This report describes the development of simple three-component chiral derivatisation protocols to determine the enantiopurity of a range of chiral amines and amino alcohols using IH and 19p NMR spectroscopic techniques. In each of the protocols described a 2-formylphenylboronic acid core participates in tandem imine formation with an amine moiety and boronate ester condensation with a chiral diol to afford a pair of diastereomeric imino-boronate esters. These derivatives show distinguishable resonances in NMR spectra; the relative integrals of which reflect the enantiopurity of the starting amine or amino alcohol. The first chapter commences with an introduction of the different methods available to scientists today to determine enantiopurity focusing primarily on assays that utilise NMR spectroscopic techniques and particularly those where chiral derivatising agents have been used. This shall be followed by a short overview of literature regarding nitrogen-boron interactions by means of an introduction to the history of the Bull/James group research, who have used this method to determine the enantiopurity of chiral amines, diols and diamines by a simple, quick chiral derivatisation protocol whereby a pair of diastereomers are formed that can be readily distinguished using I H NMR spectroscopy. The second chapter details the steps taken to establish a chiral derivatisation protocol to determine the enantiopurity of amino aIcohols (Scheme 1). Previous work in the group established that a silyl protection step of the hydroxyl moiety was necessary. The rest of the chapter informs about the selection of a chiral diol, methyl-2,3-dihydroxy-3-phenylpropionate 2, and the protocol's ability to determine the enantiopurity of a number of amino a1cohols is demonstrated. This protocol was even found to be successful when silyl-protected amino alcohols with remote stereocentres were used in a mixed solvent system. In the third and fourth chapters we report using a wide range of different boronic acids in protocols to determine the enantiopurity of a range of chiral amines, amino alcohols and diols. These boronic acids are based on the use of either 3-formylphenyl or 2-formylphenylboronic acids; with, the same tandem condensation reactions taking place to derivatise the parent compound. The boronic acids either contained novel moieties that had the potential to exhibit diagnostic resonances in IH NMR spectra or they contained a fluoro group which was designed to show distinct peaks in 19p NMR spectra. Distinct resonances (diagnostic or fluoro) corresponding to the individual diastereomers were observed and thus the relative integrals of their peaks allowed for the diastereomeric excess ( de) to be readily calculated, which, in turn, revealed the enantiomeric excess (ee) of the parent amine or amino alcohol (Scheme 2). 19p NMR spectroscopy was found to be a particularly useful tool as only two signals were produced that corresponded to each of the diastereomers formed and so there was no possibility of different resonances overlapping. However in some cases there was insufficient difference in chemical shift between the two resonances to be able to determine the enantiopurity of the starting amine successfully, which led to probing of the reagents to see if a better protocol could be established. x

Οι πολυαμίνες είναι μικρά κατιοντικά μόρια απαραίτητα για την ανάπτυξη και τη διαφοροποίηση των κυττάρων. Εμπλέκονται σε ένα μεγάλο αριθμό κυτταρικών διεργασιών και παίζουν σημαντικό ρόλο στην κυτταρική άμυνα έναντι του οξειδωτικού στρες. Σκοπός της παρούσας εργασίας είναι να μελετηθεί η διακύμανση στην ενδοκυτταρική συγκέντρωση των πολυαμινών σε κατάσταση οξειδωτικού στρες που προέρχεται από έκθεση σε κάδμιο. / Polyamines, which are small poly-cation molecules, play an important role in cell defense against various kinds of environmental stress. The aim of this study was to investigate how cadmium-induced oxidative stress affects polyamine content in cells, in order to explore the possibility to be used as a biomarker of oxidative stress. To this end, experimental studies were carried out in mussel Mytilus galloprovincialis exposed in aquarium for 15 days to 100 μg/l Cd2+.

The work presented in this thesis highlights the influence of water soluble tertiary amines in the synthesis of transition metal substituted heteropolyoxometalates (TMSPs), with particular emphasis on polyanions based on the Keggin structure and lacunary derivatives thereof. In particular, an understanding is gained into the role that N,N’-bis(2-hydroxyethyl)piperazine (bhep) and morpholine (morph) play in the polyanion self-assembly process, with the successful isolation of molecular species, chains, layers and three dimensional frameworks. Each of the ligands were used in two different sets of synthetic investigation to probe their influence on the complete self-assembly of transition metal substituted tungstophosphates using Na2WO4 as the tungstate source, and by using the [XW10O36]8- X = Si, Ge precursors. Indeed, at no point in this work has the same polyanion been isolated using both the bhep and morpholine ligands, with this observation being indicative of each ligand having structure directing properties. Synthesis of TMSPs based on the phosphotungstate clusters in the presence of (bhep) has resulted in the isolation of clusters with nuclearities {W6}, {W7}, {W9}, {W10}, and {W11} which were only possible through fine control of the reaction pH which is aided by the ligands high buffer capacity. Additionally, in these compounds the ligand is observed to adopt a variety of coordination tendencies ranging from monodentate coordination through the ligands hydroxyl groups to chelation between nitrogen and oxygen donors. Specifically, the chelation of the ligand to CoII and NiII ions has allowed the rare inclusion of transition metal complexes into lacunary polyanions through a complimentary self-assembly process. Furthermore, the (bhep) ligand has been used to directly functionalise the [γ-SiW10O36]8- polyanion through the controlled formation of W-OC linkages via a dehydration process. Interactions of the Morpholine ligand with heteropolytungsate clusters and transition metals in aqueous solution results in an array of markedly different structural motifs, which are highly depedant on the synthetic approach. The high basicity of the morpholine ligand results in its function as a buffer and cation within a pH domain that is underdeveloped in TMSP chemistry. Consequently, novel molecular species and functional materials have been isolated through the exploitation of this knowledge. The most significant of all the findings is the isolation of five mesoporous frameworks, which are composed solely of manganese or cobalt substituted Keggin polyanions which act as trigonal and tetrahedral nodes in the purely inorganic frameworks. Furthermore, the manganese containing frameworks have been shown to have cation exchange properties and are also redox active with single-crystal to single-crystal transformations being observed.

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The synthesis of amines bearing an adjacent quaternary stereocentre is challenging. Work within our group has demonstrated that the intramolecular transfer of an aryl group within a lithiated benzylic urea is possible. Subsequent cleavage of this urea moiety allows the synthesis of chiral aryl amines bearing quaternary stereocentres. This thesis details investigations into the lithiation of allylic and vinylic ureas. A sequential transformation of allyl ureas into diarylallyl ureas has been developed, a reaction that can be carried out enantioselectively using chiral lithium amides. Deprotection of the urea allows for the isolation of amines bearing highly substituted centres. It has been shown that the use of the acid-labile vinylic protecting groups allows the corresponding Cbz protected diarylallyl amines to be synthesised. Investigations have demonstrated that these analogues can be converted into otherwise synthetically challenging diarylglycine derivatives. During these investigations it has also been shown that carbolithiation of vinyl ureas is possible. The ureas formed from this tandem β-alkylation/α-arylation sequence can then be converted to their highly substituted amine counterparts in good yields. A range of allylic ureas has been investigated; their synthesis and reactivity upon lithiation are discussed within this thesis.

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Η ΒΥΠ διαθέτει αντίτυπο της διατριβής σε έντυπη μορφή στο βιβλιοστάσιο διδακτορικών διατριβών που βρίσκεται στο ισόγειο του κτιρίου της. / Στα βακτήρια, η μεγάλη ριβοσωματική υπομονάδα αποτελείται από δύο είδη RNA, το 23S και το 5S rRNA, καθώς και 33 πρωτεΐνες. Ο σχηματισμός του πεπτιδικού δεσμού και η απελευθέρωση της πεπτιδικής αλυσίδας επιτελούνται στη μεγάλη υπομονάδα, όπου εδράζεται το καταλυτικό κέντρο της πεπτιδυλοτρανσφεράσης (PTase). Εκτός αυτού, η μεγάλη υπομονάδα περιλαμβάνει το κέντρο προσδέσεως των μεταφραστικών παραγόντων, το οποίο πυροδοτεί τη GTPase δραστηριότητα των G-πρωτεϊνικών παραγόντων, που εμπλέκονται στη μετατόπιση των υποστρωμάτων και άλλες ριβοσωματικές λειτουργίες. Έχει υποτεθεί ότι το 5S rRNA παίζει ουσιώδη ρόλο στη συγκρότηση του κέντρου της PTase και στη μετάδοση σημάτων μεταξύ του καταλυτικού κέντρου και των ριβοσωματικών συστατικών που διεκπεραιώνουν τη μετατόπιση των υποστρωμάτων. Το ιοντικό περιβάλλον φαίνεται να επηρεάζει καθοριστικά τη διαμόρφωση του 5S rRNA. Για παράδειγμα, έχει βρεθεί ότι οι πολυαμίνες δεσμεύονται εκλεκτικά στο 5S rRNA και επηρεάζουν τη δραστικότητα του έναντι του διμεθυλο-θεϊκού, ενός αντιδραστηρίου-ιχνηθέτη της τριτοταγούς δομής του RNA. Αρχικά ελέγξαμε αν υπάρχουν εξειδικευμένες θέσεις πρόσδεσης των πολυαμινών στο 5S rRNA. Στη συνέχεια, με σκοπό να ελέγξουμε αν η πρόσδεση των πολυαμινών επηρεάζει τη λειτουργία του 5S rRNA, 70S ριβοσώματα προγραμματισμένα με πολύ-ουριδυλικό σχηματίσθηκαν από 50S υπομονάδες, ολικά ή εκλεκτικά φωτοσημασμένες με ένα φωτοδραστικό ανάλογο της σπερμίνης και από 30S ακατέργαστες υπομονάδες. Αυτά τα ριβοσώματα είχαν την ικανότητα να δεσμεύουν AcPhe-tRNA ελαφρώς ισχυρότερα, σε σύγκριση με ριβοσώματα συγκροτημένα από φυσικά συστατικά, μη περιέχοντα πολυαμίνες. Το γεγονός αυτό υποδηλώνει ότι η πρόσδεση πολυαμινών στο 5S rRNA επηρεάζει, σε μικρό βαθμό, τη λειτουργία του παράγοντα επιμήκυνσης EF-Tu. Συζευγμένα, όμως, τα εν λόγω ριβοσώματα με tRNAPhe στην Ε-θέση και AcPhe-tRNAστην Ρ-θέση, επέδειξαν ισχυρότερη καταλυτική δραστικότητα και αυξημένη ικανότητα για μετατόπιση των υποστρωμάτων. Τα αποτελέσματα αυτά εισηγούνται σημαντική εμπλοκή των πολυαμινών στο λειτουργικό ρόλο του 5S rRNA κατά την κατάλυση και μετατόπιση των υποστρωμάτων. / In bacteria, the large ribosomal subunit comprises two RNA species, 23S and 5S rRNA, and 33 proteins. Peptide bond formation and peptide release are catalyzed by the large subunit, where the peptidyltransferase (PTase) center is located. In addition to this center, which triggers the GTPase activities of G-protein factors involved in translocation and other ribosomal functions. It has been hypothesized that 5S rRNA plays essential role in assembling the PTase center and mediating signal transmissions between this center and the translocation machinery. Furthermore, the ionic environment seems to affect the conformation of 5S rRNA. For instance, polyamines have been found to bind specifically to 5S rRNA and influence the 5S rRNA reactivity towards dimethyl-sulfate (DMS), a chemical probe of RNA tertiary structure. Initially we examined whether there are specific sites for binding of polyamines. To test whether the binding of polyamines influence the function of 5S rRNA poly(U)-programmed 70S ribosomes were reconstituted from 50S subunits, totally or specifically photolabelled in their 5S rRNA with a photoreactive analogue of spermine, and native 30S subunits. These ribosomes were found to enzymatically bind AcPhe-tRNA better than ribosomes reconstituted from native components. This means, that furnishing 5S rRNA with spermine slightly influences the elongation factor EF-Tu function. However, equipped with tRNAPhe at the A-site and AcPhe-tRNA at the P-site, these ribosomes exhibited higher catalytic activity and enhanced tRNA translocation efficiency. These results suggest an essential impact of polyamines on the functional role of 5S rRNA in catalysis and translocation of translation substrates.