Small differences in the reactivity of weakly nucleophilic potassium aryltrifluoroborates are revealed in the silver-assisted Pd-catalyzed cross-coupling of K[4-RC6F4BF3] (R = H, Bu, MeO, EtO, PrO, iPrO, BuO, t-BuO, CH2=CHCH2O, PhCH2O, PhCH2CH2O, PhO, F, pyrazol-1-yl, pyrrol-1-yl, and indol-1-yl) with ArX (4-BrC6H4CH3, 4-IC6H4F and 3-IC6H4F). An assumed role of silver(I) compounds Ag m Y (Y = O...

The oxidative coupling of alkylboronic acids with oxygen nucleophiles offers a strategy for replacing toxic, electrophilic alkylating reagents. Although the Chan-Lam reaction has been widely applied in the arylation of heteroatom nucleophiles, O-alkylation with boronic acids is rare. We report a Cu-catalyzed nondecarboxylative methylation of carboxylic acids with methylboronic acid that proceed...

Coordination of the carbocyclic ring of hydroquinones to electrophilic transition-metal fragments such as Mn(CO)3+ and Rh(COD)+ produces stable pi-bonded eta6-complexes that are activated to facile reversible deprotonation of the -OH groups. The deprotonations are accompanied by electron transfer to the transition metal, which acts as an internal oxidizing agent or electron sink. With manganese...

two new spectrophotometric methods (m1 and m2) are developed for the determination of vardenafil in bulk and in tablet dosage forms. the method m1 involves oxidative coupling of vardenafil with 3-methyl-2-benzothiazolinone hydrazone hydrochloride in presence of ferric chloride in acidic medium yielding green colored chromogen with absorption maxima at 625 nm. the method m2 is based on the oxida...

Zinc oxide nano-particles with the average diameter of about 25 nm were modified with different mole ratios of trimetoxyvinyl silane (TMVS) and oleic acid, as coupling agents, in order to modify their surface properties and render them more hydrophobic. Then, dispersibility of the surface modified nano-particles was examined in some monomers with different levels of hydrophobicity, including me...

Investigating the alkylation and acylation of N-acylthiazolidinethione, the desired α-alkylated products and C-acylated products are not obtained, but rather the S-alkylated products and O-acylated products are obtained. The possible mechanism proposed shows that the deprotonation agent and electrophilic species are responsible for the stability of enolates. The enolates derived from N-acylthia...

titanium dioxide (tio2) nanoparticles, with an average size of about 45 nm, were encapsulated by polystyrene using in situ nitroxide mediated radical polymerization   in the presence of 3-aminopropyl triethoxy silane (aptes) as a coupling agent and 2, 2, 6, 6-tetramethylpiperidinyl-1-oxy  as a initiator. first, the initiator for nmrp was covalently bonded onto the surface of titanium dioxide na...