66684-59-1Relevant articles and documents
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).
The Effect of Fluorine Substitution on the Metabolism and Antimalarial Activity of Amodiaquine
O'Neill, Paul M.,Harrison, Anthony C.,Storr, Richard C.,Hawley, Shaun R.,Ward, Stephen A.,Park, B. Kevin
, p. 1362 - 1370 (2007/10/02)
Amodiaquine (AQ) (2) is a 4-aminoquinoline antimalarial which causes adverse side effects such as agranulocytosis and liver damage.The observed drug toxicity is believed to be related to the formation of an electrophilic metabolite, amodiaquine imine (AQQI), which can bind to cellular macro-molecules and initiate hypersensitivity reactions. 5'-Fluoroamodiaquine (5'-FAQ, 3), 5',6'-difluoroamodiaquine (5',6'-DIFAQ, 4), 2',6'-difluoroamodiaquine (2',6'-DIFAQ, 5), 2',5',6'-trifluoroamodiaquine (2',5',6'-TRIFAQ, 6) and 4'-dehydroxy-4'-fluoroamodiaquine (4'-deOH-4'-FAQ, 7) have been synthesized to assess the effect of fluorine substitution on the oxidation potential, metabolism, and in vitro antimalarial activity of amodiaquine.The oxidation potentials were measured by cyclic voltammetry, and it was observed that substitution at the 2',6'- and 4'-positions (2',6'-DIFAQ and 4'-deOH'4'-FAQ) produced analogues with significantly higher oxidation potentials than the parent drug.Fluorine substitution at the 2',6'-positions and 4'-position also produced analogues that were more resistant to bioactivation.Thus 2',6'-DIFAQ and 4'-deOH-4'-FAQ produced thioether conjugates corresponding to 2.17percent (SD: +/-0.27percent) and 0percent of the dose compared with 11.87percent (SD: +/-1.31percent) of the dose for amodiaquine.In general the fluorinated analogues had similar in vitro antimalarial activity to amodiaquine against the chloroquine resistant K1 strain of Plasmodium falciparum and the chloroquine sensitive T9-96 strain of P. falciparum with the notable exception of 2',5',6'-TRIFAQ (6).The data presented indicate that fluorine substitution at the 2',6'-positions and replacement of the 4'-hydroxyl of amodiaquine with fluorine produces analogues ( 5 and 7) that maintain antimalarial efficacy in vitro and are more resistant to oxidation and hence less likely to form toxic quinone imine metabolites.
