The first Pd-catalyzed multisite-selective acetoxylation reactions are disclosed at an unactivated alkene sp C-H bond versus secondary allylic sp C-H bond in cyclic olefins via the modulation of directing groups. The different directing groups overcome the key challenge in differentiating C-H bonds and provide a new controlling approach for site-specific C-H activation. A wide variety of substrates are readily acetoxylated under operationally simple conditions. Mechanistic studies suggest that different Pd (IV) intermediates were involved in the multisite-selective acetoxylation reactions.
A method for intramolecular sp C-H oxidative arylation of unactivated cyclic olefins has been developed to access spiro-dihydroquinoline and octahydrophenanthrene derivatives in a straightforward and efficient manner. Bearing picolinamide as a directing group, the alkenyl anilines cyclized to afford spiro-dihydroquinolines in moderate to excellent yields via direct oxidative arylation, while the alkenyl benzylamines furnished the octahydrophenanthrene derivatives in moderate yields via sequential oxidative arylation and double acetoxylation.
A method for the oxidative arylacetoxylation of alkenes has been developed to synthesize indole and indoline derivatives from readily accessible substrates. The cinnamyl tethered anilines with picolinamide as a directing group provided 3-substituted indoles via intramolecular oxidative arylacetoxylation, and the 2-methyl substituted cinnamyl anilines furnished indoline derivatives with 3-position quaternary stereocenters in good to excellent yields via sequential intramolecular oxidative arylacetoxylation, hydrolysis and oxidation steps.
A new
hybridization of berberine and benzimidazoles was performed
to produce 13-(benzimidazolylmethyl)berberines (BMB) as potentially
broad-spectrum antibacterial agents with the hope of confronting multidrug-resistant
bacterial infections in the livestock industry. Some of the newly
prepared hybrids showed obvious antibacterial effects against tested
strains. Particularly, 13-((1-octyl-benzimidazolyl)methyl)berberine 6f (OBMB-6f) was found to be the most promising
compound that not only exerted a strong activity (MIC = 0.25–2
μg/mL) and low cytotoxicity but also possessed a fast bactericidal
capacity and low propensity to develop resistance toward Staphylococcus aureus and Escherichia
coli even after 26 serial passages. Moreover, OBMB-6f displayed the ability to prevent bacterial biofilm formation
at low and high temperatures. The mechanistic exploration revealed
that OBMB-6f could significantly disintegrate bacterial
membranes, markedly facilitate intracellular ROS generation, and efficiently
intercalate into DNA. These results provided a profound insight into
BMB against multidrug-resistant bacterial infections in the livestock
industry.
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