28. Carbohydrates

Propose a mechanism for methylation of any one of the hydroxy groups of methyl α-D-glucopyranoside, using NaOH and dimethyl sulfate.

Predict the products obtained when d-galactose reacts with each reagent.

(g) excess CH₃I, Ag₂O

Draw the expected product of the reaction of the following sugars with excess methyl iodide and silver oxide.

(a) α-D-fructofuranose

Draw the expected product of the reaction of the following sugars with excess methyl iodide and silver oxide.

(b) β-D-galactopyranose

What product or products are obtained when d-galactose reacts with each of the following?

d. excess CH₃I + Ag₂O

Predict the product of the following etherification reactions.

(a)

Predict the product of the following etherification reactions.

(b)

Show the product that results when fructose is treated with an excess of methyl iodide and silver oxide.

Show what happens when the product of part (a) is hydrolyzed using dilute acid.

What do the results of parts (a) and (b) imply about the hemiacetal structure of fructose?