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The synthesis of the peracetylated ketonitrone 4 is described in four steps from l-sorbose. This cyclic nitrone is crystalline and proved to preferentially adopt a 4H3 conformation with all acetate groups in pseudo-axial orientation. Nitrone 4 undergoes regioselective cycloadditions with alkynes, affording tetra-O-acetyl-isoxazolines with good yields and stereoselectivities (4 : 1 to 9 : 1 diastereomeric ratio). Nitrone 4 and the obtained isoxazolines were smoothly deacetylated to produce the polyhydroxylated nitrone 5 and novel iminosugars containing an isoxazoline motif. Evaluation of their glycosidase inhibitory activity demonstrated their rather weak, but selective affinity for a variety of enzymes. [ABSTRACT FROM AUTHOR]

Heterocyclic chalcones were synthesized by reaction of 4-acetylpyridine with the corresponding aromatic aldehydes under Claisen Schmidt conditions. These chalcones were used as starting material for the synthesis of oximes in the presence of hydroxylamine hydrochloride. The structures of the synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and ESI-MS, HRMS spectral analyses. All the synthesized compounds were evaluated for their antioxidant activity by DPPH• method and their in vitro antimicrobial activity by disk diffusion method against two Gram-negative bacteria, one Gram-positive bacteria and two fungal strains (C. albicans and A. niger). The results showed that the synthesized compounds did not display significant antioxidant activity. However, compounds 3b, 3d, 3f, 3h, 3i showed excellent antibacterial activity better than the standard drug against the bacterial strain S. aureus (ATCC 25923). The two compounds 3c, 3d proved very active against the fungal strain A. niger (MIC= 7.81 µg/ mL, 15.62 µg/mL respectively) while the antifungal drug used as reference (Fluconazole) was inactive. Molecular docking and molecular dynamics results revealed that the synthesized compounds, 4e, 4c , and 5j , were involved in a large number of favorable interactions with the active site residues of the acetylcholinesterase protein, which can stabilize the ligands in the active site and increase their affinities. [Display omitted] [ABSTRACT FROM AUTHOR]

A series of 6H,7H-7-(4-Hydroxy-3-coumarinyl)[1]benzopyrano[4,3-b][1]benzopyran-6-ones 4a-g and 3-(2-hydroxybenzoyl)-2H-chromen-2-ones 5a-g derivatives were synthesized by reaction of 4-hydroxycoumarin with 2-hydroxyarylaldehydes 2a-f or 2-hydroxynaphtaldehyde 2g using different solvents and acid/base catalysts. The approach relies on a regioselective cascade reaction involving one/two molar equiv of the 4-hydroxy coumarin iteratively acting as active methylene substrate in a Knoevenagel condensation and in a Michael addition. The structures of all compounds were established by IR, mass spectrometry, 1H-NMR and 13C-NMR. Antioxidant activity of the synthesized compounds were determined using the DPPH scavenging assay, best results being obtained with 5b (IC 50 = 236 µg/mL). Computational studies showed that the compounds bind in the ATP-binding site of p38 MAPK, in a same manner than known polyaromatic potent inhibitors. The synthesized compounds might be considered further for cancer therapy. Image, graphical abstract [ABSTRACT FROM AUTHOR]

A diagram is presented which explains the chemical process of Perfluoroalkylation of Nitrones for the Synthesis of a Series of Fucosidase Inhibitors.