Alkaline Degradation of 1,5-Anhydro-4-0-β-D-Glucopyranosyl-2,3,4-Tri-O-Methyl-D-Glucitol

Abstract The title compound (2) was degraded at 150-180°C in oxygen-free 0.5-2.5M aqueous NaOH. Degradation occurred by cleavage of both the glycosyl-oxygen bond (80-95%) and the oxygen-aglycon bond (5-20%). Cleavage of the glycosyl-oxygen bond yielded 1, 5-anhydro-2, 3, 6-tri-O-methyl-D-glucitol (5) from the aglycon. The reactive intermediate, 1, 6-anhydro-β-D-glucopyranose, was formed from the glycosyl moiety in amounts (50-88%) dependent upon the reaction conditions. Cleavage of the oxygen-aglycon bond resulted in unidentified products, probably acidic and fragmentary in nature and quantified as a mass deficit. Data for cleavage of the glycosyl-oxygen bond is consistent with an SNicB(21) mechanism while that for oxygen-aglycon bond cleavage is consistent with an SN1 mechanism.