An efficient one-pot, three-component synthesis of indeno[1,2-b]quinoline-9,11(6H,10H)-dione, acridine-1,8(2H,5H)-dione and quinoline-3-carbonitrile derivatives from enaminones

Article abstract of DOI:10.1039/b607575d

An efficient one-pot, three-component method for the preparation of indeno[1,2-b]quinoline-9,11(6H,10H)-dione, acridine-1,8(2H,5H)-dione and various multi-substituted quinoline-3-carbonitrile derivatives has been developed through the Michael addition to

Full text of DOI:10.1039/b607575d

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PAPER
www.rsc.org/obc | Organic & Biomolecular Chemistry
An efficient one-pot, three-component synthesis of indeno[1,2-b]quinoline-
9,11(6H,10H)-dione, acridine-1,8(2H,5H)-dione and quinoline-3-
carbonitrile derivatives from enaminones†
Shu-Jiang Tu,* Bo Jiang, Run-Hong Jia, Jun-Yong Zhang, Yan Zhang, Chang-Sheng Yao and Feng Shi
Received 30th May 2006, Accepted 3rd August 2006
First published as an Advance Article on the web 17th August 2006
DOI: 10.1039/b607575d
An efficient one-pot, three-component method for the preparation of indeno[1,2-b]quinoline-
9,11(6H,10H)-dione, acridine-1,8(2H,5H)-dione and various multi-substituted quinoline-3-
carbonitrile derivatives has been developed through the Michael addition to enaminones, which was
achieved by both microwave irradiation and conventional heating.
Introduction
Multi-component reactions (MCRs) occupy an outstanding po-
sition in organic and medicinal chemistry for their high degree
of atom economy and applications in combinatorial chemistry.1
They have inherent advantages over two-component reactions in
several aspects: the simplicity of a one-pot procedure, possible
Fig. 1
structure variations, complicated synthesis and the large number
of accessible compounds.2 Nevertheless, continued efforts are
being made to explore new MCRs for developing popular organic
reactions.3
compounds containing the indenoquinoline scaffold and the
development of more rapid and efficient entry to these heterocycles
are strongly desired. In connection with our previous study
modifying the 1,4-DHP scaffold,17 in this paper we report a
rapid and efficient method for synthesizing new heterocyclic
compounds containing indenoquinoline unit using enaminones
as the precursors (Scheme 1).
Enaminones and related compounds possessing the struc-
=
=
tural unit (N–C C–Z, Z COR, CO2R, CN, etc.) are versatile
synthetic intermediates in organic chemistry that combine the
ambient nucleophilicity of enamine and the electrophilicity of
enones.4 They are frequently applied in the preparation of
heterocycles.5
1,4-Dihydropyridines (1,4-DHPs) are well-known compounds
because of their pharmacological profiles as calcium channel
modulators.6 Chemical modifications of the DHP ring such as
the introduction of different substituents or heteroatoms7 have
allowed expansion of the research of structure–activity relation-
ships, affording new insights into the molecular interactions at the
receptor level. With a 1,4-DHP parent nucleus, indenoquinoline
derivatives have showed a diverse range of biological properties
such as 5-HT-receptor binding8 and anti-inflammatory activities.9
They have also acted as antitumor agents,10 steroid reductase
inhibitors,11 acetylcholinesterase inhibitors,12 antimalarials,13 and
new potential topo I/II inhibitors.14 Because of the biologi-
cal activities they exhibit, these compounds have distinguished
themselves as heterocycles of profound chemical and biological
significance. Thus the synthesis of these molecules has attracted
considerable attention.15 Recently, the synthesis of indeno[1,2-
b]quinolin-10-one derivatives (a, Fig. 1) was reported by Lee
and co-workers.16 However, the synthesis of new heterocyclic
Scheme 1
Result and discussion
When treating aldehyde 1 with 1,3-indanedione 2 and enaminone
3 under microwave irradiation, the target compounds 4 were
obtained. We first chose 5,5-dimethyl-3-(phenylamino)cyclohex-2-
enone 3b and investigated the optimized conditions for its reaction
with 4-bromobenzaldehyde 1q and 1,3-indanedione 2 affording
indeno[1,2-b]quinoline-9,11(6H,10H)-dione derivatives 4q under
microwave irradiation (microwave oven EmrysTM Creator from
Personal Chemistry, Uppsala, Sweden) (Scheme 2). In this three-
component reaction, we found that the temperature and solvent
had a significant effect on reaction yields (Scheme 2 and Table 1).
As shown in Table 1, in the presence of acetic acid,
when the temperature was at 80 ◦C under microwave irradia-
tion, reaction of p-bromobenzaldehyde 1q with 5,5-dimethyl-3-
(phenylamino)cyclohex-2-enone 3b gave 2-(4-bromobenzylidene)-
indene-1,3-dione as main product and only trace amount of 4q
Department of Chemistry, Xuzhou Normal University, Key Laboratory of
Biotechnology for Medicinal Plant Xuzhou, Jiangsu, 211116, P.R. China.
E-mail: laotu@xznu.edu.cn; Fax: +86 516 83403164; Tel: +86 516
83500349
† Electronic supplementary information (ESI) available: Characterization
data. See DOI: 10.1039/b607575d
3664 | Org. Biomol. Chem., 2006, 4, 3664–3668
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was formed. When the temperature was increased from 80 ◦C
to 120 ◦C, the yield of product 4q was increased and the
reaction time was shortened. However, further increase of the
temperature to 130 ◦C failed to improve the yield of product
4q. Therefore, 120 ◦C was chosen as the optimum temperature
for all further microwave-assisted reactions. For optimization
of the reaction solvent, the same reaction was carried out at
120 ◦C in various solvents such as glycol, DMF, acetic acid,
and water. The reaction using acetic acid gave the best result
(Table 1). A series of aldehydes and enaminones were applied
under microwave irradiation conditions in this reaction to afford
a new type of heterocyclic compounds, the indeno[1,2-b]quinoline-
9,11(6H,10H)-dione derivatives 4 (Scheme 3). The initial results
are summarized in Table 2.
Scheme 2
Table 1 Optimization of reaction conditions for the preparation of
compound 4q
Entry
Solvent
T/◦C
Time/min
Yield (%)
1
2
3
4
5
6
7
8
9
HOAc
HOAc
HOAc
HOAc
HOAc
HOAc
Glycol
DMF
Water
80
90
10
12
8
6
4
4
8
10
12
13
63
80
85
91
90
37
84
82
100
110
120
130
120
120
120
Scheme 3
As shown in Table 2, the scope of the reaction with regard to the
aldehyde is quite large. Not only aromatic aldehydes containing
Table 2 Synthesis of compounds 4, 7, 8 and 9
Entry
Product
R
3
Ar
R1
R2
Time
Yield (%)c
Mp/◦C
1
2
3
4
5
6
7
8
9
4a
4b
4c
4d
4e
4f
4g
4h
4i
4-OH-3-NO2C6H3
4-CH3C6H4
4-NO2C6H4
4-FC6H4
3,4-OCH2OC6H3
4-BrC6H4
3,4,5-(CH3O)3C6H2
2,4-Cl2C6H3
4-(Benzo[d]oxazol-2-yl)C6H4
CH3(CH2)2CH2
CH3(CH2)10CH2
3-NO2C6H4
4-CH3OC6H4
4-OH-3-CH3OC6H3
C6H5
2-Thienyl
4-BrC6H4
4-ClC6H5
3,4-(CH3O)2C6H3
4-BrC6H4
3,4-OCH2OC6H3
4-OH-3-NO2C6H3
2,4-Cl2C6H3
4-(Benzo[d]oxazol-2-yl)C6H4
2-Thienyl
3a
3a
3a
3a
3a
3a
3a
3a
3a
3a
3a
3b
3b
3b
3b
3b
3b
3b
3a
3a
3a
3b
3b
3b
3a
3b
3a
3b
3a
3a
3b
3a
3b
3b
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
4-CH3C6H4
4-CH3C6H4
4-CH3C6H4
C6H5
C6H5
C6H5
4-CH3C6H4
C6H5
4-CH3C6H4
C6H5
4-CH3C6H4
4-CH3C6H4
C6H5
4-CH3C6H4
C6H5
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
H
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
CH3
CH3
CH3
C6H5
C6H5
C6H5
—
—
—
—
—
—
—
—
—
4a, 2.5b
6a, 3.5b
4a, 2.0b
4a, 2.5b
7a, 4.0b
4a, 3.0b
5a, 4.5b
4a, 2.0b
5a, 2.5b
10a, 4.5b
9a, 5.0b
4a, 2.5b
6a, 3.0b
6a, 4.0b
5a, 2.5b
8a, 3.5b
4a, 3.0b
4a, 3.5b
6a, 4.5b
2a,1.5b
4a, 2.0b
2a, 1.0b
2a, 1.0b
3a, 2.0b
3a, 1.5b
7a, 4.0b
8a, 3.0b
6a, 3.5b
8a, 3.0b
5a, 3.5b
7a, 3.5b
5a, 4.0b
6a, 3.5b
5a, 4.5b
90a, 88b
87a, 87b
92a, 91b
88a, 85b
85a, 82b
91a, 90b
87a, 88b
93a, 92b
92a, 89b
85a, 86b
88a, 85b
92a, 90b
86a, 87b
88a, 82b
90a, 85b
85a, 87b
91a, 90b
91a, 89b
90a, 86b
93a, 90b
92a, 91b
94a, 92b
95a, 93b
89a, 92b
90a, 91b
87a, 88b
86a, 85b
90a, 87b
85a, 83b
91a, 89b
92a, 89b
90a, 91b
91a, 89b
89a, 90b
265–266
283–285
290–291
225–227
258–260
255–256
168–170
291–293
277–278
260–261
167–169
242–244
250–251
272–274
257–258
230–232
283–284
236–237
257–259
229–230
168–169
216–218
>300
291–292
297–299
256–258
277–279
294–295
262–264
235–236
260–262
289–290
296–297
>300
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
4j
4k
4l
4m
4n
4o
4p
4q
4r
4s
7a
7b
7c
7d
7e
7f
8a
8b
8c
8d
8e
8f
H
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
H
H
H
CH3
CH3
CH3
2,4-Cl2C6H3
3,4-OCH2OC6H3
4-NO2C6H4
4-ClC6H5
3-NO2C6H4
3-NO2C6H4
9a
9b
9c
1,4-CHOC6H4
1,3-CHOC6H4
1,4-CHOC6H4
C6H5
a The time (min) and the yield of the product under microwave irradiation at 120 ◦C. b The time (h) and the yield of the product by using the traditional
heating mode at 120 ◦C. c Isolated yields.
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either electron-withdrawing groups or electron-donating groups
can be used, dialdehydes, aliphatic and heterocyclic aldehydes
gave also excellent results. A range of indeno[1,2-b]quinoline-
9,11(6H,10H)-diones 4 have been conveniently synthesized in high
yields.
In order to examine the applicability of this new three-
component cyclocondensation reaction to other active methylene
compounds, we employed 5-substituted-cyclohexane-1,3-dione 5
or malononitrile 6 instead of 1,3-indanedione 2 in the reaction with
aldehydes 1 and enaminones 3 (Scheme 4). The results (Table 2)
show that a wide range of aldehydes including aromatic aldehydes
with either electron-withdrawing or electron-donating groups and
heterocyclic aldehydes can likewise take part in this reaction,
leading to the preparation of a series of acridine-1,8(2H,5H)-
diones 7 or multi-substituted quinolines 8.
Scheme 4
Fig. 2 Crystal structure of 4g.
1
Furthermore, we have synthesized bifunctional compounds
containing two indenoquinoline units (9) using o-phthalaldehyde
and p-phthalaldehyde as precursors (Scheme 5).
protons (see H NMR data). This could be explained by the X-
ray structure of 4g. In the crystal structure of 4g (Fig. 2), the
distance between the protons at C3 and the phenyl ring (C17
˚
to C22) is 2.46 A, indicating that the proton at C3 is shielded
by the benzene ring (C17 to C22), which caused its 1H NMR
absorption to be shifted to upfield and it appeared as a doublet
at 5.19 ppm.
Conclusion
In summary, we have demonstrated
a rapid and direct
method that offered a simple and efficient route for one-pot,
three-component synthesis of highly functionalized indeno[1,2-
b]quinoline-9,11(6H,9H)-dione, acridine-1,8(2H,5H)-dione and
poly-substituted quinoline-3-carbonitrile derivatives in excellent
yields. Particularly valuable features of this method, which
was achieved by both microwave irradiation and conven-
tional heating, include high yields, broad substrate scope and
convenient operation. This series of indeno[1,2-b]quinoline,
and acridine-1,8(2H,5H)-dione, poly-substituted quinoline-3-
carbonitrile derivatives may prove to be of biological interest and
provide new classes of compounds for biomedical screening.
Scheme 5
Additionally, all the reactions were performed at 120 ◦C under
classical heating conditions in acetic acid. A comparison of
the results for the 34 compounds listed in Table 2 indicated
that the reactions are efficiently promoted by microwave ir-
radiation, and when almost quantitative yields were obtained,
the reaction time was strikingly shortened from 1.0–4.5 h in
traditional heating conditions to 2–10 min under microwave
irradiation.
All the products were characterized by IR, 1H NMR and
elemental analyses. The structure of 4g was established by an
X-ray crystallographic analysis (Fig. 2).18 The IR spectrum of
Experimental
General
compound 4g shows C O stretchings at 1686 cm−1 and 1634 cm−1.
=
It is particularly noteworthy that in the 1H NMR spectra of
compounds (4a–s and 9a–c), two absorption peaks appeared
at 4.91 ppm and 5.35 ppm, which belonged to the aromatic
Microwave irradiation was carried out with microwave oven
EmrysTM Creator from Personal Chemistry, Uppsala, Sweden.
Melting points were determined in open capillaries and are
3666 | Org. Biomol. Chem., 2006, 4, 3664–3668
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uncorrected. IR spectra were taken on a FT-IR-Tensor 27
spectrometer in KBr pellets and reported in cm−1. 1H NMR
spectra were measured on a Bruker DPX 400 MHz spectrometer
in DMSO-d6 with chemical shifts (d) given in ppm relative to
TMS as internal standard. Elemental analysis was determined by
using a Perkin-Elmer 240c elemental analysis instrument. X-Ray
crystallographic analysis was performed with a Siemens SMART
CCD and a Siemens P4 diffractometer.
Anal calcd. for C34H33NO5, C, 76.24; H, 6.21; N, 2.61; found C,
76.35; H, 6.25; N, 2.55%.
7a. IR (KBr, m, cm−1): 3033, 2956, 2929, 2870, 1634, 1575,
1484, 1363, 1223, 1009, 840, 763; 1H NMR (DMSO-d6) (d, ppm):
7.44–7.40 (m, 5H, ArH), 7.25 (d, 3H, ArH, J = 8.0 Hz), 4.99 (s,
1H, CH), 2.42 (s, 3H, CH3), 2.33–2.00 (m, 5H, CH2), 1.98–1.84
(m, 4H, CH2), 0.88 (s, 3H, CH3), 0.78 (d, 3H, CH3, J = 6.4 Hz),
0.66 (s, 3H, CH3); Anal calcd. for C29H30BrNO2, C, 69.05; H, 5.99;
N, 2.78; found C, 69.17; H, 5.91; N, 2.84%.
General procedure for the synthesis of enaminones 3 with
microwave irradiation in a monomodal EmrysTM Creator microwave
8a. IR (KBr, m, cm−1): 3459, 3321, 3214, 2959, 2870, 2179,
1651, 1592, 1564, 1374, 1258, 1042, 871, 832, 743; 1H NMR
(DMSO-d6) (d, ppm): 7.62–7.53 (m, 4H, ArH), 7.47–7.40 (m, 4H,
ArH), 5.34 (s, 2H, NH2), 4.99 (s, 1H, CH), 2.42 (d, 1H, CH2, J =
17.6 Hz), 2.18 (d, 1H, CH2 J = 16.4 Hz), 1.97 (d, 1H, CH2, J =
16.4 Hz), 1.75 (d, 1H, CH2, J = 17.6 Hz), 0.89 (s, 3H, CH3), 0.80
(s, 3H, CH3); Anal calcd. For C24H21Cl2N3O, C, 65.76; H, 4.83; N,
9.59; found C, 65.81; H, 4.79; N, 9.56%.
The reactions were performed in a monomodal EmrysTM Creator
from Personal Chemistry, Uppsala, Sweden. In a 20 mL EmrysTM
reaction vial, aromatic amine (11 mmol), dimedone (10 mmol) or
cyclohexane-1,3-dione (10 mmol) and water (3 mL) were mixed
and then capped. The mixture was irradiated for 6 min with
200 W power at 100 ◦C. The reaction mixture was cooled to
room temperature and then poured into cold water. The solid
product was filtered, washed with water and EtOH (95%), and
recrystallized from acetone to give the pure product.
Acknowledgements
We are grateful for financial support from the National Science
Foundation of China (No. 20372057) and Natural Science Foun-
dation of the Jiangsu Province (No. BK2006033).
General procedure for the synthesis of compounds 4, 7, 8 and 9
with microwave irradiation in a monomodal EmrysTM Creator
microwave
All the reactions were performed in a monomodal EmrysTM
Creator from Personal Chemistry, Uppsala, Sweden. In a 10 mL
EmrysTM reaction vial, aldehyde (1, 1 mmol), 1,3-indanedione (2,
1 mmol) (or 5-substituted-cyclohexane-1,3-dione (5, 1 mmol) or
malononitrile (6, 1 mmol)), enaminone (3, 1 mmol) and acetic acid
(1.0 mL) were mixed and then capped. The mixture was irradiated
for a certain time (Table 2) at a power of 200 W at 120 ◦C. Upon
completion of the reaction as indicated by TLC monitoring, the
reaction mixture was cooled to room temperature and then poured
into cold water. The solid product was filtered, washed with water
and EtOH (95%), and subsequently dried and recrystallized from
EtOH (95%) to give the pure product.
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with conventional heating
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4g. IR (KBr, m, cm−1): 2956, 2833, 1687, 1644, 1457, 1491,
1365, 1126, 888; H NMR (DMSO-d6) (d, ppm): 7.54–7.48 (m,
1
4H, ArH), 7.27 (d, 1H, ArH, J = 6.8 Hz), 7.18 (t, 1H, ArH, J =
7.4 Hz), 7.01 (t, 1H, ArH, J = 7.6 Hz), 6.59 (s, 2H, ArH), 5.19 (d,
1H, ArH, J = 7.6 Hz), 4.82 (s, 1H, CH), 3.76 (s, 6H, CH3), 3.61 (s,
3H, CH3), 2.50 (s, 3H, CH3), 2.48 (d, 1H, CH2, J = 16.4 Hz), 2.31
(d, 1H, CH2, J = 17.6 Hz), 2.10 (d, 1H, CH2, J = 16.4 Hz), 2.03
(d, 1H, CH2, J = 17.6 Hz), 0.97 (s, 3H, CH3), 0.93 (s, 3H, CH3).
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D. Q. Shi, Synlett, 2004, 255.
18 The single-crystal growth was carried out in ethanol at room tempera-
ture. X-Ray crystallographic analysis was performed with a Siemens
SMART CCD and a Semens P4 diffractometer. Crystal data for
4g:C34H33NO· H2O, red, crystal dimension 0.50 × 0.46 × 0.26 mm,
˚
˚
monoclinic, space group C2/c, a = 25.094(6) A, b = 12.755(3) A,
c = 19.891(5) A, a = c = 90◦, b = 103.926(4)◦, V = 6179(3)
˚
A , Mr = 544.62, Z = 8, Dc = 1.171 Mg m−3, k (Mo-Ka) =
3
˚
0.71073 A, l = 0.079 mm−1, F(000) = 2312, 2.62 < h < 25.01◦,
◦
˚
R = 0.0741, wR2 = 0.1786. S = 0.999, Largest diff. Peak and hole:
0.700 and −0.248 e A−3. CCDC reference number 602003. For crys-
˚
tallographic data in CIF or other electronic format see DOI: 10.1039/
b607575d.
3668 | Org. Biomol. Chem., 2006, 4, 3664–3668
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The Royal Society of Chemistry 2006
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