As shown in the following scheme (taken from J. Org. Chem. 1996, 61, 5208-5209), glucopyranose (15) was protected by acetic anhydride to form the triacetyl compound (16). Treatment of (16) with BnNH2 (Benzylamine), followed by hydrolysis with dilute aqueous acid furnished the pyranose (17).
As you can see, there was a selective hydrolysis which only removed the C-1 O-acetyl (at the anomeric position) while the two other O-acetyl groups were not affected. The author indicates that the reaction with benzylamine forms "amino glycoside", but I can't understand how and why. My question is: What is the mechanism of this deprotection - is it just a simple "addition-elimination" process, and if so - why does benzylamine react regioselectively with the C-1 O-acetyl group, and how does the "amino glycoside" look like? Also, what is the role of the hydrolysis with HCl(aq) in terms of mechanism?
Thank you very much in advance!