One-pot melt synthesis of resorcinol based polyarylates for UV-stable coatings

A new one-pot method for the melt synthesis of polyarylates based on resorcinol and phthalic acids has been developed. The method consists in the reaction of diphenyl carbonate, phthalic acids and resorcinol using titanium butoxide as catalyst. Model reactions have shown that the diaryl ester is generated in situ by reaction of the aromatic diacid and of the aromatic diol with diphenyl carbonate. It is thus possible to obtain polymers with tailored end-groups and molecular weight, by changing the molar ratio of the monomers and the reaction conditions. More specifically, we applied this method to the synthesis of low molecular weight polymers with carboxylic end-groups, suitable for powder coating applications. The literature actually reports that resorcinol based polyarylates present an outstanding long-term UV stability and therefore COOH terminated oligomers are highly promising materials for the preparation of super-durable powder coatings. Such method can also be applied to the preparation of polyarylates with high molecular weight, that are based not only on resorcinol and phthalic acids

Phytochemical and Antioxidant-Related Investigations on Bark of Abies Spectabilis (D. Don) Spach. from Nepal

The bark of several coniferous species, a waste product of the timber industry,contains significant amounts of natural antioxidants. In our ongoing studies of Nepalese medicinal plants, we examined the bark from Abies spectabilis as the starting material forextracting antioxidant compounds. In vitro antioxidant activity evaluated by means of three antioxidant methods, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), Briggs-Rauscher oscillating reaction (BR) and Trolox Equivalent Antioxidant Capacity (TEAC) and total phenol contents with the Folin-Ciocalteau reagent; the ferrous iron chelating capacity wasalso assessed. The methanol extract of A. spectabilis showed significant antioxidant activity and polyphenol contents (IC50 4.13 μg/mL, 0.20 μg/mL eq. resorcinol, 4.22 mM eq. Trolox, 3.9 μg/g eq. gallic Acid in the DPPH, BR, TEAC and Folin-Ciocalteau tests, respectively) and weak Fe2+ chelating capacity. Phytochemical studies were also carried out with 1D- and 2D NMR experiments and DI-ESI-MS, HPLC-DAD and LC-MSn measurements. Oligomeric C-type proanthocyanidins, mainly trimeric gallocatechin derivatives, were the most abundant compounds (16% of extract expressed as procyanindin B1). Gallocatechin oligomers (up to six units) and prodelphynidin-gallocatechin polymers were also identified in the extract. Prodelphynidin B4, cyclograndisolide and trans-docosanil ferulate were also isolated and characterized by NMR and MS spectroscopy

N-3 fatty acids in patients with multiple cardiovascular risk factors

BACKGROUND: Trials have shown a beneficial effect of n-3 polyunsaturated fatty acids in patients with a previous myocardial infarction or heart failure. We evaluated the potential benefit of such therapy in patients with multiple cardiovascular risk factors or atherosclerotic vascular disease who had not had a myocardial infarction. METHODS: In this double-blind, placebo-controlled clinical trial, we enrolled a cohort of patients who were followed by a network of 860 general practitioners in Italy. Eligible patients were men and women with multiple cardiovascular risk factors or atherosclerotic vascular disease but not myocardial infarction. Patients were randomly assigned to n-3 fatty acids (1 g daily) or placebo (olive oil). The initially specified primary end point was the cumulative rate of death, nonfatal myocardial infarction, and nonfatal stroke. At 1 year, after the event rate was found to be lower than anticipated, the primary end point was revised as time to death from cardiovascular causes or admission to the hospital for cardiovascular causes. RESULTS: Of the 12,513 patients enrolled, 6244 were randomly assigned to n-3 fatty acids and 6269 to placebo. With a median of 5 years of follow-up, the primary end point occurred in 1478 of 12,505 patients included in the analysis (11.8%), of whom 733 of 6239 (11.7%) had received n-3 fatty acids and 745 of 6266 (11.9%) had received placebo (adjusted hazard ratio with n-3 fatty acids, 0.97; 95% confidence interval, 0.88 to 1.08; P=0.58). The same null results were observed for all the secondary end points. CONCLUSIONS: In a large general-practice cohort of patients with multiple cardiovascular risk factors, daily treatment with n-3 fatty acids did not reduce cardiovascular mortality and morbidity. Copyright © 2013 Massachusetts Medical Society