1. Amines 1

2. Amines
Learning Objectives
Chapter ten discusses the following topics and by the end of this chapter the students will:
Know the structure and classification of amines
Know the naming rules for amines & precedence order of functional groups in compounds have more than one functional group.
Know the physical properties of amines
Know the effect of lone pair of electrons of N atom on basic properties of amines
Know the different methods used in synthesis of amines
Know the reactions of amines; in addition to behaving as bases amines can be nucleophiles.
145 Chem.

3. Structure & Classification
Amines
Structure & Classification
Amines are derivatives of ammonia that have one or more of the hydrogen replaced with alkyl and/ or aryl group.
Amines: are a class of organic compounds that contain the N group
Amines are formed in many biological systems. So it used as drugs and medicines.
Classification Of Amines
primary (1o) amines secondary (2o) amines tertiary (3o) amines
R N: H
R N: R
R N: R H
145 Chem.

4. Common Nomenclature Of Amines
The common names of amines are derived by listing the name (s) of the group (s) surrounding the nitrogen (in alphabetical order) and adding the suffix amine.(N.B. if two vowels come together ; the first must be omitted e.g. ethanamine.
Symmetrical 2° & 3° amines (i.e. the substituents surrounding the N atom are identical) are named by adding the multiplication prefix (di or tri) to the name of the alkyl group.
Methylamine Benzyl methyl amine Trimethyl amine
Structures with higher priority groups, the NH2 group is called amino
145 Chem.

5. IUPAC Names Of Primary Amines
If the compound does not contain a functional group except amino group, then the compound is named by finding the longest alkane chain containing the amino group and replacing the e in the IUPAC name by the suffix amine
However if the compound contain other functional groups then the order of precedence determines which group are named with prefix or suffix. (see the precedence table on slide 6)
The highest precedence group takes the appropriate suffix with all other groups taking the prefix (es), however = or Ξ bonds only take suffix form (ene, yne respectively.
5-Methyl-3-hexanamine Aminoheptanoic acid Amino-2-butanol

6. Precedence Order of Functional Groups (Descending Order)
Amines
Precedence Order of Functional Groups (Descending Order)
Class
Functional group
Prefix
suffix
Carboxylic acids
Cyclic alknes or alkenes with COOH group
COOH
oic acid
carboxylic acid
Aldehydes
Cyclic alknes or alkenes with CHO group
-CHO
Formyl al
carbaldehyde
ketone
-C=O
oxo
one
Alcohols
-OH
hydroxy ol
Amines
-NH2
amino
amine
Ethers
-OR
alkoxy -
Alkenes and aAlkynes
= & Ξ bonds
ene & yne
145 Chem.

7. Naming Of Aromatic Amines
They have common names accepted by the IUPAC system, but if the benzene ring contain groups of higher priorities (COOH > CHO > C=O > OH > NH) in this case the amino group is added as a prefix .
Pyridine Aniline o-Nitroaniline p-Toluidine p-Aminophenol
Benzenamine
4-Methyl benzenamine
145 Chem.

8. Physical Properties of Amines
1) Boiling point :
Because they possess a polar N-H bond, primary and secondary amines are capable of forming intramolecular hydrogen bonds among their molecules; therefore they have: higher boiling points than alkanes but lower than alcohols (alcohols form stronger H-bonds than amines).
Tertiary amines can not form H-bonds among their molecules and their molecules are more branched thus they have the lowest boiling points among amines.
145 Chem.

9. Amines
2) Solubility :
All amines are capable of forming hydrogen bonds with water, alcohol (hydroxylic solvent) , thus they are soluble in water.
The lower molecular weight amines with up to six carbons show appreciable solubility in water.
3) Basicity Of Amines
Base strength :
Aromatic amines less basic than aliphatic amines
Electron donating (releasing) groups on N atom increase the basicity
Electron withdrawing groups decrease the basicity
145 Chem.

10. 1) Alkylation of Ammonia:
Amines
Preparation Of Amines
1) Alkylation of Ammonia:
2) Reduction of Nitro groups:
3) Reduction of Nitriles:
4) Reduction of Amides:
145 Chem.

11. (benzene diazonium chloride)
Amines
Reaction of Amines
Salts Formation:
Amides Formation:
Imines Formation:
Diazonium Salts Formation:
Diazonium salt
(benzene diazonium chloride)
145 Chem.

12. Write the structure of p-nitrobenzylamine?
Amines
Questions
Write the structure of p-nitrobenzylamine?
How to prepare ethylamine from acetamide?
Why are aliphatic amines is more basic than aromatic amines?
Select the stronger base from each pair of compounds?
145 Chem.

13. Thank You for your kind attention !
Amines
Thank You for your kind attention !
Questions?
Comments