Phosphorylated sugars. Part XII. An unexpected phosphate-group migration during the attempted preparation of 2-deoxy-d-erythro-pentose 5-(dihydrogen phosphate) from glucometasaccharinic acid 6-phosphate

The phosphorylated 2-deoxy-D-erythro-pentose previously obtained by Ruff degradation of glucometasaccharinic acid 6-phosphate is shown to be a 4 : 1 mixture of the 4- and 5-phosphates of the deoxy-pentose; the 3-phosphate is absent. Methods are described for the electrophoretic separation of the phosphate esters fromed when 2-deoxy-D-erythro-pentose 3-, 4-, and 5-phosphates are successively treated with periodate and borohydride. By protracted oxidation of glucometasaccharinic acid 5-phosphate with periodate 2-deoxy-D-erythro-pentose 4-phosphate was obtained. In the standard conditions of Dische's diphenylamine test this ester, in contrast to the 5-phosphate, yields only 60% of the colour given by the free deoxy-pentose.