Th. doct.--Sci.--Paris 11, 1990. / Bibliogr. p. 161-167. résumé en anglais et en français.

Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.Sc.). / Written for the Dept. of Chemistry. Title from title page of PDF (viewed 2009/06/29). Includes bibliographical references.

Thesis (Ph.D.)--University of Hong Kong, 2001. / Includes bibliographical references. Also available in print.

In this work monolayers of alkyl amides adsorbed on a graphite surface have been successfully identified and investigated using a combination of synchrotron X-ray and neutron diffraction and Differential Scanning Calorimetry (DSC). Exceptionally stable solid layers have been observed at temperatures well above the bulk melting point, at both high multilayer coverages and, very unusually, at sub-monolayer coverages. The molecular structure of the two-dimensional crystals of these alkyl amides has been obtained from diffraction and interpreted in terms of the subtle intermolecular interactions, particularly the contribution of hydrogen bonding in monolayer assembly. Thermodynamic information provides insight on the mixing behaviour in adsorbed amide layers. A systematic study on the variation in monolayer crystal structures with alkyl chain length (between five and sixteen carbon atoms) of saturated alkyl amides using diffraction identifies that all the amide molecules investigated lie flat on the graphite surface. An odd-even variation isobserved in the monolayer crystal structures and this is supported by the melting enthalpies of the amides determined by DSC. The structure of the even members is found to support the qualitative monolayer arrangement proposed by an STM report of one member of the series, but with more quantitative insight here. Significantly, a new monolayer symmetry group for odd members of the homologous series has been identified. Characteristics of the hydrogen bond geometrybetween the molecules in the solid monolayers are reported exploiting the high level of detail available from the diffraction techniques. Secondly, the formation of solid monolayers of unsaturated alkyl amides has been reported and their crystal structures determined. This is believed to be the first report of these monolayer structures. The position and nature of the double bond have an important effect in the stability of the monolayer. Unusually, certain unsaturated amides that have a double bond conjugated with the amide group are found to form considerably more stable layers than their saturated homologues. The abnormally high melting points and enhanced stability of amide monolayers have been attributed to the existence of a network of hydrogen bonds in the layer. Phase diagrams obtained by DSC for binary mixtures of alkyl amides on graphite have been quantitatively analysed using a combination of thermodynamic models (ideal, eutectic and the regular solution models). The determined mixing behaviour is supported by conclusions based on the monolayer crystal structures of the individual components calculated using diffraction. Saturated amide mixtures that have the same plane group symmetry are found to mix non-ideally in the solid layer and phase separate if the symmetry is different, whereas the mixing behaviour of saturated/unsaturated amides considered here was found to depend on the nature of the double bond (cis/trans). Results from an initial investigation into the adsorption of alkyl amides at the polymer/air interface are also presented. This complements the study above and provides an alternative situation where amide monolayers have a central role. A reduction in the coefficient of friction is seen with increasing bulk concentration of the amide and with increasing time indicating migration of the amide to the surface. A powerful combination of surface reflection techniquesincluding neutron and X-ray reflection and ellipsometry have been used to gain uniquelyquantitative insight into this system. Initial estimates of the concentration of amides at the polystyrene surface are presented for the first time.

Carboxylic amides will add oxidatively via N-H activation to the complex [(COD)Ir(PMe3h]CI (where COD 1,5-cyclooctadiene) in organic solvents at 80°C to form stable iridium hydrides with the hydride arranged cis to nitrogen and trans to chloride. Acetamide will add to form the complex mer-(MeC(O)HN)IrH(PMe3)3CI which is isolable as a sticky yellow solid and soluble in all common solvents. The reaction with benzamide in toluene at 80°C produces the complex mer( PhC(O)HN)IrH(PMe3)3CI which is stabilized by a hydrogen bonding interaction with one equivalent of excess benzamide. All attempts to isolate the organometallic failed as the organometallic degraded quickly in the absence of amide. FTIR experiments indicated a significant hydrogen bonding interaction between the benzamide and mer(PhC(O)HN)IrH(PMe3)3Cl. NMR scale reactions with acrylamide and benzanalide showed that oxidative N-H addition could occur despite the presence of an unsaturate or an N-substituent. The attempts to form the thioamide analogues of the acetamide and benzamide complexes failed to produce stable iridium hydrides. Thioacetamide will add to [(COD)Ir(PMe3)3]CI in chloroform or methylene chloride; however~ any hydrido species which formed subsequently reacted with the solvent to produce fac( MeC(S)HN)Ir(PMe3)3Ch. All attempts at adding thiobenzamide to [(COD)Ir(PMe3)3)CI produced an uncharacterizable mixture of products. The reactivity ofmer-(PhC(O)HN)IrH(PMe3)3CI was probed with regard to its potential for catalytic amination. Reaction with TIPF6 in methylene chloride showed evidence for the formation of the bidentate amide mer-[(PhC(O)HN)IrH(PMe3)3]CI where the amide is chelated through the nitrogen and the oxygen; however, the species was not stable and could not be isolated. Refluxing mer-(PhC(O)HN)IrH(PMe3)3CI in water produces a rearrangement to form another isomer of mer( PhC(O)HN)IrH(PMe3)3CI in which the hydride is trans to nitrogen and cis to chloride. Reactions with unsaturates in benzene, chloroform, and water at elevated temperatures produced evidence for the formation of insertion products. The reaction of mer( PhC(O)HN)IrH(PMe3)3CI with t-butyl acetylene in water shows evidence for the formation of an amidated elimination product, though it was not shown to be catalytic. / Master of Science

Due to their large-scale production by the oil refinement industry, alkenes are some of the most ubiquitous starting materials in organic chemistry. The synthesis of many building block chemicals can be traced back to an alkene functionalization reaction. One alkene functionalization that remains underexplored is the introduction of amides. Amide formation is incredibly important, as it is the most common functional group found in bioactive molecules, and amide bond formation is the most common reaction in medicinal chemistry. My thesis will discuss several new methodologies for converting simple alkene starting materials into value-added amide products. First, I will talk about an anti-Markovnikov alkene hydroamidation procedure. Next, I will talk about leveraging chain walking to enable remote hydroamidation of internal alkenes. Finally, I will talk about alkene difunctionalization via nucleometalation to yield heterocyclic products with amides appended. In addition to reaction development, much of the talk will focus on elucidating and studying the mechanisms of each of these transformations.

No description available.

A thesis presented in the University of the Witwatersrand for the degree of Doctor of Philosophy / AC 2018

The following thesis outlines work carried out during the last three years for the development and investigation of methodologies using amides as N- and O- acylating agents. Chapter 1 highlights the range of methodologies and protocols reported in the literature that use amides as precursors for the synthesis of both functionalised amides and esters. The introduction will highlight the range of catalysts and promoters used as well as the scope of the current methodologies. As well as this it will highlight the limitations of the methodologies so emphasising where the following research fits into these areas. Chapter 2 presents the development of a transamidation methodology using zirconocene dichloride as a catalyst. The scope with respect to functional group tolerance is presented as well as the investigations into the mechanism of the reaction. Chapter 3 builds on the research presented in Chapter 2 and details the development of a more catalytically active zirconocene transamidation methodology. By the addition of a catalytic additive the temperature or time required for the reaction to be carried out could be lowered. Investigations into the mechanism were also carried out highlighting the in situ formation of an active catalytic species. Chapter 4 details the development of an operationally simple methodology for the O-acylation of alcohols using amides. Using a catalytic amount scandium triflate the substrate scope of the reaction was explored with a proposed mechanism presented based on activation of the amide.