Publications by authors named "Fraboni A"

Cellular and virus-coded long non-coding (lnc) RNAs support multiple roles related to biological and pathological processes. Several lncRNAs sequester their 3' termini to evade cellular degradation machinery, thereby supporting disease progression. An intramolecular triplex involving the lncRNA 3' terminus, the element for nuclear expression (ENE), stabilizes RNA transcripts and promotes persistent function.

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The Hepatitis B Virus (HBV) ribonuclease H (RNaseH) is a promising but unexploited drug target. Here, we synthesized and analyzed a library of 57 amide-containing α-hydroxytropolones (αHTs) as potential leads for HBV drug development. Fifty percent effective concentrations ranged from 0.

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Understanding the broader biological impact of carolacton, a macrolactone natural product, has been ongoing for the past decade. Multiple studies have shown connections to regulatory systems, acid tolerance mechanisms, biofilm formation, and recently folate dehydrogenase (FolD). Progress elucidating the cause of biofilm-specific activity in has been limited due to low-throughput analyses of carolacton-treated cells.

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The oral microbiome is a dynamic environment inhabited by both commensals and pathogens. Among these is Streptococcus mutans, the causative agent of dental caries, the most prevalent childhood disease. Carolacton has remarkably specific activity against S.

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A direct vinylogous Michael addition using linear vinylogous Michael donors has been developed. Notably, even γ-substituted Michael donors cleanly afforded γ-alkylated products in high yield and ee by this method. Moreover, control experiments revealed that, for these and related linear vinylogous Michael donors, the size of the Michael acceptor strongly influences whether α- or γ-alkylation occurs, not simply blocking effects of cocatalysts as suggested previously.

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The first catalytic method to directly introduce nitrone functionality onto aldehyde substrates is described. This reaction proceeds by an unprecedented organocatalytic redox mechanism in which an enal is oxidized to the γ-nitrone via dienamine catalysis, thereby reducing an equivalent of nitrosobenzene. This reaction is a unique example of divergent reactivity of an enal, which represents a novel strategy for rapidly accessing small libraries of N,O-heterocycles.

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Whereas cascade reactions catalyzed by secondary amines combine iminium- and/or enamine-catalyzed reactions, we introduce the feasibility of combining these modes of catalysis with dienamine-catalysis as a new general mechanism for cascade reactions. Enantioenriched β-functionalized-γ-amino alcohols were produced from simple achiral enals in one flask by combining dienamine- and iminium-catalyzed intermolecular reactions. Reaction products are precursors of γ-amino acids, γ-lactams, and pyrrolidines; one was employed in a synthesis of γ-amino acid (S)-vigabatrin, the bioactive enantiomer of Sabril.

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4-Aminophenyl cations (expediently generated by photolysis of 4-chloroaniline and its N,N-dimethyl derivative by photolysis in MeCN) added to enamines and gave the corresponding alpha-(4-aminophenyl) ketones in satisfactory yields. The yields of the same ketones were increased when silyl enol ethers were used in the place of enamines. The alpha-arylation of silyl enol ethers of aldehydes occurred with lower yields and only with the N,N-dimethyl derivative.

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Human spectrin, when isolated, purified and stored in such conditions that preserve its tetrameric form, is able to associate with human hemoglobin as it is clearly shown by gel filtration. However, this hemoglobin-spectrin association does not seem to have a significant effect on hemoglobin oxygenation as indicated by equilibrium and rapid kinetics measurements.

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