Chemistry Reference
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O
O
ethanol/H
2
O
reflux
H
2
N
NH
2
+
+
2
2
O
H
HO
O O
HO
OH
O
O
HO
OH
Ph
Ph
KMnO
4
KOH
Ph
Ph
N
N
N
N
HO
OH
O
O
50
51
Scheme 9
Synthesis of 1,10-dicarboxy-3,8-diphenyl-4,7-phenanthroline (
50
)[
55
]
2
O
NH
2
O
O
53
I
I
N
N
H
CuI, Cu
Bu
2
O, reflux
H
52
54
, 48%
H
2
SO
4
90-95 °C
N
N
55
, 52%
Scheme 10
Synthesis of 13,14-dimethyldibenzo[
b
,
j
][4,7]phenanthroline (
55
)[
56
]
R
R
R
ZnCl
2
200 °C, 9 h
+2HO
N
N
N
N
O
H
H
56
55
:R=Me, 56%
57
:R=Et, 50%
Scheme 11
One-pot synthesis of 13,14-dialkyldibenzo[
b
,
j
][4,7]phenanthrolines [
57
,
58
]
Treatment of diamine
56
with diacids
58
produced dibenzophenanthrolines
59a-c
bearing an additional 7-membered ring (Scheme
12
)[
57
]. Attempts to separate
59a
and
59b
by chiral HPLC were unsuccessful, presumably because of rapid rates of
racemization. The
1
H NMR spectrum of
59c
also indicates a rapid rate of racemiza-
tion. The presence of a stereogenic center at C13 of
59c
makesitpossibletoformtwo
diastereomeric pairs, (
S
)-(
M
)/(
R
)-(
P
)-
59c
and (
S
)-(
P
)/(
R
)-(
M
)-
59c
. Only the racemic
