Download CHM 103 Lecture 28 S07

Announcements & Agenda (04/02/07)
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Quiz on Wednesday (Chirality & Ch 13)
Will hand HW practice in lab
Today
 Esters (13.3)
 Amines (13.4)
 Amides (13.5)
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Last Time: Drawing Fischer Projections
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Last Time: Carboxylic Acids
Carboxylic acids
• are weak acids.
• ionize in water to produce carboxylate
ions and hydronium ions.
O
║
CH3−C−OH + H2O
O
║
CH3−C−O– + H3O+
~1%
Also: Neutralization Reactions! Esterification!
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Ester Products
Aspirin
• is used to relieve pain
and reduce inflammation.
• is an ester of salicylic
acid and acetic acid.
Oil of wintergreen
• is used to soothe sore
muscles.
• is an ester of salicylic
acid and methanol.
O
C OH
O
O C CH3
O
C O CH3
OH
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Naming Esters
The name of an ester contains the names of
• the alkyl group from the alcohol.
• the carbon chain from the acid with –ate ending.
methyl
ethanoate (acetate)
O

-oate: means
CH3— O—C —CH3
ester present
IUPAC: methyl ethanoate
common: methyl acetate
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Esters in Plants
Esters give flowers and fruits their
pleasant fragrances and flavors.
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Acid Hydrolysis of Esters
• an ester reacts with water to produce a
carboxylic acid and an alcohol.
• an acid catalyst is required.
O

H+
H—C—O—CH2—CH3 + H2O
O

H—C—OH
+ H—O—CH2—CH3
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Base Hydrolysis (Saponification)
• is the reaction of an ester with a strong base.
• produces the salt of the carboxylic acid and an
alcohol.
O
||
CH3—C—O—CH2—CH3 + NaOH
O

CH3—C—O– Na+ + HO—CH2—CH3
salt of carboxylic acid
alcohol
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Last Time: Base Hydrolysis of
Triglycerides Make Soaps
9
Carboxylic acids with lots of carbons are fatty
acids (usually even #, 10, 12, 14, 16, 18)
Sodium salts of fatty
acids are soaps.
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Cleaning Action of Soap
A soap
• contains a nonpolar
end that dissolves in
nonpolar fats and oils,
and a polar end that
dissolves in water.
• forms groups of soap
molecules called
micelles that dissolve in
water and are washed
away.
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Learning Check
Write the organic products when methyl acetate
reacts with
A. water and an acid catalyst.
O

CH3—C—OH + HO—CH3
B. KOH.
O

CH3—C—O– K+
+ HO—CH3
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13.4 Amines (Derivatives of NH3)
Typically 3 kinds:
• Primary (1°) amines: 1 carbon group is bonded to N
• Secondary (2°) amines: 2 carbon groups bonded to N
• Tertiary (3°) amines: 3 carbon groups bonded to N.
H
|
CH3—N—H
1°
CH3
|
CH3—N—H
2°
CH3
|
CH3—N—CH3
3°
Quaternary (4°) amines also possible (4 C groups attached
to nitrogen atom)
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Naming Amines (No need to memorize)
• Simple amines are named as alkylamines.
• Names of alkyl groups bonded to the N atom listed in
alphabetical order in front of amine.
CH3—CH2—NH2
ethylamine
CH3—NH—CH3
dimethylamine
CH3
|
CH3—N—CH2—CH3 ethyldimethylamine
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Hydrogen Bonding for Amines
• N-H bond provides hydrogen bonding in
1°and 2° amines, but not in 3° amines.
• is not as polar as the O-H bonds in alcohols.
•
H-bonding not as good 
15
Solubility in Water
• Amines with 1-5 carbon atoms are soluble in water.
• Form hydrogen bonds with the polar O-H bond in
water.
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Amines React as Bases
Like ammonia, amines are weak bases in water.
NH3 + H2O
NH4+ + OH–
ammonium hydroxide
CH3—NH2 + H2O
CH3—NH3+ + OH–
methylammonium hydroxide
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Neutralization forms Amine Salts
An amine salt
• forms when an amine is
neutralized by acid.
CH3—NH2 + HCl
Cl–
methylamine
CH3—NH3+
methylammonium chloride
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OK so far???
1. Yes
2. No
3. Kinda…
0%
0%
0%
1
2
3
4
5
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Properties of Amine Salts
•
•
•
•
solids at room temperature.
soluble in water and body fluids.
the form used for drugs.
DON’T STINK!
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Alkaloids
• physiologically active
nitrogen-containing
compounds.
• obtained from plants.
• used as anesthetics,
antidepressants, and in
stimulants such as
caffeine.
• often addictive.
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Cocaine
• sold illegally as the amine salt.
• reacted with NaOH to produce the free
amine form known as “crack.”
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Caffeine and Nicotine
Caffeine
• is a stimulant of
the central
nervous system
Nicotine
• increases adrenaline
level in blood
N
CH 3
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Morphine and Codeine
• alkaloids.
• obtained from the
oriental poppy plant.
• used as painkillers.
• modified to make
heroin.
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Amides 13.5
• In amides, an amino group(–NH2) replaces the –OH
group of carboxylic acids.
O
||
CH3—C—OH
O
||
CH3—C—NH2
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Preparation of Amides
Amides are produced
• by reacting a carboxylic acid with ammonia
or an amine (1° or 2°).
• using heat.
O

Heat
CH3—C—OH + NH3
O

CH3—C—NH2 + H2O
O
O

Heat

CH3—C—OH + CH3—NH2
CH3—C—NH—CH3 + H2O
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Some Amides in Health and Medicine
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Physical Properties of Amides
SIMILAR TO AMINES…
• primary (−NH2) or secondary (−NH−) amides
form hydrogen bonds.
• primary have higher mp’s than secondary.
•
tertiary (no H on N) do not form hydrogen bonds &
have lower melting points.
• all form hydrogen bonds with water.
• with 1-5 carbon atoms are soluble in water.
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Hydrogen Bonding of Amides
O
||
CH3—C—N—H
|
H
Hydrogen bonding occurs
between primary amides.
O
||
CH3—C—N—H
|
H
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Hydrolysis of Amides
IMPORTANT TO KNOW
Amides undergo
• Acid hydrolysis to produce a carboxylic
acid and an ammonium salt.
• Base hydrolysis to produce the salt of a
carboxylic acid and an amine or ammonia.
• REACTIONS LOOK SIMILAR TO THOSE
OF ESTERS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Hydrolysis Reactions
acid hydrolysis
O
||
CH3—C—NH2
O
||
CH3—C—OH + NH4+Cl–
HCl + H2O
NaOH
O
||
CH3—C—O– Na+ + NH3
base hydrolysis
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