3480-60-2Relevant academic research and scientific papers
Constructing a catalytic cycle for c-f to c-x (x = o, s, n) bond transformation based on gold-mediated ligand nucleophilic attack
Hu, Ji-Yun,Zhang, Jing,Wang, Gao-Xiang,Sun, Hao-Ling,Zhang, Jun-Long
supporting information, p. 2274 - 2283 (2017/01/16)
A tricoordinated gold(I) chloride complex, tBuXantphosAuCl, supported by a sterically bulky 9,9-dimethyl-4,5-bis(di-Tert-butylphosphino)xanthene ligand (tBuXantphos) was synthesized. This complex features a remarkably longer Au?Cl bond length [2.632(1) ?] than bicoordinated linear gold complexes (2.27-2.30 ?) and tricoordinated XantphosAuCl [2.462(1) ?]. Single-crystal Xray diffraction analysis of a cocrystal of tBuXantphosAuCl and pentafluoronitrobenzene (PFNB) and UV-vis spectroscopic titration experiments revealed the existence of an anion-φ interaction between the Cl anion ligand and PFNB. Stoichiometric reaction between PFNB and tBuXantphosAuOtBu, after replacement of Cl by a more nucleophilic tBuO anion ligand, showed higher reactivity and para selectivity in the transformation of C-F to C-OtBu bond, distinctively different from that when only KOtBu was used (ortho selectivity) under the identical condition. Mechanistic studies including density functional theory calculations suggested a gold-mediated nucleophilic ligand attack of the C?F bond pathway via an SNAr process. On the basis of these results, using trimethylsilyl derivatives TMS-X (X = OMe, SEt, NEt) as the nucleophilic ligand source and the fluorine acceptor, catalytic transformation of the C-F bond of aromatic substrates to the C-X (X = O, S, N) bond was achieved with tBuXantphosAuCl as the catalyst (up to 20 turnover numbers).
Fluorinated xanthene derivatives
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, (2008/06/13)
The family of dyes of the invention are fluoresceins and rhodols that are directly substituted on one or more aromatic carbons by fluorine. These fluorine-substituted fluorescent dyes possess greater photostability and have lower sensitivity to pH changes in the physiological range of 6-8 than do non-fluorinated dyes, exhibit less quenching when conjugated to a substance, and possess additional advantages. The dyes of the invention are useful as detectable tracers and for preparing conjugates of organic and inorganic substances.
Synthesis of fluorinated fluoresceins
Sun, Wei-Chuan,Gee, Kyle R.,Klaubert, Dieter H.,Haugland, Richard P.
, p. 6469 - 6475 (2007/10/03)
Several novel fluorinated fluoresceins (Oregon Green dyes) were prepared by the reaction of fluororesorcinols with phthalic anhydride and its derivatives. A novel regiospecific synthesis of fluororesorcinols was key to the successful synthesis of these new fluorophores. (Polyfluoro)- nitrobenzenes were reacted with 2 equiv of sodium methoxide followed by reduction, hydrodediazoniation, and demethylation, giving the first straightforward synthesis of 2-fluororesorcinol, 4-fluororesorcinol, 2,4- difluororesorcinol, and 2,4,5-trifluororesorcinol. These fluorinated fluoresceins have higher photostability and ionize at a lower pH (pK(a) = 3.3-6.1) than fluorescein (pK(a) = 6.5). Some of the fluorinated fluoresceins have very high quantum yields (0.85-0.97), which, in combination with their lower pK(a)s and high photostability, makes them superior fluorescent dyes for use as reporter molecules in biological systems.
