Nanomedicine and cancer joseph abel department of physics, USU

Chapter 11
Esters, Amides
Chemistry 20
Formation of Esters
RC O H
O
A carboxylic acid
=
Fischer Esterification
RCO R
'
O
RC-OH
O
H
-
O R
'
=
=
An alcohol
A carboxylic acid
An ester
H
2
SO
4
+ H
2
O

•
Name the alkyl group from the alcohol –OR.
•
Followed by name of the acid in which the suffix “-ic acid”
is replaced by suffix “-ate”.
acid alcohol
|| methyl
CH
3
—

C—O —CH
3
ethanoate IUPAC: methyl ethanoate
(acetate) common: methyl acetate
Naming of Esters
O

propyl
CH
3
—

C—O —CH
2
—CH
2
—CH
3
Propyl ethanoate (IUPAC)

Propyl acetate (common)


CH
3
—CH
2
—C—O—CH
2
—CH
3
Ethyl propanoate
Naming of Esters
O
O
Ethyl ethanoate
(Ethyl acetate)
Diethyl pentanedioate
(Diethyl glutarate)
CH
3
COCH
2
CH
3
O O
OO
O
O
A five-membered

lactone
O
Ethyl ethanoate
(Ethyl acetate)
Diethyl pentanedioate
(Diethyl glutarate)
CH
3
COCH
2
CH
3
O O
OO
O
O
A five-membered
lactone
O
Naming of Esters
Ethyl ethanoate
(Ethyl acetate)
Diethyl pentanedioate
(Diethyl glutarate)
CH
3
COCH
2
CH
3

O O
OO
O
O
A five-membered
lactone
O
Ethyl ethanoate
(Ethyl acetate)
Diethyl pentanedioate
(Diethyl glutarate)
CH
3
COCH
2
CH
3
O O
OO
O
O
A five-membered
lactone
O
Naming of Esters
Lactones: Cyclic esters
Ethyl ethanoate
(Ethyl acetate)
Diethyl pentanedioate
(Diethyl glutarate)

CH
3
COCH
2
CH
3
O O
OO
O
O
A five-membered
lactone
O

CH
3
—

C—OH + HO—CH
2
—CH
3

CH
3
—

C—O—CH
2
—CH

3
+

H
2
O
Fischer Esterification
H
2
SO
4
Ethanoic acid
(Acetic acid)
Ethanol
(Ethyl alcohol)
Ethyl ethanoate
(Ethyl acetate)
O
Esters give flowers and fruits their pleasant fragrances and
flavors.
Properties of Esters
Hydrolysis: reaction with water.
(breaking a bond and adding the elements of water)
RCO R '
O
RC-OH
O
H
-
O R

'
=
=
An alcohol
A carboxylic acid
An ester
+ H
2
O
+
Heat
Acid
Properties of Esters
Saponification (Hydrolysis): an ester reacts with a hot aqueous base.
RCO R
'
O
RCO-Na
O
H
- O R
'
=
=
An alcohol
A sodium salt
An ester
+ NaOH
+
H

2
O
Heat
-
+
CH
3
CO
CH
2
CH
3
O
CO-Na
O
CH
3
CH
2
OH
=
=
Ethanol
Sodium acetate
Ethyl Ethanoate
+ NaOH
+
-
+
CH

3
Properties of Esters
•
Esters react with ammonia and with 1° and 2° amines to form
amides.
Thus, an amide can be prepared from a carboxylic acid by first converting
the carboxylic acid to an ester by Fischer esterification and then reaction of
the ester with an amine.
OCH
2
CH
3
O
+
NH
3
NH
2
O
+
CH
3
CH
2
OH
Ethyl 2-phenyl acetate 2-Phenylacetamide
Amides
In an amide, the -OH group in the carboxyl group of a
carboxylic acid is replaced by an Amino group (-NH
2

).



CH
3
—

C—OH CH
3
—

C — NH
2

Amides
=
O
=
O
Formation of Amides
RC O H
O
A carboxylic acid
=
RCNH R
'
O
RC-OH
O

H
-
N HR
=
=
An Amine
A carboxylic acid
An amide
Heat
+ H
2
O
'
H
2
OCH
3
C-NHCH
2
CH
3
O
H HN CH
2
CH
3
CH
3
C-OH
O

+
+
Acetic acid
Ethanamine
N-ethylethanamide
Change the end of the name of the carboxylic acids from
“-oic acid” to “-amide”.
methanoic acid

H–C–NH
2
methanamide (IUPAC)

propanoic acid
CH
3
–CH
2
–C–NH
2
propanamide (IUPAC)
Naming of Amides
O
=
=
O
CH
3
–C–NH–CH
3

N-methylethanamide
CH
3
–CH
2
–C–N(CH
3
)
2
N,N-dimethylpropanamide

CH
3
–C–N(CH
2
CH
3
)
2
N,N-diethylethanamide
Naming of Amides
=
O
=
O
=
O
Lactams: Cyclic amides
Naming of Amides
O

NH
O
NH
A four-membered lactam
(a β-lactam)
A seven-membered lactam
α
β
Properties of Amides
Such as esters:
Hydrolysis in hot aqueous acid or base.
CH
3
CH
2
CH
2
CNH
2
O
H
2
O HCl
H
2
O
CH
3
CH
2

CH
2
COH
O
NH
4
+
Cl
-
Butanoic acid
Butanamide
++ +
heat
CH
3
CNH
O
NaOH
H
2
O
CH
3
CO
-
Na
+
O
H
2

N
AnilineSodium
acetate
Acetanilide
+
+
heat
Amides do not react with ammonia or with amines.
Properties of Amides