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Title from PDF of title page (University of Missouri--Columbia, viewed on March 1, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Michael Harmata. Vita. Includes bibliographical references.

The synthesis of fused nitrogen heterocycles has been investigated. Chapter 1 describes the synthesis of quinolones through a copper catalyzed amide coupling to ortho acetyl aryl halide followed by an aldol condensation that produces the quinolone in modest to good yields. The reaction works well with lactam partners and leads to tricyclic ring systems. Chapter 2 describes the synthesis of 8 membered enamide rings through a [3,3] sigmatropic rearrangement ring expansion of N-vinyl β-lactams. The N-vinyl β-lactams also undergo a 6π electrocyclization following the [3,3] sigmatropic rearrangement to furnish amino cyclobutanes. Previously reported amino cyclobutanes have been made using [2+2] photocycloaddition and resulted in a mixtures of diastereoisomers. Our method produces the amino cyclobutanes in good to high yields and with excellent levels of diastereoselectivity. Chapter 3 describes the synthesis and applications of reduced hydantoins from aziridine aldehydes and isocyanates. The resulting heterocycles contain an aziridine ring fused to a 5 membered urea. We also demonstrate that the reduced portion of the hydantoin, namely the hydroxyl group, can undergo further displacement with β-ketoesters similar to iminium ion chemistry.

The synthesis of fused nitrogen heterocycles has been investigated. Chapter 1 describes the synthesis of quinolones through a copper catalyzed amide coupling to ortho acetyl aryl halide followed by an aldol condensation that produces the quinolone in modest to good yields. The reaction works well with lactam partners and leads to tricyclic ring systems. Chapter 2 describes the synthesis of 8 membered enamide rings through a [3,3] sigmatropic rearrangement ring expansion of N-vinyl β-lactams. The N-vinyl β-lactams also undergo a 6π electrocyclization following the [3,3] sigmatropic rearrangement to furnish amino cyclobutanes. Previously reported amino cyclobutanes have been made using [2+2] photocycloaddition and resulted in a mixtures of diastereoisomers. Our method produces the amino cyclobutanes in good to high yields and with excellent levels of diastereoselectivity. Chapter 3 describes the synthesis and applications of reduced hydantoins from aziridine aldehydes and isocyanates. The resulting heterocycles contain an aziridine ring fused to a 5 membered urea. We also demonstrate that the reduced portion of the hydantoin, namely the hydroxyl group, can undergo further displacement with β-ketoesters similar to iminium ion chemistry.

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Chemistry has been defined by some as an art, by others as a science and people have gone as far as dismissing it as pure alchemy. Overall, however, one cannot help but come to the conclusion that chemistry is a unique blend of all three. The work contained within this manuscript is an attempt to delve deep into the mysteries of but one type of transformation - a ¡¥simple¡¦ cyclisation step in which one couples two different moieties to form a cyclobutane ring with the aid of SmI2. There are two opposing forces of nature which control the outcome of this reaction, namely elimination and cyclisation and it is the contest between these two driving forces that ultimately decides the fate of these transformations. This work was born from previous attempts in RAU¡¦s laboratories to synthesise chiral cyclobutane derivatives from carbohydrates as well as the apparent discrepancies in two independent scientists¡¦ publications on the effect of SmI2 on reactions utilising 1,4-diketones. Hoffmann from Germany had managed to form 1,2-cyclobutanediols from a pinacol reaction promoted by SmI2 while Ghosh in India had experienced fragmentation products under similar conditions. The information contained herein provides a bird¡¦s eye view of cyclisation vs. fragmentation in 1,4-disubstituted compounds as well as an insight into how one might avoid or exploit the particular reaction pathways. The effects of various moieties in a ¡§ƒ×¡¨ disposition to the ketone have been investigated to obtain a broader understanding of the scope of the cyclobutane ring formation. These findings also provide the information necessary for effecting cyclobutane ring closures within the realm of carbohydrate chemistry. One will learn that the ¡¥geminal¡¦ effect is not the only efficacious method for the coupling of a ketyl radical and an activated alkene to form a four-membered ring. The thesis concludes with a strategic route towards the synthesis of a potential antiviral compound containing the cyclobutane substructure, originating from the simple sugar D-ribose. / Prof. D.B.G. Williams

Thesis advisor: Shih-Yuan Liu / This dissertation describes the utility of 1,2-azaborine motif as a 4C+1B+1N synthon in organic synthesis, especially for the preparation of densely functionalized cyclobutanes based on the framework of the 1,2-azaborine photoisomerization. The substitution of a CC unit with a BN unit in benzenes significantly modifies the properties of classic benzenoid compounds, leading to new reactivities and functionalities. In this vein, Chapter 1 discloses photoisomerization of 1,2-azaborines to selectively form BN-analogues of the Dewar benzene. Three applications of the Dewar photoisomers are described herein: 1) a rhodium-catalyzed ring-opening reaction to form 1,2-azaborines; 2) furnishing cis aminoborylated cyclobutanes with the boron unit as a further functionalization handle; 3) a stereospecific ring-opening reaction to afford diene which can engage in Diels-Alder reaction. Chapter 2 elaborates on a modular and stereoselective strategy to access a variety of cyclobutane β-amino alcohols. Discussed herein are regioselective functionalizations and di-functionalizations of the 1,2-azaborine core and a tandem photoisomerization-hydrogenation-oxidation protocol to translate the functionalized azaborine core to cyclobutane amino alcohols. Also examined herein are the scope of azaborine photoisomerization and Dewar hydrogenation. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Cyclobutanes represent an underutilised structural feature in medicinal chemistry, partially due to difficulties in forming them in an easy and controlled manner. Herein is described their application to a drug discovery project and development of the enamine [2+2] cyclisation; a straightforward synthesis of functionalised cyclobutanes. A library of 30 cyclobutane based integrin antagonists have been designed and synthesised to explore the SAR around the hit dual β3 integrin antagonist ICT9055. Several of which were shown to be highly potent antagonists inhibiting cancer cell adhesion, migration and invasion while remaining non-toxic. ICT9072 had comparable β3 activity to hit compound ICT9055 but also had activity against αvβ5 and therefore showed greater inhibition of migration of DLD-1 cells. This showed the ability to modify this scaffold for multi integrin antagonism and potential benefit of this. Synthetic studies towards the marine natural product providencin has led to the development of a previously unknown intramolecular enamine [2+2] cyclisation which has been shown to proceed in a diastereoselective manner. This reaction has been applied to the synthesis of a highly functionalised enatiopure cyclobutene suitable for inclusion into the total synthesis. A model furyl cyclobutane has also been synthesised to exemplify the route from the enantiopure cyclobutene through to the furyl cyclobutane fragment of providencin. / Yorkshire Cancer Research

Yes / The Arg-Gly-Asp (RGD)-binding family of integrin receptors, and notably the β3 subfamily, are key to multiple physiological processes involved in tissue development, cancer proliferation, and metastatic dissemination. While there is compelling preclinical evidence that both αvβ3 and αIIbβ3 are important anticancer targets, most integrin antagonists developed to target the β3 integrins are highly selective for αvβ3 or αIIbβ3. We report the design, synthesis, and biological evaluation of a new structural class of ligand-mimetic β3 integrin antagonist. These new antagonists combine a high activity against αvβ3 with a moderate affinity for αIIbβ3, providing the first evidence for a new approach to integrin targeting in cancer. / This work was supported by the EPSRC (RCUK Academic Fellowship and Grant EP/H002626/1 to H.M.S.) and Prostate Cancer UK (Pilot Grant PA10-01). F.O.F.O.A-S.. was funded by the Public Authority for Applied Education and Training, Kuwait (PhD studentship).

Au cours de ce travail, nous nous sommes intéressés à la synthèse d'un analogue de Milnacipran, une molécule commercialisée sous le nom d'Ixel pour son activité anti-dépresseur. Il s'agit d'un cyclobutane trisubstitué portant deux centres stéréogènes contigus. L'objectif est de développer une voie de synthèse efficace et transposable à la version énantiosélective.Nous avons également travaillé sur la formulation nanométrique d'épiPodophyllotoxines, un produit naturel biologiquement active. Nous avons imaginé une architecture moléculaire permettant à la molécule de s'auto-assembler en micelle, ainsi elle peut être transportée de manière efficace au tumeur cancéreux. Les études in vitro et in vivo ont apporté des résultats prometteurs vis-à-vis du potentiel thérapeutique de notre nano-objet. Enfin nous avons étudié au cours de cette thèse deux méthodologies: la réactivité des époxydes en milieu alcalin fort et les dérivés d'organobismuth pour les réactions d'oxydation. Ces derniers ont été exploités afin d'oxyder des hydroxylamines en nitrone dans des conditions douces, permettant de réaliser le tandem oxydation/cycloaddition 1,3 dipolaire in situ avec des alcynes tendus. / My PhD thesis mainly involves the enantioselective synthesis of the Milnacipran's analog, a trisubstituted cyclobutane bearing two contiguous stereogenic centers. We have devised a conventional approach which consists of an intramolecular SN2 cyclization. After an acidic treatment, the key intermediate lactone was isolated with an ee > 99%, which was converted to the Milnacarre with no erosion of the ee value. We have also interested in the nanometric formulation of Podophyllotoxine derivatives. The natural product was designed to bear a hydrophilic and hydrophobic side chain. Its micellar solution was evaluated in vitro, in vivo and the obtained resuls were shown to be promising.We have also studied two methodologies: the reactivity of glycidyl ether toward alkyllithium reagents and oxydation of hydroxylamines to nitrone using triphenylbismuth carbonate. We observed in the former case an original rearrangement of the substrate to a vicinal diol, while in the latter case we have developped a mild condition to perform an tandem oxydation/1,3-dipolar cycloaddition in situ with a strained alkyne.