been developed in the past. Fluorinated compounds can be accessed via conjugation with fluorinated building blocks, via C?H fluorination or via selective activation of perfluorinated compounds to give the partially fluorinated congeners. Especially the direct activation of C?F bonds, one of the strongest σ-bonds, still remains challenging and new strategies for C?F activation are desirable. Herein a method for the photochemical activation of aromatic C?F bonds is presented. It is shown that isonitriles selectively insert into aromatic C?F bonds while aliphatic C?F bonds remain unaffected. Mechanistic studies reveal the reaction to proceed via the indirect excitation of the isonitrile to its triplet state by photoexcited acetophenone at 350 nm. Due to the relatively mild light used, the process shows high functional group tolerance and various compounds of the class of benzimidoyl fluorides are accessible from aryl isonitriles and commercially available perfluorinated arenes. (Figure presented.).
Multicomponent Coupling Reaction of Perfluoroarenes with 1,3-Butadiene and Aryl Grignard Reagents Promoted by an Anionic Ni(II) Complex
Iwasaki, Takanori,Fukuoka, Asuka,Min, Xin,Yokoyama, Wataru,Kuniyasu, Hitoshi,Kambe, Nobuaki
supporting information, p. 4868 - 4871 (2016/10/18)
An anionic Ni complex was isolated and its structure determined by X-ray crystallography. With such an anionic complex as a key intermediate, a regio- and stereoselective multicomponent coupling reaction of perfluoroarenes, aryl Grignard reagents, and 1,3-butadiene in a 1:1:2 ratio was achieved, resulting in the formation of 1,6-octadiene derivatives containing two aryl groups, one from the perfluoroarene and the other from the aryl Grignard reagent, at the 3- and 8-positions, respectively.
Synthesis of the farnesyl ether 2,3,5-trifluoro-6-hydroxy-4-[(E,E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yloxy] nitrobenzene, and related compounds containing a substituted hydroxytrifluorophenyl residue: Novel inhibitors of protein farnesyltransferase, geranylgeranyltransferase I and squalene synthase
Marriott, Jonathan H.,Moreno Barber, Amelia M.,Hardcastle, Ian R.,Rowlands, Martin G.,Grimshaw, Rachel M.,Neidle, Stephen,Jarman, Michael
, p. 4265 - 4278 (2007/10/03)
Pentafluoronitrobenzene was converted via two successive phase-transfer catalysed SNAr reactions with (E,E)-farnesol or geraniol followed by hydroxide ion into the 2,3,6-trifluoro-5-hydroxy-4-nitrophenyl farnesyl ether 3a and the geranyl ether 3b. Analogues containing a cyano (3c) or carbamoyl (3d) group in place of nitro or an epoxygeranyl (3e) group as the prenyl (3-methylbut-2-enyl) containing residue were similarly prepared. Those containing a sulfonic acid (35a, 35b) or a methyl sulfone (41) group were made by modifications of this approach involving the use of protecting groups. The synthesis of carboxy analogues (27a, 27b) involved the alkylation of a protected fluorinated ortho-hydroxybenzoic acid derivative (25) with (E,E)-farnesyl or geranyl bromide. The non-fluorinated compound 18 was analogously prepared via compound 17a. Mitsunobu reactions were used in the synthesis of 15, a dihydroxylated analogue of 3b, and of 8, the non-fluorinated analogue of 3a. The nitro compounds 3a and 3b were moderate inhibitors of both farnesyl transferase and geranylgeranyl transferase I, the geranyl carboxy derivative 27b of the latter enzyme and the farnesyl sulfonic acid derivative 35a of squalene synthase. The Royal Society of Chemistry 2000.
New Synthetic Routes to Unsymmetrical Diorganyl Sulfides
Deryagina,Korchevin,Papernaya
, p. 812 - 815 (2007/10/03)
A number of new methods for preparing unsymmetrical diorganyl sulfides was proposed. The methods rely on generation of thiolate anions from thiols, isothiuronium salts, and disulfides in the system hydrazine hydrate-KOH, followed by alkylation of the anions with alkyl halides. The hydrazine hydrate plays the role of medium and reducing agent, which prevents side thiol oxidation. The yield of sulfides reaches 98%. The reaction products are readily separated from the aqueous-hydrazine layer and purified by distillation. The yield of sulfides is reduced by a deficit of alkali and by increasing chain length and functionalization of alkyl groups in the alkyl halide. The reactivity of alkyl halides is independent of the nature of the halogen. From isothiuronium salts, 2-pyridyl sulfides were obtained in the highest yields.
Synthesis of polyfluoroarylalkyl sulfide compounds
Ward, Wayne E.,Sicree, Stephen,Chen, Brian,Tamborski, Christ
, p. 73 - 78 (2007/10/02)
Syntheses of RC6F4SR' compounds (where R = F, C6H5, H, R' = alkyl, trifluorovinyl) have been accomplished through reaction between ArfSM (where M = Cu, MgX) and an alkyl or trifluorovinyl halide in dimethylacetamide solvent.Minor by-products from competing reactions have been partially characterized by GC-MS analysis. - Keywords: Synthesis; Polyfluoroalkyl sulfides; NMR spectroscopy; Mass spectrometry
Elimination reactions: Experimental confirmation of the predicted elimination of (β-cyanoethyl)sulfonium ions through a concerted, E2 mechanism
Banait, Narinder S.,Jencks, William P.
, p. 6950 - 6958 (2007/10/02)
Extrapolation of the lifetimes of carbanion intermediates formed in the elimination reactions of a series of β-cyanoethyl thioethers with different leaving groups (J. Am. Chem. Soc. 1988, 110, 5087-5095) predicts that the carbanions will not have a significant lifetime for pKlg a 2SO/H2O, 25.0 °C). Values of βlg obtained from Br?nsted-type plots of log kB against the estimated pKa values of the leaving groups, decrease from 0.39 to 0.24 with increasing pKa of the base catalyst. The changes in β and βlg are described by the interaction coefficient pxy=d?βlg/?pK BH=?βlg/?KBH=0.026. The deuterium isotope effect for proton removal from Ph-S+(Me)-CH2CL2CN is kH/kD=4.4 and 4.9 for tris(hydroxymethyl)aminomethane and ethylamine buffers, respectively, and there is no detectable protium exchange into the deuterated substrate. The positive pxy coefficient provides evidence for coupling between proton abstraction and leaving group expulsion; it confirms the concerted AxhDHDN (E2) mechanism. The values of β and βlg indicate an imbalance in the transition state, in which proton transfer is ahead of leaving group expulsion. The change from a stepwise AxhDHH+DNN (ElcB) mechanism for thiophenoxide leaving groups to a concerted mechanism for sulfide leaving groups is consistent with the notion that the mechanism is determined solely by the lifetime of the carbanion; there is no evidence for the coexistence of stepwise and concerted mechanisms.
