A Simple and Facile Synthesis of 4-Phenylquinoline-fused Pyrrolidin-2-ones

Article abstract of DOI:10.1002/jhet.3052

In the present investigation, a simple and facile synthesis of a series of 4-phenylquinoline-fused pyrrolidin-2-ones, namely, 9-phenyl-2-substituted-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-ones is described, involving the tandem intermolecular C-N bond formation reaction between readily available ethyl 2-(chloromethyl)-4-phenylquinoline-3-carboxylate and various amines followed by in situ intramolecular C–N bond cyclization process in the presence of EtOH-AcOH (v/v, 10:1) solvent system as the reaction medium.

Full text of DOI:10.1002/jhet.3052

Month 2017 A Simple and Facile Synthesis of 4-Phenylquinoline-fused Pyrrolidin-2-ones
*
Yang Li and Hongtao Zou
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang 110866, China
*
E-mail: bhuzh@163.com
Received July 13, 2017
DOI 10.1002/jhet.3052
Published online 00 Month 2017 in Wiley Online Library (wileyonlinelibrary.com).
In the present investigation, a simple and facile synthesis of a series of 4-phenylquinoline-fused
pyrrolidin-2-ones, namely, 9-phenyl-2-substituted-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-ones is de-
scribed, involving the tandem intermolecular C-N bond formation reaction between readily available ethyl
2-(chloromethyl)-4-phenylquinoline-3-carboxylate and various amines followed by in situ intramolecular
C–N bond cyclization process in the presence of EtOH-AcOH (v/v, 10:1) solvent system as the reaction
medium.
J. Heterocyclic Chem., 00, 00 (2017).
INTRODUCTION
amides (I) under catalytic radical cation salt induced
conditions (Scheme 1a). Just recently, Yan et al. [21]
reported the copper(I)-catalyzed intramolecular tandem
amidation and oxidation reaction of 2-methyl-3-
carbamoyl-quinolines (III) with the aim of synthesizing
pyrrolo[3,4-b] quinolin-1-ones (IV), but instead, the
unexpected 1,3-dione analogues V were obtained as
the major products as shown in Scheme 1b.
In the last few years, our research group has gained
substantial ability in the application of ethyl
2-(halomethyl)quinoline-3-carboxylates [22–24] as the
valuable building blocks to reveal the synthetic potential
of the platforms in accessing important quinoline scaffold
derivatives [25–29]. Building on these evolving expertise
and considering the aforementioned findings, we hereby
would like to report a very simple and facile synthesis of
a series of such 4-phenylquinoline-fused pyrrolidin-2-one
derivatives, namely, 9-phenyl-2-substituted-2,3-dihydro-
1H-pyrrolo [3,4-b]quinolin-1-ones (3) as shown in
Scheme 1c.
Over the past few decades, pyrrolidin-2-one framework
has been an attractive synthetic target [1–3], because
compounds bearing this moiety are present in numerous
biologically active natural products such as Zinnimidine
[4], Hericerin [5], and Rigidiusculamide A [6], and
have claimed to display a significant range of biological
activities [7–9]. Apart from this, pyrrolidin-2-ones, as
fundamental building blocks in synthetic chemistry,
are used for a wide range of important transformations
[10–12], which might be another reason for the interest in
the synthesis of this class of compounds. On the other
hand, as far as the tricyclic 4-phenylquinoline scaffold is
concerned, it is also a pharmacologically significant
structural unit present in many bioactive compounds, and
has been acted as a valuable pharmacophore for drug
design [13–15]. For example, Hino and his group
have found that the introduction of 4-phenylquinoline
moiety into quipazine resulted in an increase in
the antidepressant activity [16]. In consequence,
considerable synthetic efforts have been devoted
surrounding the 4-phenylquinoline template for further
modification and functionalization with the aim of
enhancing the potency of this class of compounds [17–19].
In light of the fact that the incorporation of different
bioactive heterocyclic moieties in a single molecule often
enhances the biological activity remarkably, we felt that it
would be of great interest to look into the synthesis of
4-phenylquinoline-based pyrrolidin-2-one derivatives. A
literature survey revealed that Wang et al. [20] recently
described a direct one-step synthesis of 9-phenyl-1H-
pyrrolo[3,4-b]quinolin-3(2H)-one derivatives (II) through
sp3 C–H bond oxidation of N-aryl glycine cinnamyl
RESULT AND DISCUSSION
Recently, our group has proved that the use of EtOH-
AcOH (v/v, 10:1) mixed solvent system as the reaction
medium is very efficient for the C–N bond cyclization
reaction [30–32]. As such, we again used the reliable
approach for the present synthetic work. As shown in
Scheme 2, the substrate 1 was first reacted with 1.1
equiv. of aromatic amines 2a–i in refluxing EtOH-AcOH
(10:1, v/v) medium. The progress of the reaction was
monitored by thin-layer chromatography (TLC), which
exhibited a spot in initial stages of the reaction, and then
© 2017 Wiley Periodicals, Inc.

Y. Li and H. Zou
Vol 000
Scheme 1. Route for the preparation of 4-phenylquinoline-fused pyrrolidin-2-ones.
Scheme 2. Synthesis of N-aryl-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-ones (3a–i). [Color figure can be viewed at wileyonlinelibrary.com]
the resulting spot gradually disappeared with appearance of
a new dark spot arising from the formation of the final
product. The observation suggested that the reaction
might involve a tandem intermolecular C–N bond
formation between 1 and aromatic amines 2 followed by
in situ intramolecular C–N bond cyclization process in a
single synthetic operation. It is worthy to mention that
other organic solvents such as MeOH, CHCl3, dioxane,
dimethylformamide, and tetrahydrofuran were also tested
for their effectiveness, but they were found to be inferior
to the EtOH-AcOH system. In addition, upon conducting
the reaction under solvent-free cogrinding conditions, no
reaction occurred, and the starting materials were
recovered unchanged.
After the usual workup followed by purification of crude
products by recrystallization from ethanol, the
desired products were obtained with satisfactory yields of
76–87%. The results demonstrated that no significant
difference in the reaction outcome was observed for the
electronic nature of the substituents on these examined
aromatic amines; both the electron-donating (e.g., Me, Et,
OMe, t-Bu) and mild electron withdrawing halogen groups
(e.g., F, Cl, Br) worked well, showing little distinction.
However, when R was strong electron-withdrawing groups
(e.g., NO2 and CN), the reaction scarcely proceeded, and
the desired products were detected in negligible amount
that did not warrant isolation. A possible reason is that
the presence of the strong electron-withdrawing group
might render the aromatic amines highly electron-
deficient and retard the reaction process.
Further, due to the simplicity of the one-pot synthesis,
we decided to extend its scope to some other amines such
as ammonia (2j), methanamine (2k), and ethanamine (2l)
with the aim of diversifying our work as shown in
Scheme 3. We were pleased to discover that these species
were also viable substrates for this transformation, giving,
not unexpectedly, the expected products 3j–l without any
experimental difficulties in comparable yields of 71%,
81%, and 79%, respectively.
The structures of all the newly synthesized compounds
3a–l were easily established according to their spectral
data and elemental analyses, which were in good
agreement with the compounds expected. As an example,
the IR spectrum of 3a exhibited the presence of a typical
stretching vibration band at 1701 cmÀ1 due to the
carbonyl group of the lactam moiety, supporting the
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Month 2017
A Simple and Facile Synthesis of 4-Phenylquinoline-fused Pyrrolidin-2-ones
Scheme 3. Synthesis of N-alkyl-2,3-dihydro-pyrrolo[3,4-b]quinolin-1-ones (3j–l). [Color figure can be viewed at wileyonlinelibrary.com]
signal of its 13C NMR spectrum at 164.83 ppm for the
carbonyl carbon. Its structure was unequivocally proven
by the H NMR spectrum, which did not show signals
q = quartet, dd = doublet of doublets, m = multiplet,
J = coupling constant). Elemental analyses were carried
out on an EA 2400II elemental analyzer (PerkinElmer,
Waltham, MA). The progress of reactions was monitored
by TLC on silica gel GF254 using ethyl
acetate/petroleum ether (1:3) as the eluent. Ethyl
1
attributable to chloromethyl and ester groups of
its precursor 1 but contained a sharp two-proton singlet
line at 5.10 ppm, readily recognizable from the arising
pyrrolidin-2-one ring, supporting the signal of its 13C
NMR spectrum at 57.07 ppm. Moreover, the presence of
14 aromatic protons in the range of the aromatic region
of 7.21–8.26 ppm exactly matches its structure as well.
Further, the structure assigned to 3a was fully supported
by its elemental analysis, which established its molecular
2-(chloromethyl)-4-phenylquinoline-3-carboxylate
(1)
was prepared according to the method of the literature
[33], and the amines 2a–l used were obtained from
Fluka without further purification.
General
9-phenyl-2-substituted-2,3-dihydro-1H-
quinolin-1-ones (3a–l).
procedure
for
the
preparation
of
pyrrolo[3,4-b]
formulae
in
accordance
with
the
suggested
A
mixture
of
ethyl
molecular structure. The other synthesized compounds
exhibited similar spectral characteristics, except the
substituents, which exhibited characteristic signals with
appropriate chemical shifts.
In conclusion, we have provided an easy access to the
synthesis of various biologically intriguing 9-phenyl-
2-(chloromethyl)-4-phenylquinoline-3-carboxylate
(1,
0.326 g, 1.0 mmol) and the respective amine (2,
1.1 mmol) was refluxed in EtOH–AcOH (10 mL, v/v,
10:1) within 4 h. After complete disappearance of the
starting materials as inferred through TLC, the reaction
was quenched with 5 mL of H2O, and the resulting crude
product, which precipitated on standing, was collected.
Recrystallization from ethanol gave the desired products
3a–l.
N-substituted-2,3-dihydro-1H-pyrrolo[3,4-b]
quinolin-
1-ones. In view of the synergism of both the
4-phenylquinoline ring system and pyrrolidin-2-one
moiety in
a
molecular framework, these newly
2,9-Diphenyl-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-one
synthesized compounds would likely possess significant
biological activities and could be potentially applied for
the development of biologically and pharmaceutically
important drugs. Further investigation concerning the
bioactive properties of the generated products as well as
their application in the synthesis of more complex
heterocycles are currently under investigation in our
laboratory and will be reported in due course.
(3a). White crystals yield 79%, mp 251–253°C. IR (KBr)
ν/cmÀ1: 3056, 2914, 1701, 1595, 1498, 1446, 1381, 1327,
1291, 1201, 1176, 1146, 1057, 780 cmÀ1 1H NMR
;
(400 MHz, CDCl3) δ (ppm): 8.26 (d, J = 8.8 Hz, 1H,
ArH), 7.86–7.91 (m, 4H, ArH), 7.54–7.63 (m, 4H, ArH),
7.46–7.51 (m, 2H, ArH), 7.43 (t, J = 7.6 Hz, 2H, ArH),
7.21 (t, J = 7.6 Hz, 1H, ArH), 5.10 (s, 2H, CH2); 13C
NMR (100 MHz, CDCl3) δ (ppm): 164.83, 144.57,
143.28, 141.43, 138.08, 137.18, 135.35, 134.71, 134.61,
134.48, 133.62, 133.32, 132.65, 130.46, 127.68, 126.09,
125.38, 57.07. Anal. Calcd for C23H16N2O: C, 82.12; H,
4.79; N, 8.33. Found: C, 81.81; H, 4.81; N, 8.27.
EXPERIMENTAL
General.
Melting points (uncorrected) were
9-Phenyl-2-(m-tolyl)-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-
determined by using a WRS-1B melting point apparatus.
Infrared spectra were recorded on a Scimitar 2000 series
Fourier transform instrument from VARIAN. The 1H
(400 MHz) and 13C (100 MHz) NMR spectra were
recorded on an Agilent 400-MR spectrometer using
CDCl3 as the solvent. The reported chemical shifts
(δ values) are given in parts per million downfield from
tetramethylsilane as the internal standard (NMR
abbreviations: s = singlet, d = doublet, t = triplet,
1-one (3b). White crystals, yield 76%, mp 259–261°C.
IR (KBr) ν/cmÀ1: 3062, 2910, 1703, 1597, 1490, 1443,
1380, 1333, 1291, 1229, 1170, 1146, 1027, 771 cmÀ1
;
1H NMR (400 MHz, CDCl3) δ (ppm): 8.28 (d,
J = 8.4 Hz, 1H, ArH), 7.89 (d, J = 8.0 Hz, 2H, ArH),
7.84 (s, 1H, ArH), 7.56–7.63 (m, 5H, ArH), 7.48–7.52
(m, 2H, ArH), 7.31 (t, J = 8.0 Hz, 1H, ArH), 7.03 (d,
J = 7.2 Hz, 1H, ArH), 5.11 (s, 2H, CH2N), 2.39 (s, 3H,
CH3); 13C NMR (100 MHz, CDCl3) δ (ppm): 164.39,
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Y. Li and H. Zou
Vol 000
134.55, 132.65, 129.81, 129.74, 127.79, 125.73, 122.39,
121.61, 118.32, 115.22, 113.39, 111.80, 108.32, 106.45,
102.84, 101.56, 52.60, 21.32. Anal. Calcd for
C24H18N2O: C, 82.26; H, 5.18; N, 7.99. Found: C,
82.00; H, 6.44; N, 7.78.
9-Phenyl-2-(p-tolyl)-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-
1-one (3c). White crystals, yield 84%, mp 276–277°C. IR
ArH), 7.39–7.44 (m, 2H, ArH), 6.86 (dd, J = 8.4, 1.6 Hz,
2H, ArH), 4.96 (s, 2H, CH2N), 3.74 (s, 3H, OCH3); 13C
NMR (100 MHz, CDCl3) δ (ppm): 167.96, 152.01,
143.90, 127.72, 127.38, 126.69, 125.03, 124.20, 124.07,
123.23, 122.91, 122.72, 122.23, 116.83, 115.82, 110.01,
109.93, 109.44, 50.72, 47.05. Anal. Calcd for
C24H18N2O2: C, 78.67; H, 4.95; N, 7.65. Found: C,
(KBr) ν/cmÀ1: 3031, 2930, 1698, 1603, 1577, 1508, 1446,
1379, 1333, 1292, 1264, 1171, 1144, 815 cmÀ1; 1H NMR
(400 MHz, CDCl3) δ (ppm): 8.20 (d, J = 8.4 Hz, 1H, ArH),
7.84 (d, J = 8.0 Hz, 2H, ArH), 7.74 (d, J = 8.4 Hz, 2H,
ArH), 7.43–7.55 (m, 6H, ArH), 7.18 (d, J = 8.0 Hz, 2H,
ArH), 5.02 (s, 2H, CH2N), 2.33 (s, 3H, CH3); 13C NMR
(100 MHz, CDCl3) δ (ppm): 164.94, 159.40, 131.37,
130.49, 129.75, 129.59, 128.99, 128.91, 127.98, 127.66,
126.91, 126.21, 125.76, 124.70, 123.67, 123.18, 121.96,
119.75, 51.62, 20.87. Anal. Calcd for C24H18N2O: C,
78.91; H, 5.15; N, 7.43.
2-(4-Fluorophenyl)-9-phenyl-2,3-dihydro-1H-pyrrolo[3,4-b]
quinolin-1-one (3g). White crystals, yield 85%, mp 217–
218°C. IR (KBr) ν/cmÀ1: 3058, 2971, 2932, 1702, 1605,
1516, 1472, 1410, 1376, 1318, 1233, 1179, 1058,
1
766 cmÀ1; H NMR (400 MHz, CDCl3) δ (ppm): 8.23
(d, J = 8.0 Hz, 1H, ArH), 7.81–7.88 (m, 3H, ArH),
7.52–7.61 (m, 5H, ArH), 7.48 (t, J = 8.0 Hz, 2H, ArH),
7.07–7.12 (m, 2H, ArH), 5.05 (s, 2H, CH2N); 13C NMR
(100 MHz, CDCl3) δ (ppm): 164.88, 141.01, 135.14,
134.18, 132.49, 131.64, 129.76, 129.07, 128.97, 128.06,
127.75, 127.53, 127.13, 124.70, 121.70, 121.64, 115.92,
115.75, 51.76. Anal. Calcd for C23H15FN2O: C, 77.95; H,
82.26; H, 5.18; N, 7.99. Found: C, 82.13; H, 4.93; N, 8.17.
2-(4-Ethylphenyl)-9-phenyl-2,3-dihydro-1H-pyrrolo[3,4-b]
quinolin-1-one (3d). White crystals, yield 80%, mp 245–
246°C. IR (KBr) ν/cmÀ1: 3035, 2961, 2927, 1700, 1604,
4.27; N, 7.90. Found: C, 77.63; H, 4.19; N, 7.81.
2-(4-Chlorophenyl)-9-phenyl-2,3-dihydro-1H-pyrrolo[3,4-b]
quinolin-1-one (3h). Yellow crystals, yield 82%, mp 253–
1513, 1448, 1381, 1364, 1325, 1268, 1172, 1145, 1056,
1
838 cmÀ1; H NMR (400 MHz, CDCl3) δ (ppm): 8.24
255°C. IR (KBr) ν/cmÀ1: 3063, 2928, 1702, 1592, 1493,
(d, J = 8.4 Hz, 1H, ArH), 7.88 (d, J = 8.0 Hz, 2H, ArH),
7.78 (d, J = 8.0 Hz, 2H, ArH), 7.60–7.55 (m, 4H, ArH),
7.48–7.53 (m, 2H, ArH), 7.28 (t, J = 8.0 Hz, 2H, ArH),
5.07 (s, 2H, CH2N), 2.66 (q, J = 7.6 Hz, 2H, CH2CH3),
1.25 (t, J = 7.6 Hz, 3H, CH2CH3); 13C NMR (100 MHz,
CDCl3) δ (ppm): 165.03, 146.59, 142.27, 138.16, 136.98,
135.39, 134.59, 134.53, 134.03, 133.59, 133.27, 133.08,
132.52, 131.79, 129.09, 127.88, 126.15, 125.51, 57.24,
33.89, 21.22. Anal. Calcd for C25H20N2O: C, 82.39; H,
1451, 1416, 1378, 1355, 1290, 1172, 1124, 1100, 1007,
1
823 cmÀ1; H NMR (400 MHz, CDCl3) δ (ppm): 8.22
(d, J = 7.2 Hz, 1H, ArH), 7.83–7.89 (m, 4H, ArH),
7.54–7.62 (m, 4H, ArH), 7.46–7.51 (m, 2H, ArH), 7.37
(dd, J = 7.6, 1.6 Hz, 2H, ArH), 5.03 (s, 2H, CH2N); 13C
NMR (100 MHz, CDCl3) δ (ppm): 165.21, 159.29,
150.43, 149.06, 137.97, 132.80, 131.83, 130.18, 129.96,
129.44, 129.38, 129.29, 128.32, 127.98, 127.74, 127.31,
121.01, 120.39, 51.78. Anal. Calcd for C23H15ClN2O: C,
5.53; N, 7.69. Found: C, 82.16; H, 5.81; N, 7.53.
2-(4-(tert-Butyl)phenyl)-9-phenyl-2,3-dihydro-1H-
74.49; H, 4.08; N, 7.55. Found: C, 74.57; H, 3.92; N, 7.25.
2-(4-Bromophenyl)-9-phenyl-2,3-dihydro-1H-pyrrolo[3,4-b]
quinolin-1-one (3i). Yellow crystals, yield 80%, mp 254–
pyrrolo[3,4-b]quinolin-1-one (3e).
White crystals, yield
87%, mp 171–173°C. IR (KBr) ν/cmÀ1: 3075, 2955,
255°C. IR (KBr) ν/cmÀ1: 3059, 3034, 2930, 1709, 1608,
2834, 1692, 1617, 1514, 1449, 1374, 1340. 1261, 1204,
1
1125, 746 cmÀ1; H NMR (400 MHz, CDCl3) δ (ppm):
1585, 1491, 1430, 1413, 1378, 1327, 1287, 1220, 1170,
1
1123, 824 cmÀ1; H NMR (400 MHz, CDCl3) δ (ppm):
8.23 (d, J = 8.0 Hz, 1H, ArH), 7.86 (d, J = 8.0 Hz, 2H,
ArH), 7.77 (d, J = 7.6 Hz, 2H, ArH), 7.53–7.61 (m, 4H,
ArH), 7.45–7.49 (m, 2H, ArH), 7.40 (d, J = 7.2 Hz, 2H,
ArH), 5.06 (s, 2H, CH2N), 1.30 (s, 9H, t-Bu); 13C NMR
(100 MHz, CDCl3) δ (ppm): 164.62, 159.27, 147.93,
136.28, 132.39, 131.59, 129.02, 128.71, 127.99, 127.71,
127.51, 127.07, 126.73, 125.92, 125.07, 124.65, 120.60,
119.64, 51.44, 34.41, 31.30. Anal. Calcd for C27H24N2O:
C, 82.62; H, 6.16; N, 7.14. Found: C, 82.48; H, 6.38; N,
8.25 (d, J = 8.0 Hz, 1H, ArH), 7.88 (t, J = 8.0 Hz, 2H,
ArH), 7.82 (d, J = 8.8 Hz, 2H, ArH), 7.56–7.63
(m, 4H, ArH), 7.53 (d, J = 8.4 Hz, 2H, ArH), 7.46–7.51
(m, 2H, ArH), 5.06 (s, 2H, CH2N); 13C NMR
(100 MHz, CDCl3) δ (ppm): 164.44, 140.15, 138.95,
137.66, 137.33, 137.10, 135.27, 134.69, 134.59, 133.66,
133.35, 132.75, 128.77, 126.62, 121.94, 112.61, 98.29,
56.99. Anal. Calcd for C23H15BrN2O: C, 66.52; H, 3.64;
6.96.
N, 6.75. Found: C, 66.87; H, 3.41; N, 6.51.
9-Phenyl-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-one
(3j). White crystals, yield 71%, mp 208–210°C. IR (KBr)
2-(4-Methoxyphenyl)-9-phenyl-2,3-dihydro-1H-pyrrolo[3,4-
b]quinolin-1-one (3f). White crystals, yield 79%, mp 242–
243°C. IR (KBr) ν/cmÀ1: 3050, 2919, 2847, 1701, 1606,
ν/cmÀ1: 3443, 3064, 2927, 1707, 1609, 1588, 1514, 1489,
1437, 1392, 1336, 1295, 1228, 1181, 1130, 844 cmÀ1; 1H
NMR (400 MHz, CDCl3) δ (ppm): 8.84 (s, 1H, NH), 8.16
(dd, J = 8.0, 2.4 Hz, 1H, ArH), 7.90 (t, J = 8.0 Hz, 1H,
ArH), 7.54–7.69 (m, 5H, ArH), 7.40–7.45 (m, 2H, ArH),
1510, 1447, 1382, 1350, 1269, 1211, 1177, 1115, 1058,
823 cmÀ1; H NMR (400 MHz, CDCl3) δ (ppm): 8.16
1
(d, J = 8.4 Hz, 1H, ArH), 7.79 (t, J = 8.0 Hz, 2H, ArH),
7.70 (dd, J = 8.4, 1.6 Hz, 2H, ArH), 7.46–7.55 (m, 4H,
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Month 2017
A Simple and Facile Synthesis of 4-Phenylquinoline-fused Pyrrolidin-2-ones
4.56 (s, 2H, CH2N); 13C NMR (100 MHz, CDCl3) δ
(ppm): 163.72, 149.52, 147.00, 134.60, 133.20, 131.41,
130.31, 129.33, 128.81, 128.13, 127.25, 120.32, 46.25.
Anal. Calcd for C17H12N2O: C, 78.44; H, 4.65; N, 10.76.
[5] Li, W.; Zhou, W.; Lee, D. S.; Shim, S. H.; Kim, Y. C.; Kim,
Y. H. Tetrahedron Lett 2014, 55, 4086.
[6] Krishna, P. R.; Reddy, B. K. Helv Chim Acta 2013, 96, 1564.
[7] Sapa, J.; Filipek, B.; Kulig, K.; Malawska, B. Pharmacol Rep
2011, 63, 71.
[8] Dudek, M.; Knutelska, J.; Bednarski, M.; Nowiński, L.;
Zygmunt, M.; Kazek, G.; Mordyl, B.; Gluch-Lutwin, M.; Zareba, P.;
Kulig, K.; Sapa, J. Eur J Pharmacol 2016, 776, 146.
[9] Sapa, J.; Zygmunt, M.; Kulig, K.; Malawska, B.; Dudek, M.;
Filipek, B.; Bednarski, M.; Kusak, A.; Nowak, G. Pharmacol Rep 2014,
66, 708.
Found: C, 78.60; H, 4.75; N, 10.47.
2-Methyl-9-phenyl-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-
one (3k). White crystals, yield 81%, mp 243–245°C. IR
(KBr) ν/cmÀ1: 3063, 2908, 1685, 1608, 1564, 1508,
1483, 1458, 1395, 1347, 1277, 1233, 1135, 765 cmÀ1
;
[10] Priyadarshini, S.; Joseph, P. A.; Kantam, M. L. Tetrahedron
2014, 70, 6068.
1H NMR (400 MHz, CDCl3)
δ
(ppm): 8.20
(d, J = 8.4 Hz, 1H, ArH), 7.82–7.88 (m, 2H, ArH),
7.51–7.60 (m, 4H, ArH), 7.43–7.48 (m, 2H, ArH), 4.60
(s, 2H, CH2N), 3.23 (s, 3H, NCH3); 13C NMR
(100 MHz, CDCl3) δ (ppm): 166.38, 156.33, 156.16,
148.36, 145.37, 138.18, 136.64, 135.42, 134.60, 134.39,
133.49, 133.19, 132.38, 125.68, 58.47, 35.03. Anal.
Calcd for C18H14N2O: C, 78.81; H, 5.14; N, 10.21.
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Found: C, 79.17; H, 5.35; N, 9.99.
2-Ethyl-9-phenyl-2,3-dihydro-1H-pyrrolo[3,4-b]quinolin-1-
one (3l). White crystals, yield 79%, mp 175–176°C. IR
(KBr) ν/cmÀ1: 3059, 2974, 2926, 2875, 1692, 1617,
1577, 1512, 1458, 1412, 1373, 1347, 1234, 1079, 1025,
1
770 cmÀ1; H NMR (400 MHz, CDCl3) δ (ppm): 8.21
(d, J = 8.4 Hz, 1H, ArH), 7.87 (d, J = 8.4 Hz, 1H, ArH),
7.83 (t, J = 8.4 Hz, 1H, ArH), 7.54–7.62 (m, 4H,
ArH), 7.44–7.49 (m, 2H, ArH), 4.60 (s, 2H, CH2N), 3.71
(q, J = 7.2 Hz, 2H, CH2CH3), 1.31 (t, J = 7.2 Hz, 3H,
CH2CH3); 13C NMR (100 MHz, CDCl3) δ (ppm):
166.17, 154.13, 138.25, 136.60, 135.44, 134.57, 134.35,
133.49, 133.17, 132.83, 132.33, 55.74, 42.58, 18.86.
Anal. Calcd for C19H16N2O: C, 79.14; H, 5.59; N, 9.72.
Found: C, 78.89; H, 5.42; N, 9.57.
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Acknowledgments. The project was financially supported by the
National Natural Science Foundation of China (grant number
21402011) and the Natural Science Foundation of Liaoning
Province (grant number 201602006).
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet