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752 Chapter 22
Copyright © 2017 Pearson Education, Inc.
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CH
2
OPO
3
C (CH
2
)
4
(CH
2
)
4
(CH
2
)
4
CH
N
NH
NH
NH HC
NH
NH
CH
CH
C
HO H
HO H
H
H OH
H OH
OH
H OH
O
C O
C O
OH
1. NaBH
4
2. H
3
O
H
2
O
2
14
14
NH
NH
3
HC
HO H
H OH
H OH
14
CH
2
OPO
3
2
CH
2
OPO
3
2
CH
2
OPO
3
CH
2
OH
CH
2
OH
2
HCl
43.
a.
3-Amino-2-oxindole catalyzes the decarboxylation of an
a
-keto acid by first forming an imine, which
increases the acidity of the hydrogen on the
a
-carbon. Now the compound can be decarboxylated
because the electrons left behind are delocalized onto an oxygen.
+
+
+
OH
H B
C
C
O
O
R
N C
R
N CH
R
C
C
C
R
H
C
R
H
H
C
R
H
H
O
N
N
N
NH
2
H
NH
2
H
N
H
N
O
O
O
OO
O
O
O
O
H
N
H
N
H
N
H
H B
H
H
OH
CO
2
enolization
decarboxylation
-keto acid
imine formation
imine hydrolysis