AMINES BY VANA JAGAN MOHAN RAO

1. 1
BY
VANA JAGAN MOHAN RAO M.S.Pharm, MED.CHEM
NIPER-KOLKATA
Asst.Professor, MIPER-KURNOOL
Email: jaganvana6@gmail.com

2.  Amines are organic nitrogen compounds, formed by replacing one
or more hydrogen atoms of ammonia (NH3) with alkyl or aryl
groups.
 Amines are classified as 1°, 2°, or 3° based on the number of
alkyl groups bonded to the nitrogen atom.
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3.  When a fourth group bonds to the nitrogen through this lone pair,
the product is a quaternary ammonium ion, which has a positive
charge and forms ionic compounds with anions.
 Amines are stronger bases and better nucleophiles than other
neutral organic compounds.
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4. NOMENCLATURE OF AMINES
Common Name
 Name the alkyl group bonded to the nitrogen atom and add the
word amine, forming a single word (alkylamine).
 Secondary and Tertiary amines having identical alkyl groups
are named using the prefix di- or tri- with the name of the
primary amine (Dialkylamine or Trialkyamine)
Ethyldimethylamine
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5. IUPAC System
 If the compound does not contain a functional group except
amino group, In this system find the longest chain and give it a
suitable name and the amino group is considered as substituent,
and its position on the chain is indicated by the lowest possible
number.
Aminomethane 1-Aminopropane
2-Aminopentane
 Substituents attached to the nitrogen are indicated by using “N-”
as the location number.
N-Ethyl-1-aminopropane
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6. NOMENCLATURE OF MULTIFUNCTIONAL COMPOUNDS
N-Ethyl,N-methyl-1-aminopropane
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7.  Aromatic amines are named as derivatives of aniline. Substituents
attached to the nitrogen are indicated by using “N-” as the location
number.
2-Methylaniline 2-Nitroaniline
N-Ethyl-4-nitroaniline
Aniline
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8. Precedence Order of Functional Groups
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9. PHYSICAL PROPERTIES OF AMINES
1. Solubility in water
 1°, 2°, and 3° amines with small alkyl groups are very soluble in
water due to hydrogen bonding with the solvent.
 Solubility decreases as the molecules get heavier.
 Aromatic amines are insoluble in water.
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10. 2. Boiling point
 1° and 2° amines can hydrogen bond to each other:
 3° amines cannot hydrogen bond to each other:
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11. BASICITY OF AMINES
 Amines are basic because they possess a pair of unshared
electrons, which they can share with other atoms.
 Groups that donate or supply electrons will increase the basicity of
amines while groups that decrease the electron density around the
nitrogen decrease the basicity of the molecule.
 Aromatic amines are less basic strength than aliphatic amines.
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12. PREPARATION OF AMINES
1- Reduction of N-containing compounds
(nitro compounds, nitriles, amides, and oximes)
H2 / Pt
1) Sn / HCl / 2) NaOH
or
LiALH4 / dry ether / 2) H2O
or
Nitro compounds
Nitrile
1) Sn / HCl
2) NaOH
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13. Amides
Oxime
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14. 2- Alkylation Of Ammonia
Alkylammonium salt
Tetramethylammonium chloride
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15. 3- Hoffman Degradation Of Amides
It will reduce 1 carbon atom in this reaction
By the action of Sodium hypobromite NaOBr

16. REACTIONS OF AMINES
Reaction of Amines with Nitrous Acid
 Nitrous acid reacts with 1° alkylamines and arylamines to form
diazonium salts. This reaction is called diazotization.
 2° Alkylamines and aryl amines react with nitrous acid
to form N-nitrosamines.
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17.  3° Alkylamines react with nitrous acid to form
Water -soluuble ammoium salts.
 3° aryl amines react with nitrous acid to form
p-nitroso aromatic compounds
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18. Fluoroboric acid
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19. HALOGENATION
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20. V.JAGAN MOHAN RAO M.S.Pharm., MED.CHEM
NIPER-KOLKATA
Asst.Professor, MIPER-KURNOOL
EMAIL- jaganvana6@gmail.com

21. The amino group is one of the most important functionalities
in organic synthesis and in nature. Amines are a class of organic
compounds that contain the functional group -NH2. The
structure of amine is R-NH2, where R in the case of aliphatic
amine is an alkyl group or for aromatic amines is an aryl group.
Amines are classified as primary, secondary and tertiary
amines. Primary amines is the one in which the nitrogen
atom is bonded to one hydrocarbon atom and two hydrogen
atoms. Secondary amines is bonded with two hydrocarbon
atom and one hydrogen atom. Tertiary amines are amines in
which all the hydrogen atoms are replaced by hydrocarbon
atoms.

22. The following are the tests carried to identify the presence
of amino group present in the organic compound.
Solubility test
Litmus test
Carbylamine test
Nitrous acid test
Azo-dye test
Hinsberg test

23. (a) Solubility Test:
Amines are organic compounds which is basic in nature, so they
dissolve in mineral acids like hydrochloric acid. But this test is not a
confirmation test for amines.
The chemical reaction is given below.
C6H5NH2 + HCl → C6H5NH3
+Cl–
Note: If it is soluble in mineral acid then it may be an amine.
(b) Litmus Test:
Amines are basic in nature. So it turns red litmus paper blue. This
test is also not a confirmation test for amines.
The chemical reaction is given below.
CH3-CH2-NH2 + H2O → CH3-CH2-NH3
+ + OH–
Note: The change in the colour of red litmus paper shows the given
organic compound is a base. (may be amine)

24. (c) Carbylamine Test:
This test is also called isocyanide test, because when amines are treated
with chloroform in the presence of alkali, isocyanide is formed. Both aliphatic and
aromatic amines gives positive for this test. Secondary and tertiary amines do not
give this test.
The chemical reaction is given below.
R-NH2 + 3KOH + CHCl3 → RNC(isocyanide) + 3KCl + 3H2O
Note: An unpleasant odor confirms the presence of primary amine.
(d) Nitrous Acid Test:
This test can be used to identify primary, secondary and tertiary amines. An
aromatic primary amine reacts with nitrous acid forms a diazonium salt and at
higher temperatures the formed diazonium compounds undergoes decomposition.
C6H5NH2 + HNO2 → C6H5-N=N+Cl–(diazonium compound)
Primary aliphatic amines react with nitrous acid to give nitrogen gas, which is seen
as bubbles.
R-NH2 + HONO → R-OH + H2O + N2↑
Secondary amines react with nitrous acid to form a yellow oily nitrosamine.
R2-NH + HONO → R2N-NO + H2O
Tertiary amines react with nitrous acid to form soluble nitrite salts.
R3N + HONO → R3NH+ON–
Note: Nitrosamines are highly carcinogenic substances.

25. (e) Azo-Dye Test:
This test is performed in order to confirm the presence of aromatic
amines. Aromatic amines forms a diazonium salts when treated with
HNO2. These diazo compounds couple with phenols like β-naphthols
forms an orange azo dye which is insoluble in water.
The chemical reaction is given below.
C6H5NH2 + HNO2 → C6H5-N=N+Cl–
Note: The presence of red orange dye conforms the presence of
aromatic amines.

26. (f) Hinsberg Test:
The reagent used in this test is benzene sulfonyl chloride. Amines
reacts with benzene sulfonyl chloride in the alkaline medium.
Primary amines reacts with benzene sulfonyl chloride to produce
substituted sulfonamide which contains an acidic hydrogen and
dissolve in basic medium.

27. A secondary amine forms a substituted sulfonamide which is
insoluble in alkali because it does not have acidic hydrogen.
A tertiary amine forms a substituted sulfonamide which is insoluble
in alkali because it does not have an acidic hydrogen.

28. Note:
Tertiary amines: Precipitate in the test tube but dissolves in
concentrated HCl.
Secondary amines: Precipitate in test tube but does not dissolve in
concentrated hydrochloric acid.
Primary amines: No reaction or precipitate, on adding concentrated
hydrochloric acid insoluble material is seen.

29. Solubility test If it is soluble in mineral acid then it may be an amine
Litmus test It turns red litmus paper blue
Carbylamine test An unpleasant odor confirms the presence of primary amine.
Nitrous acid test Appearance of bubbles shows the presence of primary amines, yellow oily liquid
shows the presence of secondary amines and formation of nitrite salts conforms
the presence of tertiary amines.
Azo-dye test The presence of red orange dye conforms the presence of aromatic amines.
Hinsberg test Primary amines: No reaction or precipitate, on adding concentrated hydrochloric
acid insoluble material is seen.
Secondary amines: Precipitate in test tube but does not dissolve in concentrated
hydrochloric acid.
Tertiary amines: Precipitate in the test tube but dissolves in concentrated HCl.
Observations: