1. Amines
Indigo used in blue dyes can be obtained from tropical plants such as Indigofera tinctoria.

2. L.O. 12.2D: Amines and amino acids Learners can:
understand the mechanism of formation of amines from haloalkanes by nucleophilic substitution and from nitriles by reduction
know the classification of amines and understand that they act as Bronsted-Lowry bases
be able to explain the difference in base strength between ammonia, primary, secondary and tertiary amines
know the preparation of aromatic amines by reduction of nitro compounds
know the uses of amines as synthetic intermediates
understand what is meant by and amino acid and that they are capable of both acid and base behaviour

3. 12.  
L.O. (cont’d)
be able to use the systematic names of common amino acids and know their trivial names.
- understand that amino acids are usually optically active
- recognise the ability of amino acids to form zwitterions and understand the conditions in which this takes place
- understand the formation of peptide links and of proteins from amino acids
- recognise the potential for hydrogen bonding in proteins and understand its effects
- know how to hydrolyse proteins and understand the products formed

4. Amines smell somewhat like ammonia and dead fish!
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Amines smell somewhat like ammonia and dead fish!
1 minute Biological Importance of Amines 4 4 4

5. TYPES OF AMINES PPT - Amines 24/02/2019 ammonia 10 amine 20 amine
40 ammonium salts
ethylamine
N-ethyl-N-methlyamine
trimethylamine
Tetramethylammonium Chloride

6. Properties of Amines
Many small molar mass amines stink!!! Amino acids degradation is responsible for the odor of putrefying flesh.
45 SECONDS Chem Chanel

7. Naming Secondary and Tertiary Amines
In a secondary or tertiary amine,
The longest alkane chain is numbered.
Each alkyl group bonded to the N atom is named as a N-alkyl group
Alphabetize R groups and add “amine”
If a side chain use “–amino”
HN—CH3 |
CH3—CH2—CH2—NH—CH CH3—CH—CH2—CH3
N-Methyl-1-propanamine
N-Methyl-2-butanamine
Naming Amines 0.56 seconds

8. Learning Check Give a name for each: N-ethyl-N-methyl-1-butanamine CH3|
CH3—CH2—N—CH2—CH2—CH2—CH3

9. Nomenclature The IUPAC benzene named aniline. r N-methyl-1-phenylamine
The 1 is understood and
does not have to be used
An ether and aniline
4-methyoxyaniline

10. Naming 2 Functional Groups

11. Solution If a side chain use “–amino”
Give the IUPAC name for the following compound, which is used in the production of methadone: Who is the BOSS? Answer, OH (see priority chart) N groups are very low in priority (only DB and TB are worse (lower)
If a side chain use
“–amino”

12. Try some naming

13. Try some… CH3 CH3-N-CH2-CH3 NH2 CH3-CH-CH3 2-propanamine
N,N-Dimethylethanamine
1,6-hexanediamine

14. Biologically Important Amines
Some naturally occurring amines take part in neurochemistry

15. Boiling Points
1 minute
Amines have boiling points
between alkanes and alcohols
Tertiary amines boil lower then 1o or 2o of similar molecular weight, less contact points

16. PHYSICAL PROPERTIES Solubility Lower mass compounds are
soluble in water due to hydrogen
bonding with the solvent.
Solubility decreases as the
molecules get heavier.
Inductive effects

17. BASE STRENGTH OF AMINES
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Alkyl groups push electrons towards the N better than H (remember carbocation stability).
Base strength increases electrons more available
NH3 > 1o > 2o > 3o
Worst Best
1 minute Chem Chanel

18. : BASIC PROPERTIES C6H5 N: CH3 N: acceptor
Bases The lone pair makes amines basic;
RNH H+ ——> RNH3+
a B/L proton
acceptor
electron withdrawing benzene rings
decrease basicity as the electron density on N is
lowered and the lone pair is less available
electron releasing substituents (CH3 groups)
increase basicity as the electron density is
increased and the lone pair is more available : H
C6H N: H H
CH N: H

19. Basicity- Aliphatic versus Aromatic Amines
The smaller the pKb the stronger the base
Compound Formula pKb
ammonia NH
methylamine CH3NH2 3.36
phenylamine C6H5NH2 9.38
Rank these in order of strongest to weakest base.
Answer:
strongest base methylamine > ammonia > phenylamine weakest base
smallest pKb largest pKb
Why is methylamine strong but phenylamine a weak base?
Answer: CH3NH2 the methyl group pushes the electrons toward the :N and gives it more availability to act as a base and pick up H+
Phenylamine C6H5NH2 is the opposite, the aromatic electrons are delocalised into the ring and draws electrons away from the :N

20. CHEMICAL REACTIONS - WEAK BASES
Water Amines dissolve in water produce weak alkaline solutions
CH3NH2(g) H2O(l) CH3NH3+(aq) OH¯(aq)
Base Acid
Acids Amines react with acids to produce salts.
C6H5NH2(l) HCl(aq)  C6H5NH Cl¯(aq) phenylammonium ion

21. BASE STRENGTH OF AMINES
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BASE STRENGTH OF AMINES
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TASK 1
methylamine + nitric acid
diethylamine + sulfuric acid

22. Reactions with amines and making amines react as nucleophiles (:Nu)
CHEMICAL REACTIONS – Acid Base and NUCLEOPHILIC
Reactions with amines and making amines react as nucleophiles (:Nu)
Reagents Product Mechanism
acyl chlorides + amines amides (Cl eliminated) :Nu addition elimination (DB)
ketone/aldehydes + KCN/H hydroxynitriles (H eliminated) :Nu addition only (DB)
Haloalkanes + amines longer amines :Nu substitution, No (DB)
Why is one Addition and the other Substitution?
Answer:
:Nu Addition has the Double Bond of carbonyl compounds with HCN:
Substitution has NO double bond as with haloalkanes

23. Haloalkane  nitrile Nucleophilic Substitution Reagents and conditions
CN– ions, e.g. KCN(aq)
Can reduce to
C–C if H2 provided and (Pt)
Charge :Nucleophile
lone pair

24. Carbonyl nitrile Nucleophilic addition Reagents and conditions
CN– ions in acid, e.g. KCN(aq)/H2SO4(aq)
charge
lone pair
C–C bond forms

25. Using Access ammonia or amines
The reaction happens in two stages. In the first stage, a salt is formed – in
this case, ethylammonium bromide.
There is then the reversible reaction of if we have EXCESS ammonia
The ammonia removes a hydrogen ion from the ethylammonium ion to
leave a primary amine - ethylamine.
If you use a very large excess of ammonia (or amine), the chances are always greatest that an ammonia molecule rather than one of the amines being formed reacts.

26. NUCLEOPHILIC SUBSTITUTION N-trimethylethylammonium
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NUCLEOPHILIC SUBSTITUTION
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H on N is swapped by R from haloalkane.
Product also has lone pair on N so product reacts further.
UNCONTROLLED WHEN AMINES LIMITED
N-trimethylethylammonium
chloride

27. NUCLEOPHILIC SUBSTITUTION
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XS propylamine + chloromethane give the reaction
CONTROLLED WHEN Ammonia or XS AMINES
N-methylpropylamine
TASK 4 Q2

28. MAKING ALIPHATIC 1o AMINES
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Write this out route 1: e.g. buylamine and ammonia
route 2
TASK 1
e.g. propylamine and KCN (Step1 :CN and reduction)

29. Summary of AMINE Reactions
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1 minute. Chem Chanel BOTH reactions herein, together
Substitution 1 e.g. Using Haloalkanes
ethylamine
Addition 2 : Adding Extra Carbons using KCN
ethylbromine
methylbromine
ethanenitrile
ethylamine
ethanenitrile

30. Summary of AMINE Reactions
3. Nucleophilic addition with Ketones and Aldehydes
Reagents and conditions
CN– ions in acid, e.g. KCN(aq)/H2SO4(aq)
charge
lone pair
C–C bond forms
To make AMINES add 4[H]

31. Nitriles Reduction Reduction  amines H2 and Ni catalyst /Pt
/Pt

32. AROMATIC REDUCTION TO AMINES
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AROMATIC REDUCTION TO AMINES
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3H2 /Pt

33. Uses of Amines and their Derivatives
Azo compounds are highly coloured and can be synthesized from relatively inexpensive compounds  widely used in dyeing industry
Azo compounds are used as dyes in garments and food

34. Uses of Amines and their Derivatives
Examples:
1. Methyl orange (an orange dye for fabrics)
IUPAC: Sodium 4-[(4-dimethylamino)phenyldiazenyl]benzenesulfonate
2. Sunset Yellow FCF (an orange-yellow dye for food products)
Disodium 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate

35. Uses of Amines and their Derivatives
3. Direct Brown 138 (a brown dye for fabrics)
4. Ponceau (a red dye for food products)

36. Uses of Amines and their Derivatives
As Drugs
Amine derivatives are commonly used as drugs such as painkillers (analgesics), transquillizers and antihistamines
1. Acetaminophen (also known as paracetamol)
used to relieve pains
less harmful to the stomach compared with aspirin

37. Uses of Amines and their Derivatives
2. Chlorpheniramine
helps to relieve allergic disorders caused by cold, insect bites and stings
present in some over the counter drugs such as Coricidin, Coltaline, Piriton and Dristan

38. Uses of Amines and their Derivatives
3. Chlorpromazine
sedative effect without inducing sleep
used to relieve anxiety, excitement, restlessness and even metal disorders

39. Uses of Amines and their Derivatives
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Uses of Amines and their Derivatives
4. Methamphetamine 39 39 39 39

40. Preparation of Phenylamine through Reduction of Nitrobenzene
Preparation of Amines
Preparation of Phenylamine through Reduction of Nitrobenzene
The reduction of the nitro group can be carried out by
Catalytic hydrogenation
Treatment of the nitro compound with an acid (e.g. HCl) and Fe, Zn or Sn or a metal salt such as SnCl2

41. NUCLEOPHILIC SUBSTITUTION
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N-methylethylamine + chloroethane (write the mechanism, many times)
chloroethane
N-methydiethylamine
N-methyethylamine
To get mainly 40 ammonium salt, if you let the reaction run or do NOT use excess ammonia, then the products themselves become :Nu
N-methytriethylammonium
chloride
TASK 4 Q3

42. NUCLEOPHILIC SUBSTITUTION
1 minute Chem Chanel
HALOALKANES
Amines are also nucleophiles (lone pair on N) and can attack halogenoalkanes to produce a 2° amine.
This too is a nucleophile and can react further producing a 3° amine and, eventually an ionic quaternary ammonium salt.
C2H5NH C2H5Br ——> HBr (C2H5)2NH diethylamine, 2° amine
(C2H5)2NH + C2H5Br ——> HBr (C2H5)3N triethylamine, 3° amine
(C2H5)3N C2H5Br ——> (C2H5)4N+ Br¯ tetraethylammonium bromide
a quaternary (4°) salt
Uses Quarternary ammonium salts with long chain alkyl groups are used
as cationic surfactants in fabric softening e.g. [CH3(CH2)17]2N+(CH3)2 Cl¯

43. PPT - Amines 24/02/2019 40 Ammonium salt : USAGE
1 minute Chem Chanel
40 Ammonium salt : USAGE
Ones with some long chain alkyl groups can be used as cationic surfactants in fabric softening
Often used in fabric softener as many fabrics have +ve charge on surface.
e.g. (CH3)2N[(CH2)16CH3]2+ Cl -

44. H H2N C COOH CH3 H2N C COOH H AMINO ACIDS – OPTICAL ISOMERISM
Amino acids can exist as optical isomers
If they have different R1 and R2 groups
Optical isomers exist when a molecule
Contains an asymmetric carbon atom
Asymmetric carbon atoms have four
different atoms or groups attached
Two isomers are formed - one rotates plane
polarised light to the left, one rotates it to the right
Glycine doesn’t exhibit optical isomerism as
there are two H attached to the C atom
H2N C COOH
CH3 H
H2N C COOH H
GLYCINE
2-aminoethanoic acid

45. Acid Rx: HOOCCH2NH2 + HCl  HOOCCH2NH3+ + Cl¯ Bronsted Base Acid
AMINO ACIDS - ACID-BASE PROPERTIES
H2N C COOH R2 R1
amino acids possess acidic and basic properties
this is due to the two functional groups
COOH gives acidic properties
NH2 gives basic properties
Zwitterion
(dipolar ion)
H3N+ C COO¯ R2 R1
Acid Rx: HOOCCH2NH HCl  HOOCCH2NH3+ + Cl¯
Bronsted Base Acid
Base Rx: HOOCCH2NH NaOH  ¯OOCCH2NH2 + Na+ + H2O
Acid (carboxylic)

46. PEPTIDES - HYDROLYSIS
Peptides are broken down into their constituent amino acids by hydrolysis
• the C-N bond is broken
• hydrolysis with water is very slow
• hydrolysis in alkaline/acid conditions is quicker

47. H2N C CO CH3 H NH C CO NH C COOH PEPTIDES - HYDROLYSIS
Peptides are broken down into their constituent amino acids by hydrolysis
H2N C CO
CH3 H
NH C CO
NH C COOH
Which amino acids are formed?

48. + + H2N C CO CH3 H NH C CO NH C COOH CH3 H H2N C COOH H H2N C COOH CH3
PEPTIDES - HYDROLYSIS
Peptides are broken down into their constituent amino acids by hydrolysis
H2N C CO
CH3 H
NH C CO
NH C COOH
CH3 H
H2N C COOH H
H2N C COOH
CH3
H2N C COOH + +

49. PROTEINS • are polypeptides with high molecular masses
• chains can be lined up with each other
• the C=O and N-H bonds are polar due to a difference in electronegativity
• hydrogen bonding exists between chains
dotted lines represent hydrogen bonding

50. Spinning 2-aminobutanoic acid H2N C COOH CH3 H H 2-aminobutanoic acid
You will notice that this 2-aminobutanoic acid is not in the traditional
form of amino acids AMINO ACID USUAL FORM
2-aminobutanoic acid
H2N C COOH
CH3 H
Although you do NOT have to, it is best to spin the molecule about the
Sigma bonds to resemble the traditional form as it is easier to set
up di peptides and polypeptides this way (better for condensation reaction
depiction) H
2-aminobutanoic acid
H2N C COOH
C2H5

51. Amides

52. Nomenclature of amides
IUPAC system for naming amides:
Like esters, amides are made using carboxylic acids. The portion that comes from the carboxylic acid is named as a carboxylic acid first, before dropping the “-oic acid” from the name and adding “-amide”

53. Nomenclature of amides
Some examples:

54. Selected amides and their uses
Urea is one of the simplest amides, formed by reaction between CO2 and ammonia in a series of metabolic reactions
IUPAC (Hint: it is a aldehyde)
Answer: diamino methanal .
Acetominophen is an aromatic amide
Answer: N-phenylethanamide
or N-phenylacetamide
Runway De-icing
And fertilizer 
Physical properties of amides
Pain Relief
Intermolecular H-bonding, what does this mean for solubility and melting points?

55. Preparation of amides Amidification
Reactions that make esters from carboxylic acids and alcohols are called esterification or condensation reactions, where the carboxylic acid loses the OH and the amine loses a H atom:
Note : 30 amines will NOT react as they do not have the hydrogen.

56. Preparation of amides Amidification / Condensation
Ammonia + carboxylic acid  1o amide
1o amine + carboxylic acid  2o amide
2o amine + carboxylic acid  3o amide
Note : 30 amines will NOT react as they do not have the hydrogen.

57. Hydrolysis of amides Reverse reaction
Like esters, amides can undergo hydrolysis.
This reaction results in the amide being broken up into amine and carboxylic acid starting materials:

58. Hydrolysis of amides Saponification
Under basic conditions, the carboxylic acid is produced as an carboxylic acid salt:
Remember,:
carboxylic acids are acids
amines are bases
Amide hydrolysis carried out under basic
conditions is called amide saponification.

59. Hydrolysis of amides
Under acidic conditions, the amine is produced as an ammonium salt:
Remember,:
carboxylic acids are acids
amines are bases

60. Reduction Amides are reduced to amines
CH3CONH [H]  CH3CH2NH2 + H2O
LiAlH4