What is the role of pyridine in the acylation

The activating effect of –NH2 group can be controlled by protecting the -NH2 group by acetylation with acetic anhydride in presence of pyridine and then carrying out the

desired substitution followed by hydrolysis of the substituted amide to the substituted amine. Pyridine is a base that is used to get rid of HCl as a side product from the

reaction.