Question

Show how you would accomplish the following syntheses using amides as intermediates.

You may use any necessary reagents.

$\mathbf{\left(}\mathbf{a}\mathbf{\right)}\mathbf{benzoicacid}\to \mathbf{benzyldimethylamine}$

Short answer

Syntheses of benzyldimethylamine from benzoic acid and amide as intermediate as given below,

Step-by-step solution

Step-by-Step SolutionStep 1: Reaction of benzoic acid with thionyl chloride (SOCI2)

The benzoic acid reacts with thionyl chloride$\left({\text{SOCl}}_{\text{2}}\right)$ to give the benzoyl chloride as a first product in above reaction.

Formation of amide intermediate

When benzoyl chloride are react with dimethyl amine then there is a formation of amide.

Use of LiAIH4 reagent

${\mathbf{LiAIH}}_4$is a strong reducing agent for polar double bonds, as it easily thought of as a source of ${\text{H}}^{-}$. It will reduce aldehydes, ketones,esters, carboxylic acid chloride, carboxylic acids and even carboxylate salts to alcohols.

${\mathbf{LiAIH}}_4$is also reduce the amide and nitriles to amine, In above reaction amide is reduce to amine.

Synthesis of benzyldimethylamine from amide as intermediate.

When N-dimethyl benzamide react with strong reducing reagent${\mathbf{LiAIH}}_4{\mathbf{andH}}_2\mathbf{O}$ then there is a formation of benzyldimethylamine.

Synthesis of benzyldimethylamine