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Novel Approaches Toward the Synthesis of Pseudaminic Acid

Fields, Alexander Matthew (2019) Novel Approaches Toward the Synthesis of Pseudaminic Acid. PhD thesis, University of Sheffield.

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Abstract

Pseudaminic acid is a carbohydrate glycoside which is found on post-translationally glycosylated bacterial flagella. Disturbance of the biosynthetic pathway for this sugar nullifies the pathogenicity of the bacteria A. caviae, H. pylori & C. jejuni. In order to explore this possibility, attempts were made to develop a novel synthetic route. Parallel to efforts to synthesis the side chain of pseudaminic acid, L-allo-threonine, N-chiral imines derived from cheap and readily available (2S)-ethyl lactate were prepared and subjected to Lewis acid-mediated trimethylsilylcyanide additions as part of new methodology for robust and facile asymmetric Strecker reactions. 2,3-anti¬-β-Hydroxy-α-aminonitriles were prepared in excellent yield (77%, 4 steps) and good diastereoselectivity (90 : 10). L-allo-threonine was accessed and further functionalised to Garner-like cyclic aldehydes which were used as substrates for a doubly diastereoselective nitroaldol reaction to construct the carbon chain of pseudaminic acid. These reactions proceeded with mild selectivity and conversion. Models for the addition to both Garner aldehydes and N-chiral imines were discussed in detail.

Item Type: Thesis (PhD)
Academic Units: The University of Sheffield > Faculty of Science (Sheffield) > Chemistry (Sheffield)
Depositing User: Mr AM Fields
Date Deposited: 28 May 2019 09:14
Last Modified: 28 May 2019 09:14
URI: http://etheses.whiterose.ac.uk/id/eprint/24051

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