Thesis (Ph. D.)--University of Wisconsin--Madison, 1956. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 163-170).

Orientador : Pedro Faria dos Santos Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-07-15T00:22:42Z (GMT). No. of bitstreams: 1 Pastore_HeloisedeOliveira_M.pdf: 4360939 bytes, checksum: 4b2a06a447bd997ebe69a323312947f0 (MD5) Previous issue date: 1987 / Mestrado

Metal-catalyzed cyclopropanation of olefins with diazo reagents is one of the most general and efficient method to prepare cyclopropanes. The resulting cyclopropyl units are found as a basic structural element in a wide range of naturally occurring compounds and biologically active compounds, and can serve as versatile synthetic intermediates in the synthesis of multifunctionalized cycloalkanes and acyclic compounds. Since Co(II) complexes of D2-symmetric chiral amidoporphyrins [Co(D2-Por*)] were first introduced in 2004, Co(II)-metalloradical catalysis (MRC) have emerged as a new platform for asymmetric cyclopropanation. These metalloradical catalysts have been shown to be highly effective for asymmetric intermolecular cyclopropanation of a broad scope of substrates with different diazo reagents, with excellent diastereoselectivity and enantioselectivity. This dissertation aims to develop new Co(II)-MRC based enantioselective cyclopropanation systems. It will elaborate on three types of stereoselective cyclopropanation reactions from olefins: radical cyclopropanation with α-halodiazoacetates, asymmetric bicyclization of diazoketones, and radical cyclopropanation with fluoroaryl diazomethanes. These three processes will be examined in the context of diastereo- and enantiocontrol. And also, the application of cyclopropanation products have been demonstrated, which could potentially lead to more exciting works.

No description available.

M.S.

6-Diazo-5-oxo-L-norleucine (DON, 1) is a non-standard amino acid with proven antitumor activity found in soil bacteria of the genus Streptomyces. However, due to the considerable systemic toxicity manifested mainly in the gastrointestinal tract, DON alone is not a suitable clinical candidate for the treatment of cancer. One of the ways to solve the problem of its toxicity is the reversible structural modification of this molecule by protecting both its amino group and carboxyl functional group, by preparing the so-called prodrug of DON. The prepared prodrug may suitably alter the distribution of DON in the body and at the same time increase its permeability to brain tissue. Due to this structural modification, its side effects can be eliminated and a substance for the treatment of brain tumors, such as glioblastoma multiforme (GBM), can potentially be formed. In my dissertation, five strategies for the specific delivery of DON to the brain using different types of its prodrugs are discussed. The new prodrugs are designed to be either capable of spontaneous penetration across the blood-brain barrier or of being a substrate for one of its influx transporters. At the same time, these prodrugs should be stable in other metabolically active organs and blood plasma in order to sufficiently reduce the...

Call number: LD2668 .T4 1978 L546 / Master of Science

Includes bibliographies. / xi, 240 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The complexation of a range of monovalent and divalent metal ions by the aliphatic bridge cryptands C22C2 and C22C8; and the complexation of alkali metal ions by the pendant arm tetraaza macrocycle 1,4,7,10-tetrakis(2-methoxyethyl)1,4,7,10-tetraazacyclododecane, and the factors effecting complex stability and lability, have been investigated. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1995

The reactivities of several electron rich, low-valent group 6 complexes with a series of N-donor ligands were explored in order to gain information about the nature of M-N binding. Reactions of trimethylsilyl diazomethane (N=N=CHSiMe3) and 1-adamntyl azide (N=N=N-Ad) with the organometallic complexes [Cr(CO)3(C5R5)]2 (R = H, Me) and HMo(CO)3(C5R5) (R = H, CH3) were studied from both a kinetic and thermodynamic aspect. Ultimately, this information was used to propose plausible mechanisms by which the reactions take place. Furthermore, reactions of M(PiPr3)2(CO)3 (M = Mo, W; iPr = isopropyl) with N2, trimethylsilyl diazomethane, 1-adamantyl azide, a series of nitriles, and a choice group of N-heterocyclic compounds were studied. The use of the coordinatively unsaturated but sterically hindered M(PiPr3)2(CO)3 complex was used to evaluate the importance of sigma and pi bonding in these complexes.

Natural products and small molecules play a major role in drug development. However, using natural products as a source of medicine comes with many challenges, such as lack of natural abundance and difficulty in isolation. Consequently, synthetic organic chemistry is a solution in order to access these compounds in usable quantities. However, synthetic chemisty comes with its own challenges such as efficiency, chemoselectivity, stereoselectivity and enantioselectivity. Therefore, synthetic tools that addresses these challenges are required solve these limitations. This thesis discusses new methodologies using strained carbocycles (cyclopropanes and cyclopropenes) as the reactive subunit for the construction of different carbocyclic and heterocyclic compounds. The homo-Nazarov cyclization of alkenyl and heteroaryl cyclopropyl ketones was used in order to construct cyclohexenones, cyclohexenols, heteroaryl ring-fused cyclohexenones, dihydrofurans, furans and furanones in a mild and efficient manner. Benzofused heteroaromatic compounds were achieved via the Lewis acid-catalyzed cycloisomerization of cyclopropene-3,3-dicarbonyls and furan-3-carboxylates. These heteroaromatic compounds can be applied to medicinal chemistry and material science.