Tesis: "CHIMICA ORGANICA"

1

Loris, Alessandro <1972&gt. "Anidride carbonica e i suoi derivati in chimica organica". Doctoral thesis, Università Ca' Foscari Venezia, 2006. http://hdl.handle.net/10579/676.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Dalla, Torre Davide <1995&gt. "Alchilazione dell’Isosorbitolo attraverso la chimica dei Dialchil carbonati". Master's Degree Thesis, Università Ca' Foscari Venezia, 2021. http://hdl.handle.net/10579/18827.

Texto completo

Resumen

Al giorno d’oggi il fabbisogno energetico mondiale dipende ancora dall’utilizzo dei combustibili fossili quali petrolio, gas naturale e carbone. L’eccessivo sfruttamento di questi ultimi ha causato ed è tutt’ora la causa di pesanti ripercussioni ambientali a livello mondiale come, ad esempio, l’aumento dell’emissione dei gas serra (CO2, NOx, VOCs) e la produzione di scarti plastici che stanno minacciando la flora e la fauna marina (isola di plastica nell’Oceano Pacifico). Inoltre, la disponibilità dei combustibili fossili è limitata e non può essere ripristinata nel breve tempo. È quindi importante optare per un’industria più sostenibile che possa far fronte alle problematiche socio-ambientali ed energetiche precedentemente riportate. Una valida alternativa all’industria petrolchimica è la bioraffineria che utilizza risorse organiche naturali rinnovabili - le biomasse - come materie prime. In questo contesto, lo scopo del seguente studio di tesi è l’impiego di metodi alternativi per la funzionalizzazione di un derivato della biomassa, l’isosorbitolo e dei suoi epimeri (isomannitolo e isoiditolo). L’isosorbitolo - generalmente sintetizzato attraverso la ciclizzazione del D-sorbitolo, derivato idrogenato del D-glucosio - è un substrato interessante che possiede una struttura rigida e due funzionalità ossidriliche legate a carboni chirali che presentano una diversa reattività. Data la possibilità di ricavare il D-sorbitolo e l’isosorbitolo dalla biomassa e, in considerazione dell’interesse industriale di numerosi loro derivati (monomeri per polimeri, composti farmaceutici, solventi green), questi composti sono annoverati tra le dieci molecole piattaforma di origine rinnovabile (bio-based platform chemicals) dal Dipartimento di Energia degli Stati Uniti (DOE). Nello specifico questo studio di tesi è incentrato sulla sintesi di alchil derivati dell’isosorbitolo che possono trovare impiego come solventi aprotici altobollenti, additivi per benzine e monomeri per polimeri (diallil isosorbitolo). La prima parte della tesi è stata focalizzata sulla sintesi del dimetil isosorbitolo (DMI) a partire dall’isosorbitolo e dimetilcarbonato (DMC) – impiegato come reagente e solvente green - in presenza di un catalizzatore organico azotato. Le condizioni di reazione sono state ottimizzate e il miglior catalizzatore individuato - la N-metilpirrolidina (NMPy) – è stato studiato in dettaglio. La reazione di metilazione è stata testata in grande scala e diversi metodi di purificazione sono stati investigati per recuperare il dimetil isosorbitolo dalla miscela della reazione. Inoltre, per la prima volta tutti i sette intermedi di reazione che si formano nella conversione del sorbitolo in DMI sono stati isolati e caratterizzati; questo ha consentito lo studio dell’andamento della reazione di metilazione. Nella seconda parte di questa tesi ci si è focalizzati sulla sintesi di alchil derivati dell’isosorbitolo attraverso la chimica dei dialchil carbonati in catalisi acida in quanto questi composti si ottengono in scarsa resa in condizioni di catalisi basica. In uno studio preliminare il dietil carbonato (DEC) è stato impiegato come agente alchilante e diversi catalizzatori acidi eterogenei ed omogenei sono stati testati. Catalizzatori inorganici omogeni come ad esempio puroliti, zeoliti e idrotaliciti hanno fornito risultati migliori. Ottimizzate le condizioni di reazione (temperatura, tempo, quantità di catalizatore), diversi dialchil carbonati sono stati testati per la preparazione di una famiglia di alchil derivati dell’isosobitolo.

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

Meglioli, Nicolo' <1995&gt. "SINTESI DI BENZOSSAZEPINE E BENZOSSAZOCINE TRAMITE LA CHIMICA DEL DIMETIL CARBONATO". Master's Degree Thesis, Università Ca' Foscari Venezia, 2019. http://hdl.handle.net/10579/16126.

Texto completo

Resumen

Il laboratorio di ricerca presso il quale è stato condotto questo studio di tesi ha precedentemente riportato l’impiego dei dialchil carbonati (DACs) come agenti sacrificali - alternativi a derivati alogenati - per la sintesi di eterocicli a cinque e sei membri. Lo scopo di questo progetto è quello di esplorare il chimismo del dimetil carbonato (DMC) per la sintesi di eterocicli a sette e otto membri, nello specifico, rispettivamente benzossazepine e benzossazocine. I substrati che sono stati impiegati in questo progetto sono derivati dell’aldeide salicilica, e ammino alcoli come 2-ammino-1-etanolo (per i cicli a sette), e 3-ammino-1-propanolo (per i cicli a otto). Una tipica procedura sintetica per la sintesi delle benzossazepine prevede due steps successivi: 1. Un'amminazione riduttiva tra aldeide salicilica e l’amminoetanolo. 2. Ciclizzazione del precursore ottenuto nel primo step impiegando il DMC come solvente e reagente in presenza di una base. Questa metodologia sintetica ha portato alla sintesi di una libreria di benzossazepine, impiegando derivati dell’aldeide salicilica. Un’analoga procedura sintetica è stata applicata per la sintesi di diverse benzossazocine. Le rese dei prodotti ciclici dipende dal substrato impiegato e variano dal 40 all’80%.

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Sandron, Tommaso. "Investigation of Biological Membranes by NMR and ESI-MS Methodologies". Doctoral thesis, Università degli studi di Trento, 2010. https://hdl.handle.net/11572/368275.

Texto completo

Resumen

In the last decade there has been a new reappraisal of the function of lipids in the cell life, not only for their structural role as cell wall or for their energy storage function, but also for their significant function on signalling and protein recognition processes. This new attention on lipids has led to a new research field in the metabolomics world called “Lipidomics”. Lipidomics is more than just the complete characterization of all lipids in a particular biological sample. It is the comprehensive understanding of the influence of all lipids on a biological system with respect to cell signalling, membrane architecture, transcriptional and translational modulation, cell-cell and cell-protein interaction and response to environmental changes over time. The critical role of lipids in cell, tissue and organ physiology is already demonstrated by many human diseases involving the disruption of lipid metabolic enzymes and pathways. Examples of such diseases include diabetes, cancer, neurodegenerative disorders and infectious diseases. This represents a clue for understanding the molecular diversity observed in membrane phospholipids. Subtle biophysical properties are also another possible explanation of strong interest toward lipids especially with reference to the emerging field of heterogeneous membrane microdomains (rafts). The major goal in lipidomics is the identification of metabolic pathways which are activated or deactivated during development of an organism or when a cell is shifted from an established physiological condition to another physiological or pathological condition (metabolic learning). A better understanding of the regulation of underlying metabolic pathways is necessary to design novel strategies for intervention. In this thesis attention has been focused on two biological systems to demonstrate how the study of membrane lipids can help for a better understanding of the mechanisms involved in different biochemical processes. The first system tackled by our methodology is represented by lipid components in detergent resistant membranes (DRM) associated with the expression of Prostate-specific membrane antigen (PSMA); the latter is a 750-residue type II transmembrane glycoprotein of the normal prostate cells and one of the most promising biomarkers of prostate carcinoma as its expression is drastically increased in cancer cells protein involved in the prostate carcinoma. In particular, the complex glycosylated form of the protein is found in Lubrol insoluble DRMs. Many essential cellular events, such as protein sorting, endocytosis and signal transduction pathways, are triggered via association of the proteins directly implicated in these processes with DRMs. In the present work we report on the lipid composition of PSMA-associated microdomains. A qualitative screening was made by thin layer chromatography (TLC) followed by an extended NMR analysis of the sample. In particular, by taking 1H-, 13C- ed 31P-NMR spectra we were able to detect and quantify cholesterol and the relative contribution of all the lipids belonging to a given PL class (such as PC, PE and SM) with respect to the overall PL composition. On the other hand, Electrospray Ionization (ESI-MS) measurements and in-source collisional induced dissociations (CID) carried out on the same sample allowed us not only to establish the distribution of lipids among the PL classes but also to recognize some structural features such as the length and the number unsaturations of their acyl chains. The second problem tackled by following similar analytical methodologies was to analyze the detailed membrane lipids profile of insect larvae of the species Pseudodiamesa branickii and Diamesa cinerella to obtain information about the biochemical mechanisms involved in their thermal adaptative capabilities. Through NMR and LC-ESI-MS experiments we have obtained information about the composition of the lipid pool of these larvae that is formed essentially by triglycerides and phospholipids, with a variable inter-species PC/PE ratio. Coupling LC-MS profiling methods with in-source fragmentation data further has enhanced the ability to probe the lipidome, by supplementing lipid identification with structural information. We have observed an high level of unsaturation of the fatty acid chain as expected for low temperature-adapted species since unsaturated chain promote a more disordered and flexible membrane structure.. For Diamesa cinerella, from ESI data we could also infer some possible mechanism adopted to increase unsaturation of the fatty acid chain by the action of desaturases enzymes or by the insertion of PUFA chains.

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

CAMPANER, PIETRO. "NUOVI APPROCCI AD INIBITORI PEPTIDOMIMETICI DELLA HIV-PROTEASI". Doctoral thesis, Università degli studi di Trieste, 2007. http://thesis2.sba.units.it/store/handle/item/12303.

Texto completo

Resumen

2005/2006
La proteasi aspartica del virus HIV-1, agente responsabile dell'AIDS, è sicuramente uno tra gli enzimi attualmente più studiati e conosciuti in termini di struttura e attività. Permettendo la maturazione di nuove particelle infette e quindi il progredire dell'infezione essa svolge un ruolo cruciale nel ciclo replicativo del virus, la sua inibizione rappresenta, quindi, un importante obiettivo farmacologico, che coinvolge diverse discipline. Nel campo della chimica organica, la ricerca di efficaci inibitori peptidomimetici ha dato impulso allo sviluppo di nuove metodologie per la sintesi stereoselettiva di composti contenenti più centri chirali in forma enantiomericamente pura, da usarsi come isosteri dipeptidici per la sintesi di inibitori reversibili. L'HIV-proteasi dimostra caratteristiche del tutto peculiari; non solo è in grado, a differenza delle altre proteasi aspartiche eucariote, di idrolizzare legami ammidici aventi la prolina come residuo N-terminale, ma risulta attiva in una forma dimerica a simmetria C2 in cui l'attività idrolitica è presieduta da due residui di acido aspartico. Cercando il più possibile di sfruttare le informazioni derivanti dall'analisi della struttura dell'enzima bersaglio, in questa tesi di dottorato sono stati sviluppati alcuni protocolli per la sintesi stereoselettiva di nuovi inibitori peptidomimetici: -) un nuovo tipo di isosteri a struttura diamminodiolica contenenti un anello pirrolidinico, ottenuto mediante ciclizzazione altamente regio- e stereoselettiva di un'epossiammina, mediante deprotezione selettiva di un gruppo amminico primario in posizione ro. La sintesi dell'epossiammina viene ricondotta ad un P-chetofosfonato NBoc protetto, derivante da un amminoacido, ed un aminale ciclico N-Cbz protetto, derivante da un lattame. I diamminodioli ottenuti contengono quattro centri chirali adiacenti, il primo dei quali deriva dall' amminoacido di partenza, mentre la configurazione assoluta degli altri tre è controllata dall'induzione asimmetrica. Seguendo questo nuovo protocollo sono stati sintetizzati isosteri Val-Pro, Phe-Pro, Pro- Pro a configurazione (S,S,S,S), isosteri Phe-Pro (S,R,R,S) e (S,R,R,R) ed isosteri PhePro (S,S,S,S) in cui l'anello pirrolidinico, corrispondente al residuo della prolina, presenta dimensioni e sostituenti diversi. -) un nuovo tipo di isosteri monoidrossietilenici, in cui l'anello pirrolidinico è presente come tale o mimato da un triazolo, la cui sintesi sfrutta l'addizione coniugata di azide, controllata da uno stereocentro remoto, ad un opportuno composto carbonilico a,p-insaturo derivante da un amminoacido. -) una nuova tipologia di inibitori peptidomimetici, potenzialmente agenti con un meccanismo di inibizione irreversibile, basati su strutture epossialcoliche ottenute a partire da a-amminoacido. -) una nuova tipologia di inibitori che comuga l'azione di inibitori diversi supportati su un linker eterobifunzionale opportunamente sintetizzato ed in grado di aumentarne la biodisponibilità. Gli isosteri realizzati sono stati utilizzati per la sintesi di un piccolo set di inibitori peptidomimetici, le cui catene laterali contengono acidi fenossiacetici o sequenze peptidiche sintetizzate secondo i protocolli standard della sintesi peptidica. L'attività biologica degli inibitori realizzati, valutata seguendo l'idrolisi di substrati fluorogenici, è a livello micro- e nanomolare.
XIX Ciclo
1977
Versione digitalizzata della tesi di dottorato cartacea.

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Barbato, Francesca. "Caratterizzazione chimica della frazione organica di biochar e suoli trattati con biochar". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19423/.

Texto completo

Resumen

Il biochar, un materiale carbonioso prodotto dalla combustione di biomasse vegetali in assenza di ossigeno, utilizzato come ammendante nei suoli è in grado di apportare importanti benefici quali il sequestro di carbonio in forma stabile, il miglioramento della fertilità, l’adsorbimento superficiale di contaminanti. Tuttavia, sono presenti delle zone di incertezza che necessitano di essere indagate tra cui il suo impatto sulla dinamica della sostanza organica nel suolo. Questo aspetto è stato considerato nel presente lavoro di tesi attraverso la caratterizzazione quantitativa e qualitativa del materiale organico solubile in acqua (o disciolto, DOM) derivante dal biochar. Il DOM rappresenta la frazione più attiva e mobile del materiale organico nei suoli. Il presente studio ha indagato la quantità e le caratteristiche del DOM derivante da diversi tipi di biochar e rilasciato da suoli trattati con biochar. Sui biochar è stato studiato l’effetto dei parametri di produzione, temperatura di pirolisi, atmosfera e tipo di biomassa. Per i suoli sono stati considerati quelli di tre aziende agricole situate nel parmense coinvolte in un progetto PSR. L’obiettivo era studiare l’effetto che concentrazioni crescenti di biochar determinano sul rilascio e le caratteristiche di DOM. Il DOM è stato estratto con acqua dai campioni di biochar e suolo e le soluzioni sono state analizzate con tecniche di spettroscopia di fluorescenza in matrice di emissione eccitazione e di assorbimento molecolare UV-visibile. I dati sono stati normalizzati con il contenuto di carbonio determinato per combustione. I risultati mostrano che i parametri di pirolisi e il tipo di biomassa influenzano la composizione del DOM. Il biochar applicato a concentrazioni crescenti nei suoli in genere non modifica significativamente la quantità di DOM. In alcuni casi si è osservata una diminuzione di DOM indicando che il biochar agisce più come materiale assorbente che come fonte di carbonio organico disciolto.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Stenta, Marco <1979&gt. "Computational models in organic and bio-organic chemistry". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1069/1/Tesi_Stenta_Marco.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Stenta, Marco <1979&gt. "Computational models in organic and bio-organic chemistry". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1069/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

LUPIDI, GABRIELE. "Functionalization of Cyclic Structures for Advanced Biological and Pharmaceutical Applications". Doctoral thesis, Università degli Studi di Camerino, 2019. http://hdl.handle.net/11581/428901.

Texto completo

Resumen

The key components of the scaffold in pharmaceutical chemistry are ring systems, of different sizes, and are the fundamental factors of most of the drugs on the market today. Nowadays, the importance of cyclic structures is well understood by medicinal chemists, since they play a significant role in molecular properties such as the electronic distribution, three dimensionality, and molecule rigidity. They are often key factors in whole molecule properties such as lipophilicity or polarity and can determine molecular reactivity, metabolic stability, and toxicity. Cyclic structures have always fascinated organic and medicinal chemists, and many organic molecules form cycles with appealing biological properties. Research in cyclic chemistry continued to advance in synthetic methods development, conformational studies and investigation of their role for controlling biological functions. This work, carried out in the Prof. Marcantoni’s research group at the University of Camerino (Camerino, Italy) with the collaboration of Dompé S.p.A. (L’Aquila, Italy) from December 2015 to December 2018 and in the Prof. Poli’s research group from January 2018 to July 2018 at the University Pierre and Marie Curie (Paris, France), had the objective to investigate new synthetic methodologies for the functionalization of cyclic compounds, as well as the formation of cyclic structures from acyclic precursor, for advanced biological purposes. The first chapter focuses on the functionalization of the primary face of a β-cyclodextrin, in order to obtain a synthetic human receptor model, used for studying the possible interactions of this compound with a new class of biologically active compounds in development at Dompé S.p.A. The second chapter, carried out in the Poli’s research group, describes the selective C-3 functionalization trials of 2-furaldehyde and its derivatives by Directed ortho Metalation (DoM) chemistry in presence of organolithium compounds and focuses on the study of degradation products. The reaction of an alkyllithium compound with an aromatic structure bearing a Direct Metalation Group (DMG) normally leads to an ortho-metalated intermediate. Good DMGs are strong complexing or chelating groups that have the effect of increasing the kinetic acidity of protons in the ortho position. The third chapter focuses on the in-depth study of the mechanistic aspect on the formation of 5acylaminothiazoles starting from α-chloroglycinates, obtained by a new synthetic methodology developed in the Marcantoni’s research group. Finally, the fourth chapter focuses on the study of the role of Cerium trichloride in the formation of cyclic compounds via Nazarov cyclization.

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

STEFANINI, NICOLA. "Optimization of Industrial Polymeric Products to Improve Quality and Reduce Environmental Impact". Doctoral thesis, Università degli Studi di Camerino, 2019. http://hdl.handle.net/11581/428907.

Texto completo

Resumen

The present thesis is the result of three years’ collaboration between the University of Camerino and ELANTAS Europe Srl. The strong collaboration between university and companies allows to students like others and me to do research with an industrial approach, facing with the problematics of working life. The work was carried out among the laboratory of Organic Chemistry of Prof. Enrico Marcantoni at the University of Camerino (Camerino, Italy), the R&D laboratory of ELANTAS Europe in Ascoli Piceno (Italy) and the R&D laboratory of ELANTAS PDG INC in Saint Louis (Missouri, USA). The thesis concern the environmental impact of some industrial polymeric materials. Polymeric materials are very important in modern society: they have considerable advantages over products of other origins with lower costs with the same performance. Nevertheless, they allow some applications that some years ago would have been unthinkable (microencapsulation, shape memory materials, and many others). At the same time, environmental impact is a crucial topic strictly linked to polymeric materials (as all others materials), and to the period we are living. The production of such materials is constantly growing, exceeding the production of many others materials, and it is becoming increasingly important to find ways to produce them more efficiently and to recover waste products. The consequences of a production without limitation and control could be catastrophic for the whole world and humankind too. During my PhD, I worked on three industrial products in order to reduce their environmental impact, keeping their physical properties unchanged. After a first general introduction on polymeric materials, their uses, and their production, the second chapter concern about improving a recovery process for waste PMMA. The study allowed identifying undesirable by-products formed during the thermal depolymerization of PMMA and removing them in the consequent re-polymerization by an innovative dissolution/re-precipitation method. The third and fourth chapters deal with two coatings for wires electrical insulation, one based on polyurethanes (PU) and the other on polyesterimides (PEI). With the PU-based one, the target was to reduce the amount of loss material during the application stage and to increase the speed of application in order to reduce the energy consumption of the process. Whereas with the PEI-based enamel the purpose was to synthesized a solvent-free product using a twin-screw extruder and using recycled PET as alternative raw material to form the polyester part. The extruder technology is less energy consuming compare to the batches ones and allows working without solvents, since it can work with high viscosity materials. Moreover, the extruded product, with an additional system, can be potentially applied onto the wire with a higher thickness compare to the respective solventbased product, allowing a greater flow of current along the wire, thus improving the performance of the finished products (i.e. reducing the charging time of electrical motors).

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Calvaresi, Matteo <1979&gt. "Computational investigation of structure and reactivity in organic and bio-organic chemistry". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1038/1/Tesi_Calvaresi_Matteo.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Calvaresi, Matteo <1979&gt. "Computational investigation of structure and reactivity in organic and bio-organic chemistry". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1038/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Vetri, Buratti Veronica <1993&gt. "Advanced Organic Materials: from Additive Manufacturing to Organic Electronics and Biomedical Applications". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10321/1/PhDThesis_VetriBurattiVeronica.pdf.

Texto completo

Resumen

This manuscript represents an overview on the studies I was involved in during my PhD at the Industrial Chemistry Department “Toso Montanari”, in the ASOM (Advanced Smart Organic Materials) research group under the supervision of Prof. Letizia Sambri and Prof. Mauro Comes Franchini. Those research have been focused on the development of organic materials for advanced applications in different fields, among which organic electronics, additive manufacturing (3D Printing) and biomedical applications can be underlined.

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

CERIANI, CHIARA. "Organic Materials for (Opto)electronics introducing Sustainability in Design, Synthesis and Manufacturing". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/369035.

Texto completo

Resumen

Il progetto di ricerca si concentra sullo sviluppo di nuove strategie sintetiche per la preparazione di semiconduttori organici stampabili e scalabili industrialmente. A tal fine, è stato introdotto un nuovo metodo sintetico per una facile, economica ed eco-sostenibile produzione di semiconduttori organici coniugati. Oggigiorno, il concetto di sostenibilità è una questione molto importante per le aziende che si impegnano nel rispettare i principi della Green Chemistry al fine di ridurre l'impatto ambientale dei processi chimici. In questo quadro, la catalisi micellare si è dimostrata un'ottima soluzione permettendo di condurre le reazioni utilizzando l’acqua come l’unico mezzo di reazione generalmente in presenza di piccoli quantitativi di surfattante. Ma purtroppo non sempre la catalisi micellare risulta essere riproducibile e facilmente scalabile industrialmente. A tal proposito, è stato studiato un sistema auto-emulsionante composto da una miscela di L-α-Lecitina e Tween 80 (TL82) per la preparazione di piccole molecole organiche. La caratteristica unica di questa miscela di tensioattivi offre un nuovo ambiente per l'esecuzione di comuni reazioni di cross-coupling come le reazioni di Suzuki-Miyaura, Sonogashira e Heck in modo riproducibile su larga scala. La versatilità di questo approccio è stata verificata attraverso la sintesi di semiconduttori organici complessi basati su pigmenti insolubili. La grande attenzione all'introduzione della sostenibilità non riguarda solo la sintesi, ma anche il processing dei materiali per la produzione di dispositivi. È stato introdotto un processo innovativo che consente la preparazione di dispositivi a film sottile ad alte prestazioni a partire da dispersioni acquose di semiconduttori organici sia di tipo p- che n-. La miscela di tensioattivi auto-emulsionante TL82 viene utilizzata sia come mezzo di sintesi che di processing. Questo metodo consente la preparazione di Transistor Organici ad Effetto di Campo utilizzando esclusivamente l’acqua in tutte le fasi di preparazione, ottenendo prestazioni paragonabili ai dispositivi ottenuti dai processi svolti utilizzando solventi organici. Sono stati inoltre progettati nuovi materiali innovativi performanti per l'(opto)elettronica. In particolari sono stati progettati sia piccole molecole che polimeri coniugati originali ponendo una grande attenzione al selezionamento di materie prime a basso costo, limitando severamente l'utilizzo di sostanze chimiche tossiche e pericolose e progettando tutti i processi per un possibile up-scaling. In dettaglio, buona parte del lavoro è stata dedicata allo sviluppo di materiali sostenibili per applicazione in concentratori solari luminescenti. Le prestazioni dei materiali sintetizzati sono state confrontate con quelle dei lumofori commercialmente disponibili con caratteristiche spettrali simili. Nel complesso, i nuovi materiali sviluppati mostrano prestazioni comparabili, ma col vantaggio di essere sintetizzati in maniera green e facilmente scalabili industrialmente. Infine, è stato sviluppato un monomero derivato tiofenico asimmetrico con caratteristiche intrinseche di donatore e accettore al fine di sviluppare uno dei primi esempi di polimero regio-regolare ambipolare.
The research focuses on the development of new synthetic routes for the preparation of printable organic semiconductors, devised to be suitable for industrial scaling up. As such, a novel synthetic method for facile, cheap, and environmentally friendly production of π-extended organic semiconductors is explored. The concept sustainability is becoming a very important issue for chemical industries which are approaching green chemistry to reduce the environmental impact of chemical processes. In this frame, micellar catalysis has been demonstrated to be profitably performed in water under very mild conditions in the presence of a bit surfactant. Firstly, a self-emulsifying system L-α-Lecithin-Tween 80 mixture (TL82) is explored for the preparation of organic small molecules. The unique characteristic of this surfactant’s mixture offers a new environment for carrying out common cross coupling reactions such as Suzuki-Miyaura, Sonogashira and Heck cross-couplings in a reproducible up-scale way. The versatility of this approach is verified through the synthesis of complex organic semiconductors such as π-extended insoluble pigments. The emphasis on sustainability is not only applied to the synthesis but also to the processing of the active materials into the final target devices. Indeed, an innovative process is introduced enabling the preparation of high-performance thin film devices starting from waterborne dispersions of p- and n-type organic semiconductors. The TL82 self-emulsifying surfactant’s mixture is used both as the synthesis and processing medium. This method allows the preparation of Organic Field Effect Transistor using exclusively water in all steps with performances comparable to those synthesized and processed using common organic solvents. From the standpoint of the design of innovative materials, additional guidelines beside those aiming at achieving high performances are introduced. Original small molecules and polymers are designed selecting low-cost raw materials, severely the limiting the use of toxic and hazardous chemicals and designing all processes with up-scaling already in mind. These materials find an application in the field of (opto)electronics. An example of a good compromise between a simple design-good performance of a class of materials was investigated. In detail, a good part of the work was dedicated to the technology of luminescent solar concentrators devices, where the performances of the newly designed intrinsically sustainable materials are compared with those commercially available luminophores having similar spectral features. In the overall, we demonstrate comparable performance, but greatly improved sustainability and scalability. The final project was dedicated to the presentation of the first example of D-A regioregular polythiophene with an ambipolar character.

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Maturi, Mirko <1993&gt. "Advanced Functional Organic-Inorganic Hybrid (Nano)Materials: from Theranostics to Organic Electronics and Additive Manufacturing". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9739/1/Maturi_Mirko_tesi.pdf.

Texto completo

Resumen

This work is going to show the activities performed in the frame of my PhD studies at the University of Bologna, under the supervision of Prof. Mauro Comes Franchini, at the Department of Industrial Chemistry “Toso Montanari”. The main topic of this dissertation will be the study of organic-inorganic hybrid nanostructures and materials for advanced applications in different fields of materials technology and development such as theranostics, organic electronics and additive manufacturing, also known as 3D printing. This work is therefore divided into three chapters, that recall the fundamentals of each subject and to recap the state-of-the-art of scientific research around each topic. In each chapter, the published works and preliminary results obtained during my PhD career will be discussed in detail.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Defant, Andrea. "Design, Chemical Synthesis and Biological Evaluation of Potential New Antiviral Agents". Doctoral thesis, Università degli studi di Trento, 2012. https://hdl.handle.net/11572/368092.

Texto completo

Resumen

Acquired Immunodeficiency Syndrome (AIDS) is a disease caused by the Human Immunodeficiency Virus (HIV). Since its discovery in 1981, more than 25 million people died due to this disease. To date, an effective HIV-1 vaccine usable in prophylaxis or in the therapy of humans has not yet been identified. The failures and limited success of HIV vaccines have reinforced the role of chemotherapy and therefore research on the development of effective drugs. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) were the early agents introduced in the therapy and currently they are the most used, based on their concurrent high activity against the virus and low toxicity against human cells. In addition, the rapid development of virus resistance against these types of drugs, needs to find new molecules able to overcome this drawback. My thesis work started from the design of a small library of new molecules, with hybrid structures based on a template deriving from the natural product (+)-calanolide A and the synthetic molecule Î±-APA, both showing a potent and selective activity against reverse transcriptase. Docking calculation has allowed to select molecules having the best values of interaction energy with the viral enzyme. Chemical synthesis was carried out together with structural characterization by extensive spectroscopic analysis including NMR technique and mass spectrometry. In particular, the synthesis of the amide group present in the structure of some amino-pyrone compounds using the standard method, resulted in the expected N-acylation, but with a C-acyl byproduct. This result has suggested to look further into the study of N,C-acylation selectivity for the ambidentate amino-pyrone moiety, whose reactivity is poorly known. Regioselectivity was investigated under different conditions (organic bases, solvent, acylating agent), also for an enamino-ester taken as a model compound. Experimental procedures were optimized in order to synthesize selectively pure N- and C-acylated compounds. A preliminary enzymatic assay indicated a good activity in the early prepared compounds of the series, promising for the following in vitro tests on HIV infected cells of each molecule in the whole series. In addition, these compounds were tested against other common viruses for human infective pathologies. With the aim of identifying molecules with potential therapeutic applications, the antiviral activity must be related to cytostatic effect, in order to select the ones with a favored selectivity index. Unfortunately, the molecules showed paragonable values in antiviral and cytostatic effects, the latter one not easily predictable neither by the chemical structure, nor by a computational approach. If the drug design by molecular docking has failed in selecting a new scaffold for NNRTIs, the study has driven the interest towards new potential antitumoral molecules showing activity at sub-micromolar concentration against leukemic cell lines. Due to the structural similarity with recently studied antibacterial natural pyrones, the synthetic molecules showing the lowest values of cytotoxicity were investigated in the inhibition of bacterial strains. Some tested compounds have shown a good activity and selectivity against Gram(+) bacteria.

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Sandron, Tommaso. "Investigation of Biological Membranes by NMR and ESI-MS Methodologies". Doctoral thesis, University of Trento, 2010. http://eprints-phd.biblio.unitn.it/415/1/tesi_PhD_Latek.pdf.

Texto completo

Resumen

In the last decade there has been a new reappraisal of the function of lipids in the cell life, not only for their structural role as cell wall or for their energy storage function, but also for their significant function on signalling and protein recognition processes. This new attention on lipids has led to a new research field in the metabolomics world called “Lipidomics”. Lipidomics is more than just the complete characterization of all lipids in a particular biological sample. It is the comprehensive understanding of the influence of all lipids on a biological system with respect to cell signalling, membrane architecture, transcriptional and translational modulation, cell-cell and cell-protein interaction and response to environmental changes over time. The critical role of lipids in cell, tissue and organ physiology is already demonstrated by many human diseases involving the disruption of lipid metabolic enzymes and pathways. Examples of such diseases include diabetes, cancer, neurodegenerative disorders and infectious diseases. This represents a clue for understanding the molecular diversity observed in membrane phospholipids. Subtle biophysical properties are also another possible explanation of strong interest toward lipids especially with reference to the emerging field of heterogeneous membrane microdomains (rafts). The major goal in lipidomics is the identification of metabolic pathways which are activated or deactivated during development of an organism or when a cell is shifted from an established physiological condition to another physiological or pathological condition (metabolic learning). A better understanding of the regulation of underlying metabolic pathways is necessary to design novel strategies for intervention. In this thesis attention has been focused on two biological systems to demonstrate how the study of membrane lipids can help for a better understanding of the mechanisms involved in different biochemical processes. The first system tackled by our methodology is represented by lipid components in detergent resistant membranes (DRM) associated with the expression of Prostate-specific membrane antigen (PSMA); the latter is a 750-residue type II transmembrane glycoprotein of the normal prostate cells and one of the most promising biomarkers of prostate carcinoma as its expression is drastically increased in cancer cells protein involved in the prostate carcinoma. In particular, the complex glycosylated form of the protein is found in Lubrol insoluble DRMs. Many essential cellular events, such as protein sorting, endocytosis and signal transduction pathways, are triggered via association of the proteins directly implicated in these processes with DRMs. In the present work we report on the lipid composition of PSMA-associated microdomains. A qualitative screening was made by thin layer chromatography (TLC) followed by an extended NMR analysis of the sample. In particular, by taking 1H-, 13C- ed 31P-NMR spectra we were able to detect and quantify cholesterol and the relative contribution of all the lipids belonging to a given PL class (such as PC, PE and SM) with respect to the overall PL composition. On the other hand, Electrospray Ionization (ESI-MS) measurements and in-source collisional induced dissociations (CID) carried out on the same sample allowed us not only to establish the distribution of lipids among the PL classes but also to recognize some structural features such as the length and the number unsaturations of their acyl chains. The second problem tackled by following similar analytical methodologies was to analyze the detailed membrane lipids profile of insect larvae of the species Pseudodiamesa branickii and Diamesa cinerella to obtain information about the biochemical mechanisms involved in their thermal adaptative capabilities. Through NMR and LC-ESI-MS experiments we have obtained information about the composition of the lipid pool of these larvae that is formed essentially by triglycerides and phospholipids, with a variable inter-species PC/PE ratio. Coupling LC-MS profiling methods with in-source fragmentation data further has enhanced the ability to probe the lipidome, by supplementing lipid identification with structural information. We have observed an high level of unsaturation of the fatty acid chain as expected for low temperature-adapted species since unsaturated chain promote a more disordered and flexible membrane structure.. For Diamesa cinerella, from ESI data we could also infer some possible mechanism adopted to increase unsaturation of the fatty acid chain by the action of desaturases enzymes or by the insertion of PUFA chains.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Lena, Stefano <1972&gt. "Nuovi materiali da nucleosidi modificati". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/67/1/tesi.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Lena, Stefano <1972&gt. "Nuovi materiali da nucleosidi modificati". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/67/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Tommasi, Simona <1980&gt. "Catalizzatori altamente versatili per reazioni regio e stereoselettive in fase omogenea ed eterogenea". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/297/1/Tesi_Simona_Tommasi.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Tommasi, Simona <1980&gt. "Catalizzatori altamente versatili per reazioni regio e stereoselettive in fase omogenea ed eterogenea". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/297/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Minzoni, Mirko <1975&gt. "Stereomutazioni in sistemi arilici orto sostituiti". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/301/1/MIRKO_MINZONI_TESI.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Minzoni, Mirko <1975&gt. "Stereomutazioni in sistemi arilici orto sostituiti". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/301/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Savorani, Francesco <1973&gt. "A case study development of chemical indexes, originated from the application of chemometric methods to the Nuclear Magnetic Resonance (NMR), in the assesment of the quality and of the geographical origin of vegetable products". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/435/1/PhD_Thesis_Francesco_Savorani_XIXciclo_Scienze_Degli_Alimenti.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Savorani, Francesco <1973&gt. "A case study development of chemical indexes, originated from the application of chemometric methods to the Nuclear Magnetic Resonance (NMR), in the assesment of the quality and of the geographical origin of vegetable products". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/435/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Fiorelli, Claudio <1977&gt. "Asymmetric synthesis of 1,n diamines". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/465/1/Tesi_Claudio_Fiorelli_Dott._in_Scienze_chimiche_Chim06_XIX_c.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Fiorelli, Claudio <1977&gt. "Asymmetric synthesis of 1,n diamines". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/465/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Mazzacurati, Marzia <1978&gt. "Advanced studies on the synthesis of organophosphorus compounds". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/470/1/Tesi_Dottorato.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Mazzacurati, Marzia <1978&gt. "Advanced studies on the synthesis of organophosphorus compounds". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/470/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Brucale, Marco <1976&gt. "Design, synthesis and characterization of DNA supramolecular nanostructures". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/474/1/Brucale_PhDthesis_2007.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

Brucale, Marco <1976&gt. "Design, synthesis and characterization of DNA supramolecular nanostructures". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/474/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Bandini, Elisa <1966&gt. "Biologically Active Compounds Via 2-Aza-1,3-Dienes". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/476/1/PhD_Thesis_BANDINI_ELISA.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Bandini, Elisa <1966&gt. "Biologically Active Compounds Via 2-Aza-1,3-Dienes". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/476/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Balducci, Daniele <1975&gt. "Sintesi stereocontrollata di pseudopeptidi e studi conformazionali". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/529/1/balducci_daniele_tesi.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

Balducci, Daniele <1975&gt. "Sintesi stereocontrollata di pseudopeptidi e studi conformazionali". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/529/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Fumo, Maria Grazia <1977&gt. "Antiossidanti polifenolici contenenti zolfo". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/591/1/fumo_tesi.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Fumo, Maria Grazia <1977&gt. "Antiossidanti polifenolici contenenti zolfo". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/591/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Sandal, Massimo <1981&gt. "Each one teaches one: characterizing active forms of proteins by single molecule force spectroscopy". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/686/1/Tesi_Sandal_Massimo.pdf.

Texto completo

Resumen

This Ph.D. candidate thesis collects the research work I conducted under the supervision of Prof.Bruno Samor´ı in 2005,2006 and 2007. Some parts of this work included in the Part III have been begun by myself during my undergraduate thesis in the same laboratory and then completed during the initial part of my Ph.D. thesis: the whole results have been included for the sake of understanding and completeness. During my graduate studies I worked on two very different protein systems. The theorical trait d’union between these studies, at the biological level, is the acknowledgement that protein biophysical and structural studies must, in many cases, take into account the dynamical states of protein conformational equilibria and of local physico-chemical conditions where the system studied actually performs its function. This is introducted in the introductory part in Chapter 2. Two different examples of this are presented: the structural significance deriving from the action of mechanical forces in vivo (Chapter 3) and the complexity of conformational equilibria in intrinsically unstructured proteins and amyloid formation (Chapter 4). My experimental work investigated both these examples by using in both cases the single molecule force spectroscopy technique (described in Chapter 5 and Chapter 6). The work conducted on angiostatin focused on the characterization of the relationships between the mechanochemical properties and the mechanism of action of the angiostatin protein, and most importantly their intertwining with the further layer of complexity due to disulfide redox equilibria (Part III). These studies were accompanied concurrently by the elaboration of a theorical model for a novel signalling pathway that may be relevant in the extracellular space, detailed in Chapter 7.2. The work conducted on -synuclein (Part IV) instead brought a whole new twist to the single molecule force spectroscopy methodology, applying it as a structural technique to elucidate the conformational equilibria present in intrinsically unstructured proteins. These equilibria are of utmost interest from a biophysical point of view, but most importantly because of their direct relationship with amyloid aggregation and, consequently, the aetiology of relevant pathologies like Parkinson’s disease. The work characterized, for the first time, conformational equilibria in an intrinsically unstructured protein at the single molecule level and, again for the first time, identified a monomeric folded conformation that is correlated with conditions leading to -synuclein and, ultimately, Parkinson’s disease. Also, during the research work, I found myself in the need of a generalpurpose data analysis application for single molecule force spectroscopy data analysis that could solve some common logistic and data analysis problems that are common in this technique. I developed an application that addresses some of these problems, herein presented (Part V), and that aims to be publicly released soon.

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Sandal, Massimo <1981&gt. "Each one teaches one: characterizing active forms of proteins by single molecule force spectroscopy". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/686/.

Texto completo

Resumen

This Ph.D. candidate thesis collects the research work I conducted under the supervision of Prof.Bruno Samor´ı in 2005,2006 and 2007. Some parts of this work included in the Part III have been begun by myself during my undergraduate thesis in the same laboratory and then completed during the initial part of my Ph.D. thesis: the whole results have been included for the sake of understanding and completeness. During my graduate studies I worked on two very different protein systems. The theorical trait d’union between these studies, at the biological level, is the acknowledgement that protein biophysical and structural studies must, in many cases, take into account the dynamical states of protein conformational equilibria and of local physico-chemical conditions where the system studied actually performs its function. This is introducted in the introductory part in Chapter 2. Two different examples of this are presented: the structural significance deriving from the action of mechanical forces in vivo (Chapter 3) and the complexity of conformational equilibria in intrinsically unstructured proteins and amyloid formation (Chapter 4). My experimental work investigated both these examples by using in both cases the single molecule force spectroscopy technique (described in Chapter 5 and Chapter 6). The work conducted on angiostatin focused on the characterization of the relationships between the mechanochemical properties and the mechanism of action of the angiostatin protein, and most importantly their intertwining with the further layer of complexity due to disulfide redox equilibria (Part III). These studies were accompanied concurrently by the elaboration of a theorical model for a novel signalling pathway that may be relevant in the extracellular space, detailed in Chapter 7.2. The work conducted on -synuclein (Part IV) instead brought a whole new twist to the single molecule force spectroscopy methodology, applying it as a structural technique to elucidate the conformational equilibria present in intrinsically unstructured proteins. These equilibria are of utmost interest from a biophysical point of view, but most importantly because of their direct relationship with amyloid aggregation and, consequently, the aetiology of relevant pathologies like Parkinson’s disease. The work characterized, for the first time, conformational equilibria in an intrinsically unstructured protein at the single molecule level and, again for the first time, identified a monomeric folded conformation that is correlated with conditions leading to -synuclein and, ultimately, Parkinson’s disease. Also, during the research work, I found myself in the need of a generalpurpose data analysis application for single molecule force spectroscopy data analysis that could solve some common logistic and data analysis problems that are common in this technique. I developed an application that addresses some of these problems, herein presented (Part V), and that aims to be publicly released soon.

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Carlone, Armando <1979&gt. "Enantioselective aminocatalysis: new reactions and new directions". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1040/1/Tesi_Carlone_Armando.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Carlone, Armando <1979&gt. "Enantioselective aminocatalysis: new reactions and new directions". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1040/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Alesi, Silvia <1980&gt. "Synthesis, multiscale-multiphase characterization and applications of thiophene-based biohybrids". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1046/1/Tesi_Alesi_Silvia.pdf.

Texto completo

Resumen

Biohybrid derivatives of π-conjugated materials are emerging as powerful tools to study biological events through the (opto)electronic variations of the π-conjugated moieties, as well as to direct and govern the self-assembly properties of the organic materials through the organization principles of the bio component. So far, very few examples of thiophene-based biohybrids have been reported. The aim of this Ph. D thesis has been the development of oligothiophene-oligonucleotide hybrid derivatives as tools, on one side, to detect DNA hybridisation events and, on the other, as model compounds to investigate thiophene-nucleobase interactions in the solid state. To obtain oligothiophene bioconjugates with the required high level of purity, we first developed new synthetic ecofriendly protocols for the synthesis of thiophene oligomers. Our innovative heterogeneous Suzuki coupling methodology, carried out in EtOH/water or isopropanol under microwave irradiation, allowed us to obtain alkyl substituted oligothiophenes and thiophene based co-oligomers in high yields and very short reaction times, free from residual metals and with improved film forming properties. These methodologies were subsequently applied in the synthesis of oligothiophene-oligonucleotide conjugates. Oligothiophene-5-labeled deoxyuridines were synthesized and incorporated into 19-meric oligonucletide sequences. We showed that the oligothiophene-labeled oligonucletide sequences obtained can be used as probes to detect a single nucleotide polymorphism (SNP) in complementary DNA target sequences. In fact, all the probes showed marked variations in emission intensity upon hybridization with a complementary target sequence. The observed variations in emitted light were comparable or even superior to those reported in similar studies, showing that the biohybrids can potentially be useful to develop biosensors for the detection of DNA mismatches. Finally, water-soluble, photoluminescent and electroactive dinucleotide-hybrid derivatives of quaterthiophene and quinquethiophene were synthesized. By means of a combination of spectroscopy and microscopy techniques, electrical characterizations, microfluidic measurements and theoretical calculations, we were able to demonstrate that the self-assembly modalities of the biohybrids in thin films are driven by the interplay of intra and intermolecular interactions in which the π-stacking between the oligothiophene and nucleotide bases plays a major role.

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Alesi, Silvia <1980&gt. "Synthesis, multiscale-multiphase characterization and applications of thiophene-based biohybrids". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1046/.

Texto completo

Resumen

Biohybrid derivatives of π-conjugated materials are emerging as powerful tools to study biological events through the (opto)electronic variations of the π-conjugated moieties, as well as to direct and govern the self-assembly properties of the organic materials through the organization principles of the bio component. So far, very few examples of thiophene-based biohybrids have been reported. The aim of this Ph. D thesis has been the development of oligothiophene-oligonucleotide hybrid derivatives as tools, on one side, to detect DNA hybridisation events and, on the other, as model compounds to investigate thiophene-nucleobase interactions in the solid state. To obtain oligothiophene bioconjugates with the required high level of purity, we first developed new synthetic ecofriendly protocols for the synthesis of thiophene oligomers. Our innovative heterogeneous Suzuki coupling methodology, carried out in EtOH/water or isopropanol under microwave irradiation, allowed us to obtain alkyl substituted oligothiophenes and thiophene based co-oligomers in high yields and very short reaction times, free from residual metals and with improved film forming properties. These methodologies were subsequently applied in the synthesis of oligothiophene-oligonucleotide conjugates. Oligothiophene-5-labeled deoxyuridines were synthesized and incorporated into 19-meric oligonucletide sequences. We showed that the oligothiophene-labeled oligonucletide sequences obtained can be used as probes to detect a single nucleotide polymorphism (SNP) in complementary DNA target sequences. In fact, all the probes showed marked variations in emission intensity upon hybridization with a complementary target sequence. The observed variations in emitted light were comparable or even superior to those reported in similar studies, showing that the biohybrids can potentially be useful to develop biosensors for the detection of DNA mismatches. Finally, water-soluble, photoluminescent and electroactive dinucleotide-hybrid derivatives of quaterthiophene and quinquethiophene were synthesized. By means of a combination of spectroscopy and microscopy techniques, electrical characterizations, microfluidic measurements and theoretical calculations, we were able to demonstrate that the self-assembly modalities of the biohybrids in thin films are driven by the interplay of intra and intermolecular interactions in which the π-stacking between the oligothiophene and nucleotide bases plays a major role.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Fini, Francesco <1979&gt. "Organocatalytic asymmetric mannich-type reactions: an easy approach to optically active amine derivatives". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1047/1/Tesi_Fini_Francesco.pdf.

Texto completo

Resumen

The topics I came across during the period I spent as a Ph.D. student are mainly two. The first concerns new organocatalytic protocols for Mannich-type reactions mediated by Cinchona alkaloids derivatives (Scheme I, left); the second topic, instead, regards the study of a new approach towards the enantioselective total synthesis of Aspirochlorine, a potent gliotoxin that recent studies indicate as a highly selective and active agent against fungi (Scheme I, right). At the beginning of 2005 I had the chance to join the group of Prof. Alfredo Ricci at the Department of Organic Chemistry of the University of Bologna, starting my PhD studies. During the first period I started to study a new homogeneous organocatalytic aza-Henry reaction by means of Cinchona alkaloid derivatives as chiral base catalysts with good results. Soon after we introduced a new protocol which allowed the in situ synthesis of N-carbamoyl imines, scarcely stable, moisture sensitive compounds. For this purpose we used α-amido sulfones, bench stable white crystalline solids, as imine precursors (Scheme II). In particular we were able to obtain the aza-Henry adducts, by using chiral phase transfer catalysis, with a broad range of substituents as R-group and excellent results, unprecedented for Mannich-type transformations (Scheme II). With the optimised protocol in hand we have extended the methodology to the other Mannich-type reactions. We applied the new method to the Mannich, Strecker and Pudovik (hydrophosphonylation of imines) reactions with very good results in terms of enantioselections and yields, broadening the usefulness of this novel protocol. The Mannich reaction was certainly the most extensively studied work in this thesis (Scheme III). Initially we developed the reaction with α-amido sulfones as imine precursors and non-commercially available malonates with excellent results in terms of yields and enantioselections.3 In this particular case we recorded 1 mol% of catalyst loading, very low for organocatalytic processes. Then we thought to develop a new Mannich reaction by using simpler malonates, such as dimethyl malonate.4 With new optimised condition the reaction provided slightly lower enantioselections than the previous protocol, but the Mannich adducts were very versatile for the obtainment of β3-amino acids. Furthermore we performed the first addition of cyclic β-ketoester to α-amido sulfones obtaining the corresponding products in good yield with high level of diastereomeric and enantiomeric excess (Scheme III). Further studies were done about the Strecker reaction mediated by Cinchona alkaloid phase-transfer quaternary ammonium salt derivatives, using acetone cyanohydrin, a relatively harmless cyanide source (Scheme IV). The reaction proceeded very well providing the corresponding α-amino nitriles in good yields and enantiomeric excesses. Finally, we developed two new complementary methodologies for the hydrophosphonylation of imines (Scheme V). As a result of the low stability of the products derived from aromatic imines, we performed the reactions in mild homogeneous basic condition by using quinine as a chiral base catalyst giving the α-aryl-α-amido phosphonic acid esters as products (Scheme V, top).6 On the other hand, we performed the addition of dialkyl phosphite to aliphatic imines by using chiral Cinchona alkaloid phase transfer quaternary ammonium salt derivatives using our methodology based on α-amido sulfones (Scheme V, bottom). The results were good for both procedures covering a broad range of α-amino phosphonic acid ester. During the second year Ph.D. studies, I spent six months in the group of Prof. Steven V. Ley, at the Department of Chemistry of the University of Cambridge, in United Kingdom. During this fruitful period I have been involved in a project concerning the enantioselective synthesis of Aspirochlorine. We provided a new route for the synthesis of a key intermediate, reducing the number of steps and increasing the overall yield. Then we introduced a new enantioselective spirocyclisation for the synthesis of a chiral building block for the completion of the synthesis (Scheme VI).

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Fini, Francesco <1979&gt. "Organocatalytic asymmetric mannich-type reactions: an easy approach to optically active amine derivatives". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1047/.

Texto completo

Resumen

The topics I came across during the period I spent as a Ph.D. student are mainly two. The first concerns new organocatalytic protocols for Mannich-type reactions mediated by Cinchona alkaloids derivatives (Scheme I, left); the second topic, instead, regards the study of a new approach towards the enantioselective total synthesis of Aspirochlorine, a potent gliotoxin that recent studies indicate as a highly selective and active agent against fungi (Scheme I, right). At the beginning of 2005 I had the chance to join the group of Prof. Alfredo Ricci at the Department of Organic Chemistry of the University of Bologna, starting my PhD studies. During the first period I started to study a new homogeneous organocatalytic aza-Henry reaction by means of Cinchona alkaloid derivatives as chiral base catalysts with good results. Soon after we introduced a new protocol which allowed the in situ synthesis of N-carbamoyl imines, scarcely stable, moisture sensitive compounds. For this purpose we used α-amido sulfones, bench stable white crystalline solids, as imine precursors (Scheme II). In particular we were able to obtain the aza-Henry adducts, by using chiral phase transfer catalysis, with a broad range of substituents as R-group and excellent results, unprecedented for Mannich-type transformations (Scheme II). With the optimised protocol in hand we have extended the methodology to the other Mannich-type reactions. We applied the new method to the Mannich, Strecker and Pudovik (hydrophosphonylation of imines) reactions with very good results in terms of enantioselections and yields, broadening the usefulness of this novel protocol. The Mannich reaction was certainly the most extensively studied work in this thesis (Scheme III). Initially we developed the reaction with α-amido sulfones as imine precursors and non-commercially available malonates with excellent results in terms of yields and enantioselections.3 In this particular case we recorded 1 mol% of catalyst loading, very low for organocatalytic processes. Then we thought to develop a new Mannich reaction by using simpler malonates, such as dimethyl malonate.4 With new optimised condition the reaction provided slightly lower enantioselections than the previous protocol, but the Mannich adducts were very versatile for the obtainment of β3-amino acids. Furthermore we performed the first addition of cyclic β-ketoester to α-amido sulfones obtaining the corresponding products in good yield with high level of diastereomeric and enantiomeric excess (Scheme III). Further studies were done about the Strecker reaction mediated by Cinchona alkaloid phase-transfer quaternary ammonium salt derivatives, using acetone cyanohydrin, a relatively harmless cyanide source (Scheme IV). The reaction proceeded very well providing the corresponding α-amino nitriles in good yields and enantiomeric excesses. Finally, we developed two new complementary methodologies for the hydrophosphonylation of imines (Scheme V). As a result of the low stability of the products derived from aromatic imines, we performed the reactions in mild homogeneous basic condition by using quinine as a chiral base catalyst giving the α-aryl-α-amido phosphonic acid esters as products (Scheme V, top).6 On the other hand, we performed the addition of dialkyl phosphite to aliphatic imines by using chiral Cinchona alkaloid phase transfer quaternary ammonium salt derivatives using our methodology based on α-amido sulfones (Scheme V, bottom). The results were good for both procedures covering a broad range of α-amino phosphonic acid ester. During the second year Ph.D. studies, I spent six months in the group of Prof. Steven V. Ley, at the Department of Chemistry of the University of Cambridge, in United Kingdom. During this fruitful period I have been involved in a project concerning the enantioselective synthesis of Aspirochlorine. We provided a new route for the synthesis of a key intermediate, reducing the number of steps and increasing the overall yield. Then we introduced a new enantioselective spirocyclisation for the synthesis of a chiral building block for the completion of the synthesis (Scheme VI).

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Squassabia, Federico <1980&gt. "Sintesi di peptidi e peptidomimetici attivi verso recettori di membrana". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1048/1/Tesi_Squassabia_Federico.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Squassabia, Federico <1980&gt. "Sintesi di peptidi e peptidomimetici attivi verso recettori di membrana". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1048/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Samorì, Cristian <1976&gt. "Messa a punto di procedure per la semi-sintesi di composti ad attività antitumorale partendo da prodotti naturali. Studi di struttura-attività". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1050/1/Tesi_Samori_Cristian.pdf.

Texto completo

Resumen

Camptothecin, (CPT) is a pentacyclic alkaloid isolated for the first time from the Chinese tree Camptotheca acuminata, and which has soon attracted the attention of medicinal chemists and pharmacologists due to its promising anti-cancer activity against the most aggressive histo-types. So far, most of the synthesized camptothecin analogues are A and B ring modified compounds, which have been prepared via synthetic or semi-synthetic routes. To the best of our knowledge, a very limited number of C, D, or E ring modified analogues of CPT have been reported; moreover, the few derivatives known from the literature showed a reduced or no biological activity. This dissertation presents synthetic studies on camptothecin new derivatives along with the development of a new and general semi-synthetic methodology to obtain a large variety of analogues. We report here the semi-synthesis of a new family of 5-substituted CPT's, along with their biological activity evaluation, which will be compared with reference compounds. The use of carrier-linked prodrugs has emerged as a useful strategy to overcome some of the drawbacks related with the use of the parent drug, such as low solubility, membrane permeability properties, low oral absorption, instability, toxicity, and nontargeting. Herein we report CPT-prodrugs synthesized via ring opening of the lactone moiety as 17-O-acyl camptothecin tripartate conjugates, which bear a polyamine side chain with different architectures, as the carriers. Moreover, we found that the replacement of the oxygen atom with sulphur on the piridone D-ring, dramatically improves the potency of the novel 16a-thio-camptothecin derivatives, opening new possibilities in the modelling of this class of compounds.

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Samorì, Cristian <1976&gt. "Messa a punto di procedure per la semi-sintesi di composti ad attività antitumorale partendo da prodotti naturali. Studi di struttura-attività". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1050/.

Texto completo

Resumen

Camptothecin, (CPT) is a pentacyclic alkaloid isolated for the first time from the Chinese tree Camptotheca acuminata, and which has soon attracted the attention of medicinal chemists and pharmacologists due to its promising anti-cancer activity against the most aggressive histo-types. So far, most of the synthesized camptothecin analogues are A and B ring modified compounds, which have been prepared via synthetic or semi-synthetic routes. To the best of our knowledge, a very limited number of C, D, or E ring modified analogues of CPT have been reported; moreover, the few derivatives known from the literature showed a reduced or no biological activity. This dissertation presents synthetic studies on camptothecin new derivatives along with the development of a new and general semi-synthetic methodology to obtain a large variety of analogues. We report here the semi-synthesis of a new family of 5-substituted CPT's, along with their biological activity evaluation, which will be compared with reference compounds. The use of carrier-linked prodrugs has emerged as a useful strategy to overcome some of the drawbacks related with the use of the parent drug, such as low solubility, membrane permeability properties, low oral absorption, instability, toxicity, and nontargeting. Herein we report CPT-prodrugs synthesized via ring opening of the lactone moiety as 17-O-acyl camptothecin tripartate conjugates, which bear a polyamine side chain with different architectures, as the carriers. Moreover, we found that the replacement of the oxygen atom with sulphur on the piridone D-ring, dramatically improves the potency of the novel 16a-thio-camptothecin derivatives, opening new possibilities in the modelling of this class of compounds.

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Bencivenni, Giorgio <1978&gt. "Synthetic and mechanistic investigation of new radical processes: reaction of organic azides with group-XIII Lewis acids". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1052/1/Tesi_Bencivenni_Giorgio.pdf.

Texto completo

Resumen

Dichloroindium hydride revealed to be a valid alternative to tributyltin hydride for radical reduction of organic (alkyl, aryl, acyl, solfonyl) azides. The new approach entails mild reaction conditions and provides high yields of the corresponding amines and amides, also showing high degrees of selectivity. The system dichloroindium hydride / azides can be utilised in fivemembered ring closures of g-azidonitriles, as a new source of aminyl radicals for the attractive synthesis of interesting amidine compounds in the absence of both toxic reagents and tedious purification procedures. Allylindium dichloride seems a good substitute for dichloroindium hydride for generation of indium centred radicals under photolytic conditions, since it allows allylation of electrophilic azides (e.g. phenylsulfonyl azide) and halogen or ester δ-substituted azides, the latter through a 1,5-H transfer rearrangement mechanism. Evidences of the radical nature of the reactions mechanism were provided by ESR spectroscopy, furthermore the same technique, allowed to discover that the reaction of azides with indium trichloride and other group XIII Lewis acids, in particular gallium trichloride, gives rise to strongly coloured, persistent paramagnetic species, whose structure is consistent with the radical cation of the head-to-tail dimer of the aniline corresponding to the starting azide.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Tesis sobre el tema "CHIMICA ORGANICA"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros