2. Conversion into functional derivatives (Carboxylic acid ...
Transcript of 2. Conversion into functional derivatives (Carboxylic acid ...
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2. Conversion into functional derivatives
(Carboxylic acid derivatives)
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Nomenclature of acid chloridesAcid chlorides are named by replacing the -ic acid ending with -yl choride or
replacing the carboxylic acid ending with -carbonyl chloride.
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b- Conversion into esters.
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Nomenclature of esters
• The mechanism of esterification is necessarily the exact
reverse of the mechanism of hydrolysis of esters.
Reactivity in esterification
(CH3OH > 1 > 2> 3)
HCOOH > CH3COOH > RCH2COOH > R2CHCOOH > R3CCOOH
Nomenclature of esters
The first word of the name comes from the alkyl group of the alcohol, and
the second part comes from the carboxylate group of the carboxylic acid
used.
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Nomenclature of esters
A cyclic ester is called a lactone, and the IUPAC names of lactones are derived
by adding the term lactone at the end of the name of the parent carboxylic acid.
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• (c) Conversion into amides.
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Nomenclature of amidesAmides are named by replacing the -oic acid or -ic acid suffix of the parent carboxylic
acids with the suffix -amide, or by replacing the -carboxylic acid ending with -
carboxamide.
Alkyl groups on nitrogen atoms are named as substituents, and are prefaced by N-or
N,N-, followed by the name(s) of the alkyl group(s).
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Preparation of acid anhydrides
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Preparation of acid anhydrides• Dicarboxylic acids yield anhydrides on simple heating: in those cases where a five-
or six-membered ring
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Nomenclature of acid anhydrides
Replacing the -acid suffix of the parent carboxylic acids with the word
anhydride.
Mixed anhydrides that consist of two different acid-derived parts are
named using the names of the two individual acids with an alphabetical
order.
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1-Reaction of acid chloride
1-Conversion into acid and acid derivative.
(a) Conversion into acids. Hydrolysis
(b) Conversion into amides. Ammonolysis
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(c) Conversion into esters. Alcoholysis
2. Formation of ketones. Friedel-Crafts acylation.
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3-Formation of aldehydes by reduction.
1. Hydrolysis
2-Reaction of amide
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2-Reacation of ester
(a) Conversion into acids. Hydrolysis
(b) Conversion into amides. Ammonolysis
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(c) Conversion into esters.
Transesterification. Alcoholysis
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3-Reaction of acid anhydrides
1. Conversion into acids and acid derivatives
(a) Conversion into acids. Hydrolysis
(b) Conversion into amides. Ammonolysis
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3. Reduction
One of the few reducing agents capable of reducing an acid
directly to an alcohol is lithium aluminum hydride, LiAlH4
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4. Substitution in alkyl or aryl group
a- Alpha-halogenation of aliphatic acids. Hell-Volhard-
Zelinsky reaction
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b-Ring substitution in aromatic acids (Electrophilic aromatic
substitution)
CO2H
CO2H
NO2
CO2H
SO3H
CO2H
Br
NR
HNO3,H2SO4
H2SO4,SO3
Br2,Fe
CH3Cl,AlCl3
benzoic acid
(-COOH is deactivating and meta- directing)
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Dicarboxylic acids
If the substituent is a second carboxyl group, we have a dicarboxylic acid. For
example:
HOOCCH2COOH HOOC(CH2)2COOH, HOOC(CH2)4COOH
Malonic acid Succinic acid Adipic acid
Propanedioic acid Butanedioic acid Hexanedioic acid
• Table 2 Dicarboxylic acid
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Preparation of Dicarboxylic acid
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Spectroscopy
• IR: -COOH O—H stretch 2500 – 3000 cm-1 (b)
C=O stretch 1680 – 1725 (s)
• nmr: -COOH 10.5 – 12 ppm
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IR SPECTRUM of p-toluic acid
-COO—H stretch C=O
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NMR Spectrum of p-toluic acid
COOH
CH3 a
b
c
C b a