アスコルビン酸誘導体の製剤学的研究(第1報) : アスコルビン酸エステル類の合成およびその理化学的性質について

抄録

Synthefic reactions of ester derivatives of ascorbic acid were investigated in various ways. Thirty two compounds were prepared and their physicochemical properties determined. 1) In general, the 6-monoester and 5, 6-diester of ascorbic acid were obtained by esteri-fication of ascorbic acid in acidic medium and the 2, 6-di-, 2, 5, 6-tri-, and 2, 3, 5, 6-tetra-esters were obtained by esterification of ascorbic acid or its ester derivatives in basic medium. 2) The results obtained by using the deuteration method indicated that the OH streching absorption band of the 3-OH in ascorbic acid and its derivatives occurred near 3000 cm^-1. 3) The UV absorption maxima of the neutral molecule and anion of ascorbic acid, which appear respectively at 243 mμ and 265 mμ, decreased similarly by about 10 mμ by esterification of the 2-OH, but were scarcely affected by that of 5-OH and 6-OH. 4) The pKa' value of ascorbic acid was exceedingly decreased by esterification of the 2-OH and slightly by that of the 5-OH and 6-OH. This effect was slightly different according to the acyl group of the esters.