Ascorbic acid-2-sulfate of the brine shrimp, Artemia salina

Methods are described for the preparation of ascorbic acid-2-sulfate and for its isolation in very pure form in yields of approximately 50%. Our procedure was similar to those used by others for the synthesis of ascorbic acid-3-sulfate. A comparison of our material with ascorbic acid-3-sulfate from another laboratory demonstrated that the two were indistinguishable. Chemical and physical characteristics of this ascorbate derivative suggested to us that it was a 2-sulfate rather than the 3-sulfate previously reported and X-ray crystallographic studies of the barium salts have now demonstrated that this compound is 2- O-sulfonatoascorbic acid. Comparison of the synthetic compound with that found in brine shrimp showed them to be identical. It can be concluded, therefore, that 2- O-sulfonato- l-ascorbic acid is the naturally occurring derivative.