1. General, Organic, and Biological Chemistry
Fourth Edition
Karen Timberlake
Chapter 18
Amines and Amides
18.1
Amines
Lectures
© 2013 Pearson Education, Inc.

2. Amines Amines are derivatives of ammonia (NH3).
In the IUPAC name for amines, the e in the corresponding alkane name is replaced with amine.
When the amine has a chain of three or more carbon atoms, it is numbered to show the position of the –NH2 group and any other substituents. 2 2

3. Guide to IUPAC Naming of Amines3 3

4. Naming the Longest Carbon Chain
Name the longest carbon chain bonded to the N atom by replacing the e of its alkane name with amine.
Here, the longest carbon chain bonded to the N atom has four carbon atoms, which is named by replacing the e in the alkane name with amine to give butanamine. 4 4

5. Numbering the Carbon Chain
The N atom in the amine group is attached to carbon 1 of butanamine. 5 5

6. Alkyl Groups Attached to the N Atom
Any alkyl group attached to the N atom is indicated by the prefix N- and the alkyl name, which is placed in front of the amine name.
Alkyl groups attached to the N atom are listed alphabetically.
The IUPAC name is N-methyl-1-butanamine. 6 6

7. Naming Common Amines
Common amines are named with common names as alkylamines.
List the names of the alkyl groups bonded to the N atom in alphabetical order in front of amine.
Ethylamine
Dimethylamine
Ethyldimethylamine 7 7

8. Learning Check
Give the common and IUPAC names, and classify each as primary,
secondary, or tertiary. 8 8

9. Solution A. STEP 1 Name the longest carbon chain bonded to the N
STEP 1 atoms as alkanamines by replacing e of the
STEP 1 alkane name with amine.
STEP 2 Number the carbon chain to show the position of
STEP 2 the amine group and any substituents.
Propanamine
CH3—CH2 —CH2—NH2
Propylamine (common), 1°
1-Propanamine (IUPAC) 9 9

10. Solution (continued) B.
STEP 1 Name the longest carbon chain bonded to the N
STEP 1 atoms as alkanamines by replacing e of the
STEP 1 alkane name with amine.
STEP 2 Number the carbon chain to show the position of
STEP 2 the amine group and any substituents.
ethanamine 10 10

11. Solution (continued) B.
STEP 3 In a secondary or tertiary amine, use the prefix
STEP 3 N- to name groups attached to the N atom.
Ethyldimethylamine (common),
N,N-Dimethylethanamine (IUPAC), 3° 11 11

12. Naming Compounds with Two Functional Groups
When a compound contains more than one functional group, we need to identify which group is used as the name of the compound and which group is named as the substituent.
According to the IUPAC rules, an oxygen-containing group will have priority over an —NH2 group.
As a result, the —NH2 group is named as the substituent, amino. 12 12

13. Aromatic Amines The amine of benzene is called aniline.
may have alkyl groups attached to N that use the prefix N- and the alkyl name. 13 13

14. Learning Check
Give the common and IUPAC names for each of the following: A. B. C. 14 14

15. Solution A. B. C. Ethylmethylamine(common); N-methylethanamine
Butylethylmethylamine (common);
N-ethyl-N-methyl-1-butanamine
Aniline C. 15 15

16. Classification of Amines
Amines are classified as primary, secondary, or tertiary.
In a primary (1) amine, one carbon group is bonded to the nitrogen atom.
A secondary (2) amine has two carbon groups.
A tertiary (3) amine has three carbon groups. 16 16

17. Please insert Figure of hydrogen bonds here;
Properties of Amines
Amines contain polar N—H bonds, which allow primary and secondary amines to form hydrogen bonds with water.
Nitrogen is not as electronegative as oxygen, which results in weaker hydrogen bonds as compared to those found in alcohols.
Please insert Figure of hydrogen bonds here;
Pg 646 17 17

18. Solubility in Water
Amines are soluble in water if they have 1 to 6 carbon atoms.
Generally, 1° amines are most soluble while 3° amines are least soluble because the N atom in smaller amines forms hydrogen bonds with the polar O—H bond in water. 18 18

19. Learning Check Consider the following compounds: 1) CH3—CH2—CH2—NH2
2) CH3—CH2—NH—CH3
3) CH3—CH2—CH2—CH3
A. Which compound has the highest boiling point?
B. Which compound(s) is/are soluble in water? 19 19

20. Solution Consider the following compounds: 1) CH3—CH2—CH2—NH2
2) CH3—CH2—NH—CH3
3) CH3—CH2—CH2—CH3
A. Which compound has the highest boiling point?
B. Which compound(s) is/are soluble in water? 20 20

21. Heterocyclic Amines A heterocyclic amine is a cyclic organic compound.
has a five- or six-atom ring.
contains one or more nitrogen atoms. 21 21

22. Heterocyclic Amines in Nature
such as purine and pyrimidine rings are found in DNA and RNA.
like piperidine, are found in black pepper.
with two or three double bonds, have aromatic properties similar to benzene. 22 22

23. Learning Check Identify the following heterocyclic amines: A. B. C. 23

24. Solution Identify the following heterocyclic amines: A. B. C.
Piperidine Pyrrolidine Pyrrole 24 24

25. Alkaloids Alkaloids are
physiologically active nitrogen-containing compounds.
produced by plants.
used as stimulants, anesthetics, and antidepressants.
often habit forming.
Nicotine is an alkaloid. 25 25

26. Caffeine Caffeine is a stimulant of the central nervous system.
is found in coffee beans, tea, chocolate, and soft drinks.
contains an imidazole ring. 26 26

27. Alkaloids Related to Morphine
such as morphine and codeine, are produced by the poppy and have been used for centuries as painkillers.
such as heroin and codeine, are modifications of morphine. 27 27

28. Synthesizing Drugs: Pharmacology
Areas of pharmacology research
design drugs, such as procaine, lidocaine, and Demerol, that retain some of the characteristics of alkaloids.
modify the structures of cocaine and morphine to produce anesthesia, but without the addictive side effects. 28 28

29. Amides
In amides, an amino group(–NH2) replaces the –OH group of carboxylic acids. 29 29

30. Naming Amides: IUPAC
In both the IUPAC and the common names of amides, amides are named by dropping the -ic acid or -oic acid ending of the corresponding carboxylic acid and adding the suffix amide. 30 30

31. IUPAC Names of Amides Write the IUPAC name for
STEP 1 Determine the alkane name of the carbon chain
in the carboxyl portion and replace e with amide.
butanamide
STEP 2 Name each substituent on the N atom using the
prefix N- and the alkyl name.
N-ethylbutanamide 31 31

32. Examples of IUPAC and Common Names
N-Methylethanamide (IUPAC)
N-Methylacetamide (common)
N-Ethylpropanamide (IUPAC)
N-Ethylpropionamide (common)
CH3—C H2—C—N—CH2—CH3 O ║ H — 32 32

33. Learning Check Write the IUPAC name for the following:
CH3—CH2—CH2—CH2—C—N—CH2—CH3 O ║
CH2—CH3 │ 33 33

34. N,N-diethylpentanamide
Solution
STEP 1 Determine the alkane name of the carbon chain
in the carboxyl portion and replace e with amide.
pentanamide
STEP 2 Name each substituent on the N atom using the
prefix N- and the alkyl name.
N,N-diethylpentanamide 34 34

35. Aromatic Amides
The amide of benzene is named benzamide. 35 35

36. Learning Check
Draw the condensed structural formulas of the following amides.
A. pentanamide
B. N-methylbutyramide 36 36

37. Solution
Draw the condensed structural formulas of the following amides.
A. pentanamide
B. N-methylbutyramide 37 37

38. Classification of Amides
Amides are classified according to the number of carbon atoms bonded to the nitrogen atom.
Primary (1)
Secondary (2) amide
Tertiary (3) amide 38 38

39. Learning Check Give the common and IUPAC names for the following
amides, and classify them as primary, secondary, or tertiary. A. B. 39 39

40. Solution Give the common and IUPAC names for the following
amides, and classify them as primary, secondary, or tertiary. A. B.
Butryamide (common)
butanamide (IUPAC)
primary (1)
N-Ethyl-N-methylacetamide (common) (3)
N-ethyl-N-methylethanamide (IUPAC), tertiary 40 40

41. Melting Points of Amides
that are primary and secondary, form hydrogen bonds and have high melting points.
that are tertiary (no H on N), do not form hydrogen bonds and have lower melting points.
Insert table 18.2 here, Pg 657 41 41

42. Solubility of Amides in Water
Primary, secondary, and tertiary amides with 1 to 5 carbon atoms
form hydrogen bonds with
water.
are soluble in water. 42 42

43. Some Amides in Health and Medicine (continued)43 43

44. Neurotransmitters
A neurotransmitter is a chemical compound that transmits an impulse from a nerve cell to a target cell, such as another nerve cell, a muscle cell, or a gland cell. 44

45. Amine Neurotransmitters: Acetylcholine
Neurotransmitters contain N atoms as amines and alkyl ammonium ions.
Acetylcholine (ACh) was the first neurotransmitter to be identified.
Neurotransmitters communicate between the nervous system and the muscle.
When stimulated, it releases into the synapse where it binds to muscle cell receptors causing the muscles to contract.
Please insert acetylcholine to acetate reaction here (Pg 662) 45

46. Dopamine
Dopamine is produced in the nerve cells of the midbrain and acts as a natural stimulant to give us energy and feelings of enjoyment.
Cocaine and amphetamine block the reuptake of dopamine resulting in a longer lifetime in synapse. 46

47. Norepinephrine and Epinephrine
Norepinephrine (noradrenaline) and epinephrine (adrenaline) are hormonal neurotransmitters that play a role in sleep, attention and focus, and alertness.
Epinephrine is synthesized from Norepinephrine.
Both are normally produced in the adrenal glands.
Both are highly produced during the fight-or-flight response. 47

48. Serotonin
Serotonin helps us relax, sleep deeply and peacefully, think rationally, and it provides us a feeling of well-being and calmness.
Serotonin is synthesized from the amino acid tryptophan.
Low serotonin levels may be associated with depression, anxiety disorders, etc.
Prozac and Paxil (antidepressant drugs) are selective serotonin reuptake inhibitors (SSRIs). 48

49. Histamine
Histamine
is synthesized in the nerve cells in the hypothalamus from the amino acid, histidine.
is produced by the immune system in response to pathogens and invaders, or injury.
When histamine combines with histamine receptors, it produces allergic reactions. 49

50. Amino Acid Neurotransmitters
Glutamate
is the most abundant neurotransmitters in the nervous system.
stimulates the synthesis of nitrogen oxide (NO).
Too much glutamate in the spinal cord causes degeneration of nerve cells (known as Lou Gehrig’s disease). 50