Current Organic Chemistry - Volume 16, Issue 23, 2012

Metal nanoparticles (NPs) have been reduced with NaBH4 from Pt, Rh and Ir precursors salts in presence of (2R,4R)-2,4- bis(diphenylphosphino pentane), ((R,R)-BDPP), and SiO2. This synthesis procedure with a chiral ligand generates chiral stabilized NPs of small and narrowly distributed core sizes depending of metal precursor, metallic loading and ligand stabilizer concentration. These novel catalysts with chiral surface have b Read More

We report the use of V, Bi and Bi-V Keggin structure where Mo is partially replaced by V, Bi, and Bi and V, respectively, in the solvent-free multicomponent synthesis of 3,4-dihydropyrimidin-2-(1H)-ones by the Biginelli method. The incorporation of V, Bi and Bi-V in the structure of PMo notably increases the catalytic activity. The following correlation between the yields of the 3,4- dihydropyrimidin-2-(1H)-ones and the nu Read More

The hydrogenation of m-dinitrobenzene to m-phenylenediamine in liquid phase was studied with the platinum catalysts supported on TiO2, Al2O3 and TiO2-Al2O3 carriers. These materials were successfully activated either by simple in situ reduction technique that makes use of the same reaction conditions or conventional reduction with H2 flowing at 723K. Among the catalysts tested, the Pt/TiO2-Al2O3 catalyst showed th Read More

The oligomerization of glycerol to di- and triglycerol is an attractive reaction because these products find many applications in cosmetics, food industry and polymer industry. To control the oligomerization degree, it is necessary to develop a selective catalyst. In this work, two cesium mesoporous silica (MCM-41 and SBA-15) are compared in the selective oligomerization of glycerol into di- and triglycerol. The catalysts Read More

Palladium and platinum nanoparticles on an activated carbon were used as catalysts in the citral hydrogenation reaction in liquid phase at 363 K and 620 kPa of hydrogen pressure. The effect of metallic precursor salt to prepare mono and bimetallic catalysts was evaluated using PdCl2, Pd(NO3)2 and H2PtCl6. X-ray Photoelectron Spectroscopy suggests that Pdº, Pdδ+ (with δ close to 0) and Ptº are present on the monom Read More

The effect of FeOx on the activity and selectivity in the cinnamaldehyde hydrogenation over Ir/SiO2 catalyst was studied. FeOx/SiO2, Ir/FeOx/SiO2 and Ir/SiO2 catalysts were prepared by impregnation. Fe and Ir content by weight% was 5%Fe and 1%Ir respectively. Samples were calcined at 673 K and reduced in H2 at 573 K. All catalysts were characterized by N2 adsorption, TEM, H2-TPR and DRIFTS of CO at room temperature. Read More

Catalytic application of niobium catalysts is presented in this work. The regioselective oxidation of geraniol was studied over niobium catalysts using hydrogen peroxide (H2O2) as oxidant in the absence of any organic solvent. The catalysts studied were crystalline Nb2O5 bulk, a mixed oxide of Nb2O5/SiO2 (N-S) and Nb2O5/SiO2 mesoporous (N-M). The catalysts were characterized by nitrogen adsorption- desorption isotherms a Read More

Chiral 2-imidazolidinones have been exploited with respect to asymmetric alkylation reactions, aldol reactions, Michael addition reactions, etc, and their convenient preparation from many kinds of available materials, greater stability to ring-opening reaction than chiral oxazolidinones and high levels of asymmetric induction make them excellent and show more widely considerable promise as chiral auxiliaries in organic synthesi Read More

Xanthones belong to a class of O-heterocycles which are known for their great variety of biological/pharmacological activities. The xanthone scaffold can be considered as a privileged structure and for that reason it is an excellent starting point for the search of new bioactive molecules. This review intends not only to make a literature survey about the synthesis of xanthones, but also to organize the most important and c Read More

A novel Schiff base ligand (H2L) from the reaction of 1-phenyl-3-methyl-4-(2-furoyl)-5-pyrazolone with β-alanine and its copper (II) complex [CuLCH3OH]n (1) was synthesized and characterized by elemental analysis, UV, IR, 1H NMR, 13C NMR, MS, EPR, X-ray single crystal diffraction, variable temperature susceptibility measurement and thermogravimetric analysis. The crystal of the complex is a orthorhombic system Read More

The tremendous advances in N-Heterocyclic carbenes (NHCs) have made them the ligand of choice for many transition-metalcatalyzed transformations. Due to the stability of the transition metal complexes of NHCs as well as their stability to air and moisture, NHCs are regarded as an attractive alternative to their phosphine counterparts. To date, research has largely focused on five-membered ring carbenes. Howev Read More