With peculiar structural features at the surface of small metal nanoparticles, some discrete sites can display catalytic behaviour similar to what could be observed with mononuclear metal catalysts in solution. We have studied the transfer of two catalytic tandem reactions from homogeneous to heterogeneous conditions. Tandem cyclisation/reduction of ortho-alkynyl benzaldehyde derivatives was successfully achieved with Au nanoparticles over TiO (Au NPs/TiO) in the presence of Hantzsch ester with 45-98% yields for 15 examples (average yield: 70.
View Article and Find Full Text PDFChiral Ag-atropisomeric ligand species were studied in solution at different temperatures by P-NMR spectroscopy. The analysis and understanding of key parameters in Ag-BINAP complexes were considered in the context of an enantioselective transformation. An efficient silver-catalyzed intramolecular [4+2] cycloaddition reaction of amide-1,6-enyne provided an enantiomerically enriched tricyclic compound using simple reagents and under mild reaction conditions.
View Article and Find Full Text PDFDiastereoselective double C-H heteroarylation of chiral ferrocenes provides valuable compounds with multiple functionalities using mild reaction conditions and simple reagents. Pd-Complexes with chiral mono-protected amino acids afforded corresponding heteroarylated ferrocenyl amines in good yields and high diastereomeric purities. In this way, a variety of indole, thiophene, pyrrole, or furan substituents were introduced to the ferrocene moiety.
View Article and Find Full Text PDFStudying bacterial population diversity is important to understand healthcare associated infections' epidemiology and has a significant impact on dealing with multidrug resistant bacterial outbreaks. We characterised the extended-spectrum beta-lactamase producing K. pneumoniae (ESBLp KPN) population in our hospital using mini-MLST.
View Article and Find Full Text PDFAn efficient diastereoselective synthesis of planar chiral ferrocenes via Pd(II)-catalyzed direct C-H activation with arylboronic acids or pinacol esters is presented. The reaction was performed under mild conditions using commercially available achiral or chiral amino acids as ligands. The best results were obtained with ( R)-Boc-alanine, which yielded products in 27-83% yield with diastereoselectivities ranging from 5:1 to 20:1 (11 examples).
View Article and Find Full Text PDFThe reaction of methyl coumalate with a wide range of methylene active compounds, such as keto-esters or keto-sulfones and cyclic or acyclic diketones, afforded more than 30 2,3,5,6-tetrasubstituted 2H-pyrans. The reaction proceeds via a cascade reaction involving a Michael addition-6π-electrocyclic ring opening-proton transfer and 6π electrocyclization, in which a variety of functional groups were tolerated.
View Article and Find Full Text PDFCopper(II) complexes with fluoroquinolones in the presence of the nitrogen donor heterocyclic ligands 1,10-phenanthroline have been considered in detail. The phenanthroline moiety was introduced into the ligand environment with the aim to determine whether the nuclease activity is feasible. All suitable X-ray structures of the complexes under study reveal a distorted square pyramidal coordination geometry for Cu(II) atom.
View Article and Find Full Text PDFBiological activity, functionality, and synthesis of (fluoro)quinolones is closely related to their precursors (for instance 3-fluoroanilinoethylene derivatives) (i.e., their functional groups, conformational behavior, and/or electronic structure).
View Article and Find Full Text PDFThe basic building unit in the structure of the title compound, C(14)H(14)FNO(3), is pairs of molecules arranged in an antiparallel fashion, enabling weak C-H···O interactions. Each molecule is additionally involved in π-π interactions with neighbouring molecules. The pairs of molecules formed by the C-H···O hydrogen bonds and π-π interactions form ribbon-like chains running along the c axis.
View Article and Find Full Text PDFIn the crystal structures of the title compounds, C(11)H(9)FN(2)O, (I), and C(13)H(12)FNO(4), (II), the molecules are joined pairwise via different hydrogen bonds and the constituent pairs are crosslinked by weak C-H...
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