Chapter 18, Problem 18.53P

Interpretation Introduction

Interpretation:

The synthesis reaction of an amidine from benzonitrile by using more than one synthetic step is to be shown.

Concept introduction:

Benzonitrile is reduced to benzylamine when treated with lithium aluminum hydride. The nucleophilic hydrogen from the hydride adds to the electrophilic carbon in the cyanide group and forms a secondary amine. Rapid reduction by nucleophilic hydrogen from the hydride adds to the carbon. The $\Pi$ electron from the $\text{C=N}$ move to the cationic nitrogen, creating the amine product. In the next step, the amine acts as a nucleophile and attacks the $\text{C}\equiv \text{N}$ triple bond, followed by the protonation using alcohol. The ethanol is a source of proton in the proton transfer reaction.