39778-95-5Relevant academic research and scientific papers
Kinetics and mechanism of the oxygenation of potassium flavonolate. Evidence for an electron transfer mechanism
Barhacs, Laszlo,Kaizer, Jozsef,Speier, Gabor
, p. 3449 - 3452 (2000)
The oxygenation of the potassium salt of flavonol (flaH) in absolute DMF leads to potassium O-benzoylsalicylate and carbon monoxide in 95% yield at 40 °C. Kinetic measurements resulted in the rate law -d[flaK]/dt = k2[flaK][O2]. The rate constant, activation enthalpy, and entropy at 313.16 K are as follows: k2/M-1 s-1 = (3.28 ± 0.10) × 10-1 ΔH?/kJ mol-1 = 29 ± 2, ΔS?/J mol-1 K-1 = -161 ± 6. The reaction fits a Hammett linear free energy relationship for 4′-substituted flavonols, and electron-releasing groups make the oxygenation reaction faster. The anodic oxidation wave potentials Ea of the 4′-substituted flavonolates correlate well with reaction rates. At more negative Ea values faster reaction rates were observed. EPR spectrum of the reaction mixture (g = 2.0038, dH = 1.8 G, aH = 0.9 G) showed the presence of flavonoxyl radical as a result of a SET from the flavonolate to dioxygen.
Copper-catalyzed chemoselective oxidative o-aroylation of 2-acetylphenols, alkyl salicylates and 1,3-dicarbonyl compounds using styrene derivatives
Kumar, Upendra,Sharma, Ajay,Kumar, Naveen,Pandey, Satyendra Kumar
, (2021/03/03)
A novel copper-catalyzed chemoselective oxidative O-aroylation of 2-acetylphenols, alkyl salicylates and 1,3-dicarbonyl compounds with a wide range of styrene derivatives are described. This approach provides an efficient chemoselective preparation of phenol, alkyl salicylate and enol esters in good to excellent yields. This method represents an alternative protocol for the classical esterification reactions.
