2375-90-8Relevant 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).
Benzamidine derivatives and their use as anti-coagulants
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Page column 33, (2010/02/04)
This invention is directed to benzamidine derivatives which are useful as anti-coagulants. This invention is also directed to pharmaceutical compositions containing the compounds of the invention, and methods of using the compounds to treat disease-states characterized by thrombotic activity.
Benzamidine derivatives and their use as anti-coagulants
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, (2008/06/13)
This invention is directed to benzamidine derivatives which are useful as anti-coagulants. This invention is also directed to pharmaceutical compositions containing the compounds of the invention, and methods of using the compounds to treat disease-states characterized by thrombotic activity.
MECHANISMS FOR REACTIONS OF HALOGENATED COMPOUNDS. PART 6. INVESTIGATIONS INTO THE ACTIVATING EFFECT OF ORTHO-FLUORINE IN NUCLEOPHILIC AROMATIC SUBSTITUTION
Chambers, Richard D.,Seabury, Mark J.,Williams, D. Lyn H.,Hughes, Nigel
, p. 255 - 258 (2007/10/02)
Separate activating effects for ortho- and meta- fluorine, on nucleophilic aromatic substitution, are determinated for pyrimidine and pyridine systems.Comparisons confirm the importance of ion-dipole interactions for activation by ortho-fluorine.The effects of ortho-fluorine on anionic ?-complexes are also discussed.
Mechanisms for Reactions of Halogenated Compounds. Part 3. Variation in Activating Influence of Halogen Substituents in Nucleophilic Aromatic Substitution
Chambers, Richard D.,Close, Deborah
, p. 778 - 780 (2007/10/02)
Rate constants are reported for reactions of polyhalogeno-pyridines and -benzenes with sodium methoxide in methanol.Relative activating effects of individual fluorine and chlorine atoms at positions ortho, meta, and para to the reaction site are determined and compared with orders determined from reactions involving ammonia in aqueous dioxan.The results are remarkably similar.Additional support is provided for earlier explanations of the activating effects of ortho-fluorine and -chlorine.Activation parameters, determined for reactions of polyhalogenepyridines with ammonia in aqueous dioxan, clearly demonstrate that differences in reactivity along the series arise mainly from changes in activation energy.
