chapter 11 carboxylic acid derivatives 1chapter 11
TRANSCRIPT
Chapter 11Carboxylic Acid Derivatives
1Chapter 11
Chapter 11 2
Acid Derivatives• All acid derivatives can be converted to the
carboxylic acid by acidic or basic hydrolysis.• Esters and amides are common in nature.
Chapter 11 3
Naming EstersIUPAC Nomenclature
As usual the long chain will contain the carbonyl carbon. Drop the “e” then add oate suffix. The remaining carbon chain is named as substituent and used as a prefix.
Common NomenclatureEsters are named from the common name of the acid used to form them. Drop the “oic acid” from the common acid name and att the suffix “ate”. The other carbon group is named as a substituent.
CH3CH2 OH HO C
O
CH3
H+
+ + H2OCH3CH2 O C
O
CH3
ethanol
ethyl alcohol
ethanoic acid
acetic acid
Chapter 11 4
Naming EstersIUPAC Nomenclature
As usual the long chain will contain the carbonyl carbon. Drop the “e” then add oate suffix. The remaining carbon chain is named as substituent and used as a prefix.
Common NomenclatureEsters are named from the common name of the acid used to form them. Drop the “oic acid” from the common acid name and att the suffix “ate”. The other carbon group is named as a substituent.
CH3CH2 OH HO C
O
CH3
H+
+ + H2OCH3CH2 O C
O
CH3
ethanol
ethyl alcohol
ethanoic acid
acetic acid
ethyl ethanoate
ethyl acetate
Chapter 11 5
Name These
CH3CHCH2OCCH3
CH3 O
HCOCH2
O
Chapter 11 6
Name These
CH3CHCH2OCCH3
CH3 O
HCOCH2
O
(Common)
Chapter 11 7
Name These
CH3CHCH2OCCH3
CH3 O
HCOCH2
O
isobutyl acetate (Common)
Chapter 11 8
Name These
CH3CHCH2OCCH3
CH3 O
HCOCH2
O
isobutyl acetate (Common)
benzyl formate (common)
Chapter 11 9
Name These
CH3CHCH2OCCH3
CH3 O
HCOCH2
O
isobutyl acetate (Common)2-methylpropyl ethanoate (IUPAC)
benzyl formate (common)
Chapter 11 10
Name These
CH3CHCH2OCCH3
CH3 O
HCOCH2
O
isobutyl acetate (Common)2-methylpropyl ethanoate (IUPAC)
benzyl formate (common)benzyl methanoate (IUPAC)
Chapter 11 11
Cyclic Esters• Reaction of -OH and -COOH on same molecule
produces a cyclic ester, lactone.• To name, add word lactone to the IUPAC acid name
or replace the -ic acid of common name with -olactone.
O
O
H3C
CH3
4-hydroxy-2-methylpentanoic acid lactone
OH
O
OH
H
Chapter 11 12
Cyclic Esters• Reaction of -OH and -COOH on same molecule
produces a cyclic ester, lactone.• To name, add word lactone to the IUPAC acid name
or replace the -ic acid of common name with -olactone.
O
O
H3C
CH3
4-hydroxy-2-methylpentanoic acid lactone-methyl--valerolactone
OH
O
OH
H
Chapter 11 13
Amides• Product of the reaction of a carboxylic acid
and ammonia or an amine.• Not basic because the lone pair on nitrogen
is delocalized by resonance.
HC
O
N
H
HH
C
O
N
H
H
_
+
Bond angles around Nare close to 120.
Chapter 11 14
Classes of Amides• 1 amide has one C-N bond (two N-H).• 2 amide or N-substituted amide has two C-
N bonds (one N-H).• 3 amide or N,N-disubstituted amide has
three C-N bonds (no N-H).
Chapter 11 15
Naming Amides• For 1 amide, drop -ic or -oic acid from the
carboxylic acid name, add -amide.• For 2 and 3 amides, the alkyl groups
bonded to nitrogen are named with N- to indicate their position.
CH3CHC N
O
CH2CH3
CH3
CH3
Chapter 11 16
Naming Amides• For 1 amide, drop -ic or -oic acid from the
carboxylic acid name, add -amide.• For 2 and 3 amides, the alkyl groups
bonded to nitrogen are named with N- to indicate their position.
CH3CHC N
O
CH2CH3
CH3
CH3
N-ethyl-N,2-dimethylpropanamideN-ethyl-N-methylisobutyramide
Chapter 21 17
Cyclic Amides• Reaction of -NH2 and -COOH on same molecule
produces a cyclic amide, lactam.• To name, add word lactam to the IUPAC acid name or
replace the -ic acid of common name with -olactam.
N
O
CH3
H
NH2
O
OH
H
Chapter 21 18
Cyclic Amides• Reaction of -NH2 and -COOH on same molecule
produces a cyclic amide, lactam.• To name, add word lactam to the IUPAC acid name or
replace the -ic acid of common name with -olactam.
N
O
CH3
H
4-aminopentanoic acid lactam-valerolactam
NH2
O
OH
H
Chapter 11 19
Nitriles• -CN can be hydrolyzed to carboxylic acid,
so nitriles are acid derivatives.• Nitrogen is sp hybridized, lone pair tightly
held, so not very basic (pKb about 24).
Chapter 11 20
Naming Nitriles• For IUPAC names, add -nitrile to the alkane
name.• Common names come from the carboxylic
acid. Replace -ic acid with -onitrile.
CH3CHCH2CH2CH2CN
BrC N
Chapter 11 21
Naming Nitriles• For IUPAC names, add -nitrile to the alkane
name.• Common names come from the carboxylic
acid. Replace -ic acid with -onitrile.
CH3CHCH2CH2CH2CN
Br
5-bromohexanenitrile-bromocapronitrile
C N
Cyclohexanecarbonitrile
Chapter 11 22
Acid Halides• More reactive than acids; the halogen
withdraws e- density from carbonyl.• Named by replacing -ic acid with -yl halide.
C
O
Cl CH3CHCH2C
Br O
Br
Chapter 11 23
Acid Halides• More reactive than acids; the halogen
withdraws e- density from carbonyl.• Named by replacing -ic acid with -yl halide.
C
O
Cl CH3CHCH2C
Br O
Br
benzoyl chloride
3-bromobutanoyl bromide-bromobutyryl bromide
Chapter 11 24
Acid Anhydrides• Two molecules of acid combine with the loss
of water to form the anhydride.• Anhydrides are more reactive than acids, but
less reactive than acid chlorides.• A carboxylate ion is the leaving group in
nucleophilic acyl substitution reactions.
R C
O
O H RC
O
OH R C
O
O C
O
R
Chapter 11 25
Naming Anhydrides• The word acid is replaced with anhydride.• For a mixed anhydride, name both acids.• Diacids may form anhydrides if a 5- or 6-
membered ring is the product.
CH3 C
O
O C
O
CH3 O
O
O
=>
Chapter 11 26
Naming Anhydrides• The word acid is replaced with anhydride.• For a mixed anhydride, name both acids.• Diacids may form anhydrides if a 5- or 6-
membered ring is the product.
CH3 C
O
O C
O
CH3
ethanoic anhydrideacetic anhydride
O
O
O1,2-benzenedicarboxylic anhydride
phthalic anhydride=>
Chapter 11 27
Multifunctional Compounds• The functional group with the highest
priority determines the parent name.• Acid > ester > amide > nitrile > aldehyde >
ketone > alcohol > amine > alkene > alkyne.
C
CN
O
OCH2CH3
Chapter 11 28
Multifunctional Compounds• The functional group with the highest
priority determines the parent name.• Acid > ester > amide > nitrile > aldehyde >
ketone > alcohol > amine > alkene > alkyne.
C
CN
O
OCH2CH3ethyl o-cyanobenzoate
Chapter 11 29
Boiling Points
Even 3 amides havestrong attractions.
Chapter 11 30
Melting Points• Amides have very high melting points.• Melting points increase with increasing
number of N-H bonds.
m.p. -61C m.p. 28C m.p. 79C
Chapter 11 31
Solubility• Acid chlorides and anhydrides are too reactive
to be used with water or alcohol.• Esters, 3 amides, and nitriles are good polar
aprotic solvents.• Solvents commonly used in organic reactions:
– Ethyl acetate– Dimethylformamide (DMF)– Acetonitrile
Chapter 11 32
Interconversion ofAcid Derivatives• Nucleophile adds to the carbonyl to form a
tetrahedral intermediate.• Leaving group leaves and C=O regenerates.
Chapter 11 33
ReactivityReactivity decreases as leaving group
becomes more basic.
Chapter 11 34
Interconversion of Derivatives
More reactive derivatives can be converted to less reactive derivatives.
Chapter 11 35
Acid Chloride to Anhydride• Acid or carboxylate ion attacks the C=O.• Tetrahedral intermediate forms.• Chloride ion leaves, C=O is restored, H+ is
abstracted.
+ HClC
O
R OC
O
R'
_
C
O
R Cl
OH C
OR'
C
O
R ClR' C
O
O H+
- H+
Chapter 11 36
Acid Chloride to Ester• Alcohol attacks the C=O.• Tetrahedral intermediate forms.• Chloride ion leaves, C=O is restored, H+ is
abstracted.
+ HClC
O
R OR'
_
C
O
R Cl
OH R'
C
O
R Cl+
- H+
R' O H
Chapter 11 37
Acid Chloride to Amide• Ammonia yields a 1 amide• A 1 amine yields a 2 amide• A 2 amine yields a 3 amide
Chapter 11 38
Anhydride to Ester• Alcohol attacks one C=O of anhydride.• Tetrahedral intermediate forms.• Carboxylate ion leaves, C=O is restored, H+
is abstracted.
Chapter 11 39
Anhydride to Amide• Ammonia yields a 1 amide• A 1 amine yields a 2 amide• A 2 amine yields a 3 amide
Chapter 11 40
Ester to Amide• Nucleophile must be NH3 or 1 amine.
• Prolonged heating required.
Surprise!
Chapter 11 41
Leaving GroupsA strong base is not usually a leaving group
unless it’s in an exothermic step.
Chapter 11 42
Transesterification• One alkoxy group can be replaced by
another with acid or base catalyst.• Use large excess of preferred alcohol.
TRANSESTERIFICATION OF COCAINE
N
H
0O
Ph
O
OCH3
CH3CH2OH
N
H
0O
Ph
O
OCH2CH3
Cocaine Cocaethylene
Chapter 11 44
Hydrolysis of Acid Chlorides and Anhydrides
• Hydrolysis occurs quickly, even in moist air with no acid or base catalyst.
• Reagents must be protected from moisture.
=>
Chapter 11 45
Acid Hydrolysis of Esters
• Reverse of Fischer esterification.• Reaches equilibrium.• Use a large excess of water.
+CH3 C
O
OCH3 HOH CH3 C
O
OH + CH3OHH+
=>
Chapter 11 46
Saponification• Base-catalyzed hydrolysis of ester.• “Saponification” means “soap-making.”• Soaps are made by heating NaOH with a fat
(triester of glycerol) to produce the sodium salt of a fatty acid - a soap.
• One example of a soap is sodium stearate, Na+ -OOC(CH2)16CH3.
Chapter 11 47
Hydrolysis of AmidesProlonged heating in 6 M HCl or 40% aqueous
NaOH is required.
Chapter 11 48
Hydrolysis of Nitriles• Under mild conditions, nitriles hydrolyze to
an amide.• Heating with aqueous acid or base will
hydrolyze a nitrile to an acid.
Chapter 11 49
Reduction to AlcoholsLithium aluminum hydride reduces acids, acid
chlorides, and esters to primary alcohols.
Chapter 11 50
Acid Chloride Synthesis• Use thionyl chloride, SOCl2, or oxalyl
chloride, (COCl)2.
• Other products are gases.
Chapter 11 51
Acid Chloride Reactions (1)
acid
ester
amide
acid anhydride
Chapter 11 52
Lab Synthesis of Anhydrides
• React acid chloride with carboxylic acid or carboxylate ion.
C
O
Cl+ CH3 C
O
O_ C
O
O C
O
CH3
• Heat dicarboxylic acids to form cyclic anhydrides. C
O
OH
C
O
OHO
O
O
Chapter 11 53
Anhydride Reactions
acid
ester
amide
acylbenzene
AlCl3
Chapter 11 54
Anhydride vs. Acid Chloride• Acetic anhydride is cheaper, gives a better
yield than acetyl chloride.• Use acetic formic anhydride to produce
formate esters and formamides.
• Use cyclic anhydrides to produce a difunctional molecule.
C
O
OCH2CH3
C
O
OHO
O
O
CH3CH2OH
Chapter 11 55
Synthesis of Esters
R C
O
OR'R C
O
OH + R'OHH+
+ HOHacid
R C
O
OR'R C
O
Cl + R'OH + HClacid chloride
R C
O
OR'R C
O
O C
O
R + R'OHH+
+ RCOOH
acid anhydride
R C
O
OH CH2N2+ R C
O
OCH3 N2+methyl ester
Chapter 11 56
Synthesis of Amides
R C
O
OH + HOH+ R'NH2heat
R C
O
NHR'acid
R C
O
O C
O
R + RCOOHR'2NH R C
O
NR'2+acid anhydride
R C
O
OR'' + R''OHR'NH2 R C
O
NHR'+ester
R C
O
NH2R C N + H2OH+ or OH-
nitrile
acid chlorideR'2NH2
+Cl-+R C
O
NR'2R'2NH+ 2R C
O
Cl
Chapter 11 57
Reactions of Amides
acid and amine
amine
1° amine
nitrile
CHAPTER 11 REVIEW
Chapter 11 58
Name
a. Ethyl ethanoateb.Propyl propanoatec. Ethyl propanoated.Propyl ethanoatee.Propyl butanoate
O
COCH2CH2CH3CH3CH2
Answer
a. Ethyl ethanoateb.Propyl propanoatec. Ethyl propanoated.Propyl ethanoatee.Propyl butanoate
The longest chain is three carbons. Propyl is the alkoxy group.
Name
a. 3-Hydroxybutanoic acid lactoneb.4-Hydroxybutanoic acid lactonec. 4-Hydroxypentanoic acid lactoned.5-Hydroxypentanoic acid lactone
O
O
Answer
a. 3-Hydroxybutanoic acid lactoneb.4-Hydroxybutanoic acid lactonec. 4-Hydroxypentanoic acid lactoned.5-Hydroxypentanoic acid lactone
A lactone is a cyclic ester. The hydroxy is on the fifth carbon.
Name
a. Pentanamideb. Butanamidec. N-Ethylethanamided. N-Ethylpropanamidee. N-Methylethanamide
O
CNHCH2CH3CH3CH2
Answer
a. Pentanamideb. Butanamidec. N-Ethylethanamided. N-Ethylpropanamidee. N-Methylethanamide
Ethyl is attached to the nitrogen. The longest chain is three carbons.
21.4 Name
a. 3-Aminobutanoic acid lactamb.4-Aminobutanoic acid lactamc. 4-Aminopentanoic acid lactamd.5-Aminopentanoic acid lactam
N
O
Answer
a. 3-Aminobutanoic acid lactamb.4-Aminobutanoic acid lactamc. 4-Aminopentanoic acid lactamd.5-Aminopentanoic acid lactam
A lactam is a cyclic amide. The amino group is on the fifth carbon.
Name
a. Pentanenitrileb.Butanenitrilec. Propanenitriled.2-Methylbutanenitrilee.3-Methylbutanenitrile
N(CH3)2CHCH2C
Answer
a. Pentanenitrileb.Butanenitrilec. Propanenitriled.2-Methylbutanenitrilee.3-Methylbutanenitrile
The longest chain has four carbons. The methyl is on the third carbon.
Name
a. 1-Chloroethanoyl chlorideb.2-Chloroethanoyl chloridec. 1-Chloropropanoyl chlorided.2-Chloropropanoyl chloride
O
CClCH3CH
Cl
Answer
a.1-Chloroethanoyl chlorideb.2-Chloroethanoyl chloridec. 1-Chloropropanoyl chlorided.2-Chloropropanoyl chloride
The longest chain has three carbons. Chlorines are on the second carbon and the carbonyl carbon.
Name
a. Ethanoic methanoic anhydrideb.Methanoic propanoic anhydridec. Ethanoic anhydrided.Ethanoic propanoic anhydridee.Propanoic anhydride
O
COCH3CH2
CCH3
O
Answer
a. Ethanoic methanoic anhydrideb.Methanoic propanoic anhydridec. Ethanoic anhydrided.Ethanoic propanoic anhydridee.Propanoic anhydride
The three-carbon chain is on the left. A two-carbon chain is on the right.
a. Ethanoic methanoic anhydrideb.Methanoic propanoic anhydridec. Ethanoic anhydrided.Ethanoic propanoic anhydride
O
CClCH3CH2 HO
CCH3
O
+
Answer
a. Ethanoic methanoic anhydrideb.Methanoic propanoic anhydridec. Ethanoic anhydrided.Ethanoic propanoic anhydride
An acid halide reacts with a carboxylic acid to form an anhydride.
a. Methyl ethanoateb.Methyl propanoatec. Ethyl ethanoated.Ethyl propanoate
O
CClCH3CH2
CH3OH+
Answer
a. Methyl ethanoateb.Methyl propanoatec. Ethyl ethanoated.Ethyl propanoate
An acid halide reacts with an alcohol to form an ester.
a. N-Methylethanamideb. N-Methylpropanamidec. N,N-Dimethylethanamided. N,N-Dimethylpropanamide
O
CClCH3CH2
2 (CH3)2NH+
Answer
a. N-Methylethanamideb. N-Methylpropanamidec. N,N-Dimethylethanamided. N,N-Dimethylpropanamide
An acid halide reacts with an amine to form an amide.
a. Ethanoic acid + ethanolb.Propanoic acid + methyl ethanoatec. Ethanoic acid + ethyl ethanoated.Propanoic acid + methyl propanoatee.Ethanoic acid + ethyl propanoate
O
COCH3CH2
CCH2CH3
OCH3OH
Answer
a. Ethanoic acid + ethanolb.Propanoic acid + methyl ethanoatec. Ethanoic acid + ethyl ethanoated.Propanoic acid + methyl propanoatee.Ethanoic acid + ethyl propanoate
An anhydride reacts with an alcohol to give a carboxylic acid and an ester.
a. N,N-Diethylpropanamide + propanoic acidb. N-Ethylpropanamide + propanoic acidc. N-Ethylethanamide + ethanoic acidd. N,N-Diethylethanamide + ethanoic acid
O
COCH3CH2
CCH2CH3
OCH3CH2NH2
Answer
a. N,N-Diethylpropanamide + propanoic acidb. N-Ethylpropanamide + propanoic acidc. N-Ethylethanamide + ethanoic acidd. N,N-Diethylethanamide + ethanoic acid
An anhydride reacts with an amide to form an amide and a carboxylic acid.
a. N-Propyl propanamide + methanolb. N-Propyl ethanamide + ethanolc. N-Ethyl propanamide + methanold. N-Ethyl ethanamide + ethanole. N-Ethyl ethanamide + propanol
O
COCH3CH3CH2
CH3CH2CH2NH2
Answer
a. N-Propyl propanamide + methanolb. N-Propyl ethanamide + ethanolc. N-Ethyl propanamide + methanold. N-Ethyl ethanamide + ethanole. N-Ethyl ethanamide + propanol
An ester reacts with an amine to produce an amide and an alcohol.
a. Propanal + ammoniab.Ethanoic acid + ammoniac. Propanoic acid + methylamined.Ethanoic acid + methylamine
O
CNHCH3CH3CH2
H2SO4
Answer
a. Propanal + ammoniab.Ethanoic acid + ammoniac. Propanoic acid + methylamined.Ethanoic acid + methylamine
An amide is hydrolyzed under acidic conditions to form a carboxylic acid and an amine.
a. Propylamineb.Propanamidec. Propanoic acidd.Butanoic acide.No reaction
NCH3CH2CH2SO4
heat
Answer
a. Propylamineb.Propanamidec. Propanoic acidd.Butanoic acide.No reaction
A nitrile is hydrolyzed to a carboxylic acid in the presence of acid and heat.
a. Methanol + ethanolb.Methanol + propanolc. Ethanol + propanold.Ethanol
C
O
OCH3CH3CH2
1. LiAlH4
2. H3O+
Answer
a. Methanol + ethanolb.Methanol + propanolc. Ethanol + propanold.Ethanol
An ester is reduced to two alcohols.
a. Ethyl methyl amineb.Ethyl propyl aminec. Methyl propyl amined.Methyl amine + propanoic acide.Ethyl amine + propanoic acid
C
O
NHCH3CH3CH2
1. LiAlH4
2. H2O
Answer
a. Ethyl methyl amineb.Ethyl propyl aminec. Methyl propyl amined.Methyl amine + propanoic acide.Ethyl amine + propanoic acid
An amide is reduced to an amine with lithium aluminum hydride.
a. 2-Methyl-2-butanolb.3-Methyl-3-pentanolc. 1-Butanold.3-Methyl-2-butanole.3-Ethyl-3-pentanol
C
O
ClCH3CH2
1. 2 CH3MgBr
2. H3O+
Answer
a. 2-Methyl-2-butanolb.3-Methyl-3-pentanolc. 1-Butanold.3-Methyl-2-butanole.3-Ethyl-3-pentanol
Two methyl groups add to the carbon of the carbonyl. Hydrolysis yields the tertiary alcohol.
a. 2-Methyl-2-butanol + ethanolb.2-Methyl-2-butanol + methanolc. 2-Butanone + ethanol d.2-Methyl-2-butanol + ethanol
C
O
OCH2CH3CH3CH2
1. 2 CH3MgBr
2. H3O+
Answer
a. 2-Methyl-2-butanol + ethanolb.2-Methyl-2-butanol + methanolc. 2-Butanone + ethanol d.2-Methyl-2-butanol + ethanol
The reaction of an ester with a Grignard reagent forms a tertiary alcohol and an alcohol.
Chapter 11 97
End of Chapter 11