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Influenza viruses can cause severe respiratory infections in humans, leading to nearly half a million deaths worldwide each year. Improved antiviral drugs are needed to address the threat of development of novel pandemic strains. Current therapeutic interventions target three key proteins in the viral life cycle: neuraminidase, the M2 channel and RNA-dependent-RNA polymerase. Protein-protein interactions between influenza polymerase subunits are potential new targets for drug development. Using a newly developed assay based on AlphaScreen technology, we screened a peptide panel for protein-protein interaction inhibitors to identify a minimal PB1 subunit-derived peptide that retains high inhibition potential and can be further modified. Here, we present an X-ray structure of the resulting decapeptide bound to the C-terminal domain of PA polymerase subunit from pandemic isolate A/California/07/2009 H1N1 at 1.6 A resolution and discuss its implications for the design of specific, potent influenza polymerase inhibitors.

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.

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.

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.

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.

Various alkyl-amino-benzotriazoles obtained by reduction of the corresponding nitro compounds are used as starting materials for the synthesis of urea derivatives.

Oxymorphone was converted to naltrexone in three steps by palladium-catalyzed oxidative N-demethylation and intramolecular acyl transfer from C-14 hydroxy to N-17. Vitride™ reduction of N-acylamide to N-alkylamine proceeded with concomitant reductive deprotection of C-6 and O-3 functionalities.

N-Oxides derived from oxycodone and O-acyloxymorphone were treated with the Burgess reagent to provide the corresponding oxazolidines in excellent yields. Oxazolidines derived from O-acyloxymorphone were further hydrolyzed to noroxymorphone, whose alkylation furnished naltrexone, naloxone, and nalbuphone, which can be converted to nalbuphine, the mixed agonist-antagonist analgesic. The entire sequence from oxymorphone to the various antagonists was reduced to three one-pot operations, proceeding in excellent overall yields. In addition, quaternary salts of the oxazolidines with allyl or cyclopropylmethyl groups in fixed equatorial configurations were synthesized. Complete spectral and experimental data are provided for all compounds.

An improved preparation of buprenorphine via palladium-catalyzed N-demethylation/acylation is reported. Three routes were investigated and compared in overall yield. The first involved N-demethylation/acylation of an advanced intermediate obtained from thebaine followed by hydrolysis of the N-acetamide and alkylation with cyclopropylmethyl bromide and/or reduction of the N-acetyl group with the Schwartz reagent followed by N-alkylation. The second route employed cyclopropylcarboxylic acid anhydride in the N-demethylation/acylation protocol and subsequent reduction of the cyclopropylcarboxamide by either lithium aluminum hydride or under hydrosilylation conditions. Both of these routes originated in thebaine and therefore required O-demethylation as a final step. The third route employed an N-demethylation/acylation sequence starting from oripavine rather than thebaine, thus avoiding the O-demethylation. The routes are compared for overall efficiency and experimental and spectral data are provided for all new compounds.

Four generations of chemoenzymatic approaches to oseltamivir are presented. The first two generations relied on the use of cyclohexadiene-cis-diol derived enzymatically from bromobenzene. The third and fourth generation used the corresponding diol obtained from ethyl benzoate by fermentation with E. coli JM109(pDTG601a). Oseltamivir was obtained from ethyl benzoate by intersecting intermediate 39 (third-generation synthesis) and intermediate 45 (fourth-generation synthesis). Both of these advanced approaches benefited from symmetry considerations and translocation of the acrylate double bond with concomitant elimination of the C-1 hydroxyl. The syntheses are evaluated for overall efficiency by the use of efficiency metrics and compared with other syntheses of oseltamivir (both academic and industrial).

A short chemoenzymatic and azide-free synthesis of oseltamivir was attained with the key steps consisting of a one-pot Dauben-Michno oxidative transposition and amination and a reductive transposition of an acrylate.

A series of the title ylides was prepared by reaction of fused thiophene and selenophene derivatives with di-tert-butyl diazomalonate. Their thermal stability depended highly on their structure. While the terminal thiophenium- and selenophenium-ylides smoothly rearranged to the corresponding thiopyran and selenopyran derivatives, the internal thiophene ylides showed remarkable stability. The latter also exhibited hindered rotation around the S–C ylide bond and a high rotational barrier could be established in an NMR study.

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.

Fused thiopyrans along with products of subsequent reactions of the primary adducts of the title compounds are obtained by nonconcerted [4π + 2π] processes. The course of the reactions and formation of all products discussed.

The reaction of propanedioic acid, 2-diazo-1,3-bis(1,1-dimethylethyl) ester (di-tert-butyl diazomalonate) with a series of cyclopenta[b]thiophenes in the presence of catalytic rhodium acetate was studied. The resulting S—C ylides underwent a rearrangement to form a heterocycle with different topology; thialene, in very low yields. Experimental and spectral data for all compounds are provided.

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.

The synthesis of nalbuphine (VI) from oripavine (I) requires only five chemical transformations and is conducted with an overall yield of 45%, in contrast to current methods requiring seven to ten steps.

Buprenorphine was synthesized from oripavine by a sequence involving the conversion of oripavine into its cyclopropylmethyl quaternary salt, N-demethylation with thiolate to N-cyclopropylmethyl nororipavine, and conversion of this material to the title compound by previously available methods. The new synthesis avoids toxic reagents used previously, is shorter, and proceeds in comparable yields. Experimental and spectral data are provided for all new compounds.

A new method of synthesis of 3-substituted thieno[3,2-b][1]benzothiophenes based on a halogen dance process was developed. The cycloaddition reaction of the title compound with dimethyl acetylenedicarboxylate leads to the formation of a complex mixture of products resulting from a series of consecutive reactions of the primary adduct.

In an effort to identify an HIV-1 capsid assembly inhibitor with improved solubility and potency, we synthesized two series of pyrimidine analogues based on our earlier lead compound N -(4-(ethoxycarbonyl)phenyl)-2-(pyridine-4-yl)quinazoline-4-amine. In vitro binding experiments showed that our series of 2-pyridine-4-ylpyrimidines had IC 50 values higher than 28 μM. Our series of 2-pyridine-3-ylpyrimidines exhibited IC 50 values ranging from 3 to 60 μM. The congeners with a fluoro substituent introduced at the 4- N -phenyl moiety, along with a methyl at C-6, represent potent HIV capsid assembly inhibitors binding to the C-terminal domain of the capsid protein.