1. Functional Derivatives of Carboxylic Acids

2. Nomenclature: the functional derivatives’ names are derived from the common or IUPAC names of the corresponding carboxylic acids.
Acid chlorides: change –ic acid to –yl chloride
Anhydrides: change acid to anhydride

3. Amides: change –ic acid (common name) to –amide
-oic acid (IUPAC) to –amide
Esters: change –ic acid to –ate preceded by the name of the alcohol group

4. Nucleophilic acyl substitution:

5. Mechanism: Nucleophilic Acyl Substitution1) 2)

6. Mechanism: nucleophilic acyl substitution, acid catalyzed1) 2) 3)

7. nucleophilic acyl substitution vs nucleophilic addition to carbonyl
aldehydes & ketones – nucleophilic addition
functional deriv. of carboxylic acids – nucleophilic acyl substitution

8. Acid Chlorides
Syntheses:
SOCl2
RCOOH PCl  RCOCl
PCl5

9. Acid chlorides, reactions:
Conversion into acids and derivatives:
a) hydrolysis
b) ammonolysis
c) alcoholysis
Friedel-Crafts acylation
Coupling with lithium dialkylcopper
Reduction

10. acid chlorides: conversion into acids and other derivatives

11. Schotten-Baumann technique – aromatic acid chlorides are less reactive than aliphatic acid chlorides. In order to speed up the reactions of aromatic acid chlorides, bases such as NaOH or pyridine are often added to the reaction mixture.

12. acid chlorides: Friedel-Crafts acylation

13. acid chlorides: coupling with lithium dialkylcopper

14. acid chlorides: reduction to aldehydes

15. Anhydrides, syntheses:
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Anhydrides, reactions:
Conversion into carboxylic acids and derivatives.
a) hydrolysis
b) ammonolysis
c) alcoholysis
2) Friedel-Crafts acylation

17. 2) anhydrides, Friedel-Crafts acylation.

18. Amides, synthesis:
Indirectly via acid chlorides.

19. Amides, reactions.
1) Hydrolysis.

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22. Esters, syntheses:
From acids
RCO2H R’OH, H RCO2R’ H2O
From acid chlorides and anhydrides
RCOCl R’OH RCO2R’ HCl
From esters (transesterification)
RCO2R’ R”OH, H RCO2R” R’OH
RCO2R’ R”ONa RCO2R” R’ONa

23. Esters often have “fruity” or “floral” odors:
isopentyl acetate banana oil
n-pentyl butyrate apricot
isopentyl isovalerate apple
ethyl butyrate peach
ethyl heptanoate cognac
ethyl nonate flower bouquet
ethyl laurate tuberose
methyl butyrate pineapple
octyl acetate orange

24. “Direct” esterification is reversible and requires use of LeChatelier’s principle to shift the equilibrium towards the products. “Indirect” is non-reversible.

25. In transesterification, an ester is made from another ester by exchanging the alcohol function.

26. Esters, reactions:
Conversion into acids and derivatives
a) hydrolysis
b) ammonolysis
c) alcoholysis
Reaction with Grignard reagents
Reduction
a) catalytic
b) chemical
4) Claisen condensation

28. Tracer studies confirm that the mechanism is nucleophilic acyl substitution:

30. Esters, reaction with Grignard reagents

32. Esters, reduction
catalytic
chemical

34. Spectroscopy:
Infrared: strong absorbance ~ 1700 cm-1 for C=O
RCO2R ArCO2R RCO2Ar 1770
Esters also show a strong C—O stretch at
Amides show N—H stretch at 3050 –3550 and N—H bend in the region.
Nmr: NB in esters the protons on the alcohol side of the functional group resonate at lower field than the ones on the acid side.
RCOO—C—H 3.7 – 4.1 ppm
H—C—COOR 2 – 2.2 ppm

35. methyl propionate
C=O
C--O

36. butyramide
C=O
N—H
N—H bend

37. Ethyl acetate
CH3CO2CH2CH3
b c a
Note which hydrogens are upfield.
c b a

38. Methyl propionate
CH3CH2CO2CH3
a b c
Note which hydrogens are upfield.
c b a