Chapter 18, Problem 18.39P

(a)

Interpretation Introduction

Interpretation:

Possible mechanism for the given reaction has to be proposed.

Concept Introduction:

Reaction of an ester with ammonia or an amine:

Treatment of an ester with ammonia or a primary or secondary amine gives an amide.

The nucleophilic addition of the ammonia or amine to the carbonyl carbon occurs followed by a proton transfer and a tetrahedral addition intermediate is formed. The intermediate can directly alkoxide and lose a proton to the alkoxide to give products.

(b)

Interpretation Introduction

Interpretation:

More acidic has to be identified in the given barbital molecule and the acidity of this molecule has to be accounted.

Concept Introduction:

${\text{PK}}_{\text{a}}$Value: The ${\text{pK}}_{\text{a}}$ value computes the acidity of an acid. This value depends upon the chemical property and identity of the compound.

            ${\text{pK}}_{\text{a}}$${\text{= - log K}}_{\text{a}}$

Where,

${\text{K}}_{\text{a}}$ is the measure of strength of an acid. If the acid is strong means ${\text{K}}_{\text{a}}$ on the order of ${\text{10}}^{\text{10}}$ and weak means ${\text{K}}_{\text{a}}$ on the order of ${\text{10}}^{-50}.$ Strong acid means ${\text{pK}}_{\text{a}}$ value is low value and Weak acid means ${\text{pK}}_{\text{a}}$ value is high.

If we know which proton is the more acidic and which proton is the less acidic we can make the determination regarding basicity.