Studies on L-Ascorbic Acid Derivatives. II. L-Ascorbic Acid 3-Phosphate and 3-Pyrophosphate

Abstract

Phosphorylation of 5, 6-isopropylidene-L-ascorbic acid with phosphorus oxychloride gave mainly a mixture of four phosphates. Column chromatography on Dowex-1-bicarbonate with a solution of sodium bicarbonate as a developer was found suitable for the separation of these phosphates for the preparative purpose. Consequently, L-ascorbic acid 3-phosphate and 3-pyrophosphate were isolated as the magnesium salts. Treatment of the former with diazomethane, followed by successive amidation and ozonization gave methyl oxamate, and this provided evidence that the starting ester was the 3-phosphate. The latter ester, on treatment with acid or alkali, afforded quantitatively the same product, i.e., L-ascorbic acid 3-phosphate. These facts, together with the elemental analysis and potentiometric analysis, determined the structure of the latter to be L-ascorbic acid 3-pyrophosphate.