Phosphorylated sugars. Part 24. Methyl 3-deoxy-α-D-manno-oct-2-ulopyranosidonic acid 4-(dihydrogen phosphate): synthesis, stability in acidic medium, and colorimetric estimation

Abstract

The synthesis of the title compound was accomplished in three steps starting from methyl (methyl 5-O-benzyl-3-deoxy-α-D-manno-oct-2-ulopyranosid)onate. When treated at 100 °C with acetate buffer of pH 4.5, the phosphorylated aldulosonic acid released inorganic phosphate more rapidly than upon exposure, at the same temperature, to 0.25M-HCl. The semicarbazide and thiobarbiturate assays could not be used to determine the amount of 3-deoxyoct-2-ulosonic acid present in the complex mixture of products formed in the latter conditions, despite an apparently univocal response in the former.