Alumina-Supported Gold Nanoparticles as a Bifunctional Catalyst for the Synthesis of 2-Amino-3-arylimidazo[1,2-]pyridines.

The bifunctional catalytic efficacy of alumina-supported gold nanoparticles (Au/AlO) was investigated for the synthesis of a series of 2-amino-3-aryl-imidazopyridines through the chemoselective reduction of the corresponding 2-nitro-3-aryl-imidazo[1,2-]pyridines in high isolated yields. This highly efficient protocol was initially applied for the synthesis of 2-nitro-3-aryl imidazo[1,2-]pyridines via the reaction between 2-aminopyridine and nitroalkenes catalyzed by the present catalytic system Au/AlO. Moreover, the heterogeneous surface γ-AlO was also found to catalyze this pathway in a comparable manner.

Green photocatalytic organic transformations by polyoxometalates vs. mesoporous TiO2 nanoparticles: selective aerobic oxidation of alcohols.

In this study, the catalytic activity of decatungstate (W10O32(4-)) supported on mesoporous TiO2 nanoparticle assemblies (DT-MTA) was compared with that of homogeneous [Bu4N]4W10O32 catalysts under mild conditions. Our experiments showed that both catalytic systems achieve exceptionally high activity and selectivity under UV-visible light oxidation of various para-substituted aryl alcohols, using molecular oxygen as a "green" oxidant. The chemoselective transformation of aryl alcohols into the corresponding ketones was investigated with gas chromatography (GC) and NMR spectroscopy.

Synthesis and anti-inflammatory evaluation of novel angularly or linearly fused coumarins.

Angular [7,8]-fused coumarins were obtained from the reaction of [2,3]-fused phenols with DMAD and PPh(3), while linear [6,7]-fused coumarins were formed from the analogous reaction of [3,4]-fused phenols with DMAD and PPh(3). These compounds were tested in vitro for antioxidant activity and they found to present significant scavenging activity. In parallel, these new compounds were evaluated in vivo for anti-inflammatory activity and they found to inhibit the carrageenin-induced paw edema (34-65%).

Synthesis of hydroxycoumarins and hydroxybenzo[f]- or [h]coumarins as lipid peroxidation inhibitors.

Substituted hydroxycoumarins and 7- or 8-hydroxybenzo[f]coumarins were prepared by the treatment of phenols and naphthalenediols, respectively, with malic acid and H(2)SO(4) under microwave irradiation. 7- or 8-Hydroxybenzo[f]coumarins and 6-hydroxybenzo[h]coumarin were synthesized by the reaction of naphthalenediols with ethylpropiolate in the presence of ZnCl(2) in refluxing dioxane. The compounds were tested in vitro for their ability: (i) to interact with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) stable free radical, (ii) to inhibit lipid peroxidation, (iii) to scavenge the superoxide anion, (iv) to inhibit the activity of soybean lipoxygenase and (v) to inhibit in vivo the carrageenin-induced rat paw edema.