Chapter 18, Problem 18.54P

Interpretation Introduction

Interpretation:

The mechanism for the given reaction is to be proposed.

Concept introduction:

In the nucleophilic addition reaction of nitriles, lone pair on the cyanide group acts as a nucleophile and abstracts the proton from ammonia under weak acidic condition. Next step is nucleophilic addition of ammonia group on the electrophilic carbon atom. Under the acidic condition, the electrohile becomes stronger. The protonated group acquires the partial positive charge on its electrophilic carbon atom. After all cyano groups get protonated, the cyclic intramolecular interaction between lone pair of ${\text{NH}}_{\text{2}}$ and the electrophilic carbons takes place and forms a cyclic imidine as a product.