Thesis (Ph. D.)--University of Chicago, Dept. of Chemistry. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Chicago, Department of Chemistry, December 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xvii, 207 p. : ill. Includes abstract. Includes bibliographical references (p. 97-101).

M.Sc. (Chemistry) / The aim of this study was to investigate alternative routes for the stereocontrolled synthesis of hydroxylated indolizidine, piperidine and pyrrolidine alkaloids, starting from monosaccharides as chiral building blocks. This study was not aimed at improving consisting routes - it was rather aimed at developing new routes towards the synthesis of these alkaloids. Mixed results were obtained in the investigation into alternative routes for the synthesis of the bicyclic poly hydroxylated indolizidine alkaloids, but a new and efficient stereospecific synthesis of polyhydroxylated piperidine- and pyrrolidine alkaloids were developed. The aims and results can be summarised in more detail as follows: a. Stereospecific synthesis of castanospermine. The synthesis of this medium sized nitrogen-containing bicyclic molecule was approached in a unique way. The utilization of bifunctional Wittig- and Wittig-Horner reagents containing nitrogen functionalities was considered promising for the aims of this study. By the usage of known reactions, e.g. Wittig, Wittig-Horner, Schiff-base and Aza-Wittig reactions, it was foreseen that these bifunctional reagents could be coupled in two concurrent steps to dicarbonyl compounds to form a nitrogen containing rings. Several nitrogen containing Wittig reagents were prepared. At the one end of these reagents a phosphonate or phosphine group furnished the phosphorus moiety while the other end of these reagents comprised the nitrogen moiety by reduction of a nitrile group or azide displacement of a leaving group. No coupling was obtained between these bifunctional reagents and a dicarbonyl compound derived from D-glucose and the influence of two functional groups in such close proximity in the Wittig reagent is being further investigated. Coupling was, however, achieved by the utilization of an alternative bifunctional reagent in which a Wittig-Horner reaction was used. The successful implementation of this unique methodology in the synthesis of medium size nitrogen containing ring is being further investigated.

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The nursery/greenhouse industry is innovative. There have been several reports in the popular literature of non-traditional adjuvants used in plant propagation; however, these claims have never been evaluated in a scientific setting. Five studies, conducted at the South Mississippi Branch Experiment Station in Poplarville in 2019 and 2021 determined the impact that adding honey to water-soluble auxin solutions and surfactants to foliar applied auxin solutions on physiological responses associated with adventitious root formation. Treatments in studies presented in chapters two and three included three honey sources (multiflora, local, and Manuka). Honey-infused water-soluble auxin solutions affected plant species but not in the measured physiological responses. Studies presented in chapters four and five examined the impact of water-soluble auxin solutions containing non-ionic surfactants on physiological responses compared to the industry standard basal quick-dip. Like our results for honey, adding surfactants to foliar-applied auxin solutions was species-specific. However, for difficult-to-root species, a foliar auxin application led to similar rooting compared to the current industry standard. For this reason, we recommend a foliar application for rooting Magnolia grandiflora ‘Southern Charm’. Finally, the study presented in chapter six examined the auxin application method, surfactant concentration, and seasonal impacts in rooting challenging to propagate species. The season that cuttings were taken had a significant impact on several of our tested responses. In addition, the auxin application method was also significant. To this end, we can recommend treating fall cuttings with a foliar auxin application for the best results.

The electron rich and aromatic character of the indole group allows for a wide range of oxidative and substitution reactions, creating a versatile platform for generating structurally diverse molecules. This thesis explores enzyme and synthetic chemistries that act upon indoles and related molecules. Chapter 1 describes the results of in vivo studies of RebC, an enzyme that plays a pivotal role in the biosynthesis of the indolocarbazole alkaloid rebeccamycin. A homologous enzyme, StaC, exists in the biosynthetic pathway for staurosporine, a related indolocarbazole. Structural differences between the RebC and StaC active sites were hypothesized to play a pivotal role in determining the oxidation state in the corresponding natural products. Sequence alignment of RebC and StaC with homologous enzymes from related indolocarbazole biosynthetic pathways revealed six non-conserved residues in the active site. Three RebC variants were generated by replacement of all six, four, or two specific residues with their StaC counterparts. It was demonstrated that only two substitutions, F216V and R239N, are required to convert the specificity of RebC to that of StaC. Analysis of the structure of the RebC bound to a putative reaction intermediate supports the importance of F216 and R239 in catalysis. Based on these results, contrasting mechanisms for RebC and StaC are proposed to account for their differing specificities. Chapter 2 describes a synthetic approach to primarily heterocyclic analogues of lycogarubin C. Suzuki coupling of appropriately functionalized 3,4-dibromopyrrole or 3,4-bis(trifluoromethanesulfonyl)pyrrole was effective for numerous π-excessive five-membered heterocyclic-3-boronic acids. The optimized conditions were less effective for cross-couplings involving heteroaromatic-2-boronic acids, π-deficient heteroaromatic boronic acids, and heteroaromatic boropinacolate esters. Oxidative cyclization of the 3,4-bis(thiophen-3-yl)pyrrole and 3,4-bis(benzothiophen-3-yl)pyrrole to give analogues of the corresponding indolocarbazoles was demonstrated. Chapter 3 describes preliminary results on the development of regioselective C-5 and C-7 indole metalation tactics of indole-6-carboxamides, in order to provide new functionalized indoles. The use of an indole C-2 silicon protection strategy in combination with a sterically bulky C-6 N,N-di-isopropyl carboxamide directed metalation group overcame undesired side reactions observed with the analogous N,N-diethyl indole-6-carboxamide, affording the C-5 and C-7 substituted products in 40% and 13% yields, respectively. / Thesis (Ph.D, Chemistry) -- Queen's University, 2013-02-13 11:14:49.599

Synthesis and flash vacuum pyrolysis (FVP) of stabilised phosphorus ylides containing an o-amino functionalised benzene ring has been examined for the first time. Model studies using N-methyl-N-tosyl and N-mesyl-N-methyl ylides showed that the ylides could be prepared, although yields were variable, and had the expected spectroscopic properties. Upon FVP, however, the expected loss of Ph₃PO and the sulfonyl group was accompanied by unexpected transfer of the reactive site from nitrogen to carbon giving 3- substituted quinolines rather than the expected indole products. Moving to ylides with an α-cinnamoyl group (or heterocyclic analogue) did, however, result in the originally planned tandem cyclisation leading to ring-fused carbazole products. N-Benzyl was also found to be a suitable thermally labile group and a series of α-cinnamoyl N-benzyl-N-methyl ylides were prepared and characterised. For their synthesis, use of N-cinnamoylbenzotriazoles was found to be preferable to cinnamoyl chloride, requiring only half the amount of amino-functionalised phosphonium salt. While FVP of some of these ylides led to benzo-, furo- and thienocarbazoles in good yield, others again gave quinoline-type products pointing to a fine balance between the two alternative modes of cyclisation. It was noted that one of the furocarbazole products was very similar to a natural product, Eustifoline D, isolated from the medicinally active shrub Murraya euchrestifolia from Taiwan and its synthesis was planned. With a view to producing the required N-H carbazole, N,N-dibenzylamino amino ylides were prepared and were found to exhibit restricted rotation leading to broad NMR signals. Their FVP again led to both quinoline and carbazole products, with the former having usually, but not always, lost a phenyl group. Mechanistic pathways for the formation of the various products are proposed. Complete assignment of the complex ¹H NMR spectra of the various fused-ring heterocyclic products was achieved, assisted by simulations in many cases. The ylide precursor required for Eustifoline D was prepared in five steps and 10% overall yield from 5-methylanthranilic acid. The final FVP step gave a quinoline as the major product, but the minor product was Eustifoline D, spectroscopically identical to the natural product.

In an effort to obtain more efficient and greener chemical transformations, a substantial amount of research interest has been directed towards the use of arene C-H bonds as functional groups. Hydroarylation of alkynes through direct functionalisation of C-H bonds has been studied in recent years leading to the development of high-yielding metal-mediated processes. The main aim of the current work is the addition of a third component in the hydroarylation of alkynes trough C-H activation, in order to achieve a second C-C bond formation. Attempts at palladium-catalysed three-component reaction of unactivated indoles with alkynes and aryliodides are described. The three-component reaction was studied in the intermolecular mode with both aryliodides and the more reactive diaryliodonium salts. These latter regents are reactive arylating and oxidising agents and have been used in the direct arylation of indoles under mild conditions through a PdII-PdIV catalytic cycle. In both cases the three-component product was not obtained. The intramolecular version of the reaction using alkyne-tethered indoles and diaryliodonium salts is also described. In this case the tandem process was successful, especially when using ethynylbenzyl indole derivatives, the Z-tetrasubstituted olefins could be selectively obtained under mild conditions. Finally, a low-yielding synthesis of chromenes from propargylaryl ethers and diaryliodonium salts is also discussed.