Thèses : « CHIM/06 »

1

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.

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2

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

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3

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.

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4

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/.

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5

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.

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6

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

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7

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.

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8

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/.

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9

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.

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10

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

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11

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.

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12

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/.

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13

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.

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14

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/.

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15

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.

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16

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/.

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17

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.

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18

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/.

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19

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.

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20

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

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21

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.

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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.

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22

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/.

Texte intégral

Résumé :

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.

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23

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.

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24

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/.

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25

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.

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26

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/.

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27

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.

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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.

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28

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/.

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Résumé :

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.

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29

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.

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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).

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30

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/.

Texte intégral

Résumé :

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).

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31

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.

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32

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/.

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33

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.

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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.

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34

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/.

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Résumé :

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.

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35

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.

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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.

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36

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/.

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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.

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37

Gualandi, Andrea <1978&gt. « Asymmetric synthesis of benzylic and heterobenzylic amines ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1053/1/Tesi_Gualandi_Andrea.pdf.

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C2-Symmetrical, enantiopure 2,6-di[1-(1-aziridinyl)alkyl]pyridines (DIAZAPs) were prepared by a high-yielding, three-step sequence starting from 2,6-pyridinedicarbaldehyde and (S)-valinol or (S)-phenylglycinol. The new compounds were tested as ligands in palladium-catalyzed allylation of carbanions in different solvents. Almost quantitative yield and up to 99% enantiomeric excess were obtained in the reactions of the enolates derived from malonate, phenyl- and benzylmalonate dimethyl esters with 1,3-diphenyl-2-propenyl ethyl carbonate. Asymmetric synthesis of 2-(2-pyridyl)aziridines from chiral 2-pyridineimines bearing a stereogenic center at the nitrogen atom was development. The envisioned route involves the addition of chloromethyllithium to the imine derived from 2-pyridinealdehyde and (S)-valinol, protected as O-trimethylsilyl ether. The analogous reaction performed on the imine derived from (S)-valine methyl ester gave the product containing the aziridine ring as well as the α-chloro ketone group coming from the attack of chloromethyllithium to the ester function. Other stereogenic alkyl substituents at nitrogen gave less satisfactory results. Moreover, the aziridination protocol did not work on other aromatic imines, e.g. 3-pyridineimine and benzaldimine, which are not capable of bidentate chelation. The N-substituent could not be removed, but aziridine underwent ring-opening by attack of nitrogen, sulfur, and oxygen nucleophiles. Complete or prevalent regioselectivity was obtained using cerium trichloride heptahydrate as a catalyst. In some cases, the N-substituent could be removed by an oxidative protocol. The addition of organometallic (lithium, magnesium, zinc) reagents to 2-pyrroleimines derived from (S)-valinol and (S)-phenylglycinol gave the N-substituted-1-(2-pyrrolyl)alkylamines with high yields and diastereoselectivities. The (S,S)-diastereomers were useful intermediates for the preparation of enantiopure 1-[1-(2-pyrrolyl)alkyl]aziridines by routine cyclization of the β-aminoalcohol moiety and of (S)-N-benzoyl 1-[1-(2-pyrrolyl)alkyl]amines and their N-substituted derivatives by oxidative cleavage of the chiral auxiliary. 1-Allyl-2-pyrroleimines obtained from (S)-phenylglycinol and (S)-valinol underwent highly diastereoselective addition of allylmetal reagents, used in excess amounts, to give the corresponding secondary amines with concomitant allyl to 1-propenyl isomerisation of the 1-pyrrole substituent. Protection of the 2-aminoalcohol moiety as oxazolidinone, amide or Boc derivate followed by ring closing metathesis of the alkene groups gave the unsaturated bicyclic compound, whose hydrogenation afforded the indolizidine derivative as a mixture of separable diastereomers. The absolute configuration of the main diastereomer was assessed by X-ray crystallographic analysis.

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38

Gualandi, Andrea <1978&gt. « Asymmetric synthesis of benzylic and heterobenzylic amines ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1053/.

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C2-Symmetrical, enantiopure 2,6-di[1-(1-aziridinyl)alkyl]pyridines (DIAZAPs) were prepared by a high-yielding, three-step sequence starting from 2,6-pyridinedicarbaldehyde and (S)-valinol or (S)-phenylglycinol. The new compounds were tested as ligands in palladium-catalyzed allylation of carbanions in different solvents. Almost quantitative yield and up to 99% enantiomeric excess were obtained in the reactions of the enolates derived from malonate, phenyl- and benzylmalonate dimethyl esters with 1,3-diphenyl-2-propenyl ethyl carbonate. Asymmetric synthesis of 2-(2-pyridyl)aziridines from chiral 2-pyridineimines bearing a stereogenic center at the nitrogen atom was development. The envisioned route involves the addition of chloromethyllithium to the imine derived from 2-pyridinealdehyde and (S)-valinol, protected as O-trimethylsilyl ether. The analogous reaction performed on the imine derived from (S)-valine methyl ester gave the product containing the aziridine ring as well as the α-chloro ketone group coming from the attack of chloromethyllithium to the ester function. Other stereogenic alkyl substituents at nitrogen gave less satisfactory results. Moreover, the aziridination protocol did not work on other aromatic imines, e.g. 3-pyridineimine and benzaldimine, which are not capable of bidentate chelation. The N-substituent could not be removed, but aziridine underwent ring-opening by attack of nitrogen, sulfur, and oxygen nucleophiles. Complete or prevalent regioselectivity was obtained using cerium trichloride heptahydrate as a catalyst. In some cases, the N-substituent could be removed by an oxidative protocol. The addition of organometallic (lithium, magnesium, zinc) reagents to 2-pyrroleimines derived from (S)-valinol and (S)-phenylglycinol gave the N-substituted-1-(2-pyrrolyl)alkylamines with high yields and diastereoselectivities. The (S,S)-diastereomers were useful intermediates for the preparation of enantiopure 1-[1-(2-pyrrolyl)alkyl]aziridines by routine cyclization of the β-aminoalcohol moiety and of (S)-N-benzoyl 1-[1-(2-pyrrolyl)alkyl]amines and their N-substituted derivatives by oxidative cleavage of the chiral auxiliary. 1-Allyl-2-pyrroleimines obtained from (S)-phenylglycinol and (S)-valinol underwent highly diastereoselective addition of allylmetal reagents, used in excess amounts, to give the corresponding secondary amines with concomitant allyl to 1-propenyl isomerisation of the 1-pyrrole substituent. Protection of the 2-aminoalcohol moiety as oxazolidinone, amide or Boc derivate followed by ring closing metathesis of the alkene groups gave the unsaturated bicyclic compound, whose hydrogenation afforded the indolizidine derivative as a mixture of separable diastereomers. The absolute configuration of the main diastereomer was assessed by X-ray crystallographic analysis.

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39

Pasi, Filippo <1978&gt. « Nuovi processi catalitici in sistemi non convenzionali ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1054/1/Tesi_Pasi_Filippo.pdf.

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40

Pasi, Filippo <1978&gt. « Nuovi processi catalitici in sistemi non convenzionali ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1054/.

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41

Pandoli, Omar <1977&gt. « Supramolecular hybrid organic-inorganic multicomponent architectures in solution and on surface ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1068/1/Tesi_Pandoli_Omar.pdf.

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Supramolecular architectures can be built-up from a single molecular component (building block) to obtain a complex of organic or inorganic interactions creating a new emergent condensed phase of matter, such as gels, liquid crystals and solid crystal. Further the generation of multicomponent supramolecular hybrid architecture, a mix of organic and inorganic components, increases the complexity of the condensed aggregate with functional properties useful for important areas of research, like material science, medicine and nanotechnology. One may design a molecule storing a recognition pattern and programming a informed self-organization process enables to grow-up into a hierarchical architecture. From a molecular level to a supramolecular level, in a bottom-up fashion, it is possible to create a new emergent structure-function, where the system, as a whole, is open to its own environment to exchange energy, matter and information. “The emergent property of the whole assembly is superior to the sum of a singles parts”. In this thesis I present new architectures and functional materials built through the selfassembly of guanosine, in the absence or in the presence of a cation, in solution and on the surface. By appropriate manipulation of intermolecular non-covalent interactions the spatial (structural) and temporal (dynamic) features of these supramolecular architectures are controlled. Guanosine G7 (5',3'-di-decanoil-deoxi-guanosine) is able to interconvert reversibly between a supramolecular polymer and a discrete octameric species by dynamic cation binding and release. Guanosine G16 (2',3'-O-Isopropylidene-5'-O-decylguanosine) shows selectivity binding from a mix of different cation's nature. Remarkably, reversibility, selectivity, adaptability and serendipity are mutual features to appreciate the creativity of a molecular self-organization complex system into a multilevelscale hierarchical growth. The creativity - in general sense, the creation of a new thing, a new thinking, a new functionality or a new structure - emerges from a contamination process of different disciplines such as biology, chemistry, physics, architecture, design, philosophy and science of complexity.

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42

Pandoli, Omar <1977&gt. « Supramolecular hybrid organic-inorganic multicomponent architectures in solution and on surface ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1068/.

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Supramolecular architectures can be built-up from a single molecular component (building block) to obtain a complex of organic or inorganic interactions creating a new emergent condensed phase of matter, such as gels, liquid crystals and solid crystal. Further the generation of multicomponent supramolecular hybrid architecture, a mix of organic and inorganic components, increases the complexity of the condensed aggregate with functional properties useful for important areas of research, like material science, medicine and nanotechnology. One may design a molecule storing a recognition pattern and programming a informed self-organization process enables to grow-up into a hierarchical architecture. From a molecular level to a supramolecular level, in a bottom-up fashion, it is possible to create a new emergent structure-function, where the system, as a whole, is open to its own environment to exchange energy, matter and information. “The emergent property of the whole assembly is superior to the sum of a singles parts”. In this thesis I present new architectures and functional materials built through the selfassembly of guanosine, in the absence or in the presence of a cation, in solution and on the surface. By appropriate manipulation of intermolecular non-covalent interactions the spatial (structural) and temporal (dynamic) features of these supramolecular architectures are controlled. Guanosine G7 (5',3'-di-decanoil-deoxi-guanosine) is able to interconvert reversibly between a supramolecular polymer and a discrete octameric species by dynamic cation binding and release. Guanosine G16 (2',3'-O-Isopropylidene-5'-O-decylguanosine) shows selectivity binding from a mix of different cation's nature. Remarkably, reversibility, selectivity, adaptability and serendipity are mutual features to appreciate the creativity of a molecular self-organization complex system into a multilevelscale hierarchical growth. The creativity - in general sense, the creation of a new thing, a new thinking, a new functionality or a new structure - emerges from a contamination process of different disciplines such as biology, chemistry, physics, architecture, design, philosophy and science of complexity.

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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.

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44

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/.

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45

Graziano, Carla <1977&gt. « Architetture supramolecolari di guanosine semisintetiche per lo "scaffolding" di gruppi funzionali ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1072/1/Tesi_Graziano_Carla.pdf.

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46

Graziano, Carla <1977&gt. « Architetture supramolecolari di guanosine semisintetiche per lo "scaffolding" di gruppi funzionali ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1072/.

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47

Benfatti, Fides <1980&gt. « Design and synthesis of enzymatic inhibitors and receptor ligands ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1081/1/Tesi_Benfatti_Fides.pdf.

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48

Benfatti, Fides <1980&gt. « Design and synthesis of enzymatic inhibitors and receptor ligands ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1081/.

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49

Venturi, Luca <1978&gt. « NMR study of meat as related to its structural organisation ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1193/1/Venturi_Luca_tesi.pdf.

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50

Venturi, Luca <1978&gt. « NMR study of meat as related to its structural organisation ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amsdottorato.unibo.it/1193/.

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Thèses sur le sujet « CHIM/06 »

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