Citronellal was the major product of catalytic oxidation of dihydromyrcene with oxygen using the catalyst comprised of (MeCN)2PdClNO2 and CuCl2 in a tertiary alcohol in supercritical carbon dioxide. It was found that the chemoselectivity of the reaction and the yield of citronellal were greatly affected by the pressure of carbon dioxide, the reaction temperature and the molar ratio of Pd/Cu.
JIANG Huan-feng , YANG Xiao-yue , LI Guo-ping , ZOU Gang ?1 2 2 2 Department of Applied Chemistry, South China University of Technology, Guangzhou 510640
A novel and green method for the synthesis of dimethyl pyridine-3,5-dicarboxylate has been developed. It is PdCl2-catalyzed heterocyclotrimerization of methyl acrylate with urea in methanol/supercritical carbon dioxide. The target compound was obtained with a 75% isolated yield under the optimized con-ditions.
ZOU Bo,JIANG HuanFeng College of Chemistry,South China University of Technology,Guangzhou 510640,China
Several Mn(Ⅲ)10-(hydroxylphenyl)-5,15-bis(pentafluoro-phenyl)corroles with the hydroxyl at ortho-,meta-and para-position of 10-phenyl group were used as the catalysts in the oxidative cleavage of plasmid DNA in the presence of H2O2.The catalytic system was composed of 10 μL 0.5 mg/mL pC DNA 6 in TE buffer solution(pH=8.0,4.0×10-2 mol/L Tris,1.0×10-3 mol/L EDTA),10 μL 1.0×10-5 mol/L Mn(Ⅲ)corrole in DMSO and 10 μL 0.3% H2O2.After 8 h incubation at room temperature,significant oxidative DNA damage could be observed with the ortho-hydroxyl Mn(Ⅲ)corrole showing a better activity as detected by agarose-gel electrophoresis.Plasmid DNA was completely damaged after 12 h incubation.These observations show Mn(Ⅲ)corrole can be used as an artificial model of nuclease.
A facile and efficient method for the synthesis of tetrasubstituted olefins in supercritical carbon dioxide was developed by using carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) as the catalyst. Compared with common Pd/C, Pd/CNTs could more effectively catalyze the reaction of dibromo-substituted olefins with boronic acids, affording the corresponding tetrasubstituted olefins with moderate to good yields. This environmentally benign route with an easy-to-handle catalyst provides an appealing alternative to the currently available methods.
A facile triphenylphosphine-catalyzed Michael addition of alcohols to acrylic compounds was described. The reaction was carried out in open air at refluxing temperature in the presence of 10 mol% PPh3. Michael addition of saturated and unsaturated alcohols to acrylonitrile or acrylates has been examined. The reaction gave β-alkoxy derivatives with isolated yields of 5%-79%. PPh3 is cheaper and more stable than those trialkylphosphines previously used for the similar reactions, and the products can be easily separated from the reaction mixture via distillation.
