Search

Inhibitors of monoamine oxidases (MAOs) are of interest for the treatment of neurodegenerative disorders and other human pathologies. In this frame, the present work describes different synthetic strategies to obtain MAO inhibitors via the coupling of the aminocoumarin core with arylsulfonyl chlorides followed by copper azide-alkyne cycloaddition, leading to coumarin–sulfonamide–nitroindazolyl–triazole hybrids. The nitration position on the coumarin moiety was confirmed through nuclear magnetic resonance spectroscopy and molecular electron density theory in order to elucidate the molecular mechanism and selectivity of the electrophilic aromatic substitution reaction. The coumarin derivatives were evaluated for their inhibitory potency against monoamine oxidases and cholinesterases. Molecular docking calculations provided a rational binding mode of the best compounds in the series with MAO A and B. The work identified hybrids 14a–c as novel MAO inhibitors, with a selective action against isoform B, of potential interest to combat neurological diseases. [ABSTRACT FROM AUTHOR]

New N-alkyl-nitroindazolylacetonitriles were efficiently obtained via vicarious nucleophilic substitution of N-methyl-nitroindazoles with 4-chlorophenoxyacetonitrile. All compounds were fully characterized by NMR and mass spectroscopy techniques and the structures of some of them were additionally confirmed by X-ray diffraction analysis data. Tautomeric switching was observed in this series of nitroindazolylacetonitriles upon addition of basic anions followed by UV-Vis spectrophotometric and 1H-NMR titrations. The formation of tautomeric species induced by anionic species was endorsed by Density Functional Theory calculations. [ABSTRACT FROM AUTHOR]

The alkylation of a series of nitroindazole derivatives with 1,2-dibromoethane afforded the corresponding N-(2-bromoethyl)- and N-vinyl-nitro-1H-indazoles. The Cu(I)-catalysed azide- alkyne 1,3-dipolar cycloaddition was selected to substitute the nitroindazole core with 1,4-disubstituted triazole units after converting one of the N-(2-bromoethyl)nitroindazoles into the corresponding azide. The reactivity in 1,3-dipolar cycloaddition reactions with nitrile imines generated in situ from ethyl hydrazono-α-bromoglyoxylates was studied with nitroindazoles bearing a vinyl unit. The corresponding nitroindazole-pyrazoline derivatives were obtained in good to excellent yields. [ABSTRACT FROM AUTHOR]