Chapter 6, Problem 6.138EP

(a)

Interpretation Introduction

Interpretation:

Structure of missing substance in the given reaction that involves amides has to be drawn.

Concept Introduction:

Amides are synthesized using amidification reaction.  This involves a reaction between amine and carboxylic acid.  In this reaction, the $-\text{OH}$ group present in carboxylic acid and $-\text{H}$ from ammonia or amine is lost to give amide as the product.  Water is obtained as a by-product in this reaction.  The general reaction scheme for synthesis of amides can be given as,

$\begin{array}{l}\text{Ammonia}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{1°}\text{amide}\\ \text{1°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{2°}\text{amide}\\ \text{2°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{3°}\text{amide}\end{array}$

Answer to Problem 6.138EP

Structure of the missing substance is,

Explanation of Solution

Given reaction is,

The starting material is a carboxylic acid and a primary amine.  The product obtained on amidification reaction between carboxylic acid and a primary amine is a secondary amide.  This is formed by the loss of water molecule.  The structure of the secondary amide that is formed can be given as,

The complete reaction can be given as,

Conclusion

Structure of the missing compound is drawn.

(b)

Interpretation Introduction

Interpretation:

Structure of missing substance in the given reaction that involves amides has to be drawn.

Concept Introduction:

Amides are synthesized using amidification reaction.  This involves a reaction between amine and carboxylic acid.  In this reaction, the $-\text{OH}$ group present in carboxylic acid and $-\text{H}$ from ammonia or amine is lost to give amide as the product.  Water is obtained as a by-product in this reaction.  The general reaction scheme for synthesis of amides can be given as,

$\begin{array}{l}\text{Ammonia}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{1°}\text{amide}\\ \text{1°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{2°}\text{amide}\\ \text{2°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{3°}\text{amide}\end{array}$

Answer to Problem 6.138EP

Structure of the missing substance is,

Explanation of Solution

Given reaction is,

As the nitrogen atom present in the above amide has two hydrogen atoms bonded to it and the amide is a primary amide.  Primary amide is produced by the reaction of ammonia with carboxylic acid.  The structure of carboxylic acid can be found as shown below,

Hydrogen atom has to be added to the amine part and $-\text{OH}$ group has to be added to the acid part in order to obtain the parent molecules.  From this the missing compound is identified as,

The complete reaction can be given as,

Conclusion

Structure of the missing compound is drawn.

(c)

Interpretation Introduction

Interpretation:

Structure of missing substance in the given reaction that involves amides has to be drawn.

Concept Introduction:

Amides are synthesized using amidification reaction.  This involves a reaction between amine and carboxylic acid.  In this reaction, the $-\text{OH}$ group present in carboxylic acid and $-\text{H}$ from ammonia or amine is lost to give amide as the product.  Water is obtained as a by-product in this reaction.  The general reaction scheme for synthesis of amides can be given as,

$\begin{array}{l}\text{Ammonia}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{1°}\text{amide}\\ \text{1°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{2°}\text{amide}\\ \text{2°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{3°}\text{amide}\end{array}$

Answer to Problem 6.138EP

Structure of the missing substance is,

Explanation of Solution

Given reaction is,

As the nitrogen atom present in the above amide has no hydrogen atoms bonded to it, the amide is a tertiary amide.  Tertiary amide is produced by the reaction of secondary amine with carboxylic acid.  The parent compound structures can be identified as shown below,

Hydrogen atom has to be added to the amine part and $-\text{OH}$ group has to be added to the acid part in order to obtain the parent molecules.  From this the missing compound is identified as,

The complete reaction can be given as,

Conclusion

Structure of the missing compound is drawn.

(d)

Interpretation Introduction

Interpretation:

Structure of missing substance in the given reaction that involves amides has to be drawn.

Concept Introduction:

Amides are synthesized using amidification reaction.  This involves a reaction between amine and carboxylic acid.  In this reaction, the $-\text{OH}$ group present in carboxylic acid and $-\text{H}$ from ammonia or amine is lost to give amide as the product.  Water is obtained as a by-product in this reaction.  The general reaction scheme for synthesis of amides can be given as,

$\begin{array}{l}\text{Ammonia}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{1°}\text{amide}\\ \text{1°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{2°}\text{amide}\\ \text{2°}\text{amine}\text{+}\text{Carboxylic acid}\stackrel{\text{100 }°\text{C}}{\to }\text{3°}\text{amide}\end{array}$

Answer to Problem 6.138EP

Structure of the missing substance is,

Explanation of Solution

Given reaction is,

As the nitrogen atom present in the above amide has one hydrogen atom bonded to it and the amide is a secondary amide.  Secondary amide is produced by the reaction of primary amine with carboxylic acid.  The structure of carboxylic acid is given and the structure of primary amine has to be found out.

Hydrogen atom has to be added to the amine part and $-\text{OH}$ group has to be added to the acid part in order to obtain the parent molecules.  From this the missing compound is identified as,

The complete reaction can be given as,

Conclusion

Structure of the missing compound is drawn.