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Chapter 22 741
Copyright © 2017 Pearson Education, Inc.
13.
If the
ortho
-carboxyl substituent acts as an intramolecular base catalyst,
18
O will be incorporated into
acetic acid and not into salicylic acid.
CH
3
CO
CH
3
CO
O
−
O
HO
O
H
18
O
H
O
−
18
OH
salicylate
CH
3
CO
−
O
18
+ +
CH
3
CO
Η
18
−
CH
3
C
18
OH
OH
O
O HO
O
−
O
−
O
C
C
O
C
−
O O
C
O
C
O
If the
ortho
-carboxyl substituent acts as an intramolecular nucleophilic catalyst,
18
O would be incorporated
into both salicylic acid (if water adds to the carbonyl group attached to the benzene ring) and acetic acid
(if water adds to the carbonyl group attached to the methyl group).
CH
3
CO
−
O
−
O
HO
O
−
O O
O O
C
O
−
O
O HO
O
O
O
O
H
3
C
−
CH
3
C
O
H
2
O
18
+
CH
3
C
18
CH
3
CO
−
HO
O
−
O
18
+
H
+
HO
C
O O
−
CH
3
C
HO
18
+
H
+
O
O
O
C
C
C
C
18
H
H
O
Here water adds to the carbonyl group
attached to the benzene ring.