Studio dei fenomeni di dissesto della provincia di Sassari: il caso del paese di Castelsardo

In Castelsardo village have been locate two different phenomenas of trouble: the first built on eolian deposits of wurmian age and it produces some moviments dry sand flow type; on the contrary the second is rotational shift of rock and soil and it has interested the basset of ignimbritic rocks of Terziary present along the headlands on the sea in Castelsardo village

Studio dei fenomeni di dissesto della provincia di Sassari: il caso dell'abitato di San Lorenzo

In this work is described the slope instability situation in the S. Lorenzo village. The study is included in a more extensive investigation about the instability phenomena on the slopes in built-up areas in the territory of the Sassari district. Recent landslides tied to translative talus creep of actual beginning and to large slope moviments (gravitative deep deformations) of Pleistocenic age it could locate in the area of S. Lorenzo

Studio dei fenomeni di dissesto della provincia di Sassari: il caso della borgata di Tirialzu (Buddusò)

The report is included in the investigation on the unstable villages of Sassari district by National Group of defense by hidrogeological catastrophe U.U.O.O. n. 13 line n. 12. The study locates the landslide's phenomenas tied to exstraordinary events of precipitation that cause slope moviments in debris flow type, and this phenomena in unusual enough in the territory of island. It isn't a true risk but it produces to human activity heavy inconvenient

Nuove acquisizioni sull'impiego di bicicli solfonilici rigidi in sintesi organica e in studi di riconoscimento molecolare

Sulla base degli aspetti cardine descritti precedentemente e degli studi condotti su bicicli solfonilici rigidi negli ultimi anni, saranno presentati i più recenti risultati ottenuti, soprattutto per quanto concerne a) la reattività di alcheni biciclici come accettori di Michael in presenza di ammine chirali e b) la costruzione di famiglie di analoghi a scheletro [2.2.x]biciclico e benzo[2.2.1]biciclico, adatte alla elaborazione di modelli di riconoscimento chirale di tipo empirico, basati su analisi cromatografica (HPLC)

Alcheni policiclici a ponte fenilsolfonilsostituiti: versatili intermedi nella sintesi di molecole biologicamente attive

Nel campo della sintesi totale di molecole biologicamente attive, risultano di interesse, da un punto di vista sintetico-stereochimico, molecole policicliche a struttura pontata che, negli ultimi anni, sono state largamente studiate, sia come principi attivi che come intermedi sintetici. La ricerca di base si è quindi orientata verso lo studio della reattività di tali substrati e dei meccanismi che la regolano. In questi ambiti, il nostro interesse si rivolge verso lo studio della reattività di alcheni policiclici a ponte fenilsolfonilsostituiti

Composti policiclici bridged fenilsolfonilsostituiti: caratterizzazione mediante tecniche NMR e cromatografia liquida ad alte prestazioni (<i>HPLC</i>)

Da alcuni anni, il nostro gruppo di ricerca svolge studi che hanno portato alla definizione di protocolli sintetici asimmetrici per la preparazione di chetoni policiclici enantiopuri e di nuove preparazioni di alcheni, bromoderivati e aldeidi policiclici. In particolare, i nostri studi si rivolgono verso sistemi [2.2.1]biciclici, costituendo questi lo scheletro carbonioso di base in composti biologicamente attivi, di interesse in campo farmacologico e nell’industria profumiera

Factors Impacting σ- and π-Hole Regions as Revealed by the Electrostatic Potential and Its Source Function Reconstruction: The Case of 4,4'-Bipyridine Derivatives

Positive electrostatic potential (V) values are often associated with σ- and π-holes, regions of lower electron density which can interact with electron-rich sites to form noncovalent interactions. Factors impacting σ- and π-holes may thus be monitored in terms of the shape and values of the resulting V. Further precious insights into such factors are obtained through a rigorous decomposition of the V values in atomic or atomic group contributions, a task here achieved by extending the Bader–Gatti source function (SF) for the electron density to V. In this article, this general methodology is applied to a series of 4,4'-bipyridine derivatives containing atoms from Groups VI (S, Se) and VII (Cl, Br), and the pentafluorophenyl group acting as a π-hole. As these molecules are characterized by a certain degree of conformational freedom due to the possibility of rotation around the two C–Ch bonds, from two to four conformational motifs could be identified for each structure through conformational search. On this basis, the impact of chemical and conformational features on σ- and π-hole regions could be systematically evaluated by computing the V values on electron density isosurfaces (VS) and by comparing and dissecting in atomic/atomic group contributions the VS maxima (VS,max) values calculated for different molecular patterns. The results of this study confirm that both chemical and conformational features may seriously impact σ- and π-hole regions and provide a clear analysis and a rationale of why and how this influence is realized. Hence, the proposed methodology might offer precious clues for designing changes in the σ- and π-hole regions, aimed at affecting their potential involvement in noncovalent interactions in a desired way

Comparative enantioseparation of planar chiral ferrocenes on polysaccharide-based chiral stationary phases.

Planar chiral ferrocenes are well-known compounds that have attracted interest for application in synthesis, catalysis, material science, and medicinal chemistry for several decades. In spite of the fact that asymmetric synthesis procedures for obtaining enantiomerically enriched ferrocenes are available, sometimes, the accessible enantiomeric excess of the chiral products is unsatisfactory. In such cases and for resolution of racemic planar chiral ferrocenes, enantioselective high-performance liquid chromatography (HPLC) on polysaccharide-based chiral stationary phases (CSPs) has been used in quite a few literature articles. However, although moderate/high enantioselectivities have been obtained for planar chiral ferrocenes bearing polar substituents, the enantioseparation of derivatives containing halogens, or exclusively alkyl groups, remains rather challenging. In this study, the enantioseparation of ten planar chiral 1,2- and 1,3-disubstituted ferrocenes was explored by using five polysaccharide-based CSPs under multimodal elution conditions. Baseline enantioseparations were achieved for nine analytes with separation factors (α) ranging from 1.20 to 2.92. The presence of π-extended systems in the analyte structure was shown to impact affinity of the most retained enantiomer toward amylose-based selectors, observing retention times higher than 80 min with methanol-containing mobile phases (MPs). Electrostatic potential (V) analysis and molecular dynamics (MD) simulations were used in order to study interaction modes at the molecular level

Rational Design, Synthesis, Characterization and Evaluation of Iodinated 4,4′-Bipyridines as New Transthyretin Fibrillogenesis Inhibitors

The 3,30,5,50-tetrachloro-2-iodo-4,40-bipyridine structure is proposed as a novel chemical scaold for the design of new transthyretin (TTR) fibrillogenesis inhibitors. In the frame of a proof-of-principle exploration, four chiral 3,30,5,50-tetrachloro-2-iodo-20-substituted-4,40- bipyridines were rationally designed and prepared from a simple trihalopyridine in three steps, including a Cu-catalysed Finkelstein reaction to introduce iodine atoms on the heteroaromatic scaold, and a Pd-catalysed coupling reaction to install the 20-substituent. The corresponding racemates, along with other five chiral 4,40-bipyridines containing halogens as substituents, were enantioseparated by high-performance liquid chromatography in order to obtain pure enantiomer pairs. All stereoisomers were tested against the amyloid fibril formation (FF) of wild type (WT)-TTR and two mutant variants, V30M and Y78F, in acid mediated aggregation experiments. Among the 4,40-bipyridine derivatives, interesting inhibition activity was obtained for both enantiomers of the 3,30,5,50-tetrachloro-20-(4-hydroxyphenyl)-2-iodo-4,40-bipyridine. In silico docking studies were carried out in order to explore possible binding modes of the 4,40-bipyridine derivatives into the TTR. The gained results point out the importance of the right combination of H-bond sites and the presence of iodine as halogen-bond donor. Both experimental and theoretical evidences pave the way for the utilization of the iodinated 4,40-bipyridine core as template to design new promising inhibitors of TTR amyloidogenesis