Active-alkali metal promoted reductive desulfurization of dibenzothiophene and its hindered analogues

Reductive desulfurisation of organic compounds is of importance both in organic synthesis and in industry. Benzo- and dibenzothiophenes are between the most abundant sulphur containing impurities in crude oils, and their desulfurization is a mandatory issue in the production of non polluting fuels. Following our interest in the development of efficient alkali metal-mediated synthetic procedures and alternative protocols for the chemical transformation of widespread environmental contaminants we wish to report here on the effectiveness of sodium and lithium metals, in the presence of catalytic amounts of tetraphenylethylene (TPE), in promoting the reductive desulfurization of dibenzothiophene, as well as of the corresponding sulfone and sulfoxide

Active-alkali metal promoted reductive desulfurization of dibenzothiophene and its hindered analogues

Reductive desulfurisation of organic compounds is of importance both in organic synthesis and in industry. Benzo- and dibenzothiophenes are between the most abundant sulphur containing impurities in crude oils, and their desulfurization is a mandatory issue in the production of non polluting fuels. Following our interest in the development of efficient alkali metal-mediated synthetic procedures and alternative protocols for the chemical transformation of widespread environmental contaminants we wish to report here on the effectiveness of sodium and lithium metals, in the presence of catalytic amounts of tetraphenylethylene (TPE), in promoting the reductive desulfurization of dibenzothiophene, as well as of the corresponding sulfone and sulfoxide

I Metalli alcalini in sintesi organica: attivazione e selettività del sodio metallico in reazioni di metallazione riduttiva

This work mainly report the results obtained in the application of a new methodology , in organic synthesis, mediated by alkali metals, especially sodium metal. The reaction of 1,2-diarylethenes with Na metal in dry THF allows the generation of a wide array of 1,2-diaryl-1,2-disodioethanes, and we showed that these vic-diorganometallics are very effective reductive elimination reagents, useful in several applications. We investigated the reductive dehalogenation of several vicdisubstituted compounds, and halogenated aromatic compounds. Our procedure is tolerant of several functional groups, and shows promising applications as a new and selective protocol to be employed in the reductive removal of protecting groups. We can say that 1,2-diaryl-1,2- disodioethanes can be considered as synthetic equivalents of an activated, selective, and highly reactive form of Na metal, functioning under homogeneous reaction conditions. Finally, following our interest in the generation of polar organometallic reagents by the reductive cleavage of aromatic and benzylic ethers as well as the employment of the resulting carbanions in the synthesis of biologically active compounds, we investigated the effect of different alkali metals, namely Na and Li, on the reductive metalation of 3,4,5-trimethoxybenzyl methyl ether, Indeed, this ether can be considered as a cheap starting material allowing either the synthesis of 2,5-dialkylresorcinols, a class of naturally occurring compounds endowed with cytotoxic and antibiotic activities, or of 1,2,3- trimethoxyarenes, a class of compounds endowed, inter alia, with interesting anticancer properties

Green and convenient arene-catalized reductive lithiation of heterocyclic compounds

In the last decades reductive lithiation established itself as a particularly powerful procedure for the generation of functionalized organometals. In addition, the enormous role of this reaction in the reductive ring opening and functionalization of heterocycles has been reported. Accordingly, critical experiments were performed for the generation of lithium radical anions of several PAHs and a diene in both solvents, under both CA and SA protocols. Almost all of the above mentioned hydrocarbons rapidly generate radical anions with different fascinating visible colors at 0 °C. Based on this, influence of different electron shuttles and their efficiency in the reductive lithiation of N-phenylaziridine, phthalan will be disclosed. Moreover, we will report an interesting example of chemoselectivity concerning to the reductive lithiation of 4-chlorobenzyl methyl ether in a green solvent

Il Metodo ESAS per la modellizzazione del rischio di desertificazione: applicazione in un'area della Sardegna nord-occidentale

GIS elaboration was applied to assess the sensivity to Desertification of an area of north western Sardinia. The ESAs model was used (Environmentally Sensitive Areas to desertification, developed by MEDALUS III EC – DG RES project. The model makes use of 15 indicators grouped into 4 classes: soil, vegetation, climate, land management. For each indicator independent layers are produced according to a pre-defined weights system and are then processed to create four synthetic indexes. Finally, the sensitivity index is produced as a geometric average. The implementation highlighted the high sensitivity of the concerned area

Riduzione regioselettiva del 3,4,5-trimetossibenzil metil etere: sintesi di resorcinoli 2,5-dialchilsostituiti

Vista l'esperienza maturata nel nostro laboratorio nella generazione di reattivi organometallici di tipo benzilico e aromatico attraverso reazioni di metallazione riduttiva di alchil benzil eteri, abbiamo ritenuto che il metil etere dell'alcool 3,4,5-trimetossibenzilico, fosse un substrato adatto alle nostre necessità sintetiche

Metallazione riduttiva di 1,2-diarileteni: applicazioni sintetiche

Proseguendo nella nostra ricerca di nuove ed efficienti procedure basate sull’utilizzo di metalli alcalini in sintesi organica, abbiamo studiato la reazione di metallazione riduttiva di una serie di 1,2-diariletileni, e le possibili applicazioni sintetiche dei derivati vicdiorganometallici così ottenuti

Clinical efficacy of ivabradine in patients with inappropriate sinus tachycardia: a prospective, randomized, placebo-controlled, double-blind, crossover evaluation

Objectives The purpose of this study was to investigate the role of ivabradine in the treatment of symptomatic inappropriate sinus tachycardia using a double-blind, placebo-controlled, crossover design. Background Due to its If blocking properties, ivabradine can selectively attenuate the high discharge rate from sinus node cells, causing inappropriate sinus tachycardia. Methods Twenty-one patients were randomized to receive placebo (n = 10) or ivabradine 5 mg twice daily (n = 11) for 6 weeks. After a washout period, patients crossed over for an additional 6 weeks. Each patient underwent symptom evaluation and heart rate assessment at the start and finish of each phase. Results After taking ivabradine, patients reported elimination of >70% of symptoms (relative risk: 0.25; 95% CI: 0.18 to 0.34; p < 0.001), with 47% of them experiencing complete elimination. These effects were associated with a significant reduction of heart rate at rest (from 88 ± 11 beats/min to 76 ± 11 beats/min, p = 0.011), on standing (from 108 ± 12 beats/min to 92 ± 11 beats/min, p < 0.0001), during 24 h (from 88 ± 5 beats/min to 77 ± 9 beats/min, p = 0.001), and during effort (from 176 ± 17 beats/min to 158 ± 16 beats/min, p = 0.001). Ivabradine administration was also associated with a significant increase in exercise performance. No cardiovascular side effects were observed in any patients while taking ivabradine. Conclusions In this cohort, ivabradine significantly improved symptoms associated with inappropriate sinus tachycardia and completely eliminated them in approximately half of the patients. These findings suggest that ivabradine may be an important agent for improving symptoms in patients with inappropriate sinus tachycardia

Caratterizzazione ambientale delle acque del Golfo dell’Asinara (Sardegna) attraverso l’uso di spettrofluorimetria laser e immagini telerilevate

The general objective of this research (financed by L.R. 7 of the Autonomous Region of Sardinia for the period May 2010 –May 2012) is to calibrate bio-optical algorithm for more accurate estimates of phytoplanktonic Chl-a in the Asinara Gulf (Northern Sardinia, Italy) using remote sensing data and in situ measurements. The “sea truth” values of Chl-a were obtained with the new laser spectrofluorometric apparatus CASPER (Compact and Advanced laser SPEctrometeR – Patent ENEA). CASPER permitted not only to quantify values of Chl-a but also to detect other algal pigments (phycoerythrin, phycocyanin), chromophoric dissolved organic matter (CDOM), proteins-like components (tyrosine, tryptophan), and qualitative data on the presence of hydrocarbons and oil pollution. At the moment “sea truth” data of Chl-a were just compared to standard chlorophyll products of MODIS OC3 algorithm. In order to reach better results, the bio-optical algorithm is going to be recalibrated according to the measurements of CASPER during the next year, thus providing new estimates of phytoplanktonic Chl-a in the Asinara Gulf