We employed oleylphosphonic acid (OLPA) for the synthesis of CsPbBr 3 nanocrystals (NCs). Compared to phosphonic acids with linear alkyl chains, OLPA features a higher solubility in apolar solvents, allowing us to work at lower synthesis temperatures (100 °C), which in turn offer a good control over the NCs size. This can be reduced down to 5.0 nm, giving access to the strong quantum confinement regime. OLPA-based NCs form stable colloidal solutions at very low concentrations (∼1 nM), even when exposed to air. Such stability stems from the high solubility of OLPA in apolar solvents, which enables these molecules to reversibly bind/unbind to/from the NCs, preventing the NCs aggregation/precipitation. Small NCs feature efficient, blue-shifted emission and an ultraslow emission kinetics at cryogenic temperature, in striking difference to the fast decay of larger particles, suggesting that size-related exciton structure and/or trapping-detrapping dynamics determine the thermal equilibrium between coexisting radiative processes.

Tetra- and octavalent sialoside clusters were prepared in good yields exploiting for the first time the multiple copper-catalyzed cycloaddition of a propargyl thiosialoside with calix[4]arene polyazides. The cycloadducts featured the hydrolytically stable carbon-sulfur bond at the anomeric position and the 1,4-disubstituted triazole ring as the spacer between the sialic acid moieties and the platform. It was demonstrated that these unnatural motifs did not hamper the desired biological activity of the sialoclusters. In fact, they were able to inhibit, at submillimolar concentrations, the hemagglutination and the viral infectivity mediated both by BK and influenza A viruses.

Sugar-coated chips: Glycoside clusters are valuable tools for carbohydrate-lectin recognition studies. However, the spatial arrangement of the sugar residues is a key issue in the design of high-affinity glycoclusters. Here the affinities of linear and antenna- and calixarene-based galactoside clusters towards two lectins derived from Pseudomonas aeruginosa and Ricinus communis were compared by means of glycoarrays.Interactions between proteins and carbohydrates are involved in a large number of crucial biological events. Many efforts have been devoted to the design and synthesis of unnatural saccharides displaying high affinities towards targeted lectins. Among others, glycoside clusters have proven to be valuable tools for these recognition studies. However, the spatial arrangements of the sugar residues are a key issue in the design of high-affinity glycoclusters. Here, the affinities of linear and antenna- and calixarene-based galactoside clusters against two lectins, derived from Pseudomonas aeruginosa and Ricinus communis, have been compared by means of glycoarrays.

Novel sugar-based silica gels were prepared by exploiting the copper-catalysed azide-alkyne cycloaddition (CuAAC) of two different sugar alkynes, namely, ethynyl C-galactoside 1 and propargyl O-lactoside 2, with new single-step azido-activated silica gels. The fully characterised stationary phases were generally used for hydrophilic interaction chromatography (HILIC), with particular application in the stereoselective separation of monosaccharides. Dynamic HILIC (DHILIC) experiments were performed to evaluate the influence of mutarotation on the chromatographic peak shapes of two interconverting sugar anomers. The potential of such materials was shown in the separation of other highly polar compounds, including amino acids and flavonoids.

Lipase mediated desymmetrization of a meso-diol (1,2-cyclopentanedimethanol) allows the synthesis of both enantiomers of some chiral aldehydes, whose behavior in Passerini and Ugi reactions has been explored. Exploiting these two complementary multicomponent reactions and coupling them with a subsequent cyclization process, we observed that 6 out of all 8 possible stereoisomers of peptidomimetic pyrrolidines can be obtained in good yields. The potential of these protocols has been proved by the development of a new efficient synthesis of antiviral drug telaprevir.

This perspective aims at celebrating the 100th Anniversary of the discovery of the Passerini three component reaction. After being nearly neglected for many years, now this reaction has become quite...

In this study natural-based complex polyphenols, obtained through a smart synthetic approach, have been evaluated for their ability to inhibit the formation of Aβ42 oligomers, the most toxic species causing synaptic dysfunction, neuroinflammation, and neuronal death leading to the onset and progression of Alzheimer’s disease. In vitro neurotoxicity tests on primary hippocampal neurons have been employed to select nontoxic candidates. Solution NMR and molecular docking studies have been performed to clarify the interaction mechanism of Aβ42 with the synthesized polyphenol derivatives, and highlight the sterical and chemical requirements important for their antiaggregating activity. NMR results indicated that the selected polyphenolic compounds target Aβ42 oligomeric species. Combined NMR and docking studies indicated that the Aβ42 central hydrophobic core, namely, the 17–31 region, is the main interaction site. The length of the peptidomimetic scaffold and the presence of a guaiacol moiety were identified as important requirements for the antiaggregating activity. In vivo experiments on an Aβ42 oligomer-induced acute mouse model highlighted that the most promising polyphenolic derivative (PP04) inhibits detrimental effects of Aβ42 oligomers on memory and glial cell activation. NMR kinetic studies showed that PP04 is endowed with the chemical features of true inhibitors, strongly affecting both the Aβ42 nucleation and growth rates, thus representing a promising candidate to be further developed into an effective drug against neurodegenerative diseases of the amyloid type.

Lewis acid catalyzed Passerini reactions on chiral aldehydes derived from desymmetrized erythritol take place with unprecedented diastereoselectivity. The resulting adducts have been selectively and efficiently converted into a variety of densely functionalized, polyoxygenated heterocycles.