Abstract
In the previous paper, it was investigated the influence of water content on the change of vitamin A in aqueous ethanolic solution. In this paper, the authors report the similar studies on the stability of anhydrovitamin A, an intermediate product of vitamin A acetate, in aqueous ethanolic solution. Anhydrovitamin A was determined by spectrometric method and Carr・Price reaction. The amount of changed products of anhydrovitamin A were examined by alumina column chromatography and thin layer chromatography. The stability of anhydrovitamin A in 45-100% ethanolic solution decreased gradually as water increased. The values of remaining anhydrovitamin A by both methods were almost equal, therfore it is supposed that the Carr・Price reaction-positive intermediate is not formed. Two substances were recognized as changed products of anhydrovitamin A, the one, having maximum absorbances at 325 and 340mμ, is eluted prior to anhydrovitamin A, and the other, having maximum absorbance at 283mμ, is eluted last in column chromatogram. Retrovitamin A and unknown substances I, II which are reported previously as the changed products of vitamin A acetate were not recognized. The reversible reaction of anhydrovitmin A to vitamin A alcohol or its acetate was not observed.
