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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Some aspects of natural products chemistry

Yalpani, Mohamed January 1965 (has links)
In part I of this thesis are described some studies toward the total synthesis of tetracycline. Attempts to transform the key aromatic compounds, terrarubein and 6-methylpretetramid into actual or hypothetical biosynthetic intermediates, failed to yield useful non-aromatic products. However, several of the transformations further along the route have been achieved. Thus, the conversion of 12a-deoxy-5a,6-anhydrotetracycline into 7-chloro-5a,6-anhydrotetracycline was successfully carried out. In a different approach it was attempted to convert the synthetic tetracycline derivative 7-chloro-4-dedimethylamino-5a,6-anhydrotetracycline to 7-chloro-5a,6-anhydrotetracycline via a series of bromination-aminatipn experiments. Chromatographic evidence is presented for the formation, in trace amounts, of 7-chloro-5a,6-anhydro-4-epi-tetracycline. Part II is concerned with the study of the possible precursor activity of triacetic acid lactone, a potential polyketomethylene chain intermediate in the biosynthesis of aromatic compounds. (3,5-¹⁴ C) Triacetic acid lactone was fed to P. patulum and labelled griseofulvin was isolated and degraded. It was found that radioactivity is incorporated into griseofulvin a non-specific way. In one strain of the mould used two new metabolites were found as a result of the addition of triacetic acid lactone. Addition of triacetic acid lactone to the mould also causes an unexplained enhancement of metabolite formation. / Science, Faculty of / Chemistry, Department of / Graduate

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