Synthesis of non-natural amino acids as covalent inhibitors for protein-protein interactions.
| dc.contributor.advisor | Sithebe, Siphamandla. | |
| dc.contributor.advisor | Veale, Clinton Gareth Lancaster. | |
| dc.contributor.author | Dladla, Siphamandla Austen. | |
| dc.date.accessioned | 2024-01-18T07:49:08Z | |
| dc.date.available | 2024-01-18T07:49:08Z | |
| dc.date.created | 2023 | |
| dc.date.issued | 2023 | |
| dc.description | Masters Degree. University of KwaZulu-Natal, Pietermaritzburg. | |
| dc.description.abstract | There 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.doi | https://doi.org/10.29086/10413/22604 | |
| dc.identifier.uri | https://hdl.handle.net/10413/22604 | |
| dc.language.iso | en | |
| dc.subject.other | Amino acids. | |
| dc.subject.other | Covalent inhibitors. | |
| dc.subject.other | Sulfonyl fluorides. | |
| dc.title | Synthesis of non-natural amino acids as covalent inhibitors for protein-protein interactions. | |
| dc.type | Thesis |