Chemistry 20
Chapter 11
Esters, Amides
Formation of Esters
O
RCO H
A carboxylic acid
Fischer Esterification
O
RC- OH H-OR'
A carboxylic acid
An alcohol
H2SO4
O
RCOR' + H2O
An ester
Naming of Esters
• 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
O

methyl
CH3 — C—O —CH3
ethanoate
(acetate)
IUPAC: methyl ethanoate
common: methyl acetate
Naming of Esters
propyl
O
CH3 — C—O —CH2—CH2—CH3
Propyl ethanoate (IUPAC)
Propyl acetate (common)
O
CH3—CH2 —C—O—CH2—CH3
Ethyl propanoate
2 CH3
ate
ate)
Naming of Esters
O
O
CH3 COCH
O
2 CH3
O
O
O
O
O
Diethyl pentanedioate
O
(Diethyl glutarate)
Ethyl ethanoate
O
O
(Ethyl acetate)
Diethyl pentanedioate
A five-membered
(Diethyl glutarate)
lactone
O
CH3 COCH2 CH3
Ethyl ethanoate
(Ethyl acetate)
O
CH3 COCH2 CH3
O Ethyl ethanoate
O
A five
O
O
O
Diethyl
(Ethyl acetate)
O
O
O(Dieth
Diethyl pentanedioate
A five-membere
(Diethyl glutarate)
lactone
Naming of Esters
Lactones: Cyclic esters
O
O
O
O
Diethyl pentanedioate
(Diethyl glutarate)
O
O
A five-membered
lactone
Fischer Esterification
O
CH3 — C—OH + HO—CH2—CH3
Ethanoic acid
Ethanol
(Acetic acid)
(Ethyl alcohol)
CH3 — C—O—CH2—CH3 + H2O
Ethyl ethanoate
(Ethyl acetate)
H2SO4
Properties of Esters
Esters give flowers and fruits their pleasant fragrances and
flavors.
Hydrolysis: reaction with water.
(breaking a bond and adding the elements of water)
O
RCOR' + H2O
An ester
Heat
Acid
O
RC- OH
A carboxylic acid
+
H-OR'
An alcohol
Properties of Esters
Saponification (Hydrolysis): an ester reacts with a hot aqueous base.
O
RCOR' + NaOH
Heat
H2O
An ester
O
CH3COCH2CH3 + NaOH
Ethyl Ethanoate
O
+
RCO-Na +
A sodium salt
H- OR'
An alcohol
O
- +
CH3CO-Na + CH3CH2OH
Sodium acetate
Ethanol
Properties of Esters
• Esters react with ammonia and with 1° and 2° amines to form
amides.
O
O
OCH2 CH3 + N H3
Ethyl 2-phenyl acetate
N H2 + CH3 CH2 OH
2-Phenylacetamide
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.
Amides
Amides
In an amide, the -OH group in the carboxyl group of a
carboxylic acid is replaced by an Amino group (-NH2).
O
CH3 — C—OH
O
CH3 — C — NH2
Formation of Amides
O
RCO H
A carboxylic acid
O
RC- OH H-NHR'
A carboxylic acid
An Amine
O
CH3 C- OH + HHNCH2 CH3
Acetic acid
Ethanamine
Heat
O
RCNHR' + H2O
An amide
O
CH3 C- NHCH2 CH3 + H2 O
N-ethylethanamide
Naming of Amides
Change the end of the name of the carboxylic acids from
“-oic acid” to “-amide”.
methanoic acid
O
H–C–NH2
methanamide (IUPAC)
O
propanoic acid
CH3–CH2–C–NH2
propanamide (IUPAC)
Naming of Amides
O
CH3–C–NH–CH3
N-methylethanamide
O
CH3–CH2–C–N(CH3)2
N,N-dimethylpropanamide
O
CH3–C–N(CH2CH3)2
N,N-diethylethanamide
Naming of Amides
Lactams: Cyclic amides


O
NH
A four-memb ered lactam
(a -lactam)
O
NH
A seven-memb ered lactam
Properties of Amides
Such as esters:
Hydrolysis in hot aqueous acid or base.
O
CH3 CH2 CH2 CNH2 + H2 O + HCl
H2 O
heat
Butanamide
O
CH3 CNH
Acetanilide
+
NaOH
H2 O
heat
O
+ CH3 CH2 CH2 COH + NH4 Cl
Butanoic acid
O
+
CH3 CO Na + H2 N
Sodiu m
acetate
An iline
Properties of Amides
Amides do not react with ammonia or with amines.