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Carboxylic AcidsNitriles
Natural Products
Nomenclature
Acidity
Preparation
Reactions
Analgesics
ibuprofinHO2C
acetyl salicylic acid
CO2H
OCCH3
O
(S)(+)-
Fats and Fatty Acids
CO2H
palmitic acid (a fatty acid)
CH2
CH
CH2
OCR
OCR
O
O
O
OCR
a triglyceride
R = n-C15H31
Prostaglandins
a prostaglandin
O
HO
CO2H
OHarachadonic acid
CO2Hcyclo-
oxygenase
natural mediators of inflammation
Penicillins from moldPenicillium chrysogenum
R= NH2 ampicillin
N
S
CO2H
PhCHCNH
O
R
O
R = H penicillin G
From Ergot Fungus
(+) lysergic acid
N
NH
CH3HO2C
H
Common Nomenclature
HCO2H
CH3CO2H
CO2H
CO2H
CO2H
Prefix
form
acet
propion
butyr
valer
prefix + ic + _acid
CO2HCl
-chlorovaleric acid
CO2H
CO2H
CO2H
capro
enanth
capryl
CO2Hpelargon
CO2Hcapr
CO2H
Cl Cl
dichloro--phenylcaprylic acid
I.U.P.A.C. Nomenclature
O
OHheptanoic acid
drop e from alkane and add "oic acid"
CO2H(Z) 2-methyl-2-pentenoic acid
CO2H
cyclopentanecarboxylic acid
CH2CO2H
Brp-bromophenylethanoic acidp-bromophenylacetic acid
Dicarboxylic Acids
HO2CCO2H or ethanedioic acid
HO2CCH2CO2H
HO2CCH2CH2CO2H
HO2CCH2CH2CH2CO2H
HO2CCH2CH2CH2CH2CO2H
HO2CCH2CH2CH2CH2CH2CO2H
oxalic acid
malonic acid
succinic acid
glutaric acid
adipic acid
pimelic acid
'
A Diacid
OH
O
O
HO
Br Cl
-bromo-'-chloroadipic acid
2-bromo-4-chlorohexanedioic acid
Unusually High Melting and Boiling Points
Boiling Points
CH3COH
O
CH3CH2CH2OH
CH3CH2CH
O
b.p. Co
118
97
49
CH3CH2OCH3 8
Acidity is due to Delocalization of the Charge in the Conjugate Base
Alcohol vs. Acid
e- Withdrawing Groups Enhance Acidity
Benzoic acids
CO2H
NO2
CO2H
CHO
CO2H
H
CO2H
OCH3
pKa: 3.41 3.75 4.19 4.46
CO2H
Cl
4.0
most deactivated most activated
Deprotonation
COH
O
+ NaHCO3
CO
O
Na
+ H2CO3
pKa 4.2 pKa 6.5
Ester Formation
COH
O
1) NaOH
2) CH3CH2CH2CH2Brp.t.c.
COCH2CH2CH2CH3
O
Carboxylic Acid Preparations
• Oxidation of 1o alcohols and aldehydes with Na2Cr2O7/H2SO4
• KMnO4 oxidation of alkylbenzenes
• Grignard reaction with CO2 (Carboxylation)
• Hydrolysis of a carboxylic derivative:
e.g. acid chloride, acid anhydride, ester, amide, nitrile
Grignard Reaction with CO2
Br1) Mg, ether
2) CO2, -78oC3) H3O+
CO2H
Mechanism
CO2H
3) H3O+2) CO2, -78oC
1) Mg, etherBr
MgBr
C
O
O
C
O
O MgBr
H+Mg
Hydrolysis of a Nitrile
BrKCN
CNH3O+
or 1) NaOH2) H3O+
CO2HSN2
Reduction of Carboxylic Acids
Naming Nitriles
CH3CHCH2CH2CN
CH3
4-methylpentanenitrileCN
cyclohexanecarbonitrile
CN
5-hexynenitrile
CN
Clp-chlorobenzonitrile
Dehydration of an Amideuse strong dehydrating agent
or SOCl2+ H2O
Reduction of Nitriles
CN CH2NH2
1) LiAlH4
2) H2O
Grignard Addition to a Nitrile
CN1) CH3MgBr
2) H3O+, heat CH3
O
+ NH3heptanenitrile 2-octanone
Partial Mechanism
C N1) CH3MgBr
2) H3O+, heat CH3
O
+ NH3
CN
CH3
CN
CH3
H
an imine
H3O+
H
pH = 4-5
H3O+
imine hydrolysis
The Rest of the Mechanism
CH3
N H
H3O+
CH3
N H
H
H+
H2O
CH3
NH2OHH
NH3
CH3
OH
H+ transferintermolec.
CH3
OH
O
CH3
H2O