Efficient Friedlaender synthesis of quinoline derivatives from 2-aminoarylketones and carbonyl compounds mediated by recyclable PEG-supported sulfonic acid

Article abstract of DOI:10.1080/00397910902754283

2-Aminoarylketones undergo smooth condensation with α-methylene ketones in the presence of 10 mol% of poly(ethylene glycol) (PEG)-supported sulfonic acid under mild reaction conditions to afford the corresponding poly-substituted quinolines in excellent y

Full text of DOI:10.1080/00397910902754283

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Efficient Friedländer Synthesis
of Quinoline Derivatives from
2-Aminoarylketones and
Carbonyl Compounds Mediated
by Recyclable PEG-Supported
Sulfonic Acid
Xiao-Liang Zhang a , Qiu-Ying Wang a , Shou-Ri Sheng
a , Qing Wang a & Xiao-Ling Liu a
a College of Chemistry and Chemical Engineering,
Jiangxi Normal University, Nanchang, China
Version of record first published: 12 Aug 2009
To cite this article: Xiao-Liang Zhang, Qiu-Ying Wang, Shou-Ri Sheng, Qing Wang
& Xiao-Ling Liu (2009): Efficient Friedländer Synthesis of Quinoline Derivatives
from 2-Aminoarylketones and Carbonyl Compounds Mediated by Recyclable PEG-
Supported Sulfonic Acid, Synthetic Communications: An International Journal for
Rapid Communication of Synthetic Organic Chemistry, 39:18, 3293-3304
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Synthetic Communications1, 39: 3293–3304, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910902754283
¨
Efficient Friedlander Synthesis of Quinoline
Derivatives from 2-Aminoarylketones and
Carbonyl Compounds Mediated by Recyclable
PEG-Supported Sulfonic Acid
Xiao-Liang Zhang, Qiu-Ying Wang, Shou-Ri Sheng, Qing Wang,
and Xiao-Ling Liu
College of Chemistry and Chemical Engineering, Jiangxi Normal
University, Nanchang, China
Abstract: 2-Aminoarylketones undergo smooth condensation with a-methylene
ketones in the presence of 10 mol% of poly(ethylene glycol) (PEG)–supported
sulfonic acid under mild reaction conditions to afford the corresponding poly-
substituted quinolines in excellent yields. The catalyst can be recovered by simple
filtration and can be recycled in subsequent reactions. The method is simple,
cost-effective, and environmentally benign.
Keywords: 2-Aminoarylketone, a-methyleneketone, PEG-supported sulfonic
acid, quinoline
Quinolines and their derivatives are very important compounds because of
their wide occurrence in natural products[1] and their interesting biological
activities as antimalarial, anti-inflammatory, antiasthmatic, antibacterial,
antihypertensive, and tyrosine kinase–inhibiting agents.[2] Additionally,
quinolines are valuable synthons used for the preparation of nanostruc-
tures and polymers that combine enhanced electronic, optoelectronic, or
nonlinear optical properties with excellent mechanical properties.[3]
Various methods such as Skraup, Doebner–von Miller, Friedla¨nder, and
Received August 19, 2008.
Address correspondence to Shou-Ri Sheng, College of Chemistry and
Chemical Engineering, Jiangxi Normal University (Yaohu Campus), Nanchang
330022, China. E-mail: shengsr@jxnu.edu.cn
3293

3294
X.-L. Zhang et al.
Combes reactions have been developed for the preparation of quinolines,[4–6]
Among these methods, Friedla¨nder annulation,[6a] an acid- or base-
catalyzed condensation followed by a cycoldehydration between an aro-
matic 2-aminoaldehyde or ketone and a carbonyl compound containing
a reactive a-methylene group, is one of the simplest and most straightfor-
ward protocols for the synthesis of poly-substituted quinolines. Brønsted
acid catalysts, such as NH2SO3H, HCl, H2SO4, p-toluenesulfonic acid
(p-TSA), H3PO4, trifluoroacetic acid (TFA), NaHSO4 ꢀ SiO2, and HClO4 ꢀ
SiO2, were widely used[7] for Friedla¨nder annulation. However, many of
these methods require high temperature (150–200 ꢁC) and extended
reaction times, which lead to several side reactions. Under thermal and basic
conditions, 2-aminobezophenone fails to react with cyclohexanone, deoxy-
benzoin, and b-ketoesters.[8] Recently, Lewis acids such as FeCl3, Mg(ClO4)2,
CuSO4 ꢀ 5H2O, FeSO4 ꢀ 7H2O, SnCl2, AlCl3, Bi(OTf)3, Sc(OTf)3, Y(OTf)3,
CeCl3 ꢀ 7H2O, I2, NaF, TMSCl, NaAuCl4 ꢀ 2H2O, Nd(NO3)3 ꢀ 6H2O, and
Ag3POW12O40 have been found to be effective for this conversion.[9] Addi-
tionally, ionic liquid[10] and microwave irradiation[11] have been employed to
promote the Friedla¨nder reaction. Even some of these methods also suffer
form harsh reaction conditions, poor yields, high temperature, tedious
workup, and the use of stoichiometric and relatively expensive reagents.
Thus, the development of simple, convenient, and environmentally friendly
approaches for the synthesis of quinolines is still in demand. Over the past
few years, there has been a considerable growth in interest in the use of solu-
ble polymer-supported catalysts and reagents in organic synthesis because of
their low cost, ease of preparation, simple workup, and recoverablity of
catalysts.[12] As part of an ongoing research program focused on the use
poly(ethylene glycol) (PEG)–bound sulfonic acid in organic synthesis,[13]
we examined the synthesis of poly-substituted quinolines using PEG-bound
sulfonic acid as an efficient and recyclable catalyst through condensa-
tion=annulation reaction of 2-aminoarylketones and carbonyl compounds.
Herein, we report the results of this study (Scheme 1).
As we recently reported, PEG-supported sulfonic acid with a loading
of 0.22 mmol=g was prepared readily from the dihydroxy PEG 4000 in
Scheme 1. Friedla¨nder synthesis of quinolines catalyzed by PEG-bound sulfonic
acid.

¨
Friedlander Synthesis of Quinoline Derivatives
3295
three steps.[13] To optimize the reaction conditions, we first conducted the
Friedla¨nder condensation of 2-aminoacetophenone with ethyl aceto-
acetate (2a) to the desired ethyl 2,4-dimethylquinoline-3-carboxylate
(3a) using a catalytic amount of PEG-supported sulfonic acid at room
temperature in different solvents such as CH3OH, Et2O, CH3CN, and
CH2Cl2. To our delight, after a series of experiments, the best results were
obtained when the reaction was carried out in CH2Cl2 at reflux room
temperature for 40 min in the presence of 10 mol% of PEG-supported
sulfonic acid with respect to 2-aminoacetophenone (Table 1, entry 1).
Furthermore, it was found that the use of 10 mol% of the catalyst was
sufficient to promote the reaction, and greater amounts of the catalyst
did not improve the yields. However, in the absence of PEG-supported
sulfonic acid, the reaction did not proceed even after long reaction times
(12–24 h). Furthermore, the condensation of 2-aminoacetophenone with
2a in the presence of concd. H2SO4 afforded 3a in only 68% yield
(Table 1, entry 2). A possible mechanism for the synthesis of quinolines
using this method is shown in Scheme 2, based on the literature[9a] and
the obtained results.
To study the generality of this process, several examples were studied.
As seen from Table 1, 2-aminoacetophenone could be replaced by
2-aminobezophenone, and a-methylene ketones could be extended from
ethyl acetoacetate (2a) to methyl acetoacetate (2b), acyclic 1,3-diketones
Table 1. PEG-bound sulfonic acid–catalyzed Friedla¨nder synthesis of quinolines 3
Entry R1
R2
R3
Time (min) Product Yield (%)a
1
2
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CO2Et
CO2Et
CO2Me
COMe
40
90
40
50
75
90
60
55
40
40
45
80
90
65
50
3a
3a
3b
3c
3d
3e
3f
96
68b
95
92
94
96
90
90
94
94
94
92
95
92
92
3
4
5
CH2CH2CH2CO
6
CH3 CH2C(CH3)2CH2CO
CH3
CH3
C6H5
C6H5
C6H5
C6H5
C6H5 CH2C(CH3)2CH2CO
C6H5
C6H5
7
CH2(CH2)2CH2
CH2CH2CH2
CH3
CH3
CH3
CH2CH2CH2CO
8
3g
3h
3i
9
CO2Et
CO2Me
COMe
10
11
12
13
14
15
3j
3k
3l
CH2(CH2)2CH2
CH2CH2CH2
3m
3n
aYields refer to pure isolated products.
bConcd. H2SO4 used instead of PEG-bound sulfonic acid.

3296
X.-L. Zhang et al.
such as 2,4-pentanedione (2c), cyclic 1,3-diketones such as 1,3-cyclohexa-
nedione (2d) and 5,5-dimethyl-1,3-cyclohexanedione (2e), and simple cyclic
ketones such as cyclohexanone (2f) and cyclopentanone (2g). In the opti-
mized reaction conditions, a library synthesis of quinoline 3a–n was suc-
cessfully obtained in very good yields (90–96%) by Friedla¨nder
condensation between 2-aminoacetophenone as well as 2-aminobezophe-
none with a variety of carbonyl compounds 2a–g in the presence of
PEG-supported sulfonic acid.
After finishing the condensation reaction, dichloromethane (DCM)
was evaporated, and the PEG-bound sulfonic acid was readily recovered
by precipitation with cold diethyl ether, followed by filtration and wash-
ing with diethyl ether (average recovery yields ranged from 92 to 95%) for
the next run directly without any activation. The recovered PEG-bound
sulfonic acid was reused consecutively without losing any significant
activity. For example, the reaction of 2-aminoacetophenone and 2a
afforded the corresponding quinoline 3a in 95%, 92%, 90%, and 88%
yields over four runs. It should be noted that when the catalytic activity
of polymeric sulfonic acid decreased, the resin could be treated with
concd. HCl again to keep its catalytic activity.[13] Furthermore, this
method is clean and free from side reactions.
On the other hand, the efficacy of the PEG-bound sulfonic acid as a
catalyst for the synthesis of 3a as a model compound was compared with
that of several reported catalysts such as sulfamic acid, NaHSO4–SiO2,
Y(OTf)3, and ionic liquid (Table 2). It indicated that PEG-bound sulfonic
acid is a very efficient catalyst useful in the synthesis of quinoline deriva-
tives. From the practical point of view, the catalyst is inexpensive,
nontoxic, and readily available, and the reaction proceeded in shorter
times. Furthermore, the catalyst can be easily recovered and reused.
In summary, we have described a mild, efficient, and environmentally
benign protocol for the synthesis of quinolines and polycyclic quinolines
Scheme 2. A possible mechanism for the synthesis of quinolines.

¨
Friedlander Synthesis of Quinoline Derivatives
3297
Table 2. Comparison of the efficiency of PEG-bound sulfonic acid for synthesis
of 3a
Entry
Catalyst
Time (min)
Yield (%)a
Ref.
1
2
3
4
NH2SO3H
NaHSO4–SiO2
Y(OTf)3
90
240
360
180
89
80
83
94
7c
7e
9i
10b
Ionic liquid
aYields refer to pure isolated products.
via Friedla¨nder condensation of 2-aminoarylketones with a-methylene
ketones using PEG-bound sulfonic acid as a recyclable catalyst. This
method offers good advantages such as short reaction times, good yields,
readily available recovery, and reuse of the catalyst combined with the
straightforward and easy workup procedure.
EXPERIMENTAL
1
Melting points were uncorrected. H NMR (400 MHz) and 13C NMR
(75 MHz) spectra were recorded on a Bruker Avance (400-MHz) spectro-
meter, using CDCl3 as the solvent and tetramethylsilane (TMS) as inter-
nal standard. Fourier transform–infrared (FT-IR) spectra were taken on
a Perkin-Elmer SP One FT-IR spectrophotometer. Microanalyses were
performed with a Carlo Erba 1106 elemental analyzer. PEG-bound
sulfonic acid was prepared according to our report method.[13] The other
reagents were purchased from commercial sources and were used without
further purification.
General Procedure for the Preparation of Quinoline Derivatives (3a–n)
PEG-bound sulfonic acid (0.1 mmol, 0.45 g) was added to a solution of
2-aminoarylketone (1.0 mmol) and a-methyleneketone (1.2 mmol) in
DCM (10.0 mL), and the reaction mixture was stirred at reflux temperature
for the appropriate time according to Table 1. The progress of the reaction
was monitored by thin-layer chromatography (TLC). After completion of
the reaction, the organic solvent was removed in vacuum, and the mixture
was cooled to room temperature. Then cold diethyl ether (100 mL) was
added with vigorous stirring. For completion of the precipitation, the
suspension was left at 0ꢁC for another 30 min. The recovered PEG-bound
sulfonic acid was then collected by filtration and washed with cold diethyl

3298
X.-L. Zhang et al.
ether (2 ꢂ 20 mL) for the next run. The filtrated organic solution was
concentrated to afford crude product, which was purified by silica-gel
column chromatography (10% ethyl acetate in hexane) to afford a pure
1
product. All the products were characterized by H NMR, 13C NMR,
FT-IR, and microanalysis and also by comparison with authentic samples.
Data
Ethyl 2,4-Dimethylquinoline-3-carboxylate (3a)
Oil (lit.[10b] oil); 1H NMR: d ¼ 7.98 (d, J ¼ 8.4 Hz, 1 H), 7.90 (d,
J ¼ 8.4 Hz, 1 H), 7.66 (t, J ¼ 7.6 Hz, 1 H), 7.45 (t, J ¼ 7.6 Hz, 1 H), 4.46
(q, J ¼ 7.1 Hz, 2 H), 2.70 (s, 3 H), 2.61 (s, 3 H), 1.40 (t, J ¼ 7.1 Hz, 3 H);
13C NMR: d ¼ 168.8, 154.1, 147.2, 141.2, 129.6, 129.4, 127.7, 126.1,
125.6, 123.7, 61.1, 23.5, 15.6, 14.0; IR (neat): n ¼ 3070, 2930, 2872,
1725, 1615, 1590, 1214, 1081, 578 cmꢃ1. Anal. calcd. for C14H15NO2:
C, 73.34; H, 6.59; N, 6.11. Found: C, 73.22; H, 6.67; N, 6.02.
Methyl 2,4-Dimethylquinoline-3-carboxylate (3b)
Oil (lit.[9c] oil); 1H NMR: d ¼ 8.04 (d, J ¼ 8.4 Hz, 1 H), 7.95 (d, J ¼ 8.3 Hz,
1 H), 7.65 (t, J ¼ 7.5 Hz, 1 H), 7.45 (t, J ¼ 7.5 Hz, 1 H), 3.60 (s, 3 H), 2.71
(s, 3 H), 2.64 (s, 3 H). 13C NMR: d ¼ 168.5, 154.4, 147.0, 141.3, 129.6,
128.8, 127.7, 126.2, 125.8, 123.6, 52.5, 23.9, 15.8; IR (neat): n ¼ 3067,
2953, 1730, 1613, 1585, 1485, 1445, 1423, 1390, 1230, 1170, 1065, 965,
762, 700 cmꢃ1. Anal. calcd. for C13H13NO2: C, 72.52; H, 6.09; N, 6.51.
Found: C, 72.62; H, 6.18; N, 6.59.
1-(2,4-Dimethylquinolin-3-yl)ethanone (3c)
Oil (lit.[10b] oil); 1H NMR: d ¼ 7.99 (d, J ¼ 8.4 Hz, 1 H), 7.91 (d,
J ¼ 8.4 Hz, 1 H), 7.66 (t, J ¼ 7.6 Hz, 1 H), 7.49 (t, J ¼ 7.6 Hz, 1 H), 2.61
(s, 3 H), 2.58 (s, 3 H), 2.56 (s, 3 H); IR (neat): n ¼ 3067, 2958, 1703,
1614, 1585, 1208, 758 cmꢃ1
135.5 (2 C), 129.6, 129.0, 126.2, 123.4, 32.5, 23.2, 15.0. Anal. calcd. for
C13H13NO: C, 78.36; H, 6.58; N, 7.03. Found: C, 78.27; H, 6.50; N, 7.11.
;
13C NMR: d ¼ 206.2, 152.5, 146.6, 138.4,
9-Methyl-3,4-Dihydroacridin-1(2H)-one (3d)
Solid; mp 66–67ꢁC (lit.[7d] mp 65–66 ꢁC); 1H NMR: d ¼ 8.08 (d, J ¼ 8.0 Hz,
1 H), 7.94 (d, J ¼ 8.0 Hz, 1 H), 7.59–7.50 (m, 2 H), 3.12–3.10 (m, 2 H),

¨
Friedlander Synthesis of Quinoline Derivatives
3299
2.80–2.77 (m, 2 H), 2.61–2.58 (m, 2 H), 2.21 (s, 3 H), 1.85–1.82 (m, 2 H);
13C NMR: d ¼ 199.5, 160.1, 149.2, 147.6, 130.9, 120.0, 127.2, 126.5,
125.1, 124.3, 40.3, 34.0, 20.6, 15.6; IR (KBr): n ¼ 3030, 2928, 1570,
1478, 1348, 1165, 1076, 938, 820, 775, 708, 618 cmꢃ1. Anal. calcd. for
C14H13NO: C, 79.59; H, 6.20; N, 6.63. Found: C, 79.70; H, 6.28; N, 6.71.
3,3,9-Trimethyl-3,4-dihydroacridin-1(2H)-one (3e)
1
Solid; mp 107–108ꢁC (lit.[7d] mp 105–106 ꢁC); H NMR: d ¼ 8.20 (d,
J ¼ 8.4 Hz, 1 H), 8.01 (d, J ¼ 8.4 Hz, 1 H), 7.76 (t, J ¼ 7.5 Hz, 1 H), 7.56
(t, J ¼ 7.5 Hz, 1 H), 3.20 (s, 2 H), 3.07 (s, 3 H), 2.65 (s, 2 H), 1.14 (s,
6 H); 13C NMR: d ¼ 200.2, 160.9, 149.5, 148.1, 131.2, 120.1, 127.5,
126.3, 125.4, 124.1, 54.7, 48.3, 31.9, 28.2 (2 C), 15.8; IR (KBr): n ¼ 2956,
2968, 1684, 1560, 1495, 1375, 1280, 1214, 764 cmꢃ1. Anal. calcd. for
C16H17NO: C, 80.30; H, 7.16; N, 5.85. Found: C, 80.22; H, 7.24; N, 5.78.
9-Methyl-1,2,3,4-tetrahydroacridine (3f)
1
Solid; mp 76–78ꢁC (lit.[10b] mp 78 C); H NMR: d ¼ 7.82–7.24 (m, 4 H),
ꢁ
2.95 (t, J ¼ 7.6 Hz, 2 H), 2.60 (t, J ¼ 7.6 Hz, 2 H), 2.26 (s, 3 H), 1.74–1.72
(m, 4 H); 13C NMR: d ¼ 157.8, 145.5, 140.6, 128.5, 127.6, 126.4 (2 C),
124.6, 122.8, 33.8, 26.5, 22.8, 22.3, 12.9; IR (KBr): n ¼ 3066, 2936,
1615, 1580, 1351, 754 cmꢃ1. Anal. calcd. for C14H15N: C, 85.24; H,
7.66; N, 7.10. Found: C, 85.13; H, 7.76; N, 7.03.
9-Methyl-2,3-dihydro-1H-cyclopenta[b]quinoline (3g)
1
Solid; mp 59–61ꢁC (lit.[10b] mp 60 C); H NMR: d ¼ 8.00–7.45 (m, 4 H),
ꢁ
3.31 (t, J ¼ 7.0 Hz, 2 H), 2.98 (t, J ¼ 7.5 Hz, 2 H), 2.50 (s, 3 H), 2.22–2.20
(m, 2 H); 13C NMR: d ¼ 166.7, 147.1, 137.7, 133.6, 128.8, 127.8, 126.9,
125.0, 123.1, 34.7, 29.5, 22.6, 14.6; IR (KBr): n ¼ 3065, 2956, 1614, 908,
751 cmꢃ1. Anal. calcd. for C13H13N: C, 85.21; H, 7.15; N, 7.64. Found:
C, 85.12; H, 7.06; N, 7.73.
Ethyl 2-Methyl-4-phenylquinoline-3-carboxylate (3h)
1
Solid; mp 97–98ꢁC (lit.[9n] mp 99 C); H NMR: d ¼ 8.06 (d, J ¼ 8.4 Hz,
ꢁ
1 H), 7.70 (t, J ¼ 7.9 Hz, 1 H), 7.56–7.35 (m, 7 H), 4.09 (q, J ¼ 7.1 Hz,
2 H), 2.80 (s, 3 H); 0.96 (t, J ¼ 7.1 Hz, 3 H); 13C NMR: d ¼ 167.8, 153.5,
147.8, 145.6, 135.7 (2C), 129.5, 129.0, 128.2, 127.8, 126.5, 126.1, 125.0,

3300
X.-L. Zhang et al.
96.1, 68.9, 23.3, 13.5; IR (KBr): n ¼ 3060, 2975, 1725, 1604, 1580, 1486,
1443, 1230, 1068, 904, 700 cmꢃ1. Anal. calcd. for C19H17NO2: C, 78.33;
H, 5.88; N, 4.81. Found: C, 78.42; H, 5.96; N, 4.88.
Methyl 2-Methyl-4-phenylquinoline-3-carboxylate (3i)
Solid; mp 87–88ꢁC (lit.[9n] mp 86–88 ꢁC); 1H NMR: d ¼ 8.10 (d, J ¼ 8.4 Hz,
1 H), 8.07–7.35 (m, 8 H), 3.58 (s, 3 H), 2.79 (s, 3 H); 13C NMR: d ¼ 169.0,
154.5, 147.8, 146.4, 135.7, 130.3, 129.2, 128.9, 128.5, 128.3, 127.3, 126.5,
125.1, 52.2, 23.9; IR (KBr): n ¼ 3065, 2952, 1732, 1613, 1584, 1426,
1395, 1231, 1171, 1068, 764, 702 cmꢃ1. Anal. calcd. for C18H15NO2: C,
77.96; H, 5.45; N, 5.05. Found: C, 78.05; H, 5.56; N, 5.12.
1-(2-Methyl-4-phenylquinolin-3-yl)ethanone (3j)
1
Solid; mp 105–106ꢁC (lit.[9e] mp 105–106 ꢁC); H NMR: d ¼ 8.02 (d,
J ¼ 8.0 Hz, 1 H), 7.75–7.35 (m, 8 H), 2.68 (s, 3 H), 1.98 (s, 3 H); 13C
NMR: d ¼ 205.5, 153.0 (2C), 146.9, 144.3, 134.6 (2C), 129.4 (2C),
128.5, 128.1, 125.0, 125.5, 124.5, 31.5, 23.4; IR (KBr): n ¼ 3028, 2960,
1705, 1610, 1568, 1486, 1396, 1215, 768, 705 cmꢃ1. Anal. calcd. for
C18H15NO: C, 82.73; H, 5.79; N, 5.36. Found: C, 82.65; H, 5.87; N, 5.43.
9-Phenyl-3,4-dihydroacridin-1(2H)-one (3k)
1
Solid; mp 139–140ꢁC (lit.[9c] mp 140–142 ꢁC); H NMR: d ¼ 8.04 (d,
J ¼ 8.7 Hz, 1 H), 7.45–7.40 (m, 6 H), 7.20–7.17 (m, 2 H), 3.35 (t, J ¼ 6.5 Hz,
Hz, 2 H), 2.68 (t, J ¼ 6.5 Hz, 2 H), 2.28–2.25 (m, 2 H); 13C NMR:
d ¼ 197.1, 161.7, 150.7, 148.2, 137.2, 131.1, 128.7, 128.5, 128.1, 127.8,
127.0, 125.9, 125.2, 123.4, 40.1, 34.2, 20.9; IR (KBr): n ¼ 3032, 2946,
1690, 1553, 1485, 1390, 1220, 1160, 1023, 770, 706, 540 cmꢃ1. Anal. calcd.
for C19H15NO: C, 83.49; H, 5.53; N, 5.12. Found: C, 83.60; H, 5.64; N,
5.03.
3,3-Dimethyl-9-phenyl-3,4-dihydroacridin-1(2H)-one (3l)
1
Solid; mp 190–191ꢁC (lit.[9c] mp 190–192 ꢁC); H NMR: d ¼ 8.04 (d,
J ¼ 8.0 Hz, 1 H), 7.74 (t, J ¼ 7.8 Hz, 1 H), 7.48–7.35 (m, 5 H), 7.20–7.12
(m, 2 H), 3.30 (s, 2 H), 2.56 (s, 2 H), 1.20 (s, 6 H); 13C NMR: d ¼ 198.3,
161.4, 149.9, 148.2, 137.5, 131.3, 128.8, 128.6, 128.2, 127.5, 126.8, 125.6,
125.1, 124.0, 54.3, 48.2, 31.6, 28.0 (2 C), 15.6; IR (KBr): n ¼ 3060, 2956,

¨
Friedlander Synthesis of Quinoline Derivatives
3301
1712, 1602, 1574, 1208, 1380, 740 cmꢃ1. Anal. calcd. for C21H19NO: C,
83.69; H, 6.35; N, 4.65. Found: C, 83.75; H, 6.27; N, 4.73.
9-Phenyl-1,2,3,4-tetrahydroacridine (3m)
[9c]
1
ꢁ
Yellow solid; mp 131–132ꢁC (lit. mp 132 C); H NMR: d ¼ 8.00 (d,
J ¼ 8.1 Hz, 1 H), 7.62–7.42 (m, 5 H), 7.30–7.19 (m, 3 H), 3.20 (t, J ¼ 6.8 Hz,
Hz, 2 H), 2.60 (t, J ¼ 6.6 Hz, 2 H), 2.04–1.96 (m, 2 H), 1.84–1.74 (m, 2 H);
13C NMR: d ¼ 158.5, 146.5, 146.0, 137.5, 129.3, 128.8, 128.6, 128.2, 127.8,
127.5, 126.7, 125.5, 125.2, 34.2, 27.9, 23.2, 22.6; IR (KBr): n ¼ 3060, 2940,
1610, 1575, 1486, 1440, 1220, 768, 710 cmꢃ1. Anal. calcd. for C19H17N: C,
87.99; H, 6.61; N, 5.40. Found: C, 88.06; H, 6.68; N, 5.52.
9-Phenyl-2,3-dihydro-1H-cyclopenta[b]quinoline (3n)
Yellow solid; mp 114–115ꢁC (lit.[9c] mp 113–115 ꢁC); 1H NMR: d ¼ 8.00–
7.45 (m, 4 H), 3.31 (t, J ¼ 7.0 Hz, 2 H), 2.98 (t, J ¼ 7.5 Hz, 2 H), 2.50 (s,
3 H), 2.22–2.20 (m, 2 H); 13C NMR: d ¼ 166.7, 147.1, 137.7, 133.6,
128.8, 127.8, 126.9, 125.0, 123.1, 34.7, 29.5, 22.6, 14.6; IR (KBr):
n ¼ 3065, 2956, 1614, 1569, 1478, 1348, 1165, 1076, 940, 820, 775,
708 cmꢃ1. Anal. calcd. for C18H15N: C, 88.13; H, 6.16; N, 5.71. Found:
C, 88.24; H, 6.26; N, 5.78.
ACKNOWLEDGMENTS
We gratefully acknowledge financial support from the National Natural
Science Foundation (NSF) of China (No. 20562005), NSF of Jiangxi
Province (Nos. 0620021 and 2007GZW0185), and the Research Program
of Jiangxi Province Department of Education (No. GJJ08165).
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