Abstract
Periodate oxidation of 3-ketoglucuronic acid indicated the presence of hemiacetal ring structure and in consequence the uronic acid was assigned as 3-keto-D-glucopy-ranuronic acid (III), which on treatment with cation resin in methanol gave methyl furanoside (V). Enolization of 3-ketoglucuronic acid between C-2 and C-3 was confirmed by conversion of the Keto-acid into the corresponding enol ether, namely methyl 3-O-methyl-D-glucopyranoenediol-(2, 3)-uronate (VIII). Equilibrium between keto-and enol from of this keto-sugar in an aqueous solution was, however, found to be inclined predominantly to the keto-form (III) by means of polarography.
