Impregnated ruthenium on magnetite as a recyclable catalyst for the N-alkylation of amines, sulfonamides, sulfinamides, and nitroarenes using alcohols as electrophiles by a hydrogen autotransfer process

Various impregnated metallic salts on magnetite have been prepared, including cobalt, nickel, copper, ruthenium, and palladium salts, as well as a bimetallic palladium-copper derivative. Impregnated ruthenium catalyst is a versatile, inexpensive, and simple system for the selective N-monoalkylation of amino derivatives with poor nucleophilic character, such as aromatic and heteroaromatic amines, sulfonamides, sulfinamides, and nitroarenes, using in all cases alcohols as the initial source of the electrophile, through a hydrogen autotransfer process. In the case of sulfinamides, this is the first time that these amino compounds have been alkylated following this strategy, allowing the use of chiral sulfinamides and secondary alcohols to give the alkylated compound with a diastereomeric ratio of 92:8. In these cases, after alkylation, a simple acid deprotection gave the expected primary amines in good yields. The ruthenium catalyst is quite sensitive, and small modifications of the reaction medium can change the final product. The alkylation of amines using potassium hydroxide renders the N-monoalkylated amines, and the same protocol using sodium hydroxide yields the related imines. The catalyst can be easily removed by a simple magnet and can be reused up to ten times, showing the same activity.     

Vehicle emissions,urban air quality and current Italian legislation: the case of Messina. V

In the current program for the preparation of an urban air map, this paper reports data obtained by the five base stations in the period 1997-2000 regarding traditional pollutants and gives the first results obtained in determining continuously benzene, toulene and PM10. Additional measurements have been carried out by a mobile station at the falcate zone, never tested before, which has very low traffic but with the presence of some small metal industries and, under favourable meteorological conditions, the effects of the harbour. A statistical study on the hourly-trend of particulate suspended matter in two zones of the city which have different traffic volume for the period 1995-1997 is also reported. The ozone characteristic peak at 15.00 is fully confirmed in all stations and over all the period contrarily to most Italian cities, which present the peak about three hours earlier. PM10 annual mean value during 1999 was a little higher than the legal one. Base stations "Archimede" and "Minissale" still present some risk of a stop or limitation of traffic even with respect to traditional or "new" pollutants. Statistical analysis of particulate suspended matter confirm the very different characteristics of the base stations under consideration.     

A highly enantioselective route to either enantiomer of both alpha- and beta-amino acid derivatives

This report describes the unprecedented use of unmodified aldehydes as donors in a catalytic asymmetric Mannich-type reaction. The proline-catalyzed reaction of N-PMP-protected alpha-imino ethyl glyoxylate with unmodified aliphatic aldehydes provided a general and very mild entry to either enantiomer of beta-amino and alpha-amino acids and derivatives in high yield and stereoselectivity. Six of the seven aldehydes studied yielded products with ee values of 99% or greater. The diastereoselectivity of the reaction increased with the bulkiness of the substituents of the aldehyde donor in the order R = Me < Et < i-Pr < n-Pent. In five of the cases studied, excellent syn stereoselectivities were achieved. In addition, the corresponding chiral beta-amino aldehyde adducts can be readily converted to the corresponding amino acid derivatives. Most significantly, this approach provides facile access to substituted beta-lactams.     

Calorimetric study of spinodal decomposition in β-Cu–Al–Mn

Journal of Thermal Analysis and Calorimetry - We report data obtained from the spinodal decomposition in samples of two compositions of intermetallic Cu–Al–Mn shape memory alloys....     

Polyphenolic QTOF-ESI MS Characterization and the Antioxidant and Cytotoxic Activities of Prunus domestica Commercial Cultivars from Costa Rica

There is an increased interest in plum research because of their metabolites’ potential bioactivities. In this study, the phenolic profiles of Prunus domestica commercial cultivars (Methley, Pisardii and Satsuma) in Costa Rica were determined by Ultra Performance Liquid Chromatography coupled with High Resolution Mass Spectrometry using a quadrupole-time-of-flight analyzer (UPLC-ESI-QTOF MS) on enriched phenolic extracts obtained through Pressurized Liquid Extraction (PLE) under acidic and neutral extraction conditions. In total, 41 different phenolic compounds were identified in the skin and flesh extracts, comprising 11 flavan-3-ols, 14 flavonoids and 16 hydroxycinnamic acids and derivatives. Neutral extractions for the skins and flesh from all of the cultivars yielded a larger number of compounds, and were particularly rich in the number of procyanidin trimers and tetramers when compared to the acid extractions. The total phenolic content (TPC) and antioxidant potential using the DPPH and ORAC methods exhibited better results for neutral extracts with Satsuma skins and Methley flesh, which showed the best values (685.0 and 801.6 mg GAE/g extract; IC₅₀ = 4.85 and 4.39 µg/mL; and 12.55 and 12.22 mmol TE/g extract, respectively). A Two-Way ANOVA for cytotoxicity towards AGS gastric adenocarcinoma and SW620 colon adenocarcinoma indicated a significant difference (p < 0.05) for PLE conditions, with better results for neutral extractions, with Satsuma skin delivering the best results (IC₅₀ = 60.7 and 46.7 µg/mL respectively) along with Methley flesh (IC₅₀ = 76.3 and 60.9 µg/mL, respectively). In addition, a significant positive correlation was found between TPC and ORAC (r = 0.929, p < 0.05), as well as a significant negative correlation (p < 0.05) between TPC and cytotoxicity towards AGS and SW620 cell lines (r = −0.776, and −0.751, respectively). A particularly high, significant, negative correlation (p < 0.05) was found between the number of procyanidins and cytotoxicity against the AGS (r = −0.868) and SW620 (r = −0.855) cell lines. Finally, the PCA clearly corroborated that neutral extracts are a more homogenous group exhibiting higher antioxidant and cytotoxic results regardless of the part or cultivar; therefore, our findings suggest that PLE extracts under neutral conditions would be of interest for further studies on their potential health benefits.     

A multiresidual method based on ion-exchange chromatography with conductivity detection for the determination of biogenic amines in food and beverages

In the present work a sensitive and accurate method by ion chromatography and conductimetric detection has been developed for the determination of biogenic amines in food samples at microgram per kilogram levels. The optimized extraction procedure of trimethylamine, triethylamine, putrescine, cadaverine, histamine, agmatine, spermidine, and spermine from real samples, as well as the separation conditions based on a multilinear gradient elution with methanesulfonic acid and the use of a weak ionic exchange column, have provided excellent results in terms of resolution and separation efficiency. Extended calibration curves (up to 200 mg/kg, r?>?0.9995) were obtained for all the analyzed compounds. The method gave detection limits in the range 23–65 μg/kg and quantification limits in spiked blank real samples in the range 65–198 μg/kg. Recovery values ranged from 82 to 103 %, and for all amines, a good repeatability was obtained with precision levels in the range 0.03–0.32 % (n?=?4). The feasibility and potential of the method were tested by the analysis of real samples, such as tinned tuna fish, anchovies, cheese, wine, olives, and salami.

Thermal evaluation of cashew nutshell liquid as new bioadditives for poly(methyl methacrylate)

In this study, the thermal-oxidative stability of poly(methyl methacrylate), PMMA, 1 % additivated with replenishable phenolic lipids is evaluated by thermogravimetric (TG/DTG) analyses and differential scanning calorimetry (DSC) analyses. Since technical cashew nutshell liquid (CNSL), a byproduct from the cashew industry, is composed basically of two phenolic lipids, cardanol and cardol, the utilization of this industrial waste and its main components as a new source of bioadditives for use as antioxidants is evaluated. The TG analyses revealed that addition of the phenolic constituent of CNSL increased the thermal stability of PMMA films considerably. The results obtained were also confirmed by DSC analyses.     

Microwave-assisted oxidation of silibinin: a simple and preparative method for the synthesis of improved radical scavengers

A new and preparative oxidation of silibinin has been developed to give access to two different silibinin derivatives known for their enhanced antioxidant properties. Conventional heating methods were compared with results obtained from microwave (MW) heating. The base-catalysed oxidation of silibinin under MW heating is a very efficient method for the preparation of 2,3-dehydrosilybin and a related silybin rearrangement product. This latter compound shows enhanced radical scavenging properties. Optimised conditions were used to prepare 2,3-dehydrosilybins A and B from optically pure silybins A and B. An efficient, preparative purification method was also developed to enable isolation of different products in high purity.