6279-34-1Relevant articles and documents
Impregnated palladium on magnetite as catalyst for direct arylation of heterocycles
Cano, Rafael,Pérez, Juana M.,Ramón, Diego J.,McGlacken, Gerard P.
, p. 1043 - 1050 (2016/07/06)
Palladium impregnated on magnetite is an efficient, cheap and easy to prepare catalyst for the direct arylation of heterocycles. Good yields are afforded under relatively mild conditions and a broad substrate scope is evident. The catalyst is regioselective in many cases, affording arylated products, at the C2- or C3-position (depending of the heterocycle used). The methodology can be extended to prepare chromenes through an intramolecular direct arylation reaction. Some evidence is provided for two catalyst deactivation pathways, which prevents efficient recycling.
Intramolecular 9-membered hydrogen bonding of 2-arylmethylphenols having carbonyl groups at 2′-position
Yoshimi, Yasuharu,Maeda, Hajime,Hatanaka, Minoru,Mizuno, Kazuhiko
, p. 9425 - 9431 (2007/10/03)
Thermodynamic parameters of nine-membered intramolecular hydrogen bonding between carbonyl groups and phenolic hydroxyl groups of 2-arylmethylphenols having methoxycarbonyl, dimethylcarbamoyl, and formyl groups were determined by variable temperature 1H NMR studies and van't Hoff analysis. The enthalpy of the hydrogen bonding was related to the electron-withdrawing ability of the substituents on the phenol and the basicity of the carbonyl group. The entropy loss of the hydrogen bonding was dependent on the rotation freedom of the phenol group. The enthalpy of nine-membered intramolecular hydrogen bonding between carbonyl groups and phenolic hydroxyl groups of 2-arylmethylphenols was related to the electron-withdrawing ability of the substituents on the phenol and the basicity of the carbonyl group. The entropy loss was dependent on the rotation freedom of the phenol group.