Glucose reacts with methy1 alcohol to give:

Options

A. 2,3,4,5,6-penta-O-methyl- D-glucose
B. `alpha` - Methyl D-glucophyraonside
C. `beta`-methyl D-glucopyranoside
D. Both (2) and (3)

Answer

D

Explanation

When a small amount of gaseous hydrogen chloride is passed into a solution `D - (+) -` glucose in methanol, a reaction take place that results in the formation of anomeric methyl accetals.

Generally, carbohydrate accetals are called glycosides and an acetals of glucose is called a glucoside. (Acetals or mannose on). The methyl D- glucosides have been found to possess glucopyranoside and methyl `beta - D`- glucopyranoside.
Glycosides are stable in basic solutions because they are acetals. Again, because they are acetals, glycosides undergo hydrolysis (in acidic solutions) to produce a sugar and an alcohol. The alcohol obtained by hydrolysis of a glycoside is konwn as an aglycone.
For example, when can aqueous solution of methyl `beta-D-` glucopyransodie is made acidic, the glycoside undergoes hydrolysis to produce D-glucose as a mixture of two pyranose forms (in equilibrium with a small amount of the open chain form).