Question

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

You may use any necessary reagents.

$\mathbf{\left(}\mathbf{b}\mathbf{\right)}\mathbf{pyrrolidine}\to \mathbf{N}\mathbf{-}\mathbf{ethylpyrrolidine}$

Short answer

Syntheses of N-ethylpyrrolidine from pyrrolidine and amide as intermediate as given below,

Step-by-step solution

Step-by-Step SolutionStep 1: Use of acetyl chloride

Acetic anhydride would work as well as acetyl chloride, a base such as pyridine or sodium bicarbonate or triethylamine is usually added to consume the HCl.

Synthesis of N-acetylpyrrolidine from pyrrolidine

When pyrrolidine react with acetyl chloride then there is a formation of N-acetylpyrrolidine as a final product.

In this reaction in the first step base is used to abstract the acidic proton from nitrogen atom and formation of negative charge on the nitrogen atom, the negative charge on the nitrogen atom attack the carbonyl carbon of acetyl chloride and there is formation of N-acetylpyrrolidine and hydrochloric acids as a by product.

Use of LiAIH4reagent

${\mathbf{LiAIH}}_4$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 N-ethylpyrrolidine from N-acetylpyrrolidine i.e. amide as intermediate

When N-acetylpyrrolidine(amide) react with strong reducing agent i.e.${\mathbf{LiAIH}}_4{\mathbf{andH}}_2\mathbf{O}$ then there is a formation N-ethylpyrrolidine .

Synthesis of N-ethylpyrrolidine