Synthetic galactose-1-phosphoric acid

Abstract

Ba galactose-1-phosphate was synthesized by the action of Ag phosphate on acetobromogalactose in dry benzene, hydrolysis of tri-(tetraacetyl galactose)-l-phosphate in methyl alcohol containing 4% of aqueous 5 N HC1 for 8 hrs. at 25[degree] and neutralization of the acid with Ba(OH)2. The crude Ba salt could not be completely purified by the repeated precipitation of its aq. soln. with ethyl ale. Repeated recrystallization of the dibrucine salt from 40-85% methyl ale. effected a considerable purification. Crystallization as the di-potassium salt, either starting with the crude Ba salt or better with the dibrucine salt, yielded the pure product. The anhydrous K2 salt has [[alpha]][image] +108.2[degree], the free acid +148.5[degree], and the anhydrous Ba salt prepared from the K2 salt+ 92.7[degree]. The ester is non-reducing. It is completely hydrolysed by 0.09 N H2SO4 at 100[degree] in 2 min. The k of hydrolysis in 0.25 N HC1 is 0.89 X 10-3 at 25[degree] and 5.9 X 10-3 at 37[degree]. The ester is completely resistant to hydrolysis in 0.2 N NaOH at 100[degree] for 30 min. The method of prep, and its specific rotation strongly suggest that it is [alpha]-galactopyranose-l-phosphoric acid.