Thesis submitted for the Degree of Doctor of Medicine in the University of the Witwatersrand, Johannesburg / The interest of the biochemist in para-aminobenzoic acid is very recent and, indeed, only goes back about five years, but in this time quite a voluminous literature has accumulated on the biological aspects and importance of this aniline derivative. Attention was originally focussed on it indirectly as a result of the intensive research devoted to the understanding of the mode of action of the various sulphonamides, which were shown during the last decade to be very powerful chemothera-peutic agents against many bacteria. Fildes (1940, propounded the hypothesis that p-aminobenzoic acid was an essential meta-bolite for bacteria, that it was normally associated with an enzyme system in the bacterial cell, and that sulphanilamide, being structurally similar to p-aminobenzoic acid, was capable in sufficient concentration of displacing p-aminobenzoic acid from its enzyme and stopping this essential line of metabolism. Fildes further suggested that a substance which was found to be an essential metabolite for bacteria would also be essential in the animal kingdom, so that such a substance might be found to act as a vitamin in the higher animals and even in man. In 19U1 interest in p-aminobenzoic acid was intensified with the announcement by Ansbacher (19U1J that p-eminobenzoic acid was actually a vitamin and should be included in the vita¬min B complex. In this thesis, studies on the absorption and excretion of p-aminobenzoic acid are reported, the estimation of p-amino- bensoic acid being based on its property of antagonising the Bulphonamides. Evidence is presented that p-arainobenzoic acid la excreted ae p-acetylaminobenzoic acid, and that its conjuga- tion with the acetyl radical probably takeB place in the liver. Further it is suggested that the experiments performed do not lend support to the view that p-aminobenzolc acid is a vitamin for man. Finally the various physiological effects of p-aminobenzoic acid are discussed and an attempt is made to gauge its function in the living organism. Preliminary experiments indicating a new, hitherto unreported, role of p-aminobenzoic acid are re¬corded, namely its ability in large doses to increase the re¬sistance of animals to disease. / IT2017

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Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical chemistry and Pharmaceutical analysis Author: Jana Žecová Supervisor: PharmDr. Jan Zitko, Ph.D. Title of diploma thesis: Compounds combining pyrazinamide and 4-aminobenzoic acid fragments as potential antituberculars Tuberculosis is a severe infectious disease, which has been afflicting the human world population for centuries. It's figuring in the scale of the deadliest diseases as well as the occurring of strains resistant to therapy requires a serious approach to this problem and the research of new therapeutic means. Among the actual antituberculars figure two compounds, PZA and PAS. Pyrazinamide is a first line drug, and its derivatives are subject of the research in the Department of Pharmaceutical chemistry and Pharmaceutical analysis. Structurally similar to 4-aminobenzoic acid, PAS is a second line antitubercular, which is again actual in the therapy of resistant form of TBC. This diploma thesis treats about possibilities of the use of compounds combining fragments of PZA and 4-aminobenzoic acid as potential antituberculars. Furthermore, this thesis evaluates the influence of PAS fragment in the derivatives prepared with this antimycobacterial purpose. The theoretical part describes the actual state of...

In organic-inorganic hybrid compounds an organic and an inorganic component are combined to form either a coordination or an ionic material. Relevant to the current study are hybrid materials composed of an organic part that contains one or more functional groups, for example amine, amide or carboxylic acid functional groups, and a metal halide inorganic portion. These functional materials display a range of interesting and desired properties, as evidenced from numerous literature reports on their properties. In order to utilise these properties in applications, a detailed understanding of the way that the crystal structure influences the properties of a material is required. However, before this step can be achieved, it is necessary to obtain information on the structural trends of the materials, and to use the approach of crystal engineering to identify robust supramolecular synthons that may afford structural control and prediction. The aim of the current study was to investigate the synthesis and crystal structures of hybrid materials, both ionic and coordination, composed of divalent transition metal halides and the organic components 4-aminobenzoic acid, 4-aminobenzamide and isonicotinic acid, and to identify the structural trends and crystal engineering synthons displayed by these materials. A secondary objective was the preliminary identification of properties exhibited by selected materials, in order to decide on the suitability of the materials for detailed future property investigations. Part of the work describes the investigation of the structural characteristics of coordination materials prepared by the combination of the organic and inorganic components. Five novel crystal structures of coordination materials were determined, and these are compared with six related coordination structures reported in the literature. Two of the novel structures display interesting one-dimensional coordination polymers, one of which has never been reported previously in the literature. The molecular and structural characteristics of both the novel and the literature coordination structures are presented in detail, and this discussion includes a description of the coordination geometry, the molecular geometry, packing trends, hydrogen bonding interactions and aromatic interactions. A comparison study across the three families of organic components in which the structural trends, hydrogen bonding interactions, aromatic interactions, ligand geometry and coordination modes are compared, is included. The results of the synthesis of the coordination materials by means of a mechanochemical method are presented, and the products afforded by this method are compared with those prepared via solution crystallisation. Finally, the results of preliminary studies of the thermal and electronic propertries of the materials are presented and interpreted. The combination of the hybrid components as cations and anions to form ionic materials yielded nine novel structures, and these were compared with five related ionic structures reported in the literature. The novel structures include three polar structures that contain the 4-ammoniumbenzamide cation, and to our knowledge no structures containing this cation have ever been reported in the literature, hence a significant contribution to the structural knowledge of perhalometallate salts of 4-ammoniumbenzamide is made by this study. In addition two novel structures display interesting one-dimensional and two-dimensional polymeric anions, respectively, are reported. The discussion of the novel and literature ionic structures includes a description of the molecular geometry of each of the components, the identification of packing trends, and an analysis of the hydrogen bonding and aromatic interactions occurring in the structures. The structures of all three families of organic components are compared, and trends in structural type, anion geometry, water inclusion, hydrogen bonding and functional group recognition are presented. In addition, a detailed analysis of robust crystal engineering synthons occurring in these structures is presented. Lastly the results of preliminary property investigations of the thermal and electronic properties of the materials are presented and discussed / Dissertation (MSc)--University of Pretoria, 2011. / Chemistry / unrestricted