Efficient Lactic Acid-catalyzed Route to Naphthopyranopyrimidines under Solvent-free Conditions

Full text of DOI:10.1080/00304948.2017.1260395

Organic Preparations and Procedures International
The New Journal for Organic Synthesis
ISSN: 0030-4948 (Print) 1945-5453 (Online) Journal homepage: http://www.tandfonline.com/loi/uopp20
Efficient Lactic Acid-catalyzed Route to
Naphthopyranopyrimidines under Solvent-free
Conditions
Fatemeh Noori Sadeh, Nourallah Hazeri, Malek Taher Maghsoodlou &
Mojtaba Lashkari
To cite this article: Fatemeh Noori Sadeh, Nourallah Hazeri, Malek Taher Maghsoodlou &
Mojtaba Lashkari (2017) Efficient Lactic Acid-catalyzed Route to Naphthopyranopyrimidines
under Solvent-free Conditions, Organic Preparations and Procedures International, 49:1, 35-44
To link to this article: http://dx.doi.org/10.1080/00304948.2017.1260395
Published online: 13 Jan 2017.
Submit your article to this journal
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=uopp20
Download by: [FU Berlin]
Date: 13 January 2017, At: 09:30

Organic Preparations and Procedures International, 49:35–44, 2017
Copyright Ó Taylor & Francis Group, LLC
ISSN: 0030-4948 print / 1945-5453 online
DOI: 10.1080/00304948.2017.1260395
Efficient Lactic Acid-catalyzed Route to
Naphthopyranopyrimidines under Solvent-free
Conditions
Fatemeh Noori Sadeh,1 Nourallah Hazeri,1 Malek Taher
Maghsoodlou,1 and Mojtaba Lashkari2
1Department of Chemistry, Faculty of Sciences, University of Sistan and
Baluchestan, P.O. Box 98135-674, Zahedan, Iran
2Faculty of Sciences, Velayat University, Iranshahr, Iran
Multi-component reactions (MCRs) are pivotal because of their versatility for the genera-
tion of interesting heterocyclic scaffolds and libraries of biologically active molecules.
They have several notable advantageous feature such as flexibility, operational simplicity,
simple purification of products, minimum reaction steps, time and energy savings, and a
high degree of atom economy.1–7 In order to avoid the use of organic solvents, solvent-
free systems are also important for green chemical syntheses. Solvent-free reactions also
have other advantages, encompassing simplicity of operation, reduction of reaction times,
and increased yields due to compatibility of reagents.8,9
Naphthopyranopyrimidines are key building blocks for the preparation of biologi-
cally active products and display antimicrobial,10 anticonvulsant,11 antibacterial,12 and
antifungal13 activities. Lately Marugan has reported novel drugs for the treatment of sleep
and anxiety disorders (Figure 1).14 Previous catalysts used for the preparation of naphtho-
pyranppyrimidines from the condensation of aldehydes with b-naphthol (or 2,7-dihydrox-
ynaphthalene) and 1,3-dimethylbarbituric acid include InCl3 and P2O5, I2/HOAC,16
15
I2,17 alum (KAl(SO4)2.12H2O),18 and ZnO NPs.19
Figure 1
Biologically active compounds containing naphthopyranopyrimidine
Received May 6, 2016; in final form September 11, 2016.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.
com/uopp.
Address correspondence to Nourallah Hazeri, Department of Chemistry, Faculty of Sciences, Uni-
versity of Sistan and Baluchestan, P.O. Box 98135-674, Zahedan, Iran. E-mail: nhazeri@chem.usb.ac.ir
35

36
Hazeri et al.
As a part of our research program to develop greener methodologies,20–24 we inves-
tigated and now report the application of lactic acid as an efficient, non-toxic, natural,
commercially available and inexpensive catalyst for the preparation of various naphtho-
pyranopyrimidines in high yields.
In order to determine the optimum conditions for the synthesis of compounds 4a-i,
trial reactions on one mmole scale between benzaldehyde 1, 2,7-dihydroxynaphthalene 2,
and 1,3-dimethylbarbituric acid 3 was studied (Scheme 1), initially, by carrying out the
model reaction at different temperatures in the presence of lactic acid under solvent-free
conditions (Table 1, Entries 1–5); the best result was obtained at 70ꢀC (Table 1, Entry 4).
Next, in order to optimize the amount of catalyst, the reaction was performed using vari-
ous amounts of catalyst at 70ꢀC (Table 1, Entries 6, 7), the best yield being obtained in
the presence of 0.119 g of lactic acid.
Scheme 1
Lactic acid catalyzed one-pot synthesis of naphthopyranopyrimidines.
The used of lactic acid was extended in the condensation of benzaldehyde, b-naph-
thol, and 1,3-dimethylbarbituric acid to prepare compounds 4j-q (Scheme 1). However, it
was found that under the same conditions used for the preparation of compounds 4a-i,
this reaction was incomplete and a higher temperature and (100ꢀC) was required to give
satisfactory yields in the presence of 0.106 g lactic acid (Table 2).
The generality of this reaction was investigated using aldehydes (1, 1 mmol), 2,7-
dihydroxynaphthalene or b-naphthol (2, 1 mmol), and 1,3-dimethylbarbituric acid
(3, 1 mmol) under solvent-free conditions in the presence of lactic acid to generate
Table 1
Effect of Temperature and Amount of Catalyst
Entry
Tem (ꢀC)
Catalyst (g)
Time (min)
Yield (%)
1
2
3
4
5
6
7
r.t
50
60
70
80
70
70
0.119
0.119
0.119
0.119
0.119
0.08
24(h)
110
90
-
60
65
87
87
75
79
40
35
40
40
0.093

Efficient Lactic Acid-catalyzed Route to Naphthopyranopyrimidines
37
Table 2
Optimization of Reaction Condition
Entry
Tem (ꢀC)
Catalyst (g)
Time (min)
Yielda (%)
1
2
3
4
5
6
7
8
70
80
0.093
0.093
0.093
0.093
0.093
0.083
0.106
0.119
180
90
45
20
20
20
20
20
45
63
76
80
81
75
84
83
90
100
110
100
100
100
compounds 4a-i and compounds 4j-q. The results are summarized in Table 3. A wide
range of aldehydes containing electron-withdrawing and electron-donating groups were
evaluated. It is noteworthy that the electronic nature of substituents of the aromatic alde-
hyde has no obvious effect on the multi-component reaction.
A possible mechanism shown in Scheme 2 may proceed via the o-quinonemethides
(o-QMs) intermediate A. The initial nucleophilic addition of of 2,7-dihydroxynaphthalene
or b-naphthol 2 to aldehyde 1, assisted by lactic acid is followed by the Michael addition
of the o-QMs to 1,3-dimethylbarbituric acid 3 to provide the intermediate B. Finally, the
naphthopyranopyrimidines are obtained by intramolecular cyclization and loss of water.
In summary, lactic acid was shown to be an efficient catalyst for the greener synthesis
of naphthopyranopyrimidines. The most remarkable advantages for the use lactic acid as
Scheme 2
Proposed Mechanism for the Synthesis of Naphthopyranopyrimidines

38
Hazeri et al.
Table 3
Lactic Acid Catalysed One-pot Three-component Synthesis of
Naphthopyranopyrimidines
Mp (ꢀC)
Time (min) Yielda (%) Found ReportedRef
Entry R1
R2
Product
1
H
OH
40
87
>300
>30016
2
3
2-Cl OH
50
45
89
87
>300
>300
>30016
3-Cl OH
>300 18
4
4-Cl OH
40
93
>300
>300 18
5
4-F OH
50
95
>300
>300 18
(Continued on next page)

Efficient Lactic Acid-catalyzed Route to Naphthopyranopyrimidines
39
Table 3
Lactic Acid Catalysed One-pot Three-component Synthesis of Naphthopyranopyrimi-
dines (Continued)
Mp (ꢀC)
Entry R1
R2
Product
Time (min) Yielda (%) Found ReportedRef
6
2-NO2 OH
45
50
89
>300
>300 18
7
4-CN OH
89
>300
>300 18
8
9
2-F OH
50
45
91
93
>300
>300
This work
4-Br OH
This work
10
H
H
20
84
223–226 223–22517
(Continued on next page)

40
Hazeri et al.
Table 3
Lactic Acid Catalysed One-pot Three-component Synthesis of Naphthopyranopyrimi-
dines (Continued)
Mp (ꢀC)
Entry R1
R2
H
Product
Time (min) Yielda (%) Found ReportedRef
11
12
13
2-Cl
3-Cl
4-Cl
30
30
25
91
89
81
271–275 270–27215
233–237 221–22319
268–270 274–27617
H
H
14
4-F
H
25
84
298–301 303–30515
15
2-NO2
H
35
81
280–284 288–29015
(Continued on next page)

Efficient Lactic Acid-catalyzed Route to Naphthopyranopyrimidines
41
Table 3
Lactic Acid Catalysed One-pot Three-component Synthesis of Naphthopyranopyrimi-
dines (Continued)
Mp (ꢀC)
Entry R1
R2
H
Product
Time (min) Yielda (%) Found ReportedRef
16
3-NO2
25
30
95
313–315 310–31219
17
4-CN
H
90
290–293 288–29017
aIsolated yield
catalyst were the generation of the desired product in high yields without by-products,
with facile work-up, and purification.
Experimental Section
The melting points of all compounds were determined on an Electrothermal 9100 appara-
1
tus, and IR spectra were obtained on a FT-IR-JASCO-460 plus spectrometer. H NMR
and 13CNMR spectra were acquired on a Bruker DRX-300 and DRX-400 Avance instru-
ment in DMSO at 400 and 300 MHz. Mass spectra were taken on an Agilent Technology
(HP) spectrometer operating at an ionization potential of 70 eV. All reagents were pur-
chased from Merck (Darmstadt, Germany) and Fluka (Buchs, Switzerland) and used with-
out further purification. Elemental analyses for C, H, and N were performed using a
Heraeus CHN-O-Rapid analyzer.
Preparation of 2-Hydroxy-12-aryl-8,12-dihydro-8,10-dimethyl-9H-naphtho[10,20:5,6]
pyra-no-[2,3-d]pyrimidine-9,11-(10H)-dione and 12-Aryl-8,12-dihydro-8,10-dimethyl-9H-
naph-tho[10,20:5,6]pyrano[2,3-d]pyrimidine-9,11-(10H)diones. Gereral Procedure.
A mixture of aromatic aldehyde 1 (1.0 mmol), 2,7-dihydroxynaphthalene (weight) or
b-naphthol 2 (weight, 1.0 mmol), 1,3-dimethylbarbituric acid 3 (weight,1.0 mmol), and
lactic acid (weight) at the optimum temperature (70ꢀC or 100ꢀC), was stirred without sol-
vent in an oil bath. Completion of reaction was determined by TLC (solvent system). The
crude reaction mixture was cooled to RT, the solid formed were suspended in ethanol
(5 ml) and collected. The crude solid was recrystallized from ethanol. The structures of
the compounds were confirmed by their IR, 1H NMR and 13C NMR spectra and found to
be identical with those reported in the literature. Correct combustion analyses were
obtained for previously un-reported compounds 4h and 4i.

42
Hazeri et al.
Analytical Data for Selected Compounds
2-Hydroxy-12-phenyl-8,12-dihydro-8,10-dimethyl-9H-naphtho[10,20:5,6]pyrano[2,3-d]-
pyrimidine-9,11-(10H)dione (4a). White solid; IR (KBr, cm¡1): 3180, 3086, 2965, 1715,
1665, 1622, 1597, 1453, 1237, 1225, 1178. 1H NMR (400 MHz), (DMSO-d6):
d D 3.17 (s, 3H, CH3), 3.51 (s, 3H, CH3), 5.44 (s, 1H, CH), 7.00–7.87 (m, 10H, Ar-H),
9.97 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6): d D 28.16, 29.29, 36.04, 90.58,
105.98, 113.68, 115.47, 118.00, 126.19, 126.91, 128.63, 129.63, 130.75, 132.53, 144.61,
147.65, 150.48, 152.56, 157.06, 161.51.
2-Hydroxy-12-(2-Chlorophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho
[10,20:5,6]-pyrano[2,3-d] pyrimidine-9,11-(10H)dione (4b): White solid; IR (KBr,
1
cm¡1): 3370, 3019, 2953, 1698, 1670, 1645, 1591, 1484, 1238,1219, 1190. H NMR
(300 MHz), (DMSO-d6): d D 3.13 (s, 3H, CH3), 3.47 (s, 3H, CH3), 5.66 (s, 1H, CH),
7.01–7.80 (m, 9H, Ar-H), 9.92 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6):
d D 28.13, 29.35, 34.40, 89.48, 106.30, 113.69, 114.68, 117.89, 126.11, 127.64, 128.67,
129.98, 130.07, 130.74, 132.59, 132.83, 132.90, 141.55, 147.69, 150.48, 152.78, 157.11,
161.24.
2-Hydroxy-12-(3-Chlorophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho
[10,20:5,6]pyra-no[2,3-d] pyrimidine-9,11-(10H)-dione (4c). White solid; IR (KBr,
1
cm¡1): 3319, 3059, 2960, 1693, 1665, 1640, 1569, 1495, 1229, 1209, 1192. H NMR
(300 MHz), (DMSO-d6): d D 3.16 (s, 3H, CH3), 3.47 (s, 3H, CH3), 5.41 (s, 1H, CH),
6.99–7.86 (m, 9H, Ar-H), 10.01 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6):
d D 28.21, 29.38, 35.90, 89.85, 105.81, 113.74, 114.59, 118.11, 126.19, 127.08, 127.41,
128.48, 130.03, 130.55, 130.89, 132.40, 133.19, 146.83, 147.73, 150.49, 152.76, 157.22,
161.56.
2-Hydroxy-12-(4-Chlorophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho
[10,20:5,6]pyra-no[2,3-d] pyrimidine-9,11-(10H)-dione (4d). white solid; IR (KBr,
1
cm¡1): 3200, 3019, 2960, 1713, 1660, 1621, 1600, 1489, 1235, 1219, 1195. H NMR
(300 MHz), (DMSO-d6): d D 3.15 (s, 3H, CH3), 3.45 (s, 3H, CH3), 5.38 (s, 1H, CH),
6.98–7.83 (m, 9H, Ar-H), 9.98 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6):
d D 28.19, 29.36, 35.57, 90.07, 105.89, 113.75, 114.85, 118.09, 126.21, 128.59, 129.93,
130.50, 130.87, 131.55, 132.44, 143.48, 147.68, 150.50, 152.67, 157.17, 161.55.
2-Hydroxy-12-(4-fluorophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho
[10,20:5,6]pyra-no[2,3-d] pyrimidine-9,11-(10H)-dione (4e). White solid; IR (KBr,
1
cm¡1): 3186, 3080, 2960, 1712, 1661, 1621, 1599, 1452, 1236, 1223, 1179. H NMR
(300 MHz), (DMSO-d6): d D 3.17 (s, 3H, CH3), 3.49 (s, 3H, CH3), 5.45 (s, 1H, CH),
7.00–7.87 (m, 9H, Ar-H), 9.99 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6):
2
d D 28.20, 29.38, 35.35, 90.39, 105.88 (d, JFC D 6.052 Hz, C6H4F), 113.83, 115.38
(d, 2JFC D 21.18 Hz, C6H4F), 118.04 (d, 3JFC D 7.56 Hz, C6H4F),126.26, 129.87, 130.45
(d, 3JFC D 7.56 Hz, C6H4F), 130.90,132.44, 140.72 (d, 4JFC D 3.02 Hz, C6H4F), 147.73,
150.54, 152.73,156.98,157.14, 161.56, 161.19 (d, 1JFC D 242.83 Hz, C6H4F), 161.60.
2-Hydroxy-8,12-dihydro-8,10-dimethyl-12-(2-nitrophenyl)-9H-naphtho
[10,20:5,6]pyra-no[2,3-d] pyrimidine-9,11-(10H)-dione(4f). White solid; IR (KBr,
cm¡1): 3356, 3022, 2953, 1699, 1669, 1621, 1591, 1485, 1236, 1184. 1H NMR
(300 MHz), (DMSO-d6): d D 3.14 (s, 3H, CH3), 3.47 (s, 3H, CH3), 5.53 (s, 1H, CH),
6.97–7.99 (m, 9H, Ar-H), 10.00 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6):
d D 28.25, 29.44, 32.70, 91.27, 105.74, 113.86, 116.83, 118.12, 126.20, 126.71, 129.62,
130.88, 132.73, 135.74, 143.43, 147.78, 150.43, 152.76, 156.99, 161.77.

Efficient Lactic Acid-catalyzed Route to Naphthopyranopyrimidines
43
2-Hydroxy-12-(4-Cyanophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho
[10,20:5,6]pyra-no[2,3-d] pyrimidine-9,11-(10H)-dione (4g). White solid; IR (KBr,
1
cm¡1): 3205, 3019, 2953, 2233, 1713, 1658, 1621, 1602, 1495, 1225, 1195. H NMR
(300 MHz), (DMSO-d6): d D 3.16 (s, 3H, CH3), 3.49 (s, 3H, CH3), 5.51 (s, 1H, CH),
7.00–7.89 (m, 9H, Ar-H), 10.02 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6):
d D 28.21, 29.43, 36.35, 89.47, 105.76, 109.88, 113.80, 114.22, 118.17, 119.13, 126.21,
129.78, 130.23, 130.96, 132.39, 132.66, 147.76, 147.76, 149.82, 150.50, 152.92, 157.28,
161.54.
2-Hydroxy-12-(2-fluorophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho
[10,20:5,6]pyra-no[2,3-d] pyrimidine-9,11-(10H)-dione (4h). White solid; IR (KBr,
1
cm¡1): 3377, 3079, 2952, 1699, 1666, 1643, 1590, 1489, 1231, 1216, 1185. H NMR
(300 MHz), (DMSO-d6): d D 3.14 (s, 3H, CH3), 3.52 (s, 3H, CH3), 5.61 (s, 1H, CH),
7.01–7.85 (m, 9H, Ar-H), 10.03 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6): d D
28.15, 29.39, 30.74, 89.16, 105.36, 113.83, 114.39, 115.92 (d, 2JFC D 21.93 Hz, C6H4F),
3
117.96,124.80, 126.13, 129.15 (d, JFC D 8.32Hz, C6H4F), 129.87, 130.90, 131.18 (d,
3JFC D 12.86 Hz, C6H4F), 131.68, 132.66, 147.74, 150.59, 153.10, 157.05, 150.54,
152.83, 160.13 (d, 1JFC D 246.61 Hz, C6H4F), 161.41. MS m/z (%): 57.1 (34), 83.1 (22),
188.1 (14), 252.1 (21), 309.2 (100), 404.2 (MC, 20).
Anal. Calcd for C23H17FN2O4: C, 68.31; H, 4.24; N, 6.93. Found: C, 68.49; H, 4.28;
N, 6.97.
2-Hydroxy-12-(4-bromophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho
[10,20:5,6]pyra-no[2,3-d] pyrimidine-9,11-(10H)-dione (4i). White solid; IR (KBr,
1
cm¡1): 3202, 3019, 2960, 1713, 1661, 1621, 1596, 1491, 1236,1219, 1195. H NMR
(300 MHz), (DMSO-d6): d D 3.16 (s, 3H, CH3), 3.48 (s, 3H, CH3), 5.41 (s, 1H, CH),
7.00–7.87 (m, 9H, Ar-H), 10.02 (s, 1H, OH). 13C NMR (75.65 MHz, DMSO-d6):
d D 28.20, 29.39, 35.65, 90.01, 105.81, 113.81, 114.82, 115.47, 118.01, 120.09, 126.24,
129.97,130.64, 130.90, 131.52, 132.43,133.02, 143.90, 147.70,148.82, 150.52, 152.71,
157.01, 161.57. MS (m/z): 105.1 (13), 164.1 (28), 209.1 (21), 237.1 (15), 252.1 (56),
309.2 (100), 396.2 (14), 466.2 (MC, 30).
Anal. Calcd for C23H17BrN2O4: C, 59.37; H, 3.68; N, 6.02. Found: C, 59.55; H, 3.70;
N, 6.09.
12-phenyl-8,10-dimethyl-12H-naphtho[10,20:5,6]pyrano[2,3-d]pyrimidine-9,11-
dione (4j). White solid; IR (KBr, cm¡1): 3105, 2950, 1704, 1665, 1643, 1592, 1484,
1231, 1178. 1H NMR (400 MHz), (DMSO-d6): d D 3.16 (s, 3H, CH3), 3.51 (s, 3H, CH3),
5.67 (s, 1H, CH), 7.06–8.04 (m, 11H, Ar-H).
12-(3-Nitrophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho[10,20:5,6]pyrano
[2,3-d]pyrimidine-9,11-(10H)-dione (4p). White solid; IR (KBr, cm¡1): 3103, 2951,
1
1705, 1663, 1639, 1596, 1479, 1232, 1177. H NMR (400 MHz), (DMSO-d6): d D 3.17
(s, 3H, CH3), 3.54 (s, 3H, CH3), 5.93 (s, 1H, CH), 6.98–8.00 (m, 10H, Ar-H).
12-(4-Cyanophenyl)-8,12-dihydro-8,10-dimethyl-9H-naphtho[10,20:5,6]pyrano
[2,3-d]py-rimidine-9,11-(10H)-dione (4q). White solid; IR (KBr, cm¡1): 3079, 2959,
1
2235, 1708, 1670, 1646, 1598, 1483, 1229, 1180.. H NMR (400 MHz), (DMSO-
d6): d D 3.17 (s, 3H, CH3), 3.53 (s, 3H, CH3), 5.65 (s, 1H, CH), 6.99–8.05
(m, 10H, Ar-H).
Acknowledgements
Financial support from the Research Council of the University of Sistan and Baluchestan
is gratefully acknowledged.

44
Hazeri et al.
References
1. S. Wang, C. Cheng, F.Wu, B. Jiang, F. Shi, S. Tu, T. Rajale and G. B. Li, Tetrahedron., 67,
4485 (2011).
2. M. Herrera, I. Knepper, N. Souza, A. Villinger, V. Sosnovskikh and V. Iaroshenko, ACS. Comb.
Sci., 14, 434 (2012).
3. R. Abonia, J. Castillo, B. Insuasty, J. Quiroga, M. Nogueras and J. Cobo, ACS. Comb. Sci., 15, 2
(2013).
4. A. Domling, Chem. Rev., 106, 17 (2006).
5. I. Ugi, Pure Appl. Chem., 73, 187 (2001).
6. K. Revathy and A. Lalitha, RSC Adv., 4, 279 (2014).
7. H. Naeimi, Z. Rashid, A. H. Zarnanib and R. Ghahremanzadeh, New J. Chem., 38, 5527 (2014).
8. P. J. Walsh, H. Li and C. A. D. Parrodi, Chem. Rev., 107, 2503 (2007).
9. M. A. Zolfigol, S. Baghery, A. R. Moosavi-Zare and S. M. Vahdat, RSC Adv., 5, 32933 (2015).
10. Sh. Ch. Kuo, L. J. Huang and H. Nakamura, J. Med. Chem., 27, 539 (1984).
11. A. H. Bedair, N. A. El-Hady, M. S. A. El-Latif, A. H. Fakery and A. M. El-Agrody, Farmaco.,
55, 708 (2000).
12. K. C. Joshi, R. Jain and K. Sharma, J. Indian Chem. Soc., 45, 202 (1988).
13. H. A. Bedair, Emam, N. A. El-Hady, K. A. R. Ahmed and A. M. El-Agrody, Farmaco., 56, 965
(2001).
14. J. Marugan, K. Liu, W. Zheng, R. Eskay, N. Southall, M. Heilig, J. Inglese and C. Austin, Probe
report., MLPCN-Grant X01-DA026210-01 (2010).
15. G. C. Nandi, S. Samai, R. Kumar and M. S. Singh, Tetrahedron., 65, 7129 (2009).
16. X. J. Sun, J. F. Zhou and P. S. Zhao, J Heterocyclic Chem., 48, 1347 (2011).
17. K. P. Kumar, S. Satyanarayana, P. L. Reddy, G. Narasimhulu, N. Ravirala and B. V. S. Reddy,
Tetrahedron Lett., 53, 1738 (2012).
18. J. M. Khurana, A. Lumb, A. Chaudhary and B. Nand, RSC Adv., 3, 1844 (2013).
19. M. Mohaqeq and J. Safaei-Ghomi, Monatsh Chem., 146, 1581 (2015).
20. M. Kangani, M. T. Maghsoodlou and N. Hazeri, Chin. Chem. Let., 27, 66 (2016).
21. Z. Vafajoo, N. Hazeri, M. T. Maghsoodlou and H. Veisi, Chin. Chem. Let., 26, 973 (2015).
ꢀ
22. S. Salahi, M. T. Maghsoodlou, N. Hazeri, M. Lashkari, S. Garcıa-Granda and L. Torre-Fernan-
ꢀ
dez, Chin. J. Cat., 36, 1023 (2015).
23. F. Noori Sadeh, M. T. Maghsoodlou, N. Hazeri and M. Kangani, Res. Chem. Intermed., 41,
5907 (2014).
24. S.S. Sajadikhah and M.T. Maghsoodlou, RSC Adv., 4, 43454 (2014).