Iodine-catalyzed synthesis of 3-arylbenzoquinoline derivatives by three-component reactions

Article abstract of DOI:10.1080/00397910802431081

A mild, efficient, and general method for the synthesis of benzo[f]quinoline derivatives via three-component reaction of arylaldehyde, naphthalen-2-amine, and acetone or acetophenone is described using iodine as catalyst. The features of this procedure ar

Full text of DOI:10.1080/00397910802431081

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Iodine-Catalyzed Synthesis
of 3-Arylbenzoquinoline
Derivatives by Three-
Component Reactions
Xiang-Shan Wang a b , Qing Li a , Jian-Rong Wu a &
Yu-Ling Li a
a School of Chemistry and Chemical Engineering,
Xuzhou Normal University , Xuzhou, Jiangsu, China
b Key Laboratory of Biotechnology on Medical Plant ,
Xuzhou, Jiangsu, China
Published online: 28 Jan 2009.
To cite this article: Xiang-Shan Wang , Qing Li , Jian-Rong Wu & Yu-Ling Li
(2009) Iodine-Catalyzed Synthesis of 3-Arylbenzoquinoline Derivatives by Three-
Component Reactions, Synthetic Communications: An International Journal
for Rapid Communication of Synthetic Organic Chemistry, 39:4, 702-715, DOI:
10.1080/00397910802431081
To link to this article: http://dx.doi.org/10.1080/00397910802431081
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Synthetic Communications1, 39: 702–715, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802431081
Iodine-Catalyzed Synthesis of
3-Arylbenzoquinoline Derivatives by
Three-Component Reactions
Xiang-Shan Wang,1,2 Qing Li,1 Jian-Rong Wu,1 and Yu-Ling Li1
1School of Chemistry and Chemical Engineering, Xuzhou Normal
University, Xuzhou, Jiangsu, China
2Key Laboratory of Biotechnology on Medical Plant, Xuzhou,
Jiangsu, China
Abstract: A mild, efficient, and general method for the synthesis of benzo[f]
quinoline derivatives via three-component reaction of arylaldehyde, naphthalen-
2-amine, and acetone or acetophenone is described using iodine as catalyst.
The features of this procedure are mild reaction conditions, high yields, and
operational simplicity.
Keywords: Acetone, acetophenone, benzo[f]quinoline, iodine, synthesis
INTRODUCTION
In recent years, the use of molecular iodine in organic synthesis has
received considerable attention as an inexpensive, nontoxic, readily
available mild Lewis acid catalyst for organic transformations such as
dehydration of tertiaryalcohols to alkenes,[1] synthesis of benzyl alkyl
ethers,[2] synthesis of mixed ethers under hydrogen pressure,[3] synthesis
of benzothiophenes[4] and bis-indoles,[5] deprotection of acetals,[6]
esterification,[7] transesterification,[8] Michael addition,[9] and many other
reactions.[10]
Received April 23, 2008.
Address correspondence to Xiang-Shan Wang, School of Chemistry and
Chemical Engineering, Xuzhou Normal University, Xuzhou, Jiangsu 221116,
China. E-mail: xswang1974@yahoo.com
702

3-Arylbenzoquinoline Derivatives
703
Multicomponent reactions (MCRs), often with three or more
reactants combined in a one-pot procedure to generate a complex organic
molecule, have become increasingly popular during the past decade.[11]
They provide a powerful tool toward one-pot synthesis of diverse and
complex compounds as well as small and drug-like heterocycles.
Benzo[f]quinoline and its derivatives are very useful compounds in
various fields of chemistry including biological and pharmacological
areas. Some of these exhibit antibacterial activity,[12] uridine diphosphate-
glucuronosyl transferase (UGT) activity,[13] inhibitory activity,[14] anti-
microbial activity,[15] antimalarial activity,[16] antipsychotic activity,[17]
and antagonist activity.[18]
In view of the importance of benzoquinoline and its derivatives,
several methods for the synthesis of benzo[f]quinoline and its derivatives
were developed by Kozlov et al.[19] and other groups.[20] However, many
of these reported methods suffer from drawbacks such as harsh reaction
conditions, unsatisfactory yields, prolonged reaction time, and cumber-
some product isolation procedure. Kozlov et al.[21] recently reported
three-component reactions from arylaldehyde, naphthalen-2-amine, and
acetone catalyzed by SnCl2 but with low to moderate yields (6–74%). Thus
the development of an efficient and mild process for the preparation of
biologically active 3-arylbenzoquinoline derivatives appeared interesting.
Wang et al.[22] recently reported a Schiff base with aliphatic aldehyde
catalyzed by iodine to give 2-aryl-3-substitutedquinolines, demonstrating
that iodine was an efficient catalyst for this reaction; however, no ketones
were explored in this iodine-catalyzed reaction. In connection with our
previous research on MCRs,[23] the procedure reported herein was
successfully realized via a three-component reaction of arylaldehyde,
naphthalen-2-amine, and acetone or acetophenone catalyzed by iodine
without isolating and purifying the intermediates to afford 3-aryl-1-
substituedbenzo[f]quinolines in high yields.
RESULTS AND DISCUSSION
The treatment of arylaldehyde 1, naphthalen-2-amine 2, and acetone or
acetophenone 3 in THF in the presence of 5 mol% iodine at refluxing
temperature afforded the corresponding 3-aryl-1-substituedbenzo[f]
quinoline derivatives 4 in high yields (Scheme 1).
Initially, the reaction of 4-chlorobenzaldehyde 1a, naphthalen-
2-amine 2, and acetone 3 was used as a model reaction to optimize the
conditions. The reaction was first carried out in THF in the absence of
I2. No product was obtained at room temperature and reflux (Table 1,
entries 1 and 2). We also evaluated the amount of catalyst required for

704
X.-S. Wang et al.
Scheme 1. The reaction of arylaldehyde, naphthalen-2-amine, and ketone.
this transformation. It was found that that 5 mol% I2 at reflux in THF
was sufficient to push the reaction forward. More amounts of the catalyst
did not improve yields. To find the optimum reaction temperature, the
reaction was carried out with 5 mol% of I2 at room temperature, 50 ꢀC,
and reflux, resulting in the isolation of 4a in trace amount, 82% and
94% yields (Table 1, entries 3, 4, and 6) respectively. Thus, 5 mol% of
I2 and a reaction temperature at reflux were optimal conditions. In
addition, we also looked into the solvent effect for this reaction. As
showed in Table 1, tetrahydrofuran (THF) gave the most satisfactory
result in comparison with other solvents (Table 1, entries 8–11).
Similarly, several benzaldehydes reacted with naphthalen-2-amine
and acetone to give 3-arylbenzo[f]quinoline derivatives in high yield in a
few hours. The results are summarized in Table 2. It can be observed that
the process tolerates both electron-donating and electron-withdrawing
substituents in the benzaldehyde. In all cases, the reactions proceeded
efficiently at reflux under mild conditions to afford the corresponding
benzo[f]quinolines in high yields. Interestingly, the reactions also
Table 1. Synthesis of 4a under different reaction conditionsa
Entry
Temp. (ꢀC)
Amount (mol%)
Solvent
Yieldsb (%)
1
2
3
4
5
6
7
8
9
Rt
Reflux
Rt
0
0
5
5
5
10
20
5
5
5
THF
THF
THF
THF
THF
THF
THF
CH3CN
Benzene
DMF
0
0
trace
82
94
94
92
86
87
82
86
50 ꢀC
Reflux
Reflux
Reflux
Reflux
Reflux
80 ꢀC
Reflux
10
11
5
ClCH2CH2Cl
aReagents and conditions: 1 (2 mmol), 2 (2 mmol), 3 (2 mmol), solvent (10 mL).
bIsolated yields.

3-Arylbenzoquinoline Derivatives
705
Table 2. I2-catalyzed reactions of benzaldehyde, naphthalen-2-amine, and
acetone or acetophenone in THFa
Entry
Ar
R
Products Time (h) Yields (%)b
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
4-ClC6H4
3-NO2C6H4
3-ClC6H4
2,4-Cl2C6H3
3-BrC6H4
2-Thiophenyl
4-FC6H4
3,4-Cl2C6H3
4-NO2C6H4
4-BrC6H4
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
4a
4b
4c
4d
4e
4f
5
6
8
6
6
8
6
6
5
6
5
8
7
94
92
90
92
88
89
96
92
88
90
91
88
86
90
83
86
88
90
82
85
84
83
84
87
4g
4h
4i
4j
2-NO2C6H4
4-CH3OC6H4
3,4-(CH3)2C6H3
4k
4l
4m
4n
4o
4p
4q
4r
4s
4t
2,3-(CH3O)2C6H3 Me
8
3-BrC6H4
4-ClC6H4
4-ClC6H4
3-NO2C6H4
3-ClC6H4
2,4-Cl2C6H3
3-NO2C6H4
4-FC6H4
C6H5
12
14
10
10
14
12
12
12
14
12
4-CH3C6H4
4-NO2C6H4
4-NO2C6H4
4-BrC6H4
4-BrC6H4
4-BrC6H4
4-BrC6H4
4-FC6H4
4u
4v
4w
4x
3-BrC6H4
2,3-Cl2C6H3
4-ClC6H4
aReagents and conditions: 1 (2 mmol), 2 (2 mmol), 3 (2 mmol), I2 (10 mol%),
and THF (10 mL).
bIsolated yields.
proceeded efficiently with acetophenone to generate 1,3-diarylbenzo[f]
quinoline in high yields (Table 2, entries 15–24). However, we failed to
get the expected products when aliphatic aldehydes were used. All the
products were characterized by 1H NMR, IR, melting points, and
elemental analyses.
EXPERIMENTAL
Melting points were determined in open capillaries and are uncorrected.
IR spectra were recorded on a Tensor 27 spectrometer in KBr pellets.
1H NMR spectra were obtained from solution in DMSO-d6 or CDCl3,

706
X.-S. Wang et al.
with Me4Si as internal standard, using an Inova-400 spectrometer.
Elemental analyses were carried out using a Perkin-Elmer 240 II analyzer.
General Procedure for the Syntheses of 3-Aryl-1-
substitutedbenzo[f]quinoline Derivatives 4
A dry 50-mL flask was charged with arylaldehyde (2.0 mmol), naphtha-
len-2-amine (2.0 mmol, 0.286 g), acetone (3.0 mmol, 0.174 g) or acetophe-
none (2.0 mmol), I2 (0.2 mmol, 0.051 g), and THF (10 mL). The reaction
mixture was stirred at reflux for 5–14 h. After completion of the reaction,
as indicated by thin-layer chromatography (TLC), a little DMF was
added to the mixture until the all yellow solid was dissolved. The gener-
ated crystals were collected by filtration to give 4 when the mixture was
cooled to room temperature.
Data
3-(4-Chlorophenyl)-1-methylbenzo[f]quinoline 4a
Mp 179–181 ꢀC (lit.[21]: 182 ꢀC). 1H NMR (DMSO-d6, d, ppm): 3.20 (s, 3H,
CH3), 7.63 (d, J ¼ 7.6 Hz, 2H, ArH), 7.73 ꢁ 7.77 (m, 2H, ArH), 7.96–7.99
(m, 1H, ArH), 8.10–8.19 (m, 3H, ArH), 8.36 (d, J ¼ 7.6 Hz, 2H, ArH), 8.90
(d, J ¼ 8.0 Hz, 1H, ArH). IR (KBr, n, cmꢂ1): 3055, 1619, 1579, 1546, 1480,
1456, 1405, 1377, 1350, 1264, 1091, 1011, 889, 872, 840, 756, 713, 677.
1-Methyl-3-(3-nitrophenyl)benzo[f]quinoline 4b
1
Mp 183–185 ꢀC (lit.[21]: 186 ꢀC). H NMR (DMSO-d6, d, ppm): 3.23 (s,
3H, CH3), 7.75–7.86 (m, 2H, ArH), 7.87–7.90 (m, 1H, ArH), 8.01–8.05
(m, 1H, ArH), 8.11–8.17 (m, 2H, ArH), 8.34–8.36 (m, 2H, ArH), 8.77
(d, J ¼ 7.2 Hz, 1H, ArH), 8.93 (d, J ¼ 8.0 Hz, 1H, ArH), 9.14 (d,
J ¼ 2.0 Hz, 1H, ArH). IR (KBr, n, cmꢂ1): 3049, 2966, 1587, 1537, 1481,
1451, 1395, 1377, 1338, 1254, 1134, 1106, 1074, 930, 916, 809, 825, 802,
791, 741, 714.
3-(3-Chlorophenyl)-1-methylbenzo[f]quinoline 4c
Mp 127–128 ꢀC. 1H NMR (DMSO-d6, d, ppm): 3.20 (s, 3H, CH3),
7.56–7.62 (m, 2H, ArH), 7.72–7.78 (m, 2H, ArH), 7.99 (d, J ¼ 8.8 Hz,

3-Arylbenzoquinoline Derivatives
707
1H, ArH), 8.10–8.14 (m, 2H, ArH), 8.24 (s, 1H, ArH), 8.30 (d, J ¼ 7.2 Hz,
1H, ArH), 8.39 (s, 1H, ArH), 8.90 (d, J ¼ 8.0 Hz, 1H, ArH). IR (KBr, n,
cmꢂ1): 3054, 2984, 1594, 1578, 1549, 1481, 1452, 1422, 1376, 1335, 1293,
1276, 1252, 1211, 1142, 1096, 1077, 1033, 967, 914, 865, 832, 799, 785,
770, 749, 729, 692. Anal. Calcd. for C20H14ClN: C, 79.07; H, 4.65; N,
4.61. Found: C, 78.90; H, 4.66; N, 4.78.
3-(2,4-Dichlorophenyl)-1-methylbenzo[f]quinoline 4d
1
Mp 175–177 ꢀC. H NMR (DMSO-d6, d, ppm): 3.19 (s, 3H, CH3), 7.63
(dd, J ¼ 8.4 Hz, J0 ¼ 2.0 Hz, 1H, ArH), 7.76–7.80 (m, 3H, ArH),
7.82–7.84 (m, 2H, ArH), 7.96 (d, J ¼ 8.4 Hz, 1H, ArH), 8.13–8.17 (m,
2H, ArH), 8.94 (m, 1H, ArH). IR (KBr, n, cmꢂ1): 3050, 2982, 1588,
1556, 1475, 1453, 1383, 1344, 1245, 1101, 1046, 1031, 896, 875, 859,
829, 813, 794, 747, 706. Anal. calcd. for C20H13Cl2N: C, 71.02; H, 3.87;
N, 4.14. Found: C, 70.92; H, 3.94; N, 4.12.
3-(3-Bromophenyl)-1-methylbenzo[f]quinoline 4e
Mp 157–158 ꢀC. 1H NMR (DMSO-d6, d, ppm): 3.20 (s, 3H, CH3),
7.52–7.56 (m, 1H, ArH), 7.69–7.78 (m, 3H, ArH), 8.00 (d, J ¼ 8.8 Hz,
1H, ArH), 8.10–8.14 (m, 2H, ArH), 8.24 (s, 1H, ArH), 8.34 (d, J ¼ 7.6 Hz,
1H, ArH), 8.54 (s, 1H, ArH), 8.91 (d, J ¼ 8.0 Hz, 1H, ArH). IR (KBr,
n, cmꢂ1): 3050, 1580, 1548, 1477, 1450, 1419, 1378, 1337, 1255, 1093,
1071, 907, 865, 833, 797, 782, 742, 710, 688. Anal. calcd. for C20H14BrN:
C, 68.98; H, 4.05; N, 4.02. Found: C, 68.72; H, 4.20; N, 4.16.
1-Methyl-3-(2-thiophenyl)benzo[f]quinoline 4f
1
Mp 128–129 ꢀC. H NMR (DMSO-d6, d, ppm): 3.15 (s, 3H, CH3), 7.24
(dd, J ¼ 4.8 Hz, J0 ¼ 4.0 Hz, 1H, ArH), 7.67–7.76 (m, 3H, ArH), 7.88
(d, J ¼ 9.2 Hz, 1H, ArH), 7.98–8.00 (m, 1H, ArH), 8.07–8.10 (m, 3H,
ArH), 8.86 (d, J ¼ 8.0 Hz, 1H, ArH). IR (KBr, n, cmꢂ1): 3064, 2969,
1581, 1549, 1484, 1455, 1421, 1379, 1355, 1256, 1230, 1123, 1072, 1037,
977, 866, 530, 750, 729, 700, 665. Anal. calcd. for C18H13NS: C, 78.51;
H, 4.76; N, 5.09. Found: C, 78.40; H, 4.57; N, 5.19.
3-(4-Fluorophenyl)-1-methylbenzo[f]quinoline 4g
Mp 129–130 ꢀC (lit.[21]: 130 ꢀC). 1H NMR (DMSO-d6, d, ppm): 3.20
(s, 3H, CH3), 7.40 (t, J ¼ 8.8 Hz, 2H, ArH), 7.71–7.78 (m, 2H, ArH),

708
X.-S. Wang et al.
7.98 (d, J ¼ 8.8 Hz, 1H, ArH), 8.10–8.13 (m, 2H, ArH), 8.18 (s, 1H, ArH),
8.38–8.41 (m, 2H, ArH), 8.90 (d, J ¼ 8.0 Hz, 1H, ArH). IR (KBr, n,
cmꢂ1): 3059, 1596, 1581, 1548, 1496, 1480, 1455, 1389, 1350, 1294,
1263, 1222, 1153, 1098, 1029, 890, 808, 758.
3-(3,4-Dichlorophenyl)-1-methylbenzo[f]quinoline 4h
1
Mp 172–174 ꢀC. H NMR (DMSO-d6, d, ppm): 3.17 (s, 3H, CH3), 7.72–
7.81 (m, 3H, ArH), 7.97 (d, J ¼ 8.8 Hz, 1H, ArH), 8.08–8.13 (d, 2H,
ArH), 8.22 (s, 1H, ArH), 8.30 (dd, J ¼ 8.4 Hz, J0 ¼ 2.0 Hz, 1H, ArH),
8.54 (d, J ¼ 2.0 Hz, 1H, ArH), 8.88 (d, J ¼ 8.0 Hz, 1H, ArH). IR (KBr,
n, cmꢂ1): 3048, 2967, 1606, 1585, 1545, 1471, 1452, 1402, 1370, 1345,
1273, 1251, 1145, 1126, 1093, 1025, 917, 874, 827, 791, 744, 699, 676,
660. Anal. calcd. for C20H13Cl2N: C, 71.02; H, 3.87; N, 4.14. Found:
C, 71.30; H, 3.70; N, 4.05.
1-Methyl-3-(4-nitrophenyl)benzo[f]quinoline 4i
Mp 192–194 ꢀC; (lit.[21]: 193–194 ꢀC). 1H NMR (DMSO-d6, d, ppm): 3.15
(s, 3H, CH3), 7.72–7.75 (m, 2H, ArH), 7.96 (d, J ¼ 8.8 Hz, 1H, ArH),
8.07–8.12 (m, 2H, ArH), 8.21 (s, 1H, ArH), 8.33 (d, J ¼ 8.0 Hz, 2H,
ArH), 8.51 (d, J ¼ 8.0 Hz, 2H, ArH), 8.85 (d, J ¼ 8.0 Hz, 1H, ArH). IR
(KBr, n, cmꢂ1): 3050, 1596, 1580, 1550, 1514, 1484, 1452, 1430, 1372,
1337, 1268, 1166, 1108, 1012, 981, 849, 836, 753, 693, 675.
3-(4-Bromophenyl)-1-methylbenzo[f]quinoline 4j
1
Mp 174–176 ꢀC (lit.[21]: 177–178 ꢀC). H NMR (DMSO-d6, d, ppm): 3.20
(s, 3H, CH3), 7.71–7.78 (m, 4H, ArH), 7.98 (d, J ¼ 8.8 Hz, 1H, ArH),
8.10–8.14 (m, 2H, ArH), 8.20 (s, 1H, ArH), 8.30 (d, J ¼ 8.4 Hz, 2H,
ArH), 8.91 (d, J ¼ 8.4 Hz, 1H, ArH). IR (KBr, n, cmꢂ1): 3054, 2983,
2932, 1604, 1578, 1545, 1479, 1450, 1402, 1377, 1348, 1263, 1176, 1103,
1088, 1067, 1034, 1007, 980, 945, 886, 871, 828, 799, 753, 707.
1-Methyl-3-(2-nitrophenyl)benzo[f]quinoline 4k
Mp 184–186 ꢀC; (lit.[21]: 188 ꢀC). 1H NMR (DMSO-d6, d, ppm): 3.19 (s, 3H,
CH3), 7.72–7.81 (m, 4H, ArH), 7.84–7.88 (m, 1H, ArH), 7.91 (s, 1H, ArH),
7.94–7.96 (m, 1H, ArH), 8.06 (dd, J ¼ 8.8 Hz, J0 ¼ 0.8 Hz, 1H, ArH), 8.08–
8.14 (m, 2H, ArH), 8.92 (d, J ¼ 8.4 Hz, 1H, ArH). IR (KBr, n, cmꢂ1): 3050,

3-Arylbenzoquinoline Derivatives
709
2998, 2891, 1603, 1581, 1536, 1479, 1455, 1392, 1368, 1296, 1255, 1168,
1106, 982, 880, 863, 852, 836, 803, 777, 764, 747, 730, 715, 697.
3-(4-Methoxyphenyl)-1-methylbenzo[f]quinoline 4l
Mp 121–122 ꢀC; (lit.[21]: 124–125 ꢀC). 1H NMR (CDCl3, d, ppm): 3.16 (s,
3H, CH3), 3.88 (s, 3H, CH3O), 7.04 (J ¼ 8.8 Hz, J0 ¼ 2.0 Hz, 2H, ArH),
7.61–7.66 (m, 2H, ArH), 7.76 (s, 1H, ArH), 7.94–7.97 (m, 2H, ArH),
8.05 (d, J ¼ 9.2 Hz, 1H, ArH), 8.18 (dd, J ¼ 8.8 Hz, J0 ¼ 2.0 Hz, 2H,
ArH), 8.80 (d, J ¼ 8.0 Hz, 1H, ArH). IR (KBr, n, cmꢂ1): 3050, 2990,
2934, 2838, 1602, 1582, 1546, 1509, 1480, 1454, 1356, 1303, 1290, 1245,
1173, 1115, 1036, 983, 947, 873, 835, 818, 791, 716.
3-(3,4-Dimethylphenyl)-1-methylbenzo[f]quinoline 4m
Mp 141–142 ꢀC. 1H NMR (CDCl3, d, ppm): 2.35 (s, 3H, CH3), 2.40 (s, 3H,
CH3), 3.19 (s, 3H, CH3), 7.29 (d, J ¼ 8.0 Hz, 1H, ArH), 7.62–7.67 (m, 2H,
ArH), 7.81 (s, 1H, ArH), 7.91 (dd, J ¼ 8.0 Hz, J0 ¼ 1.6 Hz, 1H, ArH), 7.96
(d, J ¼ 9.2 Hz, 2H, ArH), 8.02 (s, 1H, ArH), 8.08 (d, J ¼ 8.8 Hz, 1H, ArH),
8.83 (d, J ¼ 8.4 Hz, 1H, ArH). IR (KBr, n, cmꢂ1): 3059, 3016, 2970, 2911,
1583, 1548, 1504, 1486, 1451, 1392, 1373, 1338, 1264, 1169, 1139, 1119,
1023, 997, 980, 911, 861, 829, 822, 744, 711. Anal. calcd. for C22H19N:
C, 88.85; H, 6.44; N, 4.71. Found: C, 88.73; H, 6.52; N, 4.72.
3-(2,3-Dimethoxyphenyl)-1-methylbenzo[f]quinoline 4n
Mp > 300 ꢀC, (lit.[21]: 305 ꢀC). 1H NMR (CDCl3, d, ppm): 3.18 (s, 3H, CH3),
3.72 (s, 3H, CH3O), 3.94 (s, 3H, CH3O), 7.02 (dd, J ¼ 8.0 Hz, J0 ¼ 1.6 Hz,
1H, ArH), 7.20–7.25 (m, 1H, ArH), 7.52 (dd, J ¼ 8.0 Hz, J0 ¼ 1.6 Hz, 1H,
ArH), 7.62–7.70 (m, 2H, ArH), 7.94–7.98 (m, 3H, ArH), 8.08 (d,
J ¼ 9.2 Hz, 1H, ArH), 8.87 (d, J ¼ 8.4 Hz, 1H, ArH). IR (KBr, n, cmꢂ1):
3059, 2998, 2965, 2932, 2838, 1579, 1544, 1468, 1421, 1355, 1304, 1257,
1169, 1083, 1062, 997, 976, 940, 862, 833, 798, 756. Anal. calcd. for
C22H19NO2: C, 80.22; H, 5.81; N, 4.25. Found: C, 80.37; H, 5.93; N, 4.10.
3-(3-Bromophenyl)-1-phenylbenzo[f]quinoline 4o
Mp 208–210 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.19–7.23 (m, 1H, ArH),
7.50–7.62 (m, 8H, ArH), 7.70–7.72 (m, 1H, ArH), 8.03–8.09 (m, 3H,
ArH), 8.18 (d, J ¼ 8.8 Hz, 1H, ArH), 8.37 (d, J ¼ 7.6 Hz, 1H, ArH),

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X.-S. Wang et al.
8.58–8.59 (m, 1H, ArH). IR (KBr, n, cmꢂ1): 3054, 1601, 1576, 1543, 1477,
1419, 1389, 1345, 1328, 1275, 1252, 1231, 1150, 1083, 1069, 996, 943, 870,
838, 781, 756, 702, 689 cmꢂ1. Anal. calcd. for C25H16BrN: C, 73.18; H,
3.93; N, 3.41. Found: C, 73.22; H, 3.79; N, 3.59.
3-(4-Chlorophenyl)-1-(4-methylphenyl)benzo[f]quinoline 4p
Mp 158–160 ꢀC. 1H NMR (DMSO-d6, d, ppm): 2.47 (s, 3H, CH3),
7.22–7.26 (m, 1H, ArH), 7.41 (s, 4H, ArH), 7.53–7.57 (m, 1H, ArH),
7.61 (d, J ¼ 8.8 Hz, 2H, ArH), 7.67 (d, J ¼ 8.8 Hz, 1H, ArH), 7.97
(s, 1H, ArH), 8.02–8.06 (m, 2H, ArH), 8.17 (d, J ¼ 9.2 Hz, 1H, ArH),
8.39 (d, J ¼ 8.4 Hz, 2H, ArH). IR (KBr, n, cmꢂ1): 3056, 3027, 2917,
1592, 1578, 1543, 1523, 1509, 1475, 1449, 1387, 1354, 1328, 1254,
1107, 1092, 1012, 875, 867, 832, 815, 759, 717 cmꢂ1. Anal. calcd.
for C26H18ClN: C, 82.20; H, 4.78; N, 3.69. Found: C, 82.09; H, 4.91;
N, 3.67.
3-(4-Chlorophenyl)-1-(4-nitrophenyl)benzo[f]quinoline 4q
Mp 286–288 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.28–7.32 (m, 1H, ArH),
7.48–7.50 (m, 1H, ArH), 7.57–7.64 (m, 3H, ArH), 7.85 (d, J ¼ 8.4 Hz, 2H,
ArH), 8.08 (d, J ¼ 8.4 Hz, 2H, ArH), 8.09 (s, 1H, ArH), 8.21–8.23 (m, 1H,
ArH), 8.41–8.47 (m, 4H, ArH). IR (KBr, n, cmꢂ1): 3101, 3074, 3048,
1596, 1580, 1544, 1514, 1493, 1476, 1449, 1408, 1388, 1344, 1305, 1282,
1177, 1152, 1107, 1091, 1010, 851, 832, 797, 758, 744, 717, 704,
692 cmꢂ1. Anal. calcd. for C25H15ClN2O2: C, 73.08; H, 3.68; N, 6.82.
Found: C, 72.91; H, 3.70; N, 6.97.
3-(3-Nitrophenyl)-1-(4-nitrophenyl)benzo[f]quinoline 4r
1
Mp 208–210 ꢀC. H NMR (CDCl3, d, ppm): 7.22–7.26 (m, 1H, ArH),
7.54–7.58 (m, 2H, ArH), 7.70–7.75 (m, 3H, ArH), 7.82 (s, 1H, ArH),
7.95 (d, J ¼ 7.6 Hz, 1H, ArH), 8.09 (d, J ¼ 8.8 Hz, 1H, ArH), 8.15–8.17
(m, 1H, ArH), 8.34 (d, J ¼ 8.0 Hz, 1H, ArH), 8.45 (d, J ¼ 8.4 Hz, 2H,
ArH), 8.61–8.63 (m, 1H, ArH), 9.10 (s, 1H, ArH). IR (KBr, n, cmꢂ1):
3094, 1597, 1579, 1511, 1450, 1343, 1257, 1170, 1154, 1106, 1071,
1014, 894, 886, 852, 835, 805, 756, 714, 704, 684 cmꢂ1. Anal. calcd.
for C25H15N3O4: C, 71.25; H, 3.59; N, 9.97. Found: C, 71.38; H, 3.71;
N, 9.82.

3-Arylbenzoquinoline Derivatives
711
1-(4-Bromophenyl)-3-(3-chlorophenyl)benzo[f]quinoline 4s
Mp 194–195 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.30–7.34 (m, 1H, ArH),
7.52 (d, J ¼ 7.6 Hz, 2H, ArH), 7.57–7.65 (m, 4H, ArH), 7.81 (d,
J ¼ 7.6 Hz, 2H, ArH), 8.05–8.09 (m, 3H, ArH), 8.19 (d, J ¼ 8.8 Hz, 1H,
ArH), 8.34 (d, J ¼ 6.4 Hz, 1H, ArH), 8.44 (s, 1H, ArH). IR (KBr, n,
cmꢂ1): 3051, 1589, 1572, 1524, 1477, 1449, 1423, 1391, 1351, 1331,
1255, 1238, 1102, 1070, 1010, 949, 889, 871, 845, 822, 801, 754, 730,
704 cmꢂ1. Anal. calcd. for C25H15BrClN: C, 67.51; H, 3.40; N, 3.15.
Found: C, 67.55; H, 3.32; N, 3.18.
1-(4-Bromophenyl)-3-(2,4-dichlorophenyl)benzo[f]quinoline 4t
Mp 172–173 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.31–7.35 (m, 1H, ArH),
7.48 (d, J ¼ 8.4 Hz, 2H, ArH), 7.59–7.67 (m, 3H, ArH), 7.71 (s, 1H, ArH),
7.78–7.87 (m, 4H, ArH), 8.03 (d, J ¼ 9.2 Hz, 1H, ArH), 8.08 (d,
J ¼ 7.6 Hz, 1H, ArH), 8.21 (d, J ¼ 8.8 Hz, 1H, ArH). IR (KBr, n,
cmꢂ1): 3082, 3046, 1586, 1562, 1551, 1524, 1473, 1448, 1389, 1378,
1347, 1332, 1248, 1139, 1100, 1069, 1047, 1037, 1009, 952, 871, 862,
834, 820, 801, 790, 750 cmꢂ1. Anal. calcd. for C25H14BrCl2N: C, 62.66;
H, 2.94; N, 2.92. Found: C, 62.70; H, 2.78; N, 3.01.
1-(4-Bromophenyl)-3-(3-nitrophenyl)benzo[f]quinoline 4u
Mp 194–195 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.30–7.34 (m, 1H, ArH),
7.52 (d, J ¼ 8.4 Hz, 2H, ArH), 7.58–7.65 (m, 2H, ArH), 7.81–7.87 (m, 3H,
ArH), 8.07 (d, J ¼ 7.6 Hz, 1H, ArH), 8.11 (d, J ¼ 8.8 Hz, 1H, ArH), 8.18
(s, 1H, ArH), 8.21 (d, J ¼ 8.8 Hz, 1H, ArH), 8.34–8.37 (m, 1H, ArH), 8.80
(d, J ¼ 8.0 Hz, 1H, ArH), 9.16–9.17 (m, 1H, ArH). IR (KBr, n, cmꢂ1):
3051, 1578, 1531, 1478, 1449, 1392, 1343, 1314, 1256, 1152, 1103, 1069,
1013, 917, 894, 878, 833, 805, 755, 747, 712, 686 cmꢂ1. Anal. calcd. for
C25H15BrN2O2: C, 65.95; H, 3.32; N, 6.15. Found: C, 65.83; H, 3.44;
N, 6.10.
1-(4-Bromophenyl)-3-(4-fluorophenyl)benzo[f]quinoline 4v
Mp 124–125 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.27–7.31 (m, 1H, ArH),
7.36–7.40 (m, 2H, ArH), 7.48 (d, J ¼ 8.4 Hz, 2H, ArH), 7.54–7.61 (m, 2H,
ArH), 7.79 (d, J ¼ 8.4 Hz, 2H, ArH), 7.98 (s, 1H, ArH), 8.04 (d,
J ¼ 9.2 Hz, 2H, ArH), 8.16 (d, J ¼ 9.2 Hz, 1H, ArH), 8.39–8.42 (m, 2H,
ArH). IR (KBr, n, cmꢂ1): 3049, 1596, 1578, 1544, 1528, 1508, 1450,

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1387, 1357, 1301, 1227, 1155, 1100, 1067, 1011, 946, 868, 835, 801, 744,
717 cmꢂ1. Anal. calcd. for C25xH15BrFN: C, 70.11; H, 3.53; N, 3.27.
Found: C, 70.25; H, 3.47; N, 3.40.
3-(3-Bromophenyl)-1-(4-fluorophenyl)benzo[f]quinoline 4w
Mp 216–218 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.27–7.31 (m, 1H, ArH),
7.43–7.47 (m, 2H, ArH), 7.51–7.61 (m, 5H, ArH), 7.71–7.73 (m, 1H,
ArH), 8.05–8.09 (m, 3H, ArH), 8.19 (d, J ¼ 8.8 Hz, 1H, ArH), 8.38
(d, J ¼ 8.0 Hz, 1H, ArH), 8.58–8.59 (m, 1H, ArH). IR (KBr, n, cmꢂ1):
3049, 1603, 1575, 1543, 1507, 1477, 1446, 1387, 1345, 1328, 1295, 1252,
1231, 1156, 1092, 1083, 1069, 1040, 995, 945, 874, 836, 795, 782, 757,
710, 690 cmꢂ1. Anal. calcd. for C25H15BrFN: C, 70.11; H, 3.53; N,
3.27. Found: C, 70.05; H, 3.49; N, 3.38.
1-(4-Chlorophenyl)-3-(2,3-dichlorophenyl)benzo[f]quinoline 4x
Mp 145–146 ꢀC. 1H NMR (DMSO-d6, d, ppm): 7.29–7.33 (m, 1H, ArH),
7.51–7.67 (m, 8H, ArH), 7.73 (dd, J ¼ 8.0 Hz, J0 ¼ 1.6 Hz, 1H, ArH), 7.78
(dd, J ¼ 8.0 Hz, J0 ¼ 1.2 Hz, 1H, ArH), 8.01 (d, J ¼ 9.2 Hz, 1H, ArH), 8.06
(d, J ¼ 8.8 Hz, 1H, ArH), 8.19 (d, J ¼ 8.8 Hz, 1H, ArH). IR (KBr, n,
cmꢂ1): 3048, 1573, 1557, 1540, 1521, 1493, 1474, 1446, 1416, 1348,
1329, 1251, 1192, 1125, 1093, 1048, 1016, 953, 840, 829, 788, 767, 756,
740, 721, 710 cmꢂ1. Anal. calcd. for C25H14Cl3N: C, 69.07; H, 3.25; N,
3.22. Found: C, 68.87; H, 3.41; N, 3.19.
CONCLUSION
In conclusion, we found an efficient method for the synthesis of 3-aryl-1-
substitutedbenzo[f]quinoline derivatives via three-component reaction
of arylaldehyde, naphthalen-2-amine, and acetone or acetophenone using
5 mol% iodine as catalyst. The features of this procedure are mild
reaction conditions, high yield, and operational simplicity.
ACKNOWLEDGMENTS
We are grateful to the Foundation of National Natural Science Founda-
tion of China (no. 20802061) and the Natural Science Foundation of the
Education Committee of Jiangsu Province (08KJD150019) for financial
support.

3-Arylbenzoquinoline Derivatives
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