Download CHM 103 Lecture 28 S07

Announcements & Agenda (04/02/07)
Last Time: Drawing Fischer Projections
Pop Quiz Right Now!
Quiz on Wednesday (Chirality
(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: Carboxylic Acids
Ester Products
Aspirin
• is used to relieve pain
and reduce inflammation.
• is an ester of salicylic
acid and acetic acid.
Carboxylic acids
• are weak acids.
• ionize in water to produce carboxylate
ions and hydronium ions.
O
║
CH3−C−OH + H2O
2
O
║
CH3−C−O– + H3O+
Oil of wintergreen
• is used to soothe sore
muscles.
• is an ester of salicylic
acid and methanol.
~1%
Also: Neutralization Reactions! Esterification!
Esterification!
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O
C OH
O
O C CH3
O
C O CH3
OH
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Naming Esters
Esters in Plants
Esters give flowers and fruits their
pleasant fragrances and flavors.
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:
oate: means
CH3— O—C —CH3
ester present
IUPAC: methyl ethanoate
common: methyl acetate
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Acid Hydrolysis of Esters
Base Hydrolysis (Saponification)
• 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
• 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
O
||
H—C—OH
+ H—O—CH2—CH3
salt of carboxylic acid
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alcohol
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Last Time: Base Hydrolysis of
Triglycerides Make Soaps
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
Learning Check
A soap
• contains a nonpolar
end that dissolves in
nonpolar fats and oils,
and a polar end that
dissolves in water.
Write the organic products when methyl acetate
reacts with
A. water and an acid catalyst.
O
||
CH3—C—OH + HO
HO—CH3
• forms groups of soap
molecules called
micelles that dissolve in
water and are washed
away.
B. KOH.
O
||
CH3—C—O– K+
11
+ HO
HO—CH3
12
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13.4 Amines (Derivatives of NH3)
Naming Amines (No need to memorize)
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.
• Simple amines are named as alkylamines.
alkylamines.
• Names of alkyl groups bonded to the N atom listed in
alphabetical order in front of amine.
amine.
H
|
CH3—N—H
1°
CH3
|
CH3—N—H
2°
CH3—CH2—NH2
CH3
|
CH3—N—CH3
3°
Quaternary (4°
(4°) amines also possible (4 C groups attached
to nitrogen atom)
ethylamine
ethylamine
dimethylamine
CH3—NH—
NH—CH3
imethylamine
CH3
|
CH3—N—CH2—CH3 ethyldimethylamine
ethyldimethylamine
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Solubility in Water
Hydrogen Bonding for Amines
• Amines with 11-5 carbon atoms are soluble in water.
• Form hydrogen bonds with the polar OO-H bond in
water.
• N-H bond provides hydrogen bonding in
1°and 2° amines, but not in 3° amines.
• is not as polar as the OO-H bonds in alcohols.
•
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H-bonding not as good /
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Amines React as Bases
Neutralization forms Amine Salts
Like ammonia, amines are weak bases in water.
An amine salt
• forms when an amine is
neutralized by acid.
NH4+ + OH–
ammonium hydroxide
NH3 + H2O
CH3—NH2 + HCl
Cl–
methylamine
CH3—NH3+ + OH–
CH3—NH2 + H2O
methylammonium hydroxide
CH3—NH3+
methylammonium chloride
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Properties of Amine Salts
OK so far???
0%
0%
1
•
•
•
•
1. Yes
2. No
3. Kinda…
Kinda…
0%
2
3
4
5
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solids at room temperature.
soluble in water and body fluids.
the form used for drugs.
DON’T STINK!
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5
Alkaloids
Cocaine
• sold illegally as the amine salt.
• reacted with NaOH to produce the free
amine form known as “crack.”
• physiologically active
nitrogennitrogen-containing
compounds.
• obtained from plants.
• used as anesthetics,
antidepressants, and in
stimulants such as
caffeine.
• often addictive.
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Caffeine and Nicotine
Morphine and Codeine
Caffeine
• is a stimulant of
the central
nervous system
Nicotine
• increases adrenaline
level in blood
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• alkaloids.
• obtained from the
oriental poppy plant.
• used as painkillers.
• modified to make
heroin.
N
CH 3
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Preparation of Amides
Amides 13.5
• In amides,
amides, an amino group(–
group(–NH2) replaces the –OH
group of carboxylic acids.
O
||
CH3—C—OH
O
||
CH3—C—NH2
Amides are produced
• by reacting a carboxylic acid with ammonia
or an amine (1°
(1° or 2°
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—
NH—CH3 + H2O
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Some Amides in Health and Medicine
Physical Properties of Amides
SIMILAR TO AMINES…
• primary (−
(−NH2) or secondary (−
(−NH−
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 11-5 carbon atoms are soluble in water.
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Hydrolysis of Amides
IMPORTANT TO KNOW
Hydrogen Bonding of Amides
O
||
CH3—C—N—H
|
H
Amides undergo
• Acid hydrolysis to produce a carboxylic
acid and an ammonium salt.
Hydrogen bonding occurs
between primary amides.
• Base hydrolysis to produce the salt of a
carboxylic acid and an amine or ammonia.
O
||
CH3—C—N—H
|
H
• REACTIONS LOOK SIMILAR TO THOSE
OF ESTERS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Hydrolysis Reactions
acid hydrolysis
O
||
CH3—C—NH2
HCl + H2O
NaOH
O
||
CH3—C—OH + NH4+Cl–
O
||
CH3—C—O– Na+ + NH3
base hydrolysis
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