Relevant articles and documents
Modeling and spectroscopic studies of synthetic diazabicyclo analogs of the HIV-1 inhibitor BMS-378806 and evaluation of their antiviral activity
Legnani, Laura Colombo, Diego Cocchi, Elena Solano, Lucrezia Villa, Stefania Lopalco, Lucia Asti, Valeria Diomede, Lorenzo Marinone Albini, Franca Toma, Lucio
Three diazabicyclo analogs of BMS-378806, in which theaxial methyl group present on its piperazine ring is replaced by a carbon bridge, were synthesized and tested, through a viral neutralization assay, on a panel of six pseudoviruses. The diazabicyclooctane and-nonane derivatives maintained a significant infectivity reduction power, whereas the diazabicycloheptane derivative was much less effective. A modeling study allowed to relate the antiviral activity to the conformational preferences of the compounds. Moreover, similarly to BMS-378806, theoretical calculations predict the existence of different conformational families corresponding to the possible arrangements at the two planar amido functions of the compounds. High-field 1H NMR spectra confirm these results, as they show two distinct series of signals. A viral neutralization assay on a panel of six HIV-related pseudoviruses allowed the determination of the antiviral activity of three diazabicyclo analogs of BMS-378806, in which the axial methyl group on its piperazine ring is replaced by a carbon bridge. The diazabicyclooctane and-nonane derivatives show a significant infectivity reduction power that is related to their conformational preference. Copyright
Cation-Cation Pairing by Ni-Ci-H?O Hydrogen Bonds
Gamrad, Waltraud Dreier, Angelika Goddard, Richard P?rschke, Klaus-Richard
The pairing of ions of opposite charge is a fundamental principle in chemistry, and is widely applied in synthesis and catalysis. In contrast, cation-cation association remains an elusive concept, lacking in supporting experimental evidence. While studying the structure and properties of 4-oxopiperidinium salts [OC5H8NH2]X for a series of anions X- of decreasing basicity, we observed a gradual self-association of the cations, concluding in the formation of an isolated dicationic pair. In 4-oxopiperidinium bis(trifluoromethylsulfonyl)amide, the cations are linked by N-H?O=C hydrogen bonds to form chains, flanked by hydrogen bonds to the anions. In the tetra(perfluoro-tert-butoxy)aluminate salt, the anions are fully separated from the cations, and the cations associate pairwise by N-C-H?O=C hydrogen bonds. The compounds represent the first genuine examples of self-association of simple organic cations based merely on hydrogen bonding as evidenced by X-ray structure analysis, and provide a paradigm for an extension of this class of compounds.
