Although the transesterification reaction of triglycerides with alcohols is well known and practiced on a commercial scale (using acid or alkaline catalysts), there is plenty of scope to improve this process. One approach involves the use of heterogeneous catalysts that could be retained in a fixed bed, and this would enable a continuous process to be developed. With this aim in mind, zinc proline (Zn(C5H8NO2)2) was used as a catalyst, which was coated onto a cordierite monolith support (62 cells/cm2). Two different coating methods were explored, and SEM images of the surface revealed interesting crystal structures on the surface of the cordierite. Experiments were then performed in a batch reactor (120 ml) to assess the activity of the catalyst (molar ratio methanol:rapeseed oil = 12:1, T = 195ºC and P = 20 bar, 2 h duration). Although high conversions could be achieved, the catalyst was found to lose activity with time, and even the cordierite support was also found to be catalytically active. These aspects were explored further, in a continuous flow reactor, which had an i.d. = 6.2 mm, and multiple heated sections (500 mm each) into which pieces (10 mm long) of catalyst coated monoliths were inserted. Experiments were performed with packed lengths of 200 and 400 mm, and with liquid flows ranging from 0.1 to 2.9 ml min-1. Although it was shown that high conversions can be achieved over extended run-times (e.g. 100 to 200 min), it was clear that the catalyst was losing its activity. Measurements also showed, that during the course of an experiment, Zn was leaching, and this clearly contributed to catalyst deactivation Despite the loss in activity of the zinc proline catalyst, the reaction system developed in this thesis was shown to work well, and that it could be used to evaluate the performance of catalytically coated sections of monolith. To demonstrate the use of this system, a few scoping studies were also performed using SrO as a catalyst, which was coated onto the cordierite monolith.

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Typescript (photocopy) / xxvi, 359 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Plant Physiology, University of Adelaide, 1982

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xiv, 107 p.; also includes graphics. Includes bibliographical references (p. 90-97). Available online via OhioLINK's ETD Center

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Poly-proline-based chiral stationary phases are relatively new stationary phases and have shown to be competitive to other commercially available chiral stationary phases for high performance liquid chromatography (HPLC). The conformational studies, solvation properties and enantio-selective mechanism of this chiral stationary phase are the main focus of this thesis. Semi-flexible models are developed based on an extensive series of ab initio calculations for proline selectors from di- to hexa-proline and a series of six chiral analytes. Then molecular dynamics simulations are performed to study the solvation, conformational preferences at the interface, and the selectivity. The solvation and conformational preferences of poly-proline selectors at the interface are examined in a normal phase n-hexane/-2propanol and a reverse phase water/methanol solvent. We noticed a significant difference between conformational preferences of poly-proline chains in these solvents indicating the effect of solvent polarity and hydrogen bonding on the relative stabilities of poly-proline conformers. Solvent partitioning occurs at the interface and this creates a polarity gradient between the stationary phase and the bulk that encourages analyte docking at the interface. Hydrogen bonding to the poly-proline selectors is shown to be a function of solvent composition and poly-proline conformation at the interface. The selectivity of the poly-proline chains was studied by molecular dynamics simulations of chiral analytes docking into the interface. The selectivity factors for a set of enantiomers were predicted successfully. Enantio-resolution has been shown to mostly happen with hydrogen bonding to poly-proline carbonyl oxygens located close to the interface. Steric interactions and conformational flexibility of the analytes are also contributing factors for enantio-resolution. / Thesis (Ph.D, Chemistry) -- Queen's University, 2013-01-28 14:31:53.316

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Dioxanones (1) are ketal- or acetal protected forms of 1,3-dihydroxyacetone (DHA). The thesis presents the stereoselective aldol transformations of dioxanones and applications to the synthesis of natural and higher carbohydrates listed in Scheme 1.<p> The field of organocatalysis has recently gained much popularity among the chemical research community. In our group, a set of conditions are developed to perform stereoselective aldol reactions on dioxanone substrate. Cs-symmetrical dioxanones have superior diasteroselectivities than C2v-symmetrical dioxanones (de up to 88% from 34%) and presence of mild Lewis acid (LiCl) or Brønsted acid additives (PyPTS) enhance the enantioselectivity into synthetically useful ranges (from 60 up to 96 % ee).<p> The first aldol addition of dioxanone (1) to desired aldehydes (possessing masked carbonyl functionality), followed by reduction of the corresponding aldol adduct and upon unmasking the aldehyde functionality (i.e dithiane or dimethoxy acetal hydrolysis) resulted in furanose (II) and pyranose (III) forms of D-ribose.<p> A new protocol was developed for the synthesis of biologically important deoxyiminosugars such as L-1-deoxymannojirimycin (DMJ, IV), L-1-deoxyidonojirimycin (DIJ, V) and N-isopropyl DIJ (IV) from readily available dioxanone (1) precursor. The key steps include diastereoselective proline-catalyzed syn-aldol transformation and a reductive amination / cyclization.<p> D-glycero-D-manno-2-octulose (VII), a higher-carbon sugar isolated from opium poppies has been synthesized in enantiomerically pure form. The short synthetic sequence involved two proline-catalyzed aldol addition reactions of dioxanone (1) to appropriate aldehydes. Here, we developed a complete dioxanone methodology towards the higher monosaccharide in a stereocontrolled fashion.<p> The enantioselective stereodivergent first total synthesis of DD- and LL-glycero-β-alloheptopyranose (IX, ent-IX) was accomplished from readily available non-chiral starting materials. The short synthetic sequence involves enamine and enolate mediated aldol reactions at α and α' positions of dioxanone (1) hence demonstrated the complementary nature of organocatalysis and organometallic methods.

Dioxanones (1) are ketal- or acetal protected forms of 1,3-dihydroxyacetone (DHA). The thesis presents the stereoselective aldol transformations of dioxanones and applications to the synthesis of natural and higher carbohydrates listed in Scheme 1.<p> The field of organocatalysis has recently gained much popularity among the chemical research community. In our group, a set of conditions are developed to perform stereoselective aldol reactions on dioxanone substrate. Cs-symmetrical dioxanones have superior diasteroselectivities than C2v-symmetrical dioxanones (de up to 88% from 34%) and presence of mild Lewis acid (LiCl) or Brønsted acid additives (PyPTS) enhance the enantioselectivity into synthetically useful ranges (from 60 up to 96 % ee).<p> The first aldol addition of dioxanone (1) to desired aldehydes (possessing masked carbonyl functionality), followed by reduction of the corresponding aldol adduct and upon unmasking the aldehyde functionality (i.e dithiane or dimethoxy acetal hydrolysis) resulted in furanose (II) and pyranose (III) forms of D-ribose.<p> A new protocol was developed for the synthesis of biologically important deoxyiminosugars such as L-1-deoxymannojirimycin (DMJ, IV), L-1-deoxyidonojirimycin (DIJ, V) and N-isopropyl DIJ (IV) from readily available dioxanone (1) precursor. The key steps include diastereoselective proline-catalyzed syn-aldol transformation and a reductive amination / cyclization.<p> D-glycero-D-manno-2-octulose (VII), a higher-carbon sugar isolated from opium poppies has been synthesized in enantiomerically pure form. The short synthetic sequence involved two proline-catalyzed aldol addition reactions of dioxanone (1) to appropriate aldehydes. Here, we developed a complete dioxanone methodology towards the higher monosaccharide in a stereocontrolled fashion.<p> The enantioselective stereodivergent first total synthesis of DD- and LL-glycero-β-alloheptopyranose (IX, ent-IX) was accomplished from readily available non-chiral starting materials. The short synthetic sequence involves enamine and enolate mediated aldol reactions at α and α' positions of dioxanone (1) hence demonstrated the complementary nature of organocatalysis and organometallic methods.

The lentiviral capsid core, which encapsulates the viral RNA genome, is delivered into the target cell cytoplasm during the viral entry process. In the cytoplasm, the conical core undergoes morphological changes, which are termed uncoating. Proper uncoating has been shown to be critical for the infectivity of the lentivirus HIV-1. In addition, the HIV-1 capsid protein is critical for the process of nuclear import of the preintegration complex (PIC). The lentivirus equine infectious anemia virus (EIAV) shares many similarities to HIV-1, including similarities in the capsid protein. In particular, both HIV-1 and EIAV capsid contain a proline-rich loop region in the amino terminal domain of capsid between helices 4 and 5. The host cellular factor cyclophilin A binds this loop in HIV-1 and is critical for proper uncoating. We hypothesized that this helix 4-5 loop was also critical for EIAV infectivity at some early step in the viral infection cycle. We created a panel of amino acid substitution mutations in this loop region. Some of the mutations resulted in severely deleterious effects on EIAV infectivity. Some mutations caused a slight increase in infectivity. The deleterious mutations did not affect uncoating or reverse transcription but appeared to block nuclear import of the PIC. Those mutations in which infectivity was slightly increased did not exhibit significantly different phenotypes from wild-type EIAV at any of the stages examined. The results of this study lend further support to the role of capsid as a determinant of nuclear import and suggest that viral and cellular factors critical to HIV-1 import may also be applicable to EIAV. Future research should focus on identifying the causes of the defects in nuclear import observed for some mutants, as well as attempt to identify the reason for the infectivity increase in others. In addition, inclusion of EIAV in future studies of nuclear import involving HIV-1 can broaden the scope of the data to lentiviruses in general rather than HIV-1 in particular.