Synthesis of bis-benzoquinoline derivatives catalyzed by iodine via ring-opening of furan

Article abstract of DOI:10.1016/j.tet.2013.06.042

A three-component reaction of aromatic aldehyde, naphthalene-2-amine, and tetrahydro-2,5-dimethoxyfuran in methanol catalyzed by iodine, is described in this paper. With the ring-opening of furan, a series of 3-aryl-2-(3-arylbenzo[f] quinolin-2-yl)benzo[f]quinoline derivatives were obtained in moderate yields.

Full text of DOI:10.1016/j.tet.2013.06.042

Tetrahedron 69 (2013) 7045e7050
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis of bis-benzoquinoline derivatives catalyzed by iodine via
ring-opening of furan
*
Dong-Sheng Chen, Yu-Ling Li, Yun Liu, Xiang-Shan Wang
School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials,
Jiangsu Normal University, Xuzhou Jiangsu 221116, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A
three-component reaction of aromatic aldehyde, naphthalene-2-amine, and tetrahydro-2,5-
Received 19 March 2013
Received in revised form 3 June 2013
Accepted 13 June 2013
dimethoxyfuran in methanol catalyzed by iodine, is described in this paper. With the ring-opening of
furan, a series of 3-aryl-2-(3-arylbenzo[f]quinolin-2-yl)benzo[f]quinoline derivatives were obtained in
moderate yields.
Available online 21 June 2013
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Quinoline
Three-component reaction
Ring-opening
Iodine
1. Introduction
In recent years, it is well known that imino-DielseAlder re-
action, also named Povarov reaction, provides an easy access to the
Multicomponent reactions (MCRs), combining three or more
reactants to a one-pot procedure to generate a complex organic
molecule, have become increasingly popular during the last
decade.1 They are considered as a new type of green chemistry in
economical reaction steps, because the ordinary multi-step
syntheses produce considerable amounts of waste in the pro-
cess of separation and purification for each step. Therefore,
MCRs provide a powerful tool toward the one-pot synthesis of
diverse and complex compounds as well as small and drug-like
heterocycles.
It is reported that quinoline and its derivatives are very useful
compounds in the fields of biological and pharmacological chem-
istry. Some of them were used as DNA methylation modulators for
the treatment of cancer and hematological disorders,2 and as an-
timalarial agents in the treatment of malarial infections.3 In addi-
tion, they also exhibited the good antimicrobial,4 antiproliferative,5
and antituberculosis activities.6 Accordingly, novel strategies for
the synthesis of quinolines continued to receive considerable at-
tention in the field of synthetic organic chemistry7 besides
the classical synthetic methods, for example, the Skraup, Doeb-
nereVon Miller, Conrad-Limbach, Combes, and Pfitzinger quinoline
syntheses.8
preparation of quinoline skeleton. The imines derived from aro-
matic amines act as the heterodienes, while the dienophiles are
various kinds of electron-rich double bonds. Generally, they are 2,3-
dihydrofuran, 3,4-dihydro-2H-pyran, vinyl ether, enol induced
from aldehyde or ketone, and indiole.9e14
Previously, we have reported an unusual THF-involved reaction
of benzaldehyde, naphthalene-2-amine catalyzed by iodine.15 The
ring-opening of THF was found to produce 2-(3-arylbenzo[f]qui-
nolin-2-yl)ethanol derivatives unexpectedly. As part of a continu-
ing effort in our laboratory toward this novel ring-opening reaction,
tetrahydro-2,5-dimethoxyfuran was chosen to react with 4-
chlorobenzaldehyde and naphthalene-2-amine with 1:1:1 molar
ratio (Scheme 1). To our delight, the designed reaction proceeded
smoothly in methanol catalyzed by iodine, and afforded bis-benzo
[f]quinoline derivatives unexpectedly in 42% yield.
Subsequently, we repeated this novel reaction using 4-
chlorobenzaldehyde, naphthalene-2-amine and tetrahydro-2,5-
dimethoxyfuran as model substrates with 2:2:1 molar ratio to op-
timize reaction conditions. Several parameters were explored as
shown in Table 1. No desired product was obtained when the re-
action was carried out in the absence of iodine (Table 1, entry 1),
and much greater in the presence of various quantities of the io-
dine, a maximum of 76% yield was obtained with 5 mol % iodine
(Table 1, entries 2e4). Other metal Lewis acids, such as CuI, AlCl3,
ZnCl2, AgOTf, Cu(OTf)2, Yb(OTf)3 were also tested in this reaction
* Corresponding author. E-mail address: xswang1974@yahoo.com (X.-S. Wang).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.06.042

7046
D.-S. Chen et al. / Tetrahedron 69 (2013) 7045e7050
Cl
CHO
Cl
N
NH2
I2
+
+
OCH3
H3CO
Methanol
O
N
Cl
Scheme 1. The model reaction.
Table 1
benzaldehydes. In all cases, the reactions proceeded efficiently at
reflux under mild conditions to afford the corresponding products in
moderate yields (Scheme 2).
Synthesis of 4a under different reaction conditionsa
Entry
Cat.
Amount/mol %
Solvent
Yieldsb/%
However, we failed to get the desired products when aliphatic
aldehydes were used as the reactants, because the aliphatic
aldehydes, such as propyl aldehyde and butyl aldehyde, not only
could react with anime to produce Schiff base as a diene, but also
act as a dienophile induced by iodine.16 In order to expand the
application of amines, anilines, such as piperonylamine and 3,4-
dimethoxyaniline were also tested in our lab, however, the re-
actions generated a very complicated system. Subsequent purifi-
cation by column chromatography only gave the poor yields
(Scheme 3). All the products were characterized by 1H NMR, 13C
NMR, IR, and HRMS, and the data were in good agreement with the
preconceived structures.
1
2
3
4
5
6
7
8
d
0
1
5
10
5
5
5
5
5
5
Methanol
Methanol
Methanol
Methanol
Methanol
Methanol
Methanol
Methanol
Methanol
Methanol
Toluenec
CH3CNd
0
I2
I2
I2
CuI
AlCl3
ZnCl2
AgOTf
Cu(OTf)2
Yb(OTf)3
I2
62
76
75
0
Trace
Trace
42
15
53
58
62
51
53
9
10
11
12
13
14
5
5
5
5
I2
I2
I2
EtOHd
DMFc
According to the structure of the product and literature,15 we
think twice Povarov reactions and aromatizations, ring-opening of
furan may take place to give the final product 4. The best reason to
explain the poor yields for anilines is that the activity of naph-
thalen-2-amine is higher than those of anilines. In the intermediate
a
Reagents and conditions: 1 (280 mg, 2.0 mmol), 2 (286 mg, 2.0 mmol), 3
(132 mg, 1.0 mmol), solvent (10 mL).
b
Isolated yields.
c
80 ꢀC.
Reflux.
d
III, the position 1 is not only the
a-cite of amino group, but also is
(Table 1, entries 5e10), and iodine was found to be the best choice
(Table 1, entry 3). Different solvents, such as toluene, CH3CN, DMF,
and EtOH were also tested, and methanol appeared to be the best
medium for this transformation (entry 3 vs 11e14).
Similarly, various kinds of aromatic aldehydes were selected to
reactwith naphthalen-2-amine and tetrahydro-2,5-dimethoxyfuran,
and it was found they all gave 3-aryl-2-(3-arylbenzo[f]quinolin-2-yl)
benzo[f]quinoline derivatives expectedly. The results are summa-
rized in Table 2. It is observed that the process can tolerate both
electron-donating and electron-withdrawing substituents in the
the -cite of another benzene. The possible reaction mechanism
a
was outlined in Scheme 4 as follows.
In order to get more insight into the reaction mechanism, tet-
rahydro-2,5-dimethoxyfuran was dissolved in CDCl3, and the 1H
NMR was determined for control-experiment. Subsequently, a little
amount of iodine was added to the above solution for 30 min, the
second 1H NMR was carried out, and new peaks were found at 5.96
and 6.26 ppm, which were identified as the hydrogen atoms of
double bonds in hydrofuran. This result indicated that the double
bond may form from tetrahydro-2,5-dimethoxyfuran. According to
the result, furan and 2-methylfuran were selected to this reaction,
however, they did not involve in the designed reaction. Perhaps, the
aromaticity for furan prevented the further continuation of Povarov
reaction.
In conclusion, we found a novel and efficient method for the
synthesis of 3-aryl-2-(3-arylbenzo[f]quinolin-2-yl)benzo[f]quin-
oline derivatives using 5 mol % iodine as catalyst. The three-
component reaction includes the interesting ring-opening of
tetrahydro-2,5-dimethoxyfuran to construct bis-benzoquinolines
in mild reaction conditions, good yields and operational
simplicity.
Table 2
Synthetic results of 4 catalyzed by iodinea
Entry
Ar
Products
Time/h
Yieldsb/%
1
2
3
4
5
6
7
8
4-ClC6H4
4-FC6H4
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
11
15
12
18
11
12
10
15
12
17
15
15
12
12
15
12
76
82
68
65
75
78
69
80
82
64
69
75
65
71
76
72
4-BrC6H4
4-CH3C6H4
4-CH3OC6H4
4-NO2C6H4
3-BrC6H4
3-FC6H4
3,4-Cl2C6H3
2-FC6H4
C6H5
3-CH3C6H4
2-Thienyl
3-NO2C6H4
3-CH3OC6H4
3-ClC6H4
9
10
11
12
13
14
15
16
2. Experimental section
2.1. General procedure for the syntheses of bis-
benzoquinoline 4 and bis-quinoline derivatives 5
a
Reagents and conditions: 1 (2.0 mmol), 2 (286 mg, 2.0 mmol), 3 (132 mg,
Aromatic aldehyde (2.0 mmol), amine (2.0 mmol), tetrahydro-
2,5-dimethoxyfuran (132 mg, 1.0 mmol), I2 (13 mg), and methanol
1 mmol), I2 (13 mg), methanol (10.0 mL).
b
Isolated yields.

D.-S. Chen et al. / Tetrahedron 69 (2013) 7045e7050
7047
Ar
NH2
+
I2
N
+
ArCHO
2
2
OCH3
H3CO
O
Methanol
N
Ar
1
2
3
4
Scheme 2. The reaction of aromatic aldehyde, naphthalen-2-amine, and tetrahydro-2,5-dimethoxyfuran.
R
Ar
NH2
+
I2
N
R
2
+
ArCHO
2
OCH3
H3CO
O
Methanol
N
Ar
R
5a: Ar = 4-BrC6H4, R = 3,4-OCH2O, 23 %
5b: Ar = 2,4-Cl2C6H3, R = 3,4-(OMe)2, 31%
5
Scheme 3. The synthesis of bis-quinolines.
I2
+
CH3OH
Ar
OCH3
OCH3
H3CO
O
I
O
1
NH2
N
2
I2
+
ArCHO
3
N
Ar
I2
II
III
I2
I2
OCH3
OCH3
OCH3
HO
Ar
O
O
OCH3
Povarov
Reaction
O
N
N
N
H
Ar
Ar
V
VI
IV
OCH3
HO
OCH3
I2
-H2O
Air
Aromatization
III
Povarov
Reaction
N
N
Ar
Ar
VII
VIII
Ar
Ar
N
N
-CH3OH
Air
4
N
N
Aromatization
Ar
Ar
H3CO
X
IX
Scheme 4. The possible reaction mechanism.

7048
D.-S. Chen et al. / Tetrahedron 69 (2013) 7045e7050
(10 mL) were added into a 25 mL flask. The reaction mixture was
stirred at reflux for 10e18 h before reaching completion, which was
monitored by TLC. The solvent was removed by distillation under
reduced pressure. The residue was purified by column chroma-
tography using ethyl acetate and petroleum ether (1:5) as eluant to
give final products 4 and 5.
1434, 1405, 1359, 1305, 1291, 1250, 1175, 1027, 833, 748 cmꢁ1
.
HRMS (ESI, m/z): calcd for C40H29N2O2 [MþH]þ 569.2229, found
569.2269.
2.1.6. 3-(4-Nitrophenyl)-2-(3-(4-nitrophenyl)benzo[f]quinolin-2-yl)
benzo[f]quinoline (4f). Yield 78% (467 mg). Pale yellow powder,
mp >300 ꢀC; 1H NMR (DMSO-d6):
d
7.05 (d, J¼8.8 Hz, 4H, ArH),
2.1.1. 3-(4-Chlorophenyl)-2-(3-(4-chlorophenyl)benzo[f]quinolin-2-
yl)benzo[f]quinoline (4a). Yield 76% (439 mg). Pale yellow powder,
mp >300 ꢀC; 1H NMR (DMSO-d6): dH 6.84 (d, J¼8.4 Hz, 4H, ArH),
7.13 (d, J¼8.4 Hz, 4H, ArH), 7.78e7.86 (m, 4H, ArH), 8.00 (d,
J¼9.2 Hz, 2H, ArH), 8.16 (d, J¼7.2 Hz, 2H, ArH), 8.23 (d, J¼8.8 Hz, 2H,
ArH), 9.12 (d, J¼8.0 Hz, 2H, ArH), 9.73 (s, 2H, ArH). 13C NMR (CDCl3):
dC 122.9, 124.5, 127.5, 127.8, 128.1, 128.2, 129.1, 129.3, 130.5, 131.8,
7.82e7.92 (m, 8H, ArH), 8.02 (d, J¼9.2 Hz, 2H, ArH), 8.18 (d, J¼7.2 Hz,
2H, ArH), 8.27 (d, J¼9.2 Hz, 2H, ArH), 9.18 (d, J¼8.0 Hz, 2H, ArH),
9.86 (s, 2H, ArH). 13C NMR (CDCl3): dC 123.05, 123.11, 125.1, 127.8,
128.0, 128.4, 129.1, 129.2, 130.2, 131.9, 132.3, 132.6, 134.3, 145.6,
147.1, 148.0, 154.4. IR (KBr):
n 3075, 3053, 1601, 1522, 1474, 1455,
1433, 1408, 1345, 1312, 1287, 1102, 1052, 1032, 1013, 902, 873, 853,
831, 758, 738, 719, 696 cmꢁ1. HRMS (ESI, m/z): calcd for C38H23 N4O4
[MþH]þ 599.1719, found 599.1752.
132.1, 132.5, 134.1, 134.2, 138.0, 147.8, 156.0. IR (KBr):
n 3053, 1595,
1580, 1561, 1491, 1475, 1444, 1431, 1406, 1390, 1282, 1093, 1014, 901,
832, 742, 671 cmꢁ1. HRMS (ESI, m/z): calcd for C38H23Cl2N2 [MþH]þ
577.1238, found 577.1244.
2.1.7. 3-(3-Bromophenyl)-2-(3-(3-bromophenyl)benzo[f]quinolin-2-
yl)benzo[f]quinoline (4g). Yield 69% (458 mg). Pale yellow powder,
mp >300 ꢀC; 1H NMR (DMSO-d6):
d
6.73 (d, J¼8.0 Hz, 2H, ArH),
2.1.2. 3-(4-Fluorophenyl)-2-(3-(4-fluorophenyl)benzo[f]quinolin-2-
yl)benzo[f]quinoline (4b). Yield 82% (446 mg). Pale yellow powder,
6.94e6.98 (m, 4H, ArH), 7.42 (d, J¼8.0 Hz, 2H, ArH), 7.79e7.87 (m,
4H, ArH), 8.02 (d, J¼9.2 Hz, 2H, ArH), 8.16 (d, J¼7.6 Hz, 2H, ArH),
8.24 (d, J¼9.2 Hz, 2H, ArH), 9.15 (d, J¼8.0 Hz, 2H, ArH), 9.76 (s, 2H,
ArH). 13C NMR (CDCl3): dC 122.8, 123.0, 124.6, 127.4, 127.5, 127.9,
128.1, 129.0, 129.1, 129.3, 130.9, 131.8, 132.1, 132.4, 132.5, 134.2, 141.2,
mp >300 ꢀC; 1H NMR (DMSO-d6):
d 6.83e6.93 (m, 8H, ArH),
7.77e7.83 (m, 4H, ArH), 7.99 (d, J¼9.2 Hz, 2H, ArH), 8.15 (d, J¼7.6 Hz,
2H, ArH), 8.22 (d, J¼8.8 Hz, 2H, ArH), 9.11 (d, J¼8.0 Hz, 2H, ArH),
9.71 (s, 2H, ArH). 13C NMR (CDCl3): dC 114.8, 115.0, 122.9, 124.3,
127.5, 127.7, 128.2, 129.0, 129.3, 130.9, 131.0, 131.7, 132.0, 132.6, 134.1,
147.8, 155.6. IR (KBr):
n 3056, 1603, 1591, 1558, 1474, 1445, 1432,
1403,1395,1355,1279,1261,1197,1068, 906, 887, 831, 800, 772, 740,
719, 694 cmꢁ1. HRMS (ESI, m/z): calcd for C38H23Br2N2 [MþH]þ
665.0228, found 665.0214.
135.68, 135.72, 147.7, 156.2, 161.4, 163.9. IR (KBr): n 3057, 1602, 1578,
1563, 1510, 1475, 1445, 1406, 1279, 1223, 1156, 1095, 1032, 1014, 831,
816, 751, 743 cmꢁ1. HRMS (ESI, m/z): calcd for C38H23F2N2 [MþH]þ
545.1829, found 545.1841.
2.1.8. 3-(3-Fluorophenyl)-2-(3-(3-fluorophenyl)benzo[f]quinolin-2-
yl)benzo[f]quinoline (4h). Yield 80% (436 mg). Pale yellow pow-
2.1.3. 3-(4-Bromophenyl)-2-(3-(4-bromophenyl)benzo[f]quinolin-2-
der, mp >300 ꢀC; 1H NMR (DMSO-d6):
d 6.56e6.62 (m, 4H,
yl)benzo[f]quinoline (4c). Yield 68% (451 mg). Pale yellow powder,
ArH), 7.05e7.08 (m, 4H, ArH), 7.79e7.87 (m, 4H, ArH), 7.99 (d,
J¼9.2 Hz, 2H, ArH), 8.16 (d, J¼7.6 Hz, 2H, ArH), 8.24 (d, J¼9.2 Hz,
2H, ArH), 9.14 (d, J¼8.0 Hz, 2H, ArH), 9.76 (s, 2H, ArH). 13C NMR
(CDCl3): dC 114.8, 115.1, 116.1, 116.3, 122.9, 124.6, 124.91, 124.94,
127.5, 127.8, 128.2, 129.1, 129.2, 129.3, 131.8, 132.1, 132.5, 134.2,
mp >300 ꢀC; 1H NMR (DMSO-d6):
d
6.78 (d, J¼8.4 Hz, 4H, ArH), 7.27
(d, J¼8.4 Hz, 4H, ArH), 7.78e7.86 (m, 4H, ArH), 8.00 (d, J¼9.2 Hz, 2H,
ArH), 8.16 (d, J¼7.2 Hz, 2H, ArH), 8.23 (d, J¼9.2 Hz, 2H, ArH), 9.11 (d,
J¼8.0 Hz, 2H, ArH), 9.72 (s, 2H, ArH). 13C NMR (CDCl3): dC 122.5,
122.9, 124.5, 127.5, 127.8, 128.2, 129.1, 129.3, 130.8, 131.1, 131.8, 132.1,
141.6, 141.7, 147.7, 155.88, 155.90, 161.4, 163.9. IR (KBr):
n 3058,
132.4, 134.2, 138.4, 147.8, 156.0. IR (KBr):
n
3051, 1604, 1586, 1561,
1609, 1587, 1579, 1564, 1475, 1446, 1437, 1404, 1296, 1281, 1267,
1221, 1191, 883, 859, 828, 797, 758, 746, 698 cmꢁ1. HRMS
(ESI, m/z): calcd for C38H23F2N2 [MþH]þ 545.1829, found
545.1835.
1474, 1445, 1433, 1407, 1390, 1358, 1279, 1074, 1010, 900, 866, 830,
748, 671 cmꢁ1. HRMS (ESI, m/z): calcd for C38H23Br2N2 [MþH]þ
665.0228, found 665.0255.
2.1.4. 3-(4-Methylphenyl)-2-(3-(4-methylphenyl)benzo[f]quinolin-2-
2.1.9. 3-(3,4-Dichlorophenyl)-2-(3-(3,4-dichlorophenyl)benzo[f]qui-
yl)benzo[f]quinoline (4d). Yield 65% (349 mg). Pale yellow powder,
nolin-2-yl)benzo[f]quinoline (4i). Yield 82% (529 mg). Pale yellow
mp >300 ꢀC; 1H NMR (DMSO-d6):
d
2.22 (s, 6H, 2CH3), 6.75 (d,
powder, mp >300 ꢀC; 1H NMR (DMSO-d6):
d
6.69 (dd, J¼8.4 Hz,
J¼8.0 Hz, 4H, ArH), 6.83 (d, J¼8.0 Hz, 4H, ArH), 7.75e7.83 (m, 4H,
ArH), 7.97 (d, J¼9.2 Hz, 2H, ArH), 8.13 (d, J¼8.0 Hz, 2H, ArH), 8.19
(d, J¼9.2 Hz, 2H, ArH), 9.06 (d, J¼8.4 Hz 2H, ArH), 9.61 (s, 2H, ArH).
13C NMR (CDCl3): dC 123.7, 123.9, 127.4, 127.6, 127.9, 128.6, 128.9,
129.3, 131.2, 131.3, 132.7, 134.9, 135.6, 136.7, 136.9, 146.6, 159.8. IR
J0¼1.6 Hz, 2H, ArH), 6.99 (d, J¼1.6 Hz, 2H, ArH), 7.30 (d, J¼8.4 Hz, 2H,
ArH), 7.80e7.86 (m, 4H, ArH), 8.02 (d, J¼9.2 Hz, 2H, ArH), 8.17 (d,
J¼7.8 Hz, 2H, ArH), 8.26 (d, J¼9.2 Hz, 2H, ArH), 9.16 (d, J¼8.0 Hz, 2H,
ArH), 9.78 (s, 2H, ArH). 13C NMR (CDCl3): dC 123.0, 124.8, 127.6,
127.8,128.0,128.1,129.1,129.2, 129.4, 131.2, 132.0,132.1,132.2, 132.5,
(KBr):
n
3053, 2918, 2864, 1604, 1582, 1561, 1474, 1444, 1434, 1406,
133.1, 134.2, 139.2, 147.9, 154.5. IR (KBr): n 3057, 1604, 1579, 1552,
1358, 1320, 1278, 1181, 1020, 835, 824, 751, 722, 677 cmꢁ1. HRMS
(ESI, m/z): calcd for C40H28N2Na [MþNa]þ 559.2150, found
559.2169.
1469, 1445, 1430, 1404, 1284, 1247, 1134, 1079, 1032, 907, 830, 801,
746 cmꢁ1
645.0459, found 645.0469.
.
HRMS (ESI, m/z): calcd for C38H21Cl4N2 [MþH]þ
2.1.5. 3-(4-Methoxyphenyl)-2-(3-(4-methoxyphenyl)benzo[f]quino-
2.1.10. 3-(2-Fluorophenyl)-2-(3-(2-fluorophenyl)benzo[f]quinolin-2-
yl)benzo[f]quinoline (4j). Yield 64% (349 mg). Pale yellow powder,
lin-2-yl)benzo[f]quinoline (4e). Yield 75% (426 mg). Pale yellow
powder, mp >300 ꢀC; 1H NMR (DMSO-d6):
d
3.67 (s, 6H, 2OCH3),
mp 275e277 ꢀC; 1H NMR (DMSO-d6):
d 6.81e8.84 (m, 2H, ArH),
6.60 (d, J¼8.4 Hz, 4H, ArH), 6.82 (d, J¼8.4 Hz, 4H, ArH),
7.74e7.82 (m, 4H, ArH), 7.97 (d, J¼9.2 Hz, 2H, ArH), 8.12
(d, J¼7.6 Hz, 2H, ArH), 8.18 (d, J¼8.8 Hz, 2H, ArH), 9.06 (d,
J¼7.6 Hz, 2H, ArH) 9.59 (s, 2H, ArH). 13C NMR (CDCl3): dC 55.3,
113.4, 122.8, 123.9, 127.3, 127.4, 128.3, 128.9, 129.5, 130.5, 131.2,
6.91e7.01 (m, 4H, ArH), 7.29e7.34 (m, 2H, ArH), 7.75e7.82 (m, 4H,
ArH), 7.95 (d, J¼8.8 Hz, 2H, ArH), 8.14e8.16 (m, 2H, ArH), 8.21 (d,
J¼9.2 Hz, 2H, ArH), 9.02 (d, J¼8.0 Hz, 2H, ArH), 9.60 (s, 2H, ArH). 13C
NMR (CDCl3): dC 115.2, 115.7, 122.9, 124.3, 127.4, 127.6, 127.8, 128.0,
128.9, 129.5, 130.3, 130.4, 131.5, 131.9, 133.2, 134.1, 147.4, 153.2, 158.1,
131.8, 132.4, 133.0, 133.9, 147.6, 157.3, 159.4. IR (KBr):
n
3050,
160.6. IR (KBr):
n 3058, 1603, 1578, 1566, 1490, 1478, 1452, 1405,
3006, 2958, 2931, 2909, 2835, 1605, 1574, 1562, 1516, 1474, 1444,
1393, 1360, 1280, 1260, 1224, 1208, 1106, 1028, 946, 910, 829, 778,

D.-S. Chen et al. / Tetrahedron 69 (2013) 7045e7050
7049
757, 747 cmꢁ1. HRMS (ESI, m/z): calcd for C38H23F2N2 [MþH]þ
810 cmꢁ1
569.2229, found 569.2267.
.
HRMS (ESI, m/z): calcd for C40H29N2O2 [MþH]þ
545.1829, found 545.1836.
2.1.11. 3-Phenyl-2-(3-phenylbenzo[f]quinolin-2-yl)benzo[f]quinoline
2.1.16. 3-(3-Chlorophenyl)-2-(3-(4-chlorophenyl)benzo[f]quinolin-2-
yl)benzo[f]quinoline (4p). Yield 72% (415 mg). Pale yellow powder,
mp >300 ꢀC; 1H NMR (CDCl3): dH 6.66 (d, J¼7.6 Hz, 2H, ArH),
6.88e6.92 (m, 2H, ArH), 6.95 (s, 2H, ArH), 7.20 (d, J¼8.0 Hz, 2H,
ArH), 7.73e7.82 (m, 4H, ArH), 8.03e8.12 (m, 6H, ArH), 8.79 (d,
J¼7.6 Hz, 2H, ArH), 9.28 (s, 2H, ArH). 13C NMR (CDCl3): dC 123.0,
124.6,127.0,127.5,127.8,128.0,128.1,128.8,129.1,129.3,129.4,131.8,
(4k). Yield 69% (351 mg). Pale yellow powder, mp >300 ꢀC; 1H
NMR (DMSO-d6):
d
6.82 (d, J¼8.0 Hz, 4H, ArH), 6.97e7.01 (m, 4H,
ArH), 7.16e7.20 (m, 2H, ArH), 7.74e7.82 (m, 4H, ArH), 7.96 (d,
J¼9.2 Hz, 2H, ArH), 8.14 (d, J¼7.8 Hz, 2H, ArH), 8.20 (d, J¼8.8 Hz,
2H, ArH), 9.09 (d, J¼8.0 Hz, 2H, ArH), 9.69 (s, 2H, ArH). 13C NMR
(CDCl3): dC 122.9, 124.2, 127.3, 127.5, 127.8, 127.9, 128.3, 129.0,
129.3, 129.5, 131.3, 132.0, 132.9, 134.1, 139.5, 147.6, 157.6. IR (KBr):
n
132.1, 132.5, 134.1, 134.5, 141.0, 147.7, 155.8. IR (KBr): n 3059, 1604,
3056, 3020, 1603, 1564, 1474, 1444, 1433, 1406, 1359, 1279, 1240,
1206, 1078, 1024, 925, 910, 828, 797, 785, 754, 737, 717, 704,
671 cmꢁ1. HRMS (ESI, m/z): calcd for C38H25N2 [MþH]þ 509.2018,
found 509.2006.
1594, 1562, 1474, 1433, 1403, 1357, 1294, 1280, 1239, 1200, 1097,
1077, 919, 908, 891, 830, 800, 784, 747, 921, 696 cmꢁ1. HRMS (ESI, m/
z): calcd for C38H23Cl2N2 [MþH]þ 577.1238, found 577.1266.
2.1.17. 6-(4-Bromophenyl)-7-(6-(4-bromophenyl)-[1,3]dioxolo[4,5-g]
quinolin-7-yl)-[1,3]dioxolo[4,5-g]quinoline (5a). Yield 23% (150 mg).
Pale yellow powder, mp >300 ꢀC; 1H NMR (DMSO-d6, 400 MHz): dH
6.26 (s, 4H, 2CH2), 6.66 (d, J¼8.0 Hz, 4H, ArH), 7.22 (d, J¼8.0 Hz, 4H,
ArH), 7.39 (s, 2H, ArH), 7.47 (s, 2H, ArH), 8.44 (s, 2H, ArH), 13C NMR
(CDCl3, 100 MHz): dC 67.0, 102.2, 102.5, 104.8, 121.1, 124.1, 129.9,
2.1.12. 3-(3-Methylphenyl)-2-(3-(3-methylphenyl)benzo[f]quinolin-
2-yl)benzo[f]quinoline (4l). Yield 75% (402 mg). Pale yellow pow-
der, mp 290e291 ꢀC; 1H NMR (DMSO-d6):
d 2.08 (s, 6H, 2CH3), 6.51
(d, J¼8.0 Hz, 2H, ArH), 6.60 (s, 2H, ArH), 6.79e6.83 (m, 2H, ArH),
7.00 (d, J¼7.6 Hz, 2H, ArH), 7.76e7.84 (m, 4H, ArH), 7.96 (d,
J¼9.2 Hz, 2H, ArH), 8.14 (d, J¼8.0 Hz, 2H, ArH), 8.20 (d, J¼9.2 Hz,
2H, ArH), 9.11 (d, J¼7.6 Hz, 2H, ArH), 9.67 (s, 2H, ArH). 13C NMR
(CDCl3): dC 20.9, 123.8, 124.1, 126.0, 126.8, 127.4, 127.6, 127.9, 128.6,
129.3, 129.8, 131.2, 131.3, 132.8, 134.9, 136.7, 139.2, 146.6, 156.9. IR
130.3, 130.6, 137.9, 138.7, 145.2, 148.1, 151.1. IR (KBr):
n 2906, 2852,
1614, 1586, 1499, 1461, 1390, 1323, 1227, 1170, 1071, 1034, 1006,
943, 924, 832, 781, 727 cmꢁ1
. HRMS (ESI, m/z): calcd for
C32H19Br2N2O4[MþH]þ 652.9712, found 652.9703.
(KBr): n 3044, 2956, 2922, 1603, 1579, 1563, 1475, 1445, 1435, 1403,
1356, 1279, 1200, 1174, 1080, 1035, 1000, 909, 828, 800, 791, 751,
720, 702 cmꢁ1. HRMS (ESI, m/z): calcd for C40H29N2 [MþH]þ
537.2331, found 537.2366.
2.1.18. 2-(2,4-Dichlorophenyl)-3-(2-(2,4-dichlorophenyl)-6,7-
dimethoxyquinolin-3-yl)-6,7-dimethoxyquinoline (5b). Yield 31%
(206 mg). Pale yellow powder, mp >300 ꢀC; 1H NMR (DMSO-d6,
400 MHz):
d 3.93 (s, 6H, 2CH3O), 3.96 (s, 6H, 2CH3O), 6.96 (b, 2H,
2.1.13. 3-(2-Thienyl)-2-(3-(2-thienyl)benzo[f]quinolin-2-yl)benzo[f]
quinoline (4m). Yield 65% (338 mg). Pale yellow powder,
ArH), 7.20 (b, 2H, ArH), 7.36e7.45 (m, 6H, ArH), 8.43 (s, 2H, ArH), 13C
NMR (CDCl3, 100 MHz): dC 56.2, 56.3, 104.6, 107.8, 122.8, 126.6,
126.9, 129.7, 130.6, 132.5, 132.7, 134.6, 138.0, 138.2, 144.3, 150.7,
mp 280e282 ꢀC; 1H NMR (DMSO-d6):
d
6.62 (d, J¼3.6 Hz, 2H,
ArH), 6.78e6.81 (m, 2H, ArH), 7.49 (d, J¼5.2 Hz, 2H, ArH),
7.71e7.77 (m, 4H, ArH), 8.05 (d, J¼9.2 Hz, 2H, ArH), 8.13e8.15 (m,
2H, ArH), 8.26 (d, J¼9.2 Hz, 2H, ArH), 8.93 (d, J¼8.8 Hz, 2H, ArH),
9.47 (s, 2H, ArH). 13C NMR (CDCl3): dC 122.9, 123.8, 127.4, 127.5,
127.8, 128.1, 128.3, 128.7, 128.9, 129.4, 130.8, 131.8, 131.9, 134.2,
153.2. IR (KBr):
n 3068, 3012, 2961, 2931, 2877, 2830, 1624, 1589,
1512, 1465, 1451, 1433, 1410, 1331, 1232, 1208, 1159, 1151, 1103, 1087,
1014, 858, 837, 810, 754 cmꢁ1
. HRMS (ESI, m/z): calcd for
C34H25Cl4N2O4 [MþH]þ 667.0539, found 667.0515.
143.9, 147.8, 150.7. IR (KBr):
n 3052, 1604, 1577, 1562, 1475, 1442,
Acknowledgements
1423, 1397, 1366, 1267, 1223, 1060, 1001, 914, 849, 830, 750,
702 cmꢁ1
521.1146, found 521.1149.
.
HRMS (ESI, m/z): calcd for C37H21N2S2 [MþH]þ
We are grateful to the National Natural Science foundation of
China (20802061, 21104064), a project funded by the Priority
Academic Program Development of Jiangsu Higher Education In-
stitutions, Qing Lan Project (10QLD008, GSFM2011003) and College
Industrialization Project (JHB2012-31) of Jiangsu Province for fi-
nancial support.
2.1.14. 3-(3-Nitrophenyl)-2-(3-(3-nitrophenyl)benzo[f]quinolin-2-yl)
benzo[f]quinoline (4n). Yield 71% (425 mg). Pale yellow powder,
mp >300 ꢀC; 1H NMR (DMSO-d6):
d
7.19 (d, J¼7.6 Hz, 2H, ArH),
7.29 (t, J¼8.0 Hz, 2H, ArH), 7.51 (s, 2H, ArH), 7.82e7.91 (m, 4H,
ArH), 8.02e8.07 (m, 4H, ArH), 8.19 (d, J¼8.0 Hz, 2H, ArH), 8.27 (d,
J¼9.2 Hz, 2H, ArH), 9.20 (d, J¼8.0 Hz, 2H, ArH), 9.89 (s, 2H, ArH).
13C NMR (CDCl3): dC 122.9, 123.1, 124.3, 125.1, 127.8, 127.9, 128.2,
128.7, 129.1, 129.2, 131.8, 132.2, 132.5, 134.4, 134.5, 141.0, 148.0,
References and notes
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148.1, 154.2. IR (KBr):
n 3082, 3050, 1604, 1526, 1482, 1446, 1403,
1350, 1270, 1219, 1097, 1033, 907, 868, 834, 812, 753, 731, 720,
689 cmꢁ1. HRMS (ESI, m/z): calcd for C38H23 N4O4 [MþH]þ
599.1719, found 599.1735.
2.1.15. 3-(3-Methoxyphenyl)-2-(3-(3-methoxyphenyl)benzo[f]quino-
lin-2-yl)benzo[f]quinoline (4o). Yield 76% (431 mg). Pale yellow
powder, mp >300 ꢀC; 1H NMR (CDCl3):
d 3.55 (s, 6H, 2OCH3), 6.42
(d, J¼7.6 Hz, 2H, ArH), 6.51 (s, 2H, ArH), 6.71e6.73 (m, 2H, ArH),
6.85e6.88 (m, 2H, ArH), 7.71e7.78 (m, 4H, ArH), 8.02e8.11 (m, 6H,
ArH), 8.77 (d, J¼8.0 Hz, 2H, ArH) 9.25 (s, 2H, ArH). 13C NMR
(CDCl3): dC 49.7, 108.2, 109.7, 116.7, 117.6, 119.0, 122.1, 122.3, 123.0,
123.2, 123.7, 124.2, 126.1, 126.7, 127.9, 128.6, 135.6, 142.3, 152.2,
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n 2961, 1622, 1588, 1487, 1465, 1451, 1433, 1410,
1331, 1233, 1208, 1159, 1151, 1087, 1039, 1014, 929, 858, 837,

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