4873-56-7Relevant articles and documents
Differentiation between chelate ring inversion and aryl rotation in a CF3-substituted phosphine-sulfonate palladium methyl complex
Feng, Ge,Conley, Matthew P.,Jordan, Richard F.
, p. 4486 - 4496 (2014)
The solution conformations and dynamic properties of the CF3-sbustituted (ortho-phosphinoarenesulfonate)Pd complexes (PO-CF3)PdMe(L) ([PO-CF3]- = 2-{(o-CF3-Ph)2P}-4-Me-benzenesulfonate, L = 2,6-lutidine (3), pyridine (4)) were studied by NMR spectroscopy, taking particular advantage of 31P-19F through-space couplings and 1H-1H and 1H-19F nuclear Overhauser effects. In CD2Cl2 solution in the temperature range of -80 to 20 °C, 3 adopts an exo2 conformation. One o-CF3-Ph ring is positioned such that the CF3 group points toward Pd (exo) and exhibits through-space 4JPF coupling. The other o-CF3-Ph ring is positioned such that the CF3 group points away from Pd (endo) and does not exhibit through-space 4JPF coupling, and the o-H lies in the deshielding region near an axial site of the Pd square plane and exhibits a low-field chemical shift (δ > 9). Complex 4 exists as a 2:1 mixture of exo2 and exo3 isomers in CD2Cl2 solution at -90 °C. In exo2-4, one CF3 group is exo and exhibits through-space 4JPF coupling, while the other CF3 group is endo and does not exhibit through-space 4JPF coupling. In exo3-4, both CF3 groups are exo and exhibit through-space 4JPF couplings. Complex 4 undergoes two dynamic processes: rotation of the axial o-CF3-Ph ring (AaR), which interconverts exo2-4 and exo3-4 (ΔG&dagger = 9.9(5) kcal/mol), and chelate ring inversion (RI), which permutes the axial and equatorial o-CF3-Ph rings (ΔG&dagger = 21(1) kcal/mol).
Development of Selective Steroid Inhibitors for the Glucose-6-phosphate Dehydrogenase from Trypanosoma cruzi
Fredo Naciuk, Fabrício,Do Nascimento Faria, Jéssica,Gonc?lves Eufrásio, Amanda,Torres Cordeiro, Artur,Bruder, Marjorie
supporting information, p. 1250 - 1256 (2020/07/27)
Chagas disease is a parasitic infection affecting millions of people across Latin America, imposing a dramatic socioeconomic burden. Despite the availability of drugs, nifurtimox and benznidazole, lack of efficacy and incidence of side-effects prompt the identification of novel, efficient, and affordable drug candidates. To address this issue, one strategy could be probing the susceptibility of Trypanosoma parasites toward NADP-dependent enzyme inhibitors. Recently, steroids of the androstane group have been described as highly potent but nonselective inhibitors of parasitic glucose-6-phosphate dehydrogenase (G6PDH). In order to promote selectivity, we have synthesized and evaluated 26 steroid derivatives of epiandrosterone in enzymatic assays, whereby 17 compounds were shown to display moderate to high selectivity for T. cruzi over the human G6PDH. In addition, three compounds were effective in killing intracellular T. cruzi forms infecting rat cardiomyocytes. Altogether, this study provides new SAR data around G6PDH and further supports this target for treating Chagas disease.
Stereocontrolled Preparation of (Z)-1,4-but-2-endiol Esters in Phase-Transfer Conditions
Malanga, C.,Pagliai, L.,Menicagli, R.
, p. 2821 - 2826 (2007/10/02)
Isomerically pure esters of (Z)-1,4-but-2-endiol are prepared, in satisfactory yields, under phase-transfer conditions.
