Search

The queens of social insects differ from sterile colony members in many aspects of their physiology. Besides adaptations linked with their specialization for reproduction and extended lifespan, the queens also invest in the maintenance of their reproductive dominance by producing exocrine chemicals signaling their presence to the nestmates. The knowledge of the chemistry of queen-specific cues in termites is scarce. In addition to the contact recognition based on cuticular hydrocarbons, long-range signals mediated by volatiles are expected to participate in queen signaling, especially in populous colonies of higher termites (Termitidae). In queens of the higher termite Silvestritermes minutus (Syntermitinae), we have detected a previously undescribed volatile. It is present in important quantities on the body surface and in the headspace, ovaries, and body cavity. MS and GC-FTIR data analyses led us to propose the structure of the compound to be a macrolide 10-pentyl-3,4,5,8,9,10-hexahydro-2 H-oxecin-2-one. We performed enantiodivergent syntheses of two possible enantiomers starting from enantiopure ( S)-glycidyl tosylate. The synthetic sequence involved macrolide-closing metathesis quenched with a ruthenium scavenging agent. The absolute and relative configuration of the compound was assigned to be (5 Z,9 S)-tetradec-5-en-9-olide. Identification and preparation of the compound allow for investigation of its biological significance.

This study focuses on design, synthesis and in vitro evaluation of inhibitory potency of two series of sialylmimetic that target an exosite ("150-cavity") adjacent to the active site of influenza neuraminidases from A/California/07/2009 (H1N1) pandemic strain and A/chicken/Nakorn-Patom/Thailand/CU-K2-2004 (H5N1). The structure-activity analysis as well as 3-D structure of the complex of parental compound with the pandemic neuraminidase p09N1 revealed high flexibility of the 150-cavity towards various modification of the neuraminidase inhibitors. Furthermore, our comparison of two methods for inhibition constant determination performed at slightly different pH values suggest that the experimental conditions of the measurement could dramatically influence the outcome of the analysis in the compound-dependent manner. Therefore, previously reported Ki values determined at non-physiological pH should be carefully scrutinized.

The biological effects of flavonoids on mammal cells are diverse, ranging from scavenging free radicals and anti-cancer activity to anti-influenza activity. Despite appreciable effort to understand the anti-influenza activity of flavonoids, there is no clear consensus about their precise mode-of-action at a cellular level. Here, we report the development and validation of a screening assay based on AlphaScreen technology and illustrate its application for determination of the inhibitory potency of a large set of polyols against PA N-terminal domain (PA-Nter) of influenza RNA-dependent RNA polymerase featuring endonuclease activity. The most potent inhibitors we identified were luteolin with an IC50 of 72 ± 2 nM and its 8-C-glucoside orientin with an IC50 of 43 ± 2 nM. Submicromolar inhibitors were also evaluated by an in vitro endonuclease activity assay using single-stranded DNA, and the results were in full agreement with data from the competitive AlphaScreen assay. Using X-ray crystallography, we analyzed structures of the PA-Nter in complex with luteolin at 2.0 A resolution and quambalarine B at 2.5 A resolution, which clearly revealed the binding pose of these polyols coordinated to two manganese ions in the endonuclease active site. Using two distinct assays along with the structural work, we have presumably identified and characterized the molecular mode-of-action of flavonoids in influenza-infected cells.

Noroxymorphone was prepared from thebaine in seven operations. The key steps involved the successive N- and O-demethylations of an iron tricarbonyl complex of thebaine followed by the unusual ceric ammonium nitrate oxidation of the methoxydiene moiety to the corresponding enone-γ-nitrate during the decomplexation of the iron tricarbonyl functionality.

N-Alkylations of monosubstituted benzotriazoles yield isomeric products with distinct topology, i. e. 1H- or to 2H-isomers. Therefore, the molecular shape of these compounds varies and this results in distinct biological and physical properties. Herein, a protocol for the simple synthesis of various alkyl-aminobenzotriazoles using 5-nitrobenzotriazole is reported. This synthetic approach furnishes 2-alkyl-5-nitro-2H-benzotriazoles as major products in most of the attempted cases. All three obtained isomers were separable from each other by standard column chromatography. In addition, three alternative approaches furnishing selectively substituted alkyl-amino-1H-benzotriazoles are described. Finally, a library of sixty-eight N-benzotriazoylureas and six N-benzotriazoylthioureas was synthesized by reactions with either isocyanates (phenyl chloroformate) or isothiocyanates.

Acetylation of 3,4-dihydroxybenzaldehyde was reinvestigated. The results in the regiochemical outcome were analyzed in detail by NMR methods and compared with previously published data.

Assembly of human immunodeficiency virus (HIV-1) represents an attractive target for antiretroviral therapy which is not exploited by currently available drugs. We established high-throughput screening for assembly inhibitors based on competition of small molecules for the binding of a known dodecapeptide assembly inhibitor to the C-terminal domain of HIV-1 CA (capsid). Screening of >70000 compounds from different libraries identified 2-arylquinazolines as low micromolecular inhibitors of HIV-1 capsid assembly. We prepared focused libraries of modified 2-arylquinazolines and tested their capacity to bind HIV-1 CA to compete with the known peptide inhibitor and to prevent the replication of HIV-1 in tissue culture. Some of the compounds showed potent binding to the C-terminal domain of CA and were found to block viral replication at low micromolar concentrations.

Thebaine was converted into its iron tricarbonyl complex, which underwent successive N- and O-demethylation with BrCN and BBr 3 , respectively. Decomplexation of the iron tricarbonyl moiety was accomplished with ammonium cerium(IV) nitrate (CAN) and base-catalyzed hydrolysis furnished nororipavine. When excess CAN was used the methoxydiene unit was converted into its C-14 nitrate that on hydrogenation and further hydrolysis furnished noroxymorphone. Full experimental and spectral data are provided for all key compounds.