The Synthesis of Carbohydrate Derivates of Importance in Biosynthesis

摘要

The objective of the work was the chemical synthesis of nucleoside diphosphate aldulose derivatives, specifically uridine diphosphate D-xylo-'4-hexosulose and its '6-deoxyanalogue, and a study of their properties. A six-stage synthesis, starting from D-galactosyl (or 6-deoxy-D-galactosyl) phosphate, has been devised and several key steps have been tested using methyl glycosides as model compounds. Thus, the oxidation of a single hydroxyl group at C-4 in a partially benzoylated pyranose derivative has been accomplished and the resulting ketone has been protected as the ethylene-dithio-ketal derivative, which was successfully desterified. Attempts to remove the ethylenedithioketal protecting group have been unsuccessful. The selective benzoylation of an aldopyranosyl phosphate has been investigated using alapha-D-glucosyl phosphate as model compounds. Attempts to fractionate and characterise the products have been unsuccessful, partly because of decomposition of the benzoyl phosphate function. Attempts to modify the benzoyl phosphate function by selective hydrolysis followed by benzylation with phenyldiazomethane, are so far incomplete. (Author)