Synthesis, basicity, structural characterization, and biochemical properties of two [(3-hydroxy-4-pyron-2-yl)methyl]amine derivatives showing antineoplastic features

The N,N'-bis[(3-hydroxy-4-pyron-2-yl)methyl]-N,N'-dimethylethylendiamine (malten) and 4,10-bis[(3-hydroxy-4-pyron-2-yl)methyl]-1,7-dimethyl-1,4,7,10-tetraazacyclododecane (maltonis) were synthesized and characterized. The acid-base behavior, structural characterizations, and biochemical studies in aqueous solution were reported. Each compound contains two 3-hydroxy-2-methyl-4-pyrone units (maltol) symmetrically spaced by a polyamine fragment, the 1,4-dimethylethylendiamine (malten), or the 1,7-dimethyl-1,4,7,10-tetraazacyclododecane (maltonis). They are present at physiological pH 7.4 in the form of differently charged species: neutral but in a zwitterion form for malten and monopositive with an internal separation of charges for maltonis. Malten and maltonis are both able to alter the chromatin structure inducing the covalent binding of genomic DNA with proteins, a feature consistent with the known antiproliferative activity exerted by this class of molecules. Solid-state results and MD simulations in water show that malten, because of its molecular topology, should be more prone than maltonis to act as a donor of H-bonds in intermolecular contacts, thus it should give a better noncovalent approach with the negatively charged DNA. Crystal structures of [H(2)malten](2+) and [H(2)maltonis](2+) cations were also reported.     

Flash vacuum pyrolysis of azolylacroleins and azolylbutadienes

2-Aryl-5-acroleinyl-1,2,3,4-tetrazoles (1a–d) and 2-aryl-5-butadienyl-1,2,3,4-tetrazoles (1e–g) were subjected to flash vacuum pyrolysis. Acroleinyl derivatives resulted in nitrogen extrusion to give nitrilimines followed by ring closure to give the corresponding indazoles 3a–d in good yields. On the other hand, butadiene derivatives underwent ring fragmentation to give p-substituted anilines without formation of the expected indazoles. Differences between thermal behaviour of 2-(4-chlorophenyl)-5-acroleinyl-1,2,3,4-tetrazole (1c) and 1-(4-chlorophenyl)-4-acroleinyl-1,2,3-triazole (2) were studied in details. DFT calculations have been used to examine the nitrilimine and carbene nature of the intermediates involved in the thermal reactions of azolyl derivatives.     

Technical improvement of the TBP (tubulin‐based polymorphism) method for plant species detection,based on capillary electrophoresis

Nowadays, feed and food safety and traceability are of primary importance. Hence, a correct labeling of the different products is highly desirable in general, but mandatory for those people who are suffering from eating disorders and food allergies. Among the technologies that have been developed for feed and food analysis, the patented tubulin‐based polymorphism (TBP) method emerges as an easy, versatile, and inexpensive diagnostic tool. Initially used to fingerprint different plant species and varieties, TBP was then successfully applied to trace species in mixtures of plant origin such as commercial feeds. TBP is a DNA‐based molecular marker, that makes use of PCR for the selective amplification of plant β‐tubulin introns. Amplified fragments are then separated by PAGE and visualized by silver staining. We have now developed an improved version of TBP. Based on capillary electrophoresis and fluorescence detection, it makes the method automatic, more sensible, reproducible, and faster. Compared to the classic TBP, this new version allows to obtain a better data resolution and an easier interpretation of the results, clearing the way to large‐scale feed/food diagnostics.     

Low-loading asymmetric organocatalysis

Asymmetric organocatalysis is now recognized as the third pillar of asymmetric synthesis. Recent years have witnessed increasing interest towards the use of highly active and stereoselective organocatalysts. This critical review documents the advances in the development of chiral organocatalysts which are systematically used in ≤3 mol% loading in all the sub-areas of the field, namely aminocatalysis, Br?nsted acids and bases, Lewis acids and bases, hydrogen bond-mediated catalysis, phase transfer and N-heterocyclic carbene catalyses (194 references).     

A physically based connection between fractional calculus and fractal geometry

We show a relation between fractional calculus and fractals, based only on physical and geometrical considerations. The link has been found in the physical origins of the power-laws, ruling the evolution of many natural phenomena, whose long memory and hereditary properties are mathematically modelled by differential operators of non integer order. Dealing with the relevant example of a viscous fluid seeping through a fractal shaped porous medium, we show that, once a physical phenomenon or process takes place on an underlying fractal geometry, then a power-law naturally comes up in ruling its evolution, whose order is related to the anomalous dimension of such geometry, as well as to the model used to describe the physics involved. By linearizing the non linear dependence of the response of the system at hand to a proper forcing action then, exploiting the Boltzmann superposition principle, a fractional differential equation is found, describing the dynamics of the system itself. The order of such equation is again related to the anomalous dimension of the underlying geometry.     

On the reaction of some 5-polyfluoroaryl-1,2,4-oxadiazoles with methylhydrazine: synthesis of fluorinated indazoles

The reaction of 5-polyfluoroaryl-1,2,4-oxadiazoles with methylhydrazine has been studied and the synthesis of fluorinated N-methylindazoles has been realized. Rearrangement reactions showed predominantly formation of N(1)-methylindazole regioisomers. Starting compounds were preliminarily functionalized at the polyfluoroaryl moiety through fluorine displacement with nucleophiles (methanol, methylamine, dimethylamine), allowing the obtainment of target indazoles substituted at the C(6) position.     

Formation of Patches on 3D SAMs Driven by Thiols with Immiscible Chains Observed by ESR Spectroscopy

Beyond stripes : The extreme lipophobicity of perfluorinated chains attached to amphiphilic thiolates triggers the formation of “stars” (or patches) surrounded by amphiphilic alkylthiolates in three‐dimensional self‐assembled monolayers. This strategy led to the first example of a water‐soluble multicompartment monolayer wrapped around a gold core.

     

Sequence determination of αs1‐casein isoforms from donkey by mass spectrometric methods

Four co‐eluting components, with experimentally measured M_r of 23 658, 23 786, 24 278 and 24 406 Da, were detected by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) analysis in the dephosphorylated casein fraction of a milk sample collected at middle lactation stage from an individual donkey belonging to the Ragusano breed. By coupling RP‐HPLC, two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE), enzymatic digestions, MALDI‐TOF MS and capillary RP‐HPLC/nano‐electrospray ionization tandem mass spectrometry (nESI‐MS/MS) analyses, the four components were identified as donkey's α_s1‐CNs and their sequences completely characterized, using the known mare's α_s1‐CN (GenBank Acc. No. AAK83668; M_r 23750.7 Da) as reference. The proteins with M_r of 23 786 and 23 658 Da differ in the presence of a glutamine residue at position 83 in the full‐length component and present the amino acid substitutions Q⁸→H and H¹¹⁵→Y with respect to the mare's α_s1‐CN. The other two components with M_r 24 406 and 24 278 Da, which also differ in the presence of a glutamine residue at position 88 in the full‐length component, show the insertion of the pentapeptide HTPRE between Leu³³ and the Glu³⁴. The two α_s1‐CNs bearing the pentapeptide insertion were named variants A (202 amino acids; M_r 24 406) and A₁ (201 amino acids; M_r 24 278), whereas the two α_s1‐CNs without the pentapeptide were named variants B (197 amino acids; M_r 23 786) and B₁ (196 amino acids; M_r 23 658). Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of tea tree oil quality and ascaridole: A deep study by means of chiral and multi heart-cuts multidimensional gas chromatography system coupled to mass spectrometry detection

The natural-like assessment of essential oils is a demanding task due to the growing trend toward adulterations. Usually chiral chromatography was used for this purpose due to the capability of assessing stereospecificity which is directly related to the enzymatic pathways of each plant species. On the other hand, the quality of an essential oil involves also the evaluation of its oxidative state, mainly connected with the age and storage conditions. In fact, some modifications in the chemical profile of the oil can occur if not properly preserved. Alterations of the components due to oxidative reactions lead to the formation of peroxides, endoperoxides and epoxides, such as ascaridole and 1,2,4-trihydroxymenthane, usually present in very low amount, formed by the oxidation of terpinen-4-ol and α-terpinene, respectively. Therefore, in the present research, the quality of Australian Tea Tree oil (Melaleuca alternifolia (Maiden & Betche) Cheel, Myrtaceae) was investigated by means of a multi heart-cut multidimensional gas chromatographic system coupled to a mass spectrometer detector and by conventional enantio-GC. The MDGC system allowed the complete separation of the compounds of interest transferred from the first column to a second dimension based on a different separation mechanism. The MS detector at the end of the second column provided the identification of the peaks with high similarity values because of their high purities after the multidimensional separation. Method validation was carried out, in order to use this procedure for routine application, monitoring the repeatability of 1D retention times and 2D peak areas, LoD and LoQ. Finally, enantiomeric ratios for chiral compounds were established to support quality data obtained.     

A new Antarctic certified reference material for trace elements: Adamussium colbecki

The certification of a new reference material for trace elements based on the Antarctic bivalve Adamussium colbecki is reported. This certified reference material (CRM), labelled IRMM 813, was produced in the frame of the Italian National Program for Research in Antarctica (Programma Nazionale di Ricerca in Antartide, PNRA). About 40 kg of the scallop were collected at Terra Nova Bay (Ross Sea). The raw material was freeze-dried, jet-milled and homogenized so as to make it suitable for certification. The elements selected for the certification project were As, Cd, Cu, Cr, Fe, Mn, Ni and Zn. Homogeneity and short- and long-term stability were preliminarily investigated so as to assess the suitability of the freeze-dried mass as a candidate CRM. The candidate material was found to be fit for purpose, thus allowing the following phases of the certification project to be undertaken, in the first place the selection of expert laboratories for the accomplishment of the certification campaign. Eighteen laboratories from twelve countries accepted to participate in the certification project which thus could be successfully completed.