Polar effects in free-radical reactions. A new type of homolytic aromatic alkylation by silver catalyzed oxidation of acetone by peroxydisulphate in the presence of olefins.

Silver catalyzed peroxydisulphate oxidation of acetone in the presence of olefins and protonated heteroaromatic bases leads to compound I via addition of acetonyl radical to the olefin and scavenging of the resulting radical adduct by the aromatic base.     

Total Syntheses and In Vivo Quantitation of Novel Neurofuran and Dihomo‐isofuran Derived from Docosahexaenoic Acid and Adrenic Acid

Neurofurans (NeuroFs) and dihomo‐isofurans (dihomo‐IsoFs) are produced in vivo by non‐enzymatic free‐radical pathways from docosahexaenoic and adrenic acids, respectively. As these metabolites are produced in minute amounts, their analyses in biological samples remain challenging. Syntheses of neurofuran and dihomo‐isofurans described are based on a pivotal strategy, thanks to an enantiomerically enriched intermediate, which allowed, for the first time, access to both families: the alkenyl and enediol. Owing to this formation, quantitation of specific NeuroF and dihomo‐IsoFs in biological samples was attainable.     

New examples of template catalysis based processes: glycerol-like units as efficient promoters for dehydrative nucleophilic substitutions of ferrocenylmethanol

The direct high-yield synthesis without solvent and catalyst, under mild conditions, of eleven novel mono substituted ferrocenylmethyl ethers and amine derivatives from ferrocenemethanol and vicinal oxygenated alcohols and amines is here reported. The peculiar ability of these classes of non acidic compounds to favor the dehydrative nucleophilic substitution is attributed to the presence of vicinal oxygen atoms to the reactive group able to build a hydrogen bonding network with the reactant. The role of carbon dioxide and hexafluoroisopropanol was investigated to support the hypothesis that a template catalysis effect is occurring. The in vitro anti-fungal activity of some of these derivatives was tested on two plant fungi, Botrytis cinerea and Penicillium species, with moderate activity.     

Weak -property in Σ-products

It is shown that each Σ-product of paracompact p-spaces has the weak -property.     

Chemistry of cultural glasses: the early medieval glasses of Monselice's hill (Padova, Italy)

To investigate the mechanisms of deterioration of historical glasses, under natural evolution, some early medieval glasses from the archaeological site of the Monselice's hill have been analysed. By an archaeological approach, developed at the Dipartimento di Scienze dell'Antichità, University of Padova, the glasses were dated between the VI and the beginning of the VII century and they were ascribed to the same artist or school. By a geological approach, developed at the Dipartimento di Mineralogia e Petrologia, University of Padova, it was found that some pieces of glasses, from the same archaeological site, were made of silica, rich in sodium and calcium, with iron and manganese. The composition was analogous the one of glasses produced during Roman empire, using `natron' (Na<sub>2</sub>CO<sub>3</sub>·NaHCO<sub>3</sub>·2H<sub>2</sub>O) as melting agent and glasses produced during medieval age, in the Mediterranean basin, using plant ash like `Salsola Kali' as melting agent. It was also found that there was a surface layer, with a special lamellar structure, easy to remove. The surface layer was found poor in alkali and alkaline-earth elements. By surface and microscopic analyses (optical microscopy, SEM-EDS, microRaman, XPS, SIMS and Mössbauer) it has been found that all the samples have a composition rich in silica, sodium and calcium except one that, unexpectedly, was rich in potassium and poorer in sodium. This sample, as composition, seems just like medieval glasses produced north of the Alps, using plant ash like ferns as melting agent. In all the samples the surface layers have less alkaline elements and the depletion goes to ten μm of depth. The extreme consequence of this depletion is the formation, in some samples, of an alteration layer, easy to remove, that the XPS analyses tell us it is made of very hydrated silica. The surface layers show a little accumulation of calcium. The calcium ion is also present in some birefringent crystal aggregates immersed in the glass that, in some samples, are around one mm large. These aggregates have a circular shape, with a nucleation centre in them. By microRaman spectroscopy it was found that the crystal aggregates are made of vateritic and calcitic calcium carbonate. By Mössbauer spectroscopy it was found that in the flat yellow coloured glasses, richer in iron, the Fe(III) species predominates. Instead in the pale green ones, poorer in iron, the Fe(II) prevails.     

Random field singularities in renormalization group transformations on Van der Waals-Ising models

Griffiths-Pearce “peculiarities” of renormalization transformations acting on nonrandom mean field Ising models are studied exactly and shown to occur in connection with critical singularities in the quenched free energies of systems with random magnetic fields. The result applies to the transformations of the full hamiltonian, considered as a function of spin configurations, and not only to the recurrence relations for its interaction constants.     

Discovery of a new series of jatrophane and lathyrane diterpenes as potent and specific P-glycoprotein modulators

A new series of diterpenes, the jatrophanes euphoscopin M (1), euphoscopin N (2) and euphornin L (3), and the lathyrane euphohelioscopin C (7) were isolated from plants of Euphorbia helioscopia L., together with four other known analogues, euphoscopin C (4), euphornin (5), epieuphoscopin B (6) and euphohelioscopin A (8). The new compound stereostructures were elucidated by NMR analysis and computational data. The resulting isolated diterpenes were found to be potent inhibitors of P-glycoprotein (ABCB1), while showing an absence of significant activity against BCRP (ABCG2), despite the high substrate overlapping of these transporters, thus including them in the third-generation class of specific multidrug transporter modulators.     

Carrier ampholytes for IEF, on their fortieth anniversary (1967-2007), brought to trial in court: the verdict

The present review summarizes the data accumulated in 1-year work, by exploring, via a 3-D methodology (Rotofor fractionation followed by CE-MS), all the narrow (2 pH unit wide) carrier ampholyte (CA) compounds for IEF, produced by three companies (Pharmacia with Pharmalyte and Ampholine, BioRad with Bio-Lyte and Serva with Servalyt). All species have been assessed by measuring the types of pH gradient produced, the total number of individual chemicals (with M(r) values) and isoforms and their focusing behavior ('good' or 'poor' ampholytes). Servalyt contains a grand total of 686 chemical entities and no less than 3899 isoforms; Pharmalyte 643 and 2211; Bio-Lyte 255 and 1192; Ampholine 294 and 1182, respectively. In terms of M(r) distribution, although all 2-pH-unit ranges start with the same low M(r) values (ca. 200) their upper limits are quite different. Thus, Pharmalyte reaches an upper M(r) value of 1179 (in the pH 4-6 range), versus 907 for Servalyt, 835 for Bio-Lyte and 893 for Ampholine. In general, in going towards the more alkaline pH intervals (e.g. pH 8-10) the molecular mass of carrier ampholytes (CAs) is reduced to as low as 491 (Bio-Lyte), indicating that the alkaline species are probably made with shorter oligoamines and are, in general, less substituted. All acidic pH intervals (up to pH 6-8) appear to be constituted by a very large proportion of well focusing species, indicating small values of DeltapK across their pI. Above pH 8, all brands of CAs worsen, the vast majority being unable to focus properly and sustain adequately the pH gradient. General guidelines are given for the synthesis of new alkaline species for improving the basic pH ranges.