1. In the first part of this thesis, the concept of a tether based intramolecular crossed -acyloin reaction mediated by heterogeneous lithium/ 4,4' -di-teti-butylbiphenyl (Li/DBB) reducing conditions was examined. The objective of the project was to accomplish an intramolecular crossed-acyloin reaction, by employing non-symmetric di-esters, linked with a suitable tether (diol) between the two acyl functionalities. Chapter 1: Introduction - Acyloin Condensation. The concept of carbon-carbon coupling reactions between two carbonyl functionalities to synthesise a-hydroxyketone (acyloin) moieties is described. Generally, there are two methods, either by bimolecular reductive coupli ng of esters, known as acyloin condensation or the umpo/ung dimerisation of aldehydes, known as benzoin condensation. The background and recent developments in these reaction categori es are discussed in this section. In addition, this section outlines the project's aims and describes the previous work conducted in the group. Chapter 2: Results & Discussion - An Alternative Route to Crossed-ocyloin In this section, the tether based intramolecular crossed-acyloin reaction mediated by Li/DBB reducing conditions is introduced. This work is based on the hypothesis that a suitable tether, could promote an intramolecular crossed-acyloin reaction. The objective was successfully achieved through a series of competition experiments, which demonstrated that the application of exo-exo norbornenediol as a tether exclusively formed crossed-acyloin products. This discovery was accompanied by an investigation into regi oselective crossed-acyloin reaction. 2. In the second part of this thesis, the Sharpless Asymmetric Epoxidation (SAE) desymmetrisation reaction of O'-symmetric diene 1,3-diols was exami ned. It was suggested that formation of the epoxide would trigger a stereoselective 5-exo-tet ring closure to deliver predominately trans-THF adducts. Chapter 3: Introduction - Metal Mediated Synthetic Routes to trans-2,5-Disubstituted THFs This section introduces the transition metal mediated cyciisation of bishomoallylic alcohol, to the corresponding trans- THF moieties. In particular, the development and application of three methods were highlighted; rhenium mediated (3+2) oxidative cyclisation, cobalt catalysed oxidative cyclisation and an rc-allylpalladium complex catalysed reaction. In addition, the concept of the Sharpless Asymmetric Epoxidation (SAE) is introduced and the project objectives are outlined. Chapter 4: Results & Discussion - A NOJel Route Towards trans- THFs The primary effort was to design a robust route to form the test substrate, (3R,55}hepta-1,6-diene- 3,5-diol, which was accomplished in good yield by Ring Opening/Crossed metathesis (ROM) of silyl ether protected (1 R, 35 }cyclopent-4-ene-1,3-diol. The expe rimental results have demonstrated that SAE of the diene 1,3 diol formed trans-THF. Chapter 5: Experimental Full experimental procedures and characterisation of the synthesised molecules are reported.

This thesis details the synthesis and characterisation of s-block metal (lithium, sodium and magnesium) phosphonium ylide, R(_3)PCHR', and iminophosphorane complexes, R(_3)PNR', together with some related phosphine oxide, R(_3)PO, and sulfide, R(_3)PS, species, where R= Ph or Me(_2)N and R' = H, Me or Ph. The first three chapters of the thesis provide an introduction to the topic, with details of the experimental methods employed and results obtained. Chapter 4 presents a systematic study of Lewis base complexed s-block metal aryloxides, (ArOM L)(_2) where Ar = C(_6)H(_3)Ph(_2) or MeC(_6)H(_2)((^1)Bu)(_2), L = R(_3)PCHR', R(_3)PNR', R(_3)PO or R(_3)PS, and M = Li, Na, and (ArO)(_2)Mg(L)(_2) where Ar = MeC(_6)H(_2)(^1)Bu)(_2) and L = R(_3)PCHR’ or R(_3)PNR'. This includes a discussion of the single crystal XRD structures of the eight neutral ligands used, L, and ten new complexes containing either lithium or sodium. Chapter 5 describes the application of some related s-block metal ylide complexes, e.g. Ph(_3)PCHMe-LiN(CH(_2)Ph(_2))(_2) and Ph(_3)PCHMe-NaN(SiMe(_3))(_2), to the Wittig reaction, together with some solution-state and solid-state discussions (two single crystal XRD structures) of s-block metal amide-phosphonium ylide complexes, R(_3)PCHR'.MNR'(_2) where R = Ph or Me(_2)N, R’ = H or Me, and R" = SiMe(_3) or CH(_2)Ph Chapter 6 details a range of N-s-block metallated iminophosphorane complexes (e.g. Ph(_3)PNLi-LiBr.2thf and R(_3)PNMgX-L where R = Ph or Me(_2)N and L = Lewis base) their application to transmetallation reactions with copper(I) compounds, solution-state and solid-state NMR studies and six new single- crystal XRD structures. Chapter 7 describes some very recent work involving alkyldiphenylphosphonium ylides, MePh(_2)PCHPh, and imines, MePh(_2)PNPh, including a single crystal XRD structural study of the latter and three of its lithium derivatives, e.g. [CH(_2)LiPh(_2)PNPh](_4). Chapter 8 is concerned with a number of unexpected results, including the synthesis, solid-state structure and proposed mechanism of a novel A^-phosphino- iminophosphorane, Ph(_2)(C(_3)H(_4)Ph)PNP(C(_3)H(_5))Ph, and two aminophosphonium salts, [R(_3)PNH(_2)](^+)[OC(_6)H(_3)Ph(_2)]" where R = Ph or Me(_2)N.

Residues of 2,4,6-trinitrotoluene (TNT) in soil and groundwater near former production and processing plants generate large environmental concerns. A cyclodextrin (CD) mediated Fenton remediation of TNT contaminated water and sand (soil analogy) is presented. Kinetic studies were performed to elucidate the role of cyclodextrin in Fenton remediation of TNT contaminated water. The rate and extent of TNT degraded by Fe2+- CD-H2O2 systems were significantly enhanced as compared to the classic Fenton method. Further, in water system with interfering substance - humic acid, which tends to associate with TNT, the addition of cyclodextrin helped to improve the efficiency of Fenton degradation. This technique has also been successfully applied to remediate TNT contaminated soil systems (sand). Four systems were investigated: clean sand, sand and humic acid, sand and fulvic acid, sand and natural organic matter. This technique has shown superior performance than classic Fenton method in all of the four above systems.

Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2016. / The Maillard reaction (MR) involves the condensation reaction between amino acids or proteins with reducing sugars, which occurs commonly in food processing and storage. Maillard reaction products (MRPs) were prepared from glucose-casein model system at pH 8, heated at 60, 75 and 90°C for 6, 12 and 24 h, respectively. Browning intensity (BI) of MRPs, as monitored by absorbance at 420 nm increased with an increase in reaction temperature. The reducing power (RP) of MRPs increased (p < 0.05) as the reaction time increased at 60 and 75°C, while at 90°C an increase in RP was observed from 6 to 12 h and thereafter a slight decrease was observed up to 24 h. The 2,2-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging activity (ABTS-RS) and Peroxyl radical scavenging (PRS) activity of glucose-casein MRPs produced at 90°C decreased as the reaction time increased. In this study, the ferrous chelation activity of MRPs was higher than that of tert-butylhydroquinone (TBHQ) (0.02%) and Trolox (1 mM), respectively. Moreover, the 1, 1-diphenyl-2-picryl-hydrazil radical scavenging (DPPH-RS) of MRPs increased (p < 0.05) as the reaction time increased irrespective of the heating temperature. The primary and secondary lipid oxidation products were measured using the Peroxide value (PV) and Thiobarbituric acid reactive substance (TBARs) assay in sunflower oil-in-water emulsion, respectively. MRPs derived at 90°C for 12 h had the lowest peroxide value, while the TBARs inhibitory by MRPs ranged from 39.05 – 88.66%. Glucose-casein MRPs displayed superior antioxidant activity than TBHQ (0.02%) and Trolox (1 mM), respectively, as measured by the TBARs assay. The differential scanning calorimetry (DSC) and Rancimat techniques set at 110°C were used to evaluate the oxidative stability the lipid-rich media containing MRPs. At the same temperature program, DSC gave significantly lower reduction times than the Rancimat. Furosine (N-ε-Fructosyl-lysine) and Pyrraline (2-amino-6-(2-formyl-5-hydroxymethyl-1-pyrrolyl)-hexanoic acid) were determined using high pressure liquid chromatography to evaluate the extent of the MR. Furosine concentration of glucose-casein MRPs ranged between 0.44 – 1.075 mg.L-1 in MRPs derived at 60°C, while at 75°C an increase as function of time was observed. MRPs derived at 60 and 75°C exhibited a varied concentration of pyrraline as the reaction time increased with higher temperatures resulted in higher concentrations (0.39 mg.L-1). The results of this study clearly indicated that MRPs possess antioxidant activity and can be used as natural antioxidants in the food industry.

Amplification techniques such as the Polymerase Chain Reaction (PCR) are held to be largely qualitative procedures and are widely used as such. Since the efficiency of amplification is less than perfect, small changes in efficiency can yield dramatic differences in the final amount of product generated. Despite this unpredictability the exquisite sensitivity of PCR makes the demanding goal of absolute quantification highly desirable. Consequently, the use of this technique for the quantification of nucleic acids has increased at an exponential rate. However, the ability of PCR to accurately quantify absolute levels of DNA is still not universally accepted. The overall aim of this investigation was to determine the critical factors affecting the quantification of DNA using PCR and to use these findings to develop an assay for the absolute quantification of DNA in a model system. The novel work presented here illustrates the need for careful examination of sequencesfo r GC-rich domains which could give rise to stable secondary structures and reduce the efficiency of amplification by serving as termination sites. To determine the accuracy of competitive PCR, CE and IP-RP-HPLC were employed to quantify PCR- products. These two techniques provided valuable information on the identification and elimination of sources of error which led to improvements in speed, accuracy and precision, as well as ease of quantification by PCR. They also yielded information on the process of heteroduplex formation whilst simultaneously revealing assay limitations. Consequently, the on-line fluorescence monitoring of PCR was used as an alternative method for the quantification of Legionella pneumophila. This technique was highly reproducible however, mispriming and the subsequent amplification of non-specific PCR products limited the level of detection. The Y-end labelling of degraded DNA with DIG prevented short DNA fragments from mispriming (and consequently extending) allowing the amplification of DNA targets. Therefore, to reduce mispriming and hence improve assay sensitivity, this approach was adapted for the first time to produce 5'-degenerate, 3'- DIG-terminated competitive primer analogues. These analogues, coupled with the use of the LightcyclerTm, allowed the detection and absolute quantification of a single cell of Legionella pneumophila. This is the first time that this level of sensitivity has been achieved using this type of assay. This technique should provide a very rapid and sensitive alternative for quantification comparedt o the other,m oree xpensivete chnologiesa vailablea t present.

This work has compared polymerase chain reaction (PCR) assays and traditional visual disease assessment to evaluate the severity of Fusarium ear blight (FEB) ofwheat under field and glasshouse conditions. In a field trial, PCR analysis highlighted the problem of diagnosis of FEB of wheat based on visual disease assessment where natural inoculum was present. PCR-based analysis detected F. poae predominantly in the glumes and Microdochium nivale sub-species were predominantly found in the rachis component of ears. M nivale var. majus was more frequently observed than var. nivale (64 and 36 %, respectively). Quantitative PCR analysis and conventional visual disease assessment were used to evaluate fungicide efficacy against FEB of wheat caused by F. culmorum and F. poae in three glasshouse trials (1994/5-1996/7). Prochloraz and tebuconazole significantly decreased both visual symptoms of FEB and fungal DNA content of F. culmorum and F. poae ear blight of wheat. Overall, both fungicides appeared equally effective, although the efficacy ofthese fungicides was consistently greater as measured by PCR analysis rather than by visual disease assessment. Inoculation with F. culmorum significantly reduced yield (1000 grain weight) whereas inoculation with F. poae had no significant effect on yield. Fusarium culmorum was successfully transformed with the GUS reporter gene. GUS activity levels of transformants varied, but transformation did not affect pathogenicity on wheat seedlings. A GUS transformant was used to study the effectiveness of two fungicides against F. culmorum foot rot of wheat. Primers to the Tri5 gene were used to develop a PCR-based assay for the specific detection ofpotential trichothecene-producing Fusarium species. These primers were also used to develop an RT-PCR-based assay for the detection and semiquantification of F. culmorum Tri5 gene expression 'relative to p-tubulin gene expression' in RNA extracts from F. culmorum. This assay was used to show that time and fungicides can affect Tri5 gene expression in liquid culture.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Includes bibliographical references. / by Herbert Russell Gillis, Jr. / Ph.D.

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The first part of this dissertation is devoted to the study of an asymmetric [3+2] cycloaddition sequence developed in our laboratory. The cycloaddition sequence used a sulfonamide-based homoenolate equivalent which was cyclocondensed with a cyclic enone. The stereochemistry of the final product was fixed during the first step, the Michael addition to the enone. Our study focused thus on the Michael addition of sulfonamides to enones. We have synthesized a series of chiral and achiral sulfonamides. We then studied the regiochemistry and the stereochemistry of the addition of the anions derived from these sulfonamides to cyclohexenone. The presence of a heteroatom at the (gamma)-carbon of the sulfonamide was crucial for the regiochemical outcome of the reaction. The substituent on the sulfonamide also influenced the facial selectivity of the reaction with chiral sulfonamides, but had no influence on the diastereoselectivity with achiral sulfonamides. The sequence had been applied to various cyclenones. We were also able to apply the method to an acyclic enone with good enantioselectivities. However the method could not be applied to other Michael acceptors. Another part of the present work was devoted to search a new catalytic asymmetric cyclopentannulation sequence. Two different approaches were studied. Phase-transfer catalysis seemed the most appropriate strategy for our objective. We soon realized that sulfur-stabilized nucleophiles could not be used under these conditions. Ketals derived from 3-nitropropanal were thus chosen as potential annulation agents. The racemic version was quite efficient and could be applied to less active acceptors such as unsaturated lactams and lactones. Unfortunately we were not able to realize the reaction with good enantioselectivities. However two new catalysts, obtained by the reaction of cinchonine with 1- and 2-methylnaphthyl chloride, emerged as interesting candidates for the phase-transfer reactions. Organocatalysis was our second approach. The use of rubidium prolinate or the use of proline in the presence of a base proved to be very efficient and the Michael adducts could be obtained with good enantioselectivities. The Michael adducts were easily cyclized and the nitro group could be removed under mild conditions.