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Carboxylic Anhydrides,
Esters and Amides
O
R
O
O
O
Anhydride
R
R
O
O R
Ester
R
O NR2
Amide
Naming Anhydrides
O
O
O
O
O
O
Butanoic anhydride
Isobutanoic anhydride
O
O
O
hexanoic propanoic anhydride
Drop the word acid and say anhydride
Naming Esters
O
O
O
Butyl heptonoate
O
Propyl isopetanoate
Name the alkyl group bonded to the oxygen
Then name the acid part but change the
ending from oic acid to oate
Naming Amides
O
O
N
N-Ethylbutanamide
N
N-Ethyl-N-Propylpropanamide
Drop the oic acid part and say amide
Formation of Esters
O
R
O H
+
R'
O H
O
O H
+
Butyric Acid
O H
+
O R'
R
+
H2O
O
H2SO4
Ethanol
O
O H
Butyric Acid
CH3CH2
O
H2SO4
O
+
H2O
Pineapple Flavor
CH2OH
H2SO4
O
O
Cherry Flavor
Benzyl Alcohol
+
H2O
Amides: Preparation
• Addition of ammonia results in an ammonium salt:
OH
R
C
O
H
+
NH 2
R
O- NH 4+
C
O
NH2
O
ammonium salt
Heating will remove a water and give the Amid
This is not the most common way
+
H2 O
Formation of Amides
• Anhydride + amine = amide + acid
O
O
CH3 C O C CH3 + H3C CH2 NH 2
acetic anhydride
ethylamine
Do The YouTube
http://www.youtube.com/watch?v=f4I2S0jUoh4
http://www.youtube.com/watch?v=G-k08VVz0Vc
O
CH3 C NH CH2 CH3
N-ethylacetamide
O
H3C
OH
Reactions
•
•
•
•
Hydrolysis of esters with acid
Hydrolysis of esters with base (saponification)
Reaction of Anhydrides with Alcohol
Reaction of Esters with ammonia
Hydrolysis of Ester with Acid
Hydrolysis breaks a carboxyl bond by
addition of water, alcohol, or amine
S-
S+
H
S+
S-
O
R
O
R
O R
O
R
O
H
+
O R""
O
H+
R'
R
H
O
OR'
OR'
O R""
+
H O R""
Hydrolysis of Esters
Hydrolysis = Reverse of esterification
– Acid or base catalyzed
– Produces acid and alcohol
O
CH3 C O CH2 CH3 + H 2O
ethyl acetate
H2SO 4
O
CH3 C OH
acetic acid
+ CH3 CH2 OH
ethyl alcohol
Hydrolysis of Esters with Base
• Base catalyzed hydrolysis (saponification)
O
NaOH
CH3 CH2 CH2 C O CH3 + H 2 O
methyl butyrate
O
CH3 CH2 CH2 C O-Na + + CH3 OH
sodium butyrate
methyl alcohol
Reaction of Anhydrides
with Alcohols
O
O
O
O
+
HO
O
Ester
+
O
HO
Acid
Reaction of Esters with Ammonia
O
O
O
+
NH3
NH2
+
OH
Phosphoric Anhydrides
• Anhydrides of Phosphoric Acid
• The phosphorus structure is very common in
biological systems
• For example - the phosphate portion of DNA
O
H O
P
O
O H
+
H O
P
O H
-H2O
O
H O
P
O
O
P
O
O
O
O
H
H
H
H
phosphoric acid
phosphoric acid
O H
pyrophosphoric acid
H3PO4
anhydride form
Phosphoric Anhydrides
• Anhydrides of Phosphoric Acid
O
H O
P
O
O H
+
H O
P
O
O
P
O
O
O
H
H
H
phosphoric acid
O H
-H2O
pyrophosphoric acid
O
H O
P
O
O
O
P
O
O
O
P
O
H
H
H
triphosphoric acid
O H
Phosphoric Anhydrides
• Anhydrides of Phosphoric Acid
– Contain HIGH ENERGY bonds (linkages)
• Release of energy when broken
O
H O
P
O
O
P
O
O
H
H
O H
Phosphoric Anhydrides
• Anhydrides of Phosphoric Acid
– Esters found in Biochem reactions
– ATP, ADP, etc.
O
-O
O
P
O
O
-
P
O
O
-
O
P
O
O R
-
As these bonds break, energy is released.