RESUMEN
Correction for 'Visible light-promoted alkylation of imines using potassium organotrifluoroborates' by Davis P. Plasko et al., Photochem. Photobiol. Sci., 2018, 17, 534-538.
RESUMEN
A mild, redox-neutral, alkylation of imines with potassium alkyltrifluoroborates is described. The reaction proceeds under photoredox conditions at â¼30 °C with primary, secondary, and tertiary alkyltrifluoroborates, leading to alkylation products in moderate to good yield in most cases. Aryl-, vinyl-, and cyclopropyltrifluoroborates failed to react under the reported conditions.
RESUMEN
3,3',4,4'-Tetrahydroxybiphenyl and three isomeric 3,3â³,4,4â³-tetrahydroxyterphenyls with varying geometries around the central phenyl ring have been synthesized and evaluated for their in vitro activity against aggregation of Alzheimer's amyloid-ß peptide (Aß). Results from Congo red spectral-shift assays reveal that all four compounds successfully inhibit association of Aß monomers. For the tetrahydroxyterphenyls, efficacy varies with linker geometry: the ortho-arrangement affords the most successful inhibition and the para-geometry the least, perhaps due to differing abilities of these compounds to bind Aß. Of the four small molecules studied, 3,3',4,4'-tetrahydroxybiphenyl is the most effective inhibitor, reducing Aß aggregation by 50% when present in stoichiometric concentrations.
Asunto(s)
Péptidos beta-Amiloides/antagonistas & inhibidores , Compuestos de Bifenilo/química , Compuestos de Terfenilo/química , Péptidos beta-Amiloides/metabolismo , Compuestos de Bifenilo/síntesis química , Compuestos de Bifenilo/metabolismo , Rojo Congo/química , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/metabolismo , Unión Proteica , Compuestos de Terfenilo/síntesis química , Compuestos de Terfenilo/metabolismoRESUMEN
3-Acylpyridine N-oxide tosylhydrazones give good overall yields of a mixture of pyrazolo[3,4-b]pyridines and pyrazolo[4,3-c]pyridines when treated with an electrophilic additive and an amine base. (Z)-Hydrazones cyclize readily, while (E)-hydrazones fail to react under the reported conditions. The reaction takes place at room temperature, and moderate regiocontrol over the cyclization can be achieved by varying the electrophile/solvent combination.
RESUMEN
The synthesis of a variety of novel benzisoxazolo[2,3-a]pyridinium tetrafluoroborates is described. These compounds are conveniently prepared from pyridine N-oxide via a microwave-promoted palladium-catalyzed direct arylation of pyridine N-oxide with 2-bromoacetanilides to give 2-(2-acetamidoaryl)pyridine N-oxides, followed by hydrolysis, diazotization and intramolecular displacement of nitrogen which affords the target benzisoxazolo[2,3-a]pyridinium tetrafluoroborates.
RESUMEN
A convenient protocol for the synthesis of biaryls from arenediazonium salts and potassium aryltrifluoroborates in refluxing methanol catalyzed by Pd/C is described. The protocol is simple to execute and gives moderate to high yields of cross-coupling products in most cases.