Biodiesel production from rapeseed oil and low free fatty acid waste cooking oil using a cesium modified natural phosphate catalyst.

The present study focuses on the catalytic activity of cesium modified natural phosphate in biodiesel production from rapeseed oil and low free fatty acids (FFA) used in cooking oil. The catalyst was prepared by impregnation of cesium chloride (CsCl) on the natural phosphate followed by calcination up to 800 °C. The phosphate based catalyst was thermally, structurally, morphologically, and texturally characterized in order to determinate the relationship between its physicochemical properties and its catalytic activity. The chosen catalyst was demonstrated to be an active catalyst for the transesterification of rapeseed oil achieving a biodiesel yield of 99.55% under suitable reaction conditions: a methanol to oil molar ratio of 12 : 1, reaction temperature of 70 °C, catalyst amount of 4 wt% based on oil weight and reaction time of 6 h. Results from low FFA waste cooking oil transesterification indicated that a methyl esters yield of 99.52% could be obtained. Furthermore, results from esterification/transesterification of acidified rapeseed oil indicate that a yield of 93% may be obtained, thus giving rise to a potential application in 2nd generation biodiesel production from low acidic oils. Some important physicochemical properties of the obtained biodiesel were evaluated and compared with the EN14214 and ASTM D-6751 standards for biodiesel specifications.

Aqueous-phase catalytic hydroxylation of phenol with H2O2 by using a copper incorporated apatite nanocatalyst.

Copper incorporated apatite (Cu-apatite) nanomaterial was prepared by a co-precipitation method. The obtained material was characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) and Raman spectroscopy, scanning electron microscopy (SEM, STEM) and nitrogen adsorption-desorption. The as-prepared Cu-apatite was used to catalyze phenol hydroxylation with hydrogen peroxide as an oxidant. The influencing parameters including reaction time, temperature, H2O2/phenol ratio and catalyst mass have been investigated. Under the optimized conditions, the Cu-apatite catalyst gave a phenol conversion of 64% with 95% selectivity to dihydroxybenzenes. More importantly, the results of catalyst recycling indicated that the same catalytic performance has been obtained after four cycles with a slight loss of activity and selectivity.

Synthesis and bioactivity of novel amino-pyrazolopyridines.

Here we describe the synthesis and biological activity of novel amino-pyrazolopyridines with anti-NF-κB and pro-apoptotic potential. α-Methylene ketones were used as a starting point for synthesis of amino-pyrazolopyridine 3. The alkylidene malononitriles 1 were obtained by the Knoevenagel reaction of ketones with malononitriles. Vilsmeier-Haack reaction allowed direct access to 2-chloro-3-cyanopyridines 2. Those products, by refluxing with hydrazine hydrate, allowed cyclization to amino-pyrazolopyridines 3a-g, which were not previously described in the literature. Bioactivity results indicated that amino-pyrazolopyridines 3a, 3b and 3g induced apoptotic cell death in K562 cancer cells with an IC50 of 36.5 ± 3.9 µM, 27.6 ± 4.5 µM and 35.0 ± 2.3 µM, respectively, after 72 h. In addition, compounds 3a, 3b and 3g exerted NF-κB inhibition activity with an IC50 of 4.7 ± 1.6 µM, 6.9 ± 1.9 µM and 39.8 ± 3.9 µM, respectively, after 8 h in K562 cells activated with TNFα. Compounds 3b and 3g showed interesting differential toxicity as viability of peripheral blood mononuclear cells (PBMCs) from healthy donors remained largely unaffected by this treatment.

Synthesis and optimization of an original V-shaped collection of 4-7-disubstituted pyrido[3,2-d]pyrimidines as CDK5 and DYRK1A inhibitors.

We here report the synthesis and biological evaluation of an original collection of 4,7-disubstituted pyrido[3,2-d]pyrimidines designed as potential kinase inhibitors. The collection was generated from a single starting material, 4,7-dichloropyrido[3,2-d]pyrimidine, which afforded the final compounds after two steps: a sequential or one-pot sequence including selective cross coupling reactions in C-4, followed by the second cross-coupling in C-7. In position C-4, a Suzuki-Miyaura type reaction led to monosubstituted derivatives whereas in position C-7, synthesis was achieved via a Suzuki or a Buchwald type reaction using commercially available or undescribed boron derivatives. The biological activity of the V-shaped family was measured in protein kinase assays. The structure activity relationship (SAR) revealed that some compounds selectively inhibited DYRK1A and CDK5 without affecting GSK3. Docking studies furnished possible explanations that correlate with the SAR data. The most active compound on the two biological targets was 27 which exhibited the following IC50: 110 nM for CDK5, 24 nM for DYRK1A and only 1.2 µM for GSK3. In the C-7 amino subfamily, the best derivative was indubitably compound 48 which led to a near selective action on DYRK1A and a remarkable IC50 of 60 nM.

Quantitative structure-diastereoselectivity relationships for arylsulfoxide derivatives in radical chemistry.

Quantitative structure-diastereoselectivity relationships were studied for the intermolecular radical addition of deuterium and allyltributyltin to chiral arylsulfoxides by means of multiple linear regression and artificial neural networks (ANN). The values of diastereoselectivity (% syn) of the compounds studied were well correlated with the descriptors encoding the chemical structure. Using the pertinent descriptors revealed by the regression analysis, a square correlation coefficient of 0.9577 ( s=5.3825) for the training set was obtained for the ANN model in a 2-4-1 configuration. The results obtained from this study indicate that the diastereoselectivity of arylsulfoxide derivatives is strongly dependent on the shape of the R and X groups. FIGURE General structure of alpha-sulfinyl radicals