Chapter 3, Problem 3.33P

Identify each functional group located in the following rings. Which structure

represents a lactone-a cyclic ester- and which represents a lactam-a cyclic amide?

a. b. c. d.

Interpretation Introduction

(a)

Interpretation: The functional group present in the given ring and the structure that represent a lactone and a lactam is to be stated.

Concept introduction: The table representing the general formula of different functional groups according to IUPAC convention is given below.

General formula	Functional group	Functional group name
$\text{R}-\text{OH}$	$-\text{OH}$	Alcohol
$\text{R}-\text{CHO}$	$-\text{CHO}$	Aldehyde
$\text{R}-\text{CO}-\text{R}$	$-\text{CO}-$	Ketone
$\text{R}-{\text{NH}}_2$	$-{\text{NH}}_2$	Amine
$\text{R}-\text{O}-\text{R}$	$-\text{O}-$	Ether
$\text{R}-\text{COO}-{\text{R}}^1$	$-\text{COO}-{\text{R}}^1$	Ester

Answer to Problem 3.33P

The functional group present in the given ring is amine. The given structure neither represents a lactone nor a lactam.

Explanation of Solution

The given structure is,

Figure 1

The given structure contains amine as a functional group. In the given structure, nitrogen is bonded to three carbon atoms. Therefore, the given ring is a tertiary amine.

Lactone is a cyclic ester, whereas lactam is a cyclic amide. Thus, the given structure neither represents a lactone nor a lactam.

Conclusion

The functional group present in the given ring is amine. The given structure neither represents a lactone nor a lactam.

Interpretation Introduction

(b)

Interpretation: The functional group present in the given ring and the structure that represent a lactone-cyclic ester and a lactam-a cyclic amide is to be stated.

Concept introduction: The table representing the general formula of different functional groups according to IUPAC convention is given below.

General formula	Functional group	Functional group name
$\text{R}-\text{OH}$	$-\text{OH}$	Alcohol
$\text{R}-\text{CHO}$	$-\text{CHO}$	Aldehyde
$\text{R}-\text{CO}-\text{R}$	$-\text{CO}-$	Ketone
$\text{R}-{\text{NH}}_2$	$-{\text{NH}}_2$	Amine
$\text{R}-\text{O}-\text{R}$	$-\text{O}-$	Ether
$\text{R}-\text{COO}-{\text{R}}^1$	$-\text{COO}-{\text{R}}^1$	Ester

Answer to Problem 3.33P

The functional group present in the given ring is ether. The given structure neither represents a lactone nor a lactam.

Explanation of Solution

The given structure is,

Figure 2

The given structure contains ether as a functional group. The given functional group is in cyclic form. Therefore, the given structure is cyclic ether. Lactone is a cyclic ester, whereas lactam is a cyclic amide. Thus, the given structure neither represents a lactone nor a lactam.

Conclusion

The functional group present in the given ring is ether. The given structure neither represents a lactone nor a lactam.

Interpretation Introduction

(c)

Interpretation: The functional group present in the given ring and the structure that represent a lactone-cyclic ester and a lactam-a cyclic amide is to be stated.

Concept introduction: The table representing the general formula of different functional groups according to IUPAC convention is given below.

General formula	Functional group	Functional group name
$\text{R}-\text{OH}$	$-\text{OH}$	Alcohol
$\text{R}-\text{CHO}$	$-\text{CHO}$	Aldehyde
$\text{R}-\text{CO}-\text{R}$	$-\text{CO}-$	Ketone
$\text{R}-{\text{NH}}_2$	$-{\text{NH}}_2$	Amine
$\text{R}-\text{O}-\text{R}$	$-\text{O}-$	Ether
$\text{R}-\text{COO}-{\text{R}}^1$	$-\text{COO}-{\text{R}}^1$	Ester

Answer to Problem 3.33P

The functional group present in the given ring is ester. The given structure represents a lactone-cyclic ester.

Explanation of Solution

The given structure is,

Figure 3

In the given structure, the functional group present is ester. The given functional group is in cyclic form. Therefore, the given structure represents a lactone-cyclic ester.

Conclusion

The functional group present in the given ring is ester. The given structure represents a lactone-cyclic ester.

Interpretation Introduction

(d)

Interpretation: The functional group present in the given ring and the structure that represent a lactone-cyclic ester and a lactam-a cyclic amide is to be stated.

Concept introduction: The table representing the general formula of different functional groups according to IUPAC convention is given below.

General formula	Functional group	Functional group name
$\text{R}-\text{OH}$	$-\text{OH}$	Alcohol
$\text{R}-\text{CHO}$	$-\text{CHO}$	Aldehyde
$\text{R}-\text{CO}-\text{R}$	$-\text{CO}-$	Ketone
$\text{R}-{\text{NH}}_2$	$-{\text{NH}}_2$	Amine
$\text{R}-\text{O}-\text{R}$	$-\text{O}-$	Ether
$\text{R}-\text{COO}-{\text{R}}^1$	$-\text{COO}-{\text{R}}^1$	Ester

Answer to Problem 3.33P

The functional group present in the given ring is amide. The given structure represents a lactam-a cyclic amide.

Explanation of Solution

The given structure is,

Figure 4

In the given structure, the functional group present is amide. The given functional group is in cyclic form. Therefore, the given structure represents a lactam-a cyclic amide.

Conclusion

The functional group present in the given ring is amide. The given structure represents a lactam-a cyclic amide.