- Title
- Synthesis and evaluation of novel HIV-1 enzyme inhibitors
- Creator
- Olomola, Temitope Oloruntoba
- Subject
- HIV infections -- Treatment HIV infections -- Chemotherapy HIV (Viruses) Enzyme inhibitors AZT (Drug) Reverse transcriptase Proteolytic enzymes Ligands Psoralens Resorcinol
- Date Issued
- 2011
- Date
- 2011
- Type
- Thesis
- Type
- Doctoral
- Type
- PhD
- Identifier
- vital:4369
- Identifier
- http://hdl.handle.net/10962/d1005034
- Description
- This study has involved the design, synthesis and evaluation of novel HIV-1 enzyme inhibitors accessed by synthetic elaboration of Baylis-Hillman adducts. Several series of complex coumarin-AZT and cinnamate ester-AZT conjugates have been prepared, in high yields, by exploiting the click reaction between appropriate Baylis-Hillman derived precursors and azidothymidine (AZT), all of which have been fully characterised using spectroscopic techniques. These conjugates, designed as potential dual-action HIV-1 inhibitors, were tested against the appropriate HIV-1 enzymes, i.e. HIV-1 reverse transcriptase and protease or HIV-1 reverse transcriptase and integrase. A number of the ligands have exhibited % inhibition levels and IC50 values comparable to drugs in clinical use, permitting their identification as lead compounds for the development of novel dual-action inhibitors. In silico docking of selected ligands into the active sites of the respective enzymes has provided useful insight into binding conformations and potential hydrogen-bonding interactions with active-site amino acid residues. A series of furocoumarin carboxamide derivatives have been synthesised in four steps starting from resorcinol and these compounds have also been tested for HIV-1 integrase inhibition activity. The structures of unexpected products isolated from Aza-Baylis-Hillman reactions of N-tosylaldimines have been elucidated by spectroscopic analysis, and confirmed by single crystal X-ray analysis. A mechanism for what appears to be an unprecedented transformation has been proposed. Microwave-assisted SeO₂ oxidation of Baylis-Hillman-derived 3-methylcoumarins has provided convenient and efficient access to coumarin-3-carbaldehydes, and a pilot study has revealed the potential of these coumarin-3-carbaldehydes as scaffolds for the construction of tricyclic compounds. The HCl-catalysed reaction of tert-butyl acrylate derived Baylis-Hillman adducts has been shown to afford 3-(chloromethyl)coumarins and α-(chloromethyl)cinnamic acids, the Zstereochemistry of the latter being established by X-ray crystallography. ¹H NMR-based experimental kinetic and DFT-level theoretical studies have been undertaken to establish the reaction sequence and other mechanistic details. Base-catalysed cyclisation on the other hand, has been shown to afford 2H-chromene rather than coumarin derivatives.
- Format
- 256 leaves
- Format
- Publisher
- Rhodes University
- Publisher
- Faculty of Science, Chemistry
- Language
- English
- Rights
- Olomola, Temitope Oloruntoba
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