Structure Determination of Sucrose by Acetylation and Acid Hydrolysis

Abstract

For the structure determination of D-(+)-sucrose, which consists of <TEX>${\alpha}$</TEX>-D-(+)-glucose and <TEX>${\beta}$</TEX>-D-(+)-fructose, it was acetylated with acetic anhydride and triethyl amine, pyridine, zinc chloride, and sodium acetate as catalysts. The acetylated D-(+)-sucrose was acid-hydrolyzed using sulfuric acid and sodium chloride in methanolic solution. The structures of the reaction products were determined by <TEX>$^1H$</TEX>-NMR and <TEX>$^{13}C$</TEX>-NMR spectra. The yield of the acetylation indicated the high value in zinc chloride as 70% in zinc chloride catalyst. The acid-hydrolyzed product of the acetylated D-(+)-sucrose, 2,3,4,6,1',3',4',6'-octa-O-acetyl-D-(+)-sucrose, gave 2,3,4,6-tetra-O-acetyl-<TEX>${\beta}$</TEX>-D-(+)-glucose and it suggests that the acetylated D-(+)-sucrose was rearranged through the formation of oxonium ion by mutarotation in the 2,3,4,6-tetra-O-acetyl-<TEX>${\alpha}$</TEX>-D-(+)-glucose moiety and through the ring opening in the 1',3',4',6'-tetra-O-acetyl-<TEX>${\beta}$</TEX>-D-(+)-fructose moiety.