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As part of our ongoing attempt to broaden the applications of the amidoxime moiety as a potential source of new antileishmanial agents, this study focuses on the product 4-(5-Benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-2-nitrobenzamide. This unexpected amide was obtained in an 85% yield as the major product with a conventional amidoxime synthesis protocol (Ethanol/Na2CO3) involving the reaction of hydroxylamine and a nitrile group. The formation of this amide derivative instead of the expected amidoxime can be attributed to two complementary effects: the strong electron effect of the nitro group and the influence of ethanol, a polar protic solvent. Alternatively, the desired amidoxime derivative, 4-(5-benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-N′-hydroxy-2-nitrobenzimidamide, was obtained in an 80% yield by an alternative protocol (DMSO/KOtBu). This original compound, featuring a nitro group in the ortho position to the amidoxime, will be further evaluated, both in the field of medicinal chemistry and in other relevant areas, highlighting an unusual method to access amidoximes from hindered substrates. [ABSTRACT FROM AUTHOR]

As part of our ongoing research into the antileishmanial properties of amidoxime derivatives, we report a preliminary assessment of the antiparasitic properties of a novel compound, diethyl (5-benzyl-2-(4-(N′-hydroxycarbamimidoyl)phenyl)-5-methyl-4,5-dihydrofuran-3-yl)phosphonate. This compound was evaluated in vitro for the first time against the promastigote form of Leishmania amazonensis. Compounds containing both amidoxime and phosphonyl functional groups in dihydrofuran scaffolds are relatively rare, despite the extensive study of this heterocycle in various biological applications. Therefore, this work makes a valuable contribution to the fight against Leishmania spp. as a neglected disease. The cyclized 4,5-dihydrofuran intermediate scaffold was obtained via a three-step synthetic route that had previously been developed for accessing other derivatives, including the sulfone moiety. This synthesis was performed using a manganese-based free radical oxidative method under microwave irradiation. The intermediary 4,5-dihydrofuran, which included a nitrile group, tolerated the subsequent reaction with hydroxylamine hydrochloride, resulting in the formation of the target product. The target compound showed moderate activity in vitro against the promastigote form of L. amazonensis (IC50 = 91.1 µM). [ABSTRACT FROM AUTHOR]

The use of visible absorbing and fluorescent tags for sensing and structural analysis of carbohydrates is a promising route in a variety of medical, diagnostic, and therapeutic contexts. Here we report an easy method for covalent attachment of nonfluorescent push–pull chromophores based on the 4-cyano-5-dicyanomethylene-2-oxo-3-pyrroline ring to carbohydrate moieties. The impact of sugar grafting on the optical properties of the push–pull chromophore in the gas phase and in solution was investigated by absorption and action spectroscopy and theoretical methods. The labeled sugars efficiently absorb photons in the visible range, as demonstrated by their intense photodissociation in a quadrupole ion trap. A strong blue shift (−70 nm) of the gas-phase photodissociation intensity maximum is observed upon sugar grafting, whereas no such effect is visible on the solution absorption spectra. Molecular dynamics simulations of labeled maltose in the gas phase describe strong interactions between the sulfonated chromophore and the carbohydrate, which lead to cyclic conformations. These are not observed in the simulations with explicit solvation. Time-dependent density functional theory (TD-DFT) calculations on model molecules permit us to attribute the observed shift to the formation of such cyclic conformations and to the displacement of the negative charge relative to the aromatic moiety of the chromophore. [ABSTRACT FROM AUTHOR]