Constitution of Ascorbic Acid

WE have now confirmed the accuracy of the structure (I) cooH.co.co.CHOH.CHOH.CH2OH which we had previously assigned to the first (reversible) oxidation product of ascorbic acid on the ground that it yields oxalic acid and trihydroxybutyric acid (l–threonic acid) on further oxidation1. The above formulation represents an open chain acid, but it is now evident that at the moment of formation the substance behaves as a lactone of (I) and not as the free acid. We have already advanced a constitutional formula for ascorbic acid (represented by (II) and its tautomerides) which shows the relationship between (I) and (II) to be as follows :2