Synthesis of Amides H3C C O Cl + 2NH3 H3C C O NH2 + NH4 fast ...

Synthesis of Amides
H 3 C
C 6 H 5
C
C
O
Cl
acetyl chloride
O
Cl
O
+
+ 2NH 3 H 3 C C + NH 4 Cl -
fast
NH 2
acetamide
ethanamide
+ 2H 2 NC 2 H 5 C 6 H 5 C O NHC 2 H 5
+ C 2 H 5 NH 3
+
Cl -
benzoyl chloride ethylamine N-ethyl benzamide
Synthesis of Esters
1) Acyl halide and alcohol
O
H 3 C C +
Cl
OH
H 3 C
C
O
O
O 2 N
acetyl chloride
Preparation of 3,5-dinitrobenzoates
O
C
Cl
NO 2
cyclohexanol
cyclohexyl acetate
cyclohexyl ethanoate
O 2 N
H
O H
+ HO C CH
C O C CH 3
3
CH
CH 3 3
O 2 N
2) Fischer esterification
2-propyl 3,5-dinitrobenzoate
solid since high MW
R
C
O
Cl
+ R'OH
H 3 O +
R
C
O
OR'
+ H 2 O
This reaction is driven to the right by using excess R'OH or by removing the water as it is formed
The mechanism is acid-catalyzed nucleophilic substitution at the acyl carbon. The mechanism is important.
R
C
O
OH
H + R C
-H +
OH
OH
R C
OH R'OH OH
OR'
H
R
OH 2
C OR'
O H
R
C
O
OR'
H +
-H +
H 2 O
R
C
OH
-H 2 O
OR'

Reactions of Esters
1) Reduction
O 1) LiAlH 4 /ether
R C
RCH 2 OH + R'OH
OR'
2) H 2 O
esters reduce more readily than carboxylic acids
O
e.g. 1) LiAlH 4 /ether
C6 H 5 C
C 6 H 5 CH 2 OH + CH 3 OH
OCH 2) H
3
2 O
2) Grignard reaction
O 1) R"MgX/ether OH
R C
OR' 2) H 3 O + R C R" + R'OH
R"
tertiary alcohol is formed
in which two of the R groups
are the same. They both come
from the Grignard reagent
Mechanism
R
C
O
OR'
OMgX
O
+ R"MgX R C OR' R C R" + R'OMgX
R"
R"MgX
H 3 CH 2 C
C
O
OC 2 H 5
OH
R C R"
R"
1) 2CH 3 MgBr
H 3 O +
2) H 3 O + H 3 CH 2 C C CH 3
CH 3
1) 2C 6 H 5 MgBr
OH
OH
OMgX
R C R"
R"
3) Ester Hydrolysis
O
R C
OR'
OH -
H 3 O +
heat
2) H 3 O + H 3 CH 2 C C C 6 H 5
C 6 H 5
R
R
C
C
O
O
O -
OH
+ HOR'
+ HOR'
base hydrolysis is non-reversible so is
preferred method
reverse of Fischer esterification
read mechanism backwards

Condensation Polymers - formed by the removal of a small molecule
1) Terylene, Fortrel, Dacron, Mylar film
H 3 CO
O
C
O
C OCH 3
+ HOCH 2 CH 2 OH
dimethyl terephthalate
- CH 3 OH
ethylene glycol
O
O
O
C
C
H O
O
2 CH 2 C CH 2 CH 2 O C
repeating unit
n
O
C
O
CH 2 CH 2 O
2) Nylon
O
C (CH 2 ) 6
Cl
C O Cl
+
H
N (CH 2 ) 6
H
N
H
H
- HCl
N
H
O
O
C (CH 2 ) 6 C
(CH 2 ) 6
N N
H H
repeating unit
Nylon 66
O
C
(CH 2 ) 6
C
O
N
(CH 2 ) 6
N
H
peptide link
H
present in proteins
also amide group
Fats and Oils - found in nature
These materials are esters of glycerol and are long-chain fatty acids
e.g. trimyristin, the fat from nutmeg
O
H 2 C O C
O (CH 2 ) 12 CH 3 it is not usual to have all of the acids attached to glycerol
the same; we usually have a mixed ester
HC O C (CH 2 ) 12 CH 3
H 2 C O C (CH 2 ) 12 CH 3
O
fats are defined as solids at room temperature and are usually from animals
oils are liquids at room temperature and are from the seeds of plants
When fats are treated with base they hydrolyse to the free fatty acids and glycerol.