An Efficient Route for the Synthesis of 11-Aroyldiindeno[1,2-b:2′,1′-e]pyridine-10,12-diones

Article abstract of DOI:10.1002/jhet.2949

A series of novel 11-aroyldiindeno[1,2-b:2′,1′-e]pyridine-10,12-dione derivatives were synthesized, in good to excellent yields and short reaction times via one-pot, three-component reactions between indan-1,3-dione, ammonium acetate, and arylglyoxal hydrates in the presence of solid p-toluenesulfonic acid.

Full text of DOI:10.1002/jhet.2949

Month 2017
An Efficient Route for the Synthesis of 11-Aroyldiindeno[1,2-b:20,10-e]
pyridine-10,12-diones
*
Ahmad Poursattar Marjani,
Jabbar Khalafy, and Aynaz Haghi
Department of Organic Chemistry, Faculty of Chemistry, Urmia University, Urmia, Iran
*
E-mail: a.poursattar@gmail.com; a.poursattar@urmia.ac.ir
Received January 9, 2017
DOI 10.1002/jhet.2949
Published online 00 Month 2017 in Wiley Online Library (wileyonlinelibrary.com).
A series of novel 11-aroyldiindeno[1,2-b:20,10-e]pyridine-10,12-dione derivatives were synthesized, in
good to excellent yields and short reaction times via one-pot, three-component reactions between
indan-1,3-dione, ammonium acetate, and arylglyoxal hydrates in the presence of solid p-toluenesulfonic
acid.
J. Heterocyclic Chem., 00, 00 (2017).
INTRODUCTION
room
temperature
afforded
the
corresponding
intermediates 3a–i, as shown in Scheme 1.
Recently, the use of one-pot, multicomponent reactions
have received considerable interest in the synthesis of
However, our main goal was to find a way for ring
closure in the intermediate 3a–i. In this respect,
indandione (1), arylglyoxal as their hydrates 2a–i,
ammonium acetate, and catalytic amount of p-TSA in
ethanol/chloroform under reflux conditions afforded a
new series of 11-aroyldiindeno[1,2-b:20,10-e]pyridine-
10,12-diones 4a–i by one-pot, three-component reaction
as shown in Scheme 2.
A number of alternative procedures to achieve this
outcome have been examined, but poor results were
realized. Some of these attempts are shown in Table 1.
As we note in Table 1, among all catalysts, p-TSA under
reflux conditions gave the corresponding product 4a with
94% yield. We next verified the scope of this reaction
with diverse arylglyoxals 2a–i, indan-1,3-dione (1), and
ammonium acetate to for our desired products 4a–i in
74–94% yields, p-TSA as a catalyst under reflux
conditions. The reaction conditions, melting points
(decomposing points), and yields of products 4a–i are
listed in Table 2.
A proposed mechanism for this reaction is shown in
Scheme 3. The 1H-NMR and 13C-NMR spectra of the
intermediate 3a and compound 4a were measured in
CDCl3, but because of the extreme insolubility of products
4b–i, their 1H-NMR spectra could not be measured in
CDCl3, and therefore, their 1H-NMR spectra were
measured in DMSO-d6, but their 13C-NMR spectra could
not be measured even at high temperature because of the
low solubility. The structures of all products were
elucidated by their 1H-NMR, FTIR spectral data, mass
spectroscopy, and microanalysis.
heterocyclic
compounds
with
biological
and
pharmacological activities by a route with three or more
components, which avoids the spread of poisonous
intermediates [1–6]. The simplicity of a one-pot, liner-
type synthesis, the accessible complexity of the
compounds, shorter reaction times, efficiency over
conventional procedures, and high selectivity are
advantages of multicomponent reactions [7,8].
Heterocyclic compounds containing the indenopyridine
nucleus are important targets in synthetic and medicinal
chemistry due to the presence of this fragment in
numerous biologically and pharmaceutically active
molecules [9–14].
In continuation of our previous work in the synthesis of
heterocyclic compounds [15–30], we now report an
efficient synthesis of a series of new indeno[1,2-b:20,10-e]
pyridine-10,12-diones by a one-pot, three-component
reaction, through Hantzsch pyridine synthesis, involving
intramolecular cyclocondensation of arylglyoxal hydrates,
indandione, and ammonium acetate in the presence
of catalytic amounts of p-toluenesulfonic acid (p-TSA)
in chloroform/ethanol (2:3) under reflux conditions.
These substituted 11-aroyldiindeno[1,2-b:20,10-e]pyridine-
10,12-diones can be considered as potential DNA
intercalators [9].
RESULT AND DISCUSSION
Reaction of arylglyoxal as their hydrates 2a–i with 2 mol
of indandione (1) in the presence of ammonium acetate at
© 2017 Wiley Periodicals, Inc.

A. Poursattar Marjani, J. Khalafy, and A. Haghi
Vol 000
Scheme 1. Synthesis of intermediates 3a–i. [Color figure can be viewed at wileyonlinelibrary.com]
Scheme 2. Synthesis of diindenopyridine derivatives 4a–i catalyzed by p-TSA. [Color figure can be viewed at wileyonlinelibrary.com]
Table 1
Optimization of reaction conditions for the synthesis of compound 4a. [Color table can be viewed at wileyonlinelibrary.com]
Entry
Solvent
Catalyst
Conditions
Yield (4a %)
1
2
3
4
5
6
7
8
Water
—
Alginic acid
—
—
NH4Cl
—
AcOH
—
Pyridine
Et3N
NH4Cl
p-TSA
Reflux
Reflux
RT/Reflux
Microwave
RT
Reflux
Reflux
Reflux
Reflux
RT/Reflux
RT
—
30
15
—
—
23
—
42
25
33
—
94
Water/Ethanol
Water/Ethanol
Solvent free
Water/Methanol
Ethanol
Ethanol
AcOH
Water/Ethanol
Methanol/Chloroform
Ethanol/Chloroform
Ethanol/Chloroform (3:2)
9
10
11
12
Reflux
CONCLUSIONS
derivatives in high yields via a one-pot, three-component
reaction of various arylglyoxals with indandione and
ammonium acetate by using the readily available p-TSA
as a catalyst. The final products are suitable for the
In conclusion, we have developed an efficient, economic,
simple route for the synthesis of diindenopyridine
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2017
An Efficient Route for the Synthesis of 11-Aroyldiindeno[1,2-b:20,10-e]pyridine-
10,12-diones
Table 2
The yields and melting points of compounds 4a–i.
Entry
Substrate
Product
Ar
Time (h)
Yield (%)
mp (dec.)/°C
1
2
3
4
5
6
7
8
9
2a
2b
2c
2d
2e
2f
2g
2h
2i
4a
4b
4c
4d
4e
4f
4g
4h
4i
C6H5
4-BrC6H4
4-ClC6H4
4-FC6H4
4-MeC6H4
3-MeOC6H4
4-MeOC6H4
4-O2NC6H4
3,4-(MeO)2C6H3
5
7
6
8
7
8
8
9
9
94
86
82
79
94
74
78
91
90
327–329
344–346
341–344
329–331
347–350
330–332
342–343
377–380
335–337
Scheme 3. Pathway leading to the synthesis of 4. [Color figure can be viewed at wileyonlinelibrary.com]
synthesis of a series of polycyclic heterocycles that could be
expected to intercalate with DNA [9].
Armarego [31]. Melting points were measured on a
Philip Harris C4954718 (Birmingham, UK) apparatus and
are uncorrected. Infrared spectra were recorded on a
Thermo Nicolet Nexus 670 (Thermo Fisher Scientific,
Waltham, MA) FTIR instrument by using KBr discs.
1H-NMR and 13C-NMR spectra were recorded on a
Bruker Avance AQS (Bruker Corp., Billerica, MA)
300 MHz spectrometer at 300 and 75.5 MHz,
EXPERIMENTAL SECTION
Freshly distilled solvents were used throughout, and
anhydrous solvents were dried according to Perrin and
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

A. Poursattar Marjani, J. Khalafy, and A. Haghi
Vol 000
respectively. Chemical shifts were measured in CDCl3 or
DMSO-d6 as solvents with reference to trimethylsilyl as
the internal standard. Elemental analyses were performed
by using a Leco Analyzer 932 (Leco Corp., St. Joseph,
MI). Mass spectra were recorded on an Agilent
Technologies (HP) MS Model: 5975C VL MSD
mass spectrometer (Santa Clara, CA) operating at an
ionization potential of 70 eV.
11-(4-Chlorobenzoyl)diindeno[1,2-b:20,10-e]pyridine-10,12-
dione (4c).
Yellow precipitate; 1H-NMR (300 MHz,
DMSO-d6) δ (ppm): 8.04 (d, J = 8.1 Hz, 2H, ArH), 7.98
(d, J = 8.1 Hz, 2H, ArH), 7.88–7.79 (m, 3H, ArH), 7.72–
7.66 (m, 3H, ArH), 7.60 (d, J = 8.7 Hz, 2H, ArH); FTIR
(υmax, cmꢀ1): 3434, 3076, 2938, 1716, 1673, 1598, 1545,
1463, 1380, 1266, 1164, 1030, 870, 753; MS: m/z (%):
422 [M + 2]+ (13), 420 [M]+ (49), 283 (63), 227 (32),
225 (86), 198 (30), 141 (74), 139 (100), 113 (78), 111
(100), 75 (95). Anal. Calc. for C26H12ClNO3: C, 74.03;
H, 2.87; N, 3.32. Found: C, 73.94; H, 2.91; N, 3.21%.
11-(4-Fluorobenzoyl)diindeno[1,2-b:20,10-e]pyridine-10,12-
General procedure for the synthesis of 2,2-(2-oxo-2-
phenylethane-1,1-dil)bis(1H)-inden-1,3(2H)-dione (3a).
A
mixture of indan-1,3-dione (2 mmol), phenylglyoxal
hydrate (1 mmol), and NH4OAc (5 mmol) in H2O (5 mL)
was stirred at room temperature for 5 h. The precipitate
was filtered, washed with cold water and cold ethanol to
give product as white solid; yield 96%; mp 202–204°C;
1H-NMR (300 MHz, CDCl3) δ (ppm): 7.97–7.83 (m, 6H,
ArH), 7.80–7.48 (m, 4H, ArH), 7.60–7.26 (m, 3H, ArH),
5.12 (bt, J = 4.5 Hz, 1H, CH), 3.81 (d, J = 4.5 Hz, 2H,
2 × CH); 13C-NMR (75.5 MHz, CDCl3) δ (ppm): 44.61,
51.77, 128.90, 133.31, 135.56, 135.71, 135.86, 141.36,
142.38, 192.61, 198.28, 198.54; FTIR (υmax, cmꢀ1):
3440, 3065, 2916, 1711, 1595, 1342, 1293, 1235, 985,
760, 695 cmꢀ1. Anal. Calc. for C25H16O5: C, 76.46; H,
3.95. Found: C, 76.29; H, 4.02%.
dione (4d).
Yellow precipitate; 1H-NMR (300 MHz,
DMSO-d6) δ (ppm): 8.01 (d, J = 6.6 Hz, 2H, ArH), 7.92–
7.65 (m, 4H, ArH), 7.62–7.35 (m, 5H, ArH), 7.07 (d,
J = 8.4 Hz, 1H, ArH), 3.84 (s, 3H, OMe); FTIR (υmax
,
cmꢀ1): 3417, 3296, 2943, 1716, 1543, 1264, 1142, 1018,
748; MS: m/z (%): 406 [M + 1]+ (6), 405 [M]+ (24), 283
(58), 254 (15), 226 (31), 225 (33), 199 (18), 123 (100),
95 (97), 79 (33). Anal. Calc. for C26H12FNO3: C, 77.03;
H, 2.98; N, 3.46. Found: C, 76.94; H, 3.07; N, 3.50%.
11-(4-Methylbenzoyl)diindeno[1,2-b:20,10-e]pyridine-10,12-
dione (4e).
Yellow precipitate; 1H-NMR (300 MHz,
DMSO-d6) δ (ppm): 8.04 (d, J = 6.6 Hz, 2H, ArH), 7.87–
7.78 (m, 2H, ArH), 7.84 (d, J = 6.9 Hz, 2H, ArH), 7.71–
7.66 (m, 4H, ArH), 7.33 (bd, J = 6.8 Hz, 2H, ArH), 2.39
(s, 3H, Me); FTIR (υmax, cmꢀ1): 3423, 3247, 3063, 2920,
1715, 1601, 1546, 1459, 1384, 1266, 1173, 1015, 750;
MS: m/z (%): 402 [M + 1]+ (7), 401 [M]+ (28), 283 (44),
254 (13), 225 (23), 199 (13), 149 (13), 119 (100), 91
(70), 65 (23). Anal. Calc. for C27H15NO3: C, 80.79; H,
3.77; N, 3.49. Found: C, 80.67; H, 3.83; N, 3.36%.
General procedure for synthesis of new 11-aroyldiindeno
[1,2-b:20,10-e]pyridine-10,12-dione derivatives (4a–i).
A
mixture of indan-1,3-dione (2 mmol), arylglyoxal hydrate
(1 mmol), and NH4OAc (2.5 mmol) in the presence of p-
TSA (30 mg) in chloroform/ethanol (v:v, 2:3 mL) was
stirred under reflux conditions for the appropriate time
(Table 2). The precipitate was filtered, washed with hot
ethanol (5 mL), respectively, to give the desired products
as colored solids in 74–94% yields.
11-(3-Methoxybenzoyl)diindeno[1,2-b:20,10-e]pyridine-10,12-
dione (4f).
Yellow precipitate; 1H-NMR (300 MHz,
11-Benzoyldiindeno[1,2-b:20,10-e]pyridine-10,12-dione (4a).
DMSO-d6) δ (ppm): 8.03 (d, J = 7.2 Hz, 2H, ArH), 7.84
(bt, J = 8.1 Hz, 2H, ArH), 7.70–7.58 (m, 4H, ArH), 7.50–
7.45 (m, 2H, ArH), 7.43 (d, J = 7.5 Hz, 1H, ArH), 7.29 (d,
1
Yellow precipitate; H-NMR (300 MHz, CDCl3) δ (ppm):
8.91 (bd, J = 6.6 Hz, 1H, ArH), 7.99 (d, J = 6.6 Hz, 2H,
ArH), 7.95–7.52 (m, 10H, ArH); FTIR (υmax, cmꢀ1): 3412,
3340, 3195, 3068, 1716, 1676, 1618, 1585, 1547, 1489,
1379, 1271, 1193, 1089, 1026, 947, 755; MS: m/z (%):
387 [M]+ (25), 358 (29), 297 (100), 269 (29), 240 (40),
213 (17), 135 (12), 105 (62), 77 (59), 51 (12). Anal. Calc.
for C26H13NO3: C, 80.61; H, 3.38; N, 3.62. Found: C,
80.54; H, 3.43; N, 3.58%.
J = 6.6 Hz, 1H, ArH), 3.82 (s, 3H, OMe); FTIR (υmax
,
cmꢀ1): 3428, 3066, 2922, 2875, 1704, 1593, 1524, 1443,
1340, 1266, 1097, 987, 757, 698; MS: m/z (%): 418
[M + 1]+ (13), 417 [M]+ (45), 384 (13), 283 (24), 226 (23),
199 (13), 135 (100), 107 (50), 90 (30), 77 (38). Anal. Calc.
for C27H15NO4: C, 77.69; H, 3.62; N, 3.36. Found: C,
77.59; H, 3.77; N, 3.20%.
11-(4-Bromobenzoyl)diindeno[1,2-b:20,10-e]pyridine-10,12-
11-(4-Methoxybenzoyl)diindeno[1,2-b:20,10-e]pyridine-10,12-
Yellow precipitate; 1H-NMR (300 MHz,
dione (4g).
Yellow precipitate; 1H-NMR (300 MHz,
dione (4b).
DMSO-d6) δ (ppm): 8.03–7.90 (m, 2H, ArH), 7.88 (d,
J = 8.4 Hz, 2H, ArH), 7.85–7.79 (m, 2H, ArH), 7.76 (d,
J = 8.1 Hz, 2H, ArH), 7.66–7.55 (m, 4H, ArH). FTIR
(υmax, cmꢀ1): 3408, 3078, 1710, 1548, 1265, 1170, 1069,
892, 751; MS: m/z (%): 467 [M + 2]+ (25), 465 [M]+
(24), 386 (10), 283 (36), 225 (80), 185 (86), 183 (86),
155 (100), 153 (100), 76 (72), 50 (31). Anal. Calc. for
C26H12BrNO3: C, 66.97; H, 2.59; N, 3.00. Found: C,
66.82; H, 2.69; N, 2.97%.
DMSO-d6) δ (ppm): 8.10–7.98 (m, 2H, ArH), 7.94–7.76
(m, 4H, ArH), 7.68–7.59 (m, 4H, ArH), 7.18–6.90 (m, 2H,
ArH), 3.84 (s, 3H, OMe); FTIR (υmax, cmꢀ1): 3434, 3071,
2931, 2856, 1719, 1665, 1598, 1557, 1418, 1385, 1266,
1172, 1021, 846, 756; MS: m/z (%): 417 [M]+ (19), 283
(19), 254 (11), 226 (23), 225 (27), 199 (13), 135 (100), 107
(16), 90 (47), 77 (57), 62 (21). Anal. Calc. for C27H15NO4:
C, 77.69; H, 3.62; N, 3.36. Found: C, 77.52; H, 3.71; N,
3.22%.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2017
An Efficient Route for the Synthesis of 11-Aroyldiindeno[1,2-b:20,10-e]pyridine-
10,12-diones
11-(4-Nitrobenzoyl)diindeno[1,2-b:20,10-e]pyridine-10,12-
dione (4h).
[10] Ghorab, M. M.; Al-Said, M. S. Arch Pharm Res 2012, 35,
Yellow precipitate; 1H-NMR (300 MHz,
987.
[11] Moreno, L.; Berenguer, I.; Diaz, A.; Marín, P.; Párraga, J.;
DMSO-d6) δ (ppm): 8.32 (d, J = 8.7 Hz, 2H, ArH), 8.23
(d, J = 8.7 Hz, 2H, ArH), 8.05 (d, J = 7.8 Hz, 2H, ArH),
7.89–7.80 (m, 2H, ArH), 7.71–7.62 (m, 4H, Ar); FTIR
(υmax, cmꢀ1): 3421, 3083, 2927, 1716, 1601, 1543, 1360,
1267, 1181, 1024, 860, 753; MS: m/z (%): 433 [M + 1]+
(20), 432 [M]+ (68), 385 (40), 357 (25), 282 (31), 254
(42), 226 (64), 225 (72), 199 (28), 150 (87), 104
(100), 76 (98), 50 (42). Anal. Calc. for C26H12N2O5: C,
72.22; H, 2.80; N, 6.48. Found: C, 72.38; H, 2.76; N,
Caignard, D. -H.; Figadère, B.; Cabedo, N.; Cortes, D. Bioorg Med Chem
Lett 2014, 24, 3534.
[12] Kadayat, T. M.; Song, C.; Kwon, Y.; Lee, E. -S. Bioorg Chem
2015, 62, 30.
[13] Brahmbhatt, D. I.; Patel, C. V.; Bhila, V. G.; Patel, N. H.;
Patel, A. A. Med Chem Res 2015, 24, 1596.
[14] Kadayat, T. M.; Song, C.; Shin, S.; Magar, T. B. T.; Bist, G.;
Shrestha, A.; Thapa, P.; Na, Y.; Kwon, Y.; Lee, E. -S. Bioorg Med Chem
2015, 23, 3499.
[15] Molla Ebrahimlo, A. R.; Khalafy, J.; Poursattar Marjani, A.;
Prager, R. H. ARKIVOC 2009, xii, 17.
[16] Poursattar Marjani, A.; Khalafy, J. Chem Heterocycl Comp
2011, 47, 96.
[17] Poursattar Marjani, A.; Khalafy, J.; Molla Ebrahimlo, A. R.;
Prager, R. H. Bull Korean Chem Soc 2011, 32, 2183.
[18] Poursattar Marjani, A.; Khalafy, J.; Molla Ebrahimlo, A. R.
Synth Commun 2011, 41, 2475.
6.33%.
11-(3,4-Dimethoxybenzoyl)diindeno[1,2-b:20,10-e]pyridine-
10,12-dione (4i). Yellow precipitate; 1H-NMR (300 MHz,
DMSO-d6) δ (ppm): 8.01 (d, J = 6.6 Hz, 2H, ArH), 7.92–
7.68 (m, 2H, ArH), 7.70–7.50 (m, 5H, ArH), 7.05 (d,
J = 8.4 Hz, 1H, ArH), 6.82 (d, J = 8.7 Hz, 1H, ArH),
[19]
Poursattar Marjani, A.; Khalafy, J.; Prager, R. H. Chem
Heterocycl Comp 2012, 48, 931.
3.84 (s, 3H, OMe), 3.80 (s, 3H, OMe); FTIR (υmax
,
[20]
Khalafy, J.; Etivand, N.; Dilmaghani, S.; Ezzati, M.;
cmꢀ1): 3417, 3296, 2943, 1716, 1543, 1264, 1142, 1018,
748; MS: m/z (%): 448 [M + 1]+ (12), 447 [M]+ (36), 446
(30), 283 (40), 254 (29), 227 (51), 225 (54), 194 (24),
165 (100), 122 (23), 79 (70), 77 (49), 50 (37). Anal. Calc.
for C28H17NO5: C, 75.16; H, 3.83; N, 3.13. Found: C,
75.22; H, 3.71; N, 3.02%.
Poursattar Marjani, A. Tetrahedron Lett 2014, 55, 3781.
[21] Khalafy, J.; Poursattar Marjani, A.; Salami, F. Tetrahedron
Lett 2014, 55, 6671.
[22] Khalafy, J.; Ezzati, M.; Rimaz, M.; Poursattar Marjani, A.;
Yaghoobnejad Asl, H. J Iran Chem Soc 2014, 11, 1067.
[23] Poursattar Marjani, A.; Parsa Habashi, B.; Rahchamani, H.;
Khalafy, J.; Dadrass, A. R.; Yaghoobnejad Asl, H. Chinese J Struct Chem
2014, 33, 1460.
[24]
Poursattar Marjani, A.; Khalafy, J.; Salami, F.; Ezzati, M.
ARKIVOC 2015, v, 277.
[25]
Poursattar Marjani, A.; Khalafy, J.; Salami, F.;
Acknowledgments. The authors are grateful to Urmia University
for financial support.
Mohammadlou, M. Synthesis 2015, 47, 1656.
[26] Khalafy, J.; Mohammadlou, M.; Mahmoody, M.; Salami, F.;
Poursattar Marjani, A. Tetrahedron Lett 2015, 56, 1528.
[27] Poursattar Marjani, A.; Khalafy, J.; Mahmoodi, S. ARKIVOC
2016, iii, 262.
REFERENCES AND NOTES
[28] Khalafy, J.; Badparvar, F.; Poursattar Marjani, A. J Chil Chem
Soc 2016, 61, 3112.
[1]
Zhu, J.; Bienayme, H. Multicomponent Reactions; Wiley-
VCH: Weinheim, Germany, 2005.
[29]
Poursattar Marjani, A.; Khalafy, J.; Rostampoor, A. J
[2] Mobinikhaledi, A.; Foroughifar, N.; Ebrahimi, S.; Rahimi, F.;
Zandi, F. Phosphorus Sulfur Silicon Relat Elem 2011, 186, 1988.
[3] Baharfar, R.; Porahmad, N. Phosphorus Sulfur Silicon Relat
Elem 2011, 186, 457.
[4] Hasaninejad, A.; Zare, A.; Shekouhy, M.; Ameri Rad, J. J
Comb Chem 2010, 12, 844.
Heterocycl Chem 2017, 54, 648.
[30] Poursattar Marjani, A.; Khalafy, J.; Chitan, M.; Mahmoodi, S.
Iran J Chem Chem Eng (IJCCE) 2017, 36, 1.
[31] Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals; Pergamon Press: Oxford, UK, 1988, p. 1.
[5] Valizadeh, H.; Fakhari, A. Mol Divers 2011, 15, 233.
[6] Xin, X.; Wang, Y.; Kumar, S.; Liu, X.; Lin, Y.; Dong, D. Org
Biomol Chem 2010, 8, 3078.
SUPPORTING INFORMATION
[7] Fringuelli, F.; Piermatti, O.; Pizzo, F. Synthesis 2003 2331.
[8]
Rodinovskaya, L.; Shestopalov, A.; Gromova, A.;
Additional Supporting Information may be found online
in the supporting information tab for this article.
Shestopalov, A. Synthesis 2006 2357.
[9]
Miri, R.; Javidnia, K.; Hemmateenejad, B.; Azarpira, A.;
Amirghofran, Z. Bioorg Med Chem 2004, 12, 2529.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet