An Investigation into the Synthesis of 5,7-diamino-3,5,7,9-tetradeoxy-nonulosonic acid analogues

Abstract

This thesis describes the results of a research program aimed at investigating synthetic methodology towards obtaining novel 5,7-diamino-3,5,7,9-tetradeoxy-nonulosonic acid analogues. Syntheses outlined in this thesis comprise varied approaches which include a chemoenzymatic approach and two chemical approaches from differing starting materials. Pseudaminic acid and legionaminic acid are 5,7-diamino-3,5,7,9-tetradeoxy-nonulosonic acids that play an essential role in the pathogenic capabilities of numerous clinically relevant Gram-negative bacteria. Over the past twenty-five years several structural and functional group derivatives of these carbohydrates have been isolated from many bacterial species, highlighting the fact that these compounds are widespread throughout nature. However, to date their exact biological significance is yet to be clearly determined and the limited syntheses described within the literature are for the parent compounds only, not structural analogues. Therefore, the primary aim of this research program was to fill a void in the literature in regard to creating a versatile and efficient synthesis of pseudaminic acid and legionaminic acid analogues.