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Synthesis of non-natural amino acids as covalent inhibitors for protein-protein interactions.

dc.contributor.advisorSithebe, Siphamandla.
dc.contributor.advisorVeale, Clinton Gareth Lancaster.
dc.contributor.authorDladla, Siphamandla Austen.
dc.date.accessioned2024-01-18T07:49:08Z
dc.date.available2024-01-18T07:49:08Z
dc.date.created2023
dc.date.issued2023
dc.descriptionMasters Degree. University of KwaZulu-Natal, Pietermaritzburg.
dc.description.abstractThere is still a need to develop new cancer therapies for troubling cancers. Hence, a resurging interest in compounds that engage their target through covalent interactions. Lysine’s amine can be engaged covalently with a weak electrophile (SO2F) extending the potential of covalent inhibitors. Herein, we were prompted to investigate the synthesis of non-natural amino acids, modified to include weakly electrophilic warheads, which could potentially target specific lysine residues. Three new non-natural amino acids were successfully synthesized, methyl (S)-2-((tert-butoxycarbonyl)amino)-3-(4-((fluorosulfonyl)oxy)phenyl)propanoate, 3.5, methyl (S)-2-((tert-butoxycarbonyl)amino)-2-(4-((fluorosulfonyl)oxy)phenyl)acetate, 3.9, and methyl (S)-2-((tert-butoxycarbonyl)phenyl)propanoate, 3.35, in 85%, 89%, and 63.7% yield, respectively. Our study explored the synthetic pathway of a three-step procedure toward the target compounds, with the initial esterification of the carboxylic acid group, followed by the N-Boc protection of the amine group. Finally, the key sulfonation of the N-Boc protected amino methyl ester, where for 3.5 and 3.9, was performed through ex-situ generation of sulfuryl fluoride, which was installed following the substitution of the hydrogen on the hydroxyl group by SO2F. For 3.35, it was achieved through a palladium-catalyzed system and an in-situ fluorine introduction, where para iodine was substituted by the SO2 generated from DABSO. Under physiological conditions, compound 3.5 was assessed for possible interaction through its electrophilic warhead, with nucleophilic N-Boc-lysine side chain. The LCMS and NMR buffered assays were conducted, and in both these studies, the characteristics of a possible binding happening can be observed, hence an adduct N2-(tert-butoxycarbonyl)-N6-((4-((S)-2-((tert-butoxycarbonyl)amino)-3-methoxy-3-oxopropyl)phenoxy)sulfonyl)-L-lysine 3.5a formation.
dc.identifier.doihttps://doi.org/10.29086/10413/22604
dc.identifier.urihttps://hdl.handle.net/10413/22604
dc.language.isoen
dc.subject.otherAmino acids.
dc.subject.otherCovalent inhibitors.
dc.subject.otherSulfonyl fluorides.
dc.titleSynthesis of non-natural amino acids as covalent inhibitors for protein-protein interactions.
dc.typeThesis
local.sdgSDG3

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