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630 Chapter 18
Copyright © 2017 Pearson Education, Inc.
72.
COOH
COOH
COOH
COOH
COOH
CH
3
CCH
3
CH
3
a.
b.
c.
73.
Recall that the highest frequency signal is given by the most deshielded proton, that is, the one with the
least electron density (the signal farthest to the left on the spectrum).
a.
The oxygen withdraws electrons inductively from the carbon bonded to the hydrogens being compared,
so the oxygen-containing compound has the signal at the highest frequency.
_
CH
3
O CH
2
CH
3
b.
The oxygen donates electrons by resonance, so the oxygen-containing compound has the signal at the
lowest frequency.
+
CH
3
O CH CH
2
CH
3
O CH CH
2
_
Therefore, the non-oxygen-containing compound has the signal at the highest frequency.
CH
3
CH CH
2
_
74.
generation of the electrophile
+
H F
+
F
−
+
reaction of benzene with the electrophile
+
+
H
+
B
75.
a.
CH
3
C
OH
O
H
2
CrO
4
SOCl
2
2 CH
3
NH
2
C
Cl
O
C
NHCH
3
O
b.
CH
3
CH
2
Br
Br
2
h
ν
Mg
Et
2
O
1. CO
2
2. HCl
CH
2
MgBr
OH
O