p-Toluenesulfonic acid coated natural phosphate as an efficient catalyst for the synthesis of 2-substituted benzimidazole

Article abstract of DOI:10.3184/174751918X15420201703363

2-Substituted benzimidazoles are selectively synthesised in high yields via the condensation of o-phenylenediamine derivatives with aldehyde derivatives using catalytic amount of p-toluenesulfonic acid coated natural phosphate (NP/PTSA) under mild conditions. The use of NP/PTSA as a reusable catalyst makes this process simple, convenient, and environmentally friendly.

Full text of DOI:10.3184/174751918X15420201703363

614 RESEARCH PAPER
VOL. 42 DECEMBER, 614–617
JOURNAL OF CHEMICAL RESEARCH 2018
p-Toluenesulfonic acid coated natural phosphate as an efficient catalyst for
the synthesis of 2-substituted benzimidazole
a
a
a
c
b
Soumia Belkharchach , Hanane Elayadi , Hana Ighachane , Said Sebti , Mustapha Ait Ali * and
a
Hassan B. Lazrek
a
Laboratory of Biomolecular and Medicinal Chemistry, Faculty of Science Semlalia, Marrakech 40000, Morocco
Laboratory of Coordination Chemistry and Catalysis, Faculty of Science Semlalia, Marrakech 40000, Morocco
Laboratory of Organic Chemistry Catalysis and Environment, University Hassan II Casablanca, Faculty of Sciences Ben M’sik, Casablanca, Morocco
b
c
2
-Substituted benzimidazoles are selectively synthesised in high yields via the condensation of o-phenylenediamine derivatives with
aldehyde derivatives using catalytic amount of p-toluenesulfonic acid coated natural phosphate (NP/PTSA) under mild conditions. The use
of NP/PTSA as a reusable catalyst makes this process simple, convenient, and environmentally friendly.
Keywords: benzimidazole, heterogeneous catalysis, natural phosphate, p-toluenesulfonic acid
Although some heterogeneous catalysts can be used in bulk
or non-supported form, many involve materials that cannot be
used directly without the aid of an additional material, termed a
it is conveniently modified and can catalyse several organic
2
6
transformations. Some examples include trans-esterification,
2
7
28
29,30
nucleoside derivatives, Michael-addition, Suziki reaction,
1
31
catalyst support. Compared to conventional homogeneous acid
and N-alkylation of pyrimidines.
catalysts, heterogeneous solid acids are more beneficial as they
are adapted for large scale industrial processes. Advantages
In view of these observations, we report here the synthesis
and characterisation of NP coated with p-toluenesulfonic acid
(PTSA) and its application as a solid acid catalyst (NP/PTSA) in
the synthesis of 2-substituted benzimidazoles from the reaction
of aromatic aldehydes with o-phenylenedianmines.
2
of this approximation include simplicity in processing and
handling, easy separation, high selectivity, reusability and
3,4
environmentally safe disposal.
The past decade has proved interesting in the field of the
5,6
chemistry of benzimidazole. It is one of the most promising
moieties that are present in many clinically useful drugs. The
antiviral activity of benzimidazole derivatives against human
Results and discussion
With the aim of exploring the synthetic application and
limitations of (NP/PTSA), we investigated its use as a catalyst
in the synthesis of 2-substituted benzimidazoles via the
condensation of different 1,2-phenylenediamines with aldehyde
derivatives (Scheme 1). The use of NP/PTSA catalyst is crucial
for the reaction evolution; otherwise, without catalyst or with
NP alone, no product 3a was detected even after 1 h of reaction
time. Thereafter, the use of (NP/PTSA) as a catalyst was
investigated. We performed a set of preliminary experiments
to optimise the reaction conditions. The results are shown in
Table 1.
immunodeficiency retrovirus (HIV-1), hepatitis
B virus
(
HBV), hepatitis C virus (HCV) as well as human respiratory
7–10
syncytial virus (human RSV) has been evaluated. Moreover,
a huge market for commercially available benzimidazole-
based drugs signifies the need to develop new and more
environmentally friendly synthetic methods. The traditional
synthesis of benzimidazoles requires the reaction between an
o-phenylenediamine and a carboxylic acid or its derivatives
(
ortho-esters, nitriles, amidates) under severe dehydrating
3,4
conditions. Currently, a number of synthetic routes have
been developed to bring out new reagents for the synthesis of
benzimidazoles, for instance the reaction of o-phenylenediamine
with aldehydes in the presence of acidic catalysts under various
Table 1 Effect of varying amounts of PTSA on the synthesis of
2
-phenylbenzimidazole 3a
11–18
a,b
Entry
1
2
3
4
5
PTSA (mmol)
NP/PTSA
PTSA
Yield (%)
reaction conditions.
In recent years, different catalytic
systems of various Lewis acids have been developed for the
synthesis of benzimidazole, with different groups highlighting
1
57
78
77
31
0
c
0.75
0.5
0.25
0
NPA3
19
d
the advantages of their protocol over the other methods.
NPA2
e
However, the main difficulties of these methods are the use of
metals and expensive reagents, unsatisfactory yields and harsh
NPA1
NP
2
0–25
reaction conditions.
Therefore, the search continues for a
a
b
Isolated yield.
better catalyst for the synthesis of benzimidazoles, in terms of
operational simplicity, economic viability and selectivity. In an
effort to develop a new heterogeneous system, we have initiated
a programme aimed at introducing natural phosphate (NP), as
The reaction was performed using CH CN as solvent at 80 °C for 1 h.
3
c
473 mg (43.mg, 0.25 mmol of PTSA).
d
516 mg (86 mg, 0.5 mmol of PTSA).
60 mg (130 mg, 0.75 mmol of PTSA).
e
5
H
NH2
catalyst
N
O
+
N
H
solvent
T°C/Time
NH2
1
mmol
1mmol
3a
1a
2a
Scheme 1 Reaction for synthesis of 2-phenyl-1H-benzimidazole 3a.
*
Correspondent. E-mail: aitali@uca.ac.ma

JOURNAL OF CHEMICAL RESEARCH 2018 615
Different ratios of the catalyst were examined to determine the
catalytic amount of PTSA. The results indicate that NP/PTSA
with 0.5 mmol of PTSA is a good catalyst for this reaction (Table
shows that the substituent groups did not play any significant role
in the reactivity of the substrate. On the other hand, comparing
to previous work, Table 4 shows that 2-phenylbenzimidazole
derivatives are obtained in short time with good to excellent
yields in moderate conditions, using a cheap, and reusable
catalyst.
1, entry 3). However, the increase in yield is not dramatic, from
0.5 mmol of PTSA to 0.75 mmol (Table 1, entry 4).
The effect of different solvents such as CH OH, EtOH,
3
H O, CH CN and dioxane has been also studied for the model
In this procedure, the products were easily isolated by simple
filtration and column chromatography. All known products
were characterised by comparison of the melting points and
the analytical data ( H and C NMR spectroscopy) with those
reported for authentic samples.
2
3
synthesis (Table 2). All solvents tested led to the desired
product 3a with low to moderate yields. The water, as green
solvent, led to only a 58% yield after 2 h, despite the increase
in temperature to 100 °C (Table 2, entry 2). The best result
was obtained using acetonitrile as solvent, yielding 77% of the
corresponding product (Table 2, entry 3).
1
13
The proposed mechanism for NP/PTSA catalysed synthesis
of 2-substituted benzimidazoles may be visualised to occur
via a sequence of reactions as depicted in Scheme 3. The
synthesis involves the activation of the aldehydic carbonyl
oxygen by the acid part of PTSA supported on NP through
intermolecular hydrogen bonding, and protonation of the
benzylidene-o-phenelenediamine (A) and ring closure leading
to a five-membered ring in a concerted manner (B) followed by
Furthermore, different acid catalysts were also investigated. We
tested NP/H SO , NP/H PO , NP/HClO and NP/ZnCl to evaluate
2
4
3
4
4
2
their catalytic activity in comparison with NP/PTSA and PTSA
alone. The results shown in Table 4 clearly indicate the promoting
effect of acid catalysis. It appears that NP/PTSA is the most active
catalyst (Table 3, entry 3). As a result, the optimised reaction
conditions were observed when the reaction was conducted with
39,40
rearrangement and proton transfer to give PTSA.
NP/PTSA (5/1) in 5 mL of CH CN at 80 °C for 1 h.
The recycling procedure is as follows: at the end of the
reaction the catalyst was filtered, washed with CH Cl and
3
With the optimised conditions in hand, we next explored
the scope and generality of the procedure using a variety of
aldehydes (aliphatic, aromatic and unsaturated) with different
2
2
acetone; dried at 100 °C for 1 h; and subsequently reused. The
recycled catalyst was used under the same conditions for four
cycles in an attempt to evaluate its chemical stability. After two
runs the catalytic activity of the catalyst was almost the same as
those of the freshly used catalyst. In the third run, we noticed a
small decrease in yield (Table 5).
1,2-phenylenediamines in the presence of catalytic amount of
NP/PTSA at 80 °C and CH CN as solvent. The corresponding
3
2
-phenylbenzimidazole derivatives (Scheme 2) were obtained
in good to excellent yields (Table 4). As shown in Table 4,
the reaction of various aryl amines and aldehydes carrying
either electron-donating or electron-withdrawing substituents
were successfully reacted to produce their corresponding
Table 4 Synthesis of 2-phenylbenzimidazole derivatives catalysed by
NP/PTSA
Yield
Yield (%)
[time]
67 [4 h]
2
-phenylbenzimidazole derivative in good yields. This result
Entry
Product
a,b
Reference
(
%)
77
76
62
82
73
81
69
70
73
71
Table 2 Effect of solvent, time and temperature on the yield of 3a
1
2
3
1
2
3
4
5
6
7
8
9
3a: R = R =H, R = C H
32
33
34
35
32
33
36
37
34
38
6
5
a,b
1
2
3
Entry
Solvent
Temperature (°C)
Time (h)
Yield (%)
52
70
58
77
3b: R = R = H, R = C H
52 [12 h]
55 [24 h]
82 [24 h]
71 [20 h]
75 [12 h]
90 [12 h]
86 [3.5 h]
55 [24 h]
60 [24 h]
3
7
1
2
3
1
2
3
4
5
CH OH
EtOH
H2O
65
80
100
80
1.5
1.5
2
1
2
3c: R = R =H, R =C H O
3
3 4
1
2
3
3d: R = R = H, R =C H
8 7
1
2
3
3e: R = R = H, R =C H NO
6 4 2
1
2
3
CH CN
3f: R = R = H, R = C H Cl
6 4
3
1
2
3
Dioxane
80
37
3g: R = R = CH , R = C H
3 6 5
a
b
1
2
3
Isolated yield.
3h: R = R = H, R =C H Cl
6 3 2
1
2
3
The reaction was performed using 5 mL of solvent with NP/PTSA (0.5 mmol of PTSA)
as catalyst.
3i: R = R = H, R =C H F
6 4
1
2
3
10
3j: R = R = H, R =C H Br
6 4
Table 3 Comparison between NP/PTSA and several heterogeneous
catalysts in the synthesis of 3a
a
b
Isolated yield.
The reaction was performed using CH CN (5 mL) as solvent at 80 °C for 1 h with
3
a,b
Entry
1
2
3
4
5
6
7
Catalyst
NP
PTSA
Yield (%)
516 mg of catalyst.
0
57
77
58
37
23
58
Table 5 Recycling and reusing of the catalyst
a,b
Entry
1
2
3
Runs
Fresh
First
Second
Third
Yield (%)
NP/PTSA
77
77
62
60
NP/H SO4
2
NP/H PO4
3
NP/HClO4
NP/ZnCl2
4
a
b
a
b
Isolated yield.
Isolated yield.
The reaction was performed using CH CN (5 mL) as solvent at 80 °C for 1 h with NP/PTSA
The reaction was performed using CH CN as solvent at 80 °C for 1 h with 516 mg of
3
3
(
516 mg; 0.5 mmol PTSA) as catalyst.
catalyst.
R1
NH2
NH2
NP/PTSA
16 mg
R1
R2
H
N
5
R3
+
R3
O
R2
N
H
5ml CH CN
3
t/reflux
1
mmol
1
a
2a
3a
Scheme 2 Synthesis of 2-phenylbenzimidazole derivatives catalysed by NP/PTSA.

616 JOURNAL OF CHEMICAL RESEARCH 2018
Scheme 3 The proposed mechanism for NP/PTSA catalysed 2-substituted benzimidazole synthesis.
Conclusion
and IR spectroscopy (see ESI). The chemical composition was
determined to be Ca (54.12%), P (34.24%), F (3.37%), Si (2.42%), S
2.21%), C (1.13%), Na (0.92%), Mg (0.68%), Al (0.46%), Fe (0.36%),
In summary, NP coated with PTSA exhibited remarkable
reactivity as a heterogeneous organocatalyst. The yields of
obtained products are very good for a range of substrates
showing that this coated material is highly active and versatile.
The catalyst was recovered for successive condensation
showing an appreciable catalytic activity. The yields of
corresponding 2-phenylbenzimidazole were still reasonably
good after the fourth run. The easy work-up procedure and very
good yields make this method a valid contribution to existing
methodologies.
(
K (0.04%), and other metals less than 6 ppm. The specific surface
area of NP was determined by the BET method from the adsorption–
desorption isotherm of nitrogen at its liquid temperature (77 K). The
total pore volume was calculated by the BJH method at P/P0 ¼ 0.98.
2
–1
The NP shows a very low surface area (1–2 m g ) together with a low
3
–1 41
total pore volume (VT ¼ 0.007 cm g ).
Synthesis of NP/PTSA
PTSA (200 mg) was dissolved in 5 mL of H O then 1000 mg of NP was
2
added and put into a 50 mL volumetric flask. The suspended NP was
stirred at room temperature for 1 h. The water was removed by rotary
evaporation and the remaining solid was dried in an oven at 110 °C for
1 h. The obtained material was analysed by X-ray diffraction pattern,
IR spectroscopy and scanning electron micrograph (see ESI).
Experimental
All the reagents and solvents for synthesis and analysis were
commercially available and used directly. The stretching vibration
frequency of the catalyst was recorded by FTIR spectroscopy
−1
in the range of 400–4000 cm using a Bruker vertex 70 DTGS
spectrometer. Spectrometer XRD measurements were performed
on a XPERT-MPD Philips diractometer using CuKα radiation
as the X-ray source in the range of 20–80°. Morphology of the
microstructures were carried out on a VEGA3 TESCAN microscope
equipped with an energy dispersive X-ray spectrometer (EDAX
TEAM). BET specific surface areas and average pore diameter of
the prepared catalyst were measured by N2 adsorption–desorption
technique using a Micromeritics analyser (P/N 05098-2.0 Rev
A). Liquid chromatography was performed on silica gel (Merck 60,
Synthesis of 2-phenylbenzimidazole using NP/PTSA in acetonitrile;
general procedure
A mixture of o-phenylenediamine (1 mmol), benzaldehyde (1 mmol)
and catalyst NP/PTSA (0.5 mmol PTSA) (516 mg) in acetonitrile
(5 mL) was refluxed under stirring for 1 h. The mixture was filtered
off and the solvent was evaporated. The crude product was purified
by column chromatography over silica gel by using hexane/ethyl
acetate (4/1) as eluent to give the desired product. All compounds gave
spectroscopic data in accordance with their proposed structures and
32–37
1
13
those reported for authentic samples(see ESI).
Spectroscopic data of 2-substituted benzimidazoles
-Phenyl-1H-benzo[d]imidazole (3a): Yield 77%; m.p. 288–290 °C
220–440 mesh; eluents: hexane–AcOEt). H and C NMR spectra
were recorded at 300 MHz a Brucker Avance spectrometer using
CDCl as the solvent, TMS as the internal standard and coupling
3
2
constant (J) in Hz.
42
1
(
lit 291–293 °C); H NMR (300 MHz, DMSO-d ): δ 11.88 (s, 1H),
6
Synthesis of the catalyst and structural characteristics
8.209−8.186 (m, 2H), 7.677 (d, J = 7.3 Hz, 1H), 7.578−7.483 (m, 4H),
13
NP was obtained in the Khouribga region (Morocco). Prior to use, NP
requires initial treatment such as crushing and washing. To be used
appropriately in heterogeneous synthesis, the NP is treated according
to techniques of attrition, sifting, calcinations, and washing. A portion
of 100–400 mm grain size was isolated, washed with water, calcined
at 900 °C for 2 h, washed again, calcined at 900 °C for 30 min, and
7.245−7.189 (m, 2H) ppm; C NMR (75 MHz, DMSO-d ): δ 151.7,
6
140.3, 135.5, 130.6, 130.3, 129.4, 123.0, 119.3 ppm.
2-Isopropyl-1H-benzo[d]imidazole (3b):
231–233 °C (lit. 232–234 °C); H NMR (300 MHz, DMSO-d ): δ
Yield 76%; m.p.
33
1
6
12.20 (s, 1H), 7.45–7.41 (m, 2H), 7.14–7.10 (m, 2H), 3.15–3.13 (m, 1H),
13
1.31 (d, J = 7.2 Hz, 6H) ppm; C NMR (75 MHz, DMSO-d ): δ 150.2,
6
41
ground (63–125 mm) to give the NP catalyst.
141.2, 122.3, 118.0, 28.8, 21.5 ppm.
The structure of calcined phosphate NP is similar to that of
fluorapatite Ca (PO ) F , as shown by the X-ray diffraction pattern
2-(Furan-2-yl)-1H-benzo[d]imidazole (3c): Yield 62%; m.p.
43
1
294–296°C (lit. 296 °C); H NMR (300 MHz, DMSO-d ): δ 12.78 (s,
10
4
6
2
6

JOURNAL OF CHEMICAL RESEARCH 2018 617
1
1
1
H), 7.96–7.95 (m, 1H), 7.55 (s, 2H), 7.25–7.21 (m, 3H), 6.72–6.70 (m,
4
5
6
7
8
9
S. Sajjadifar, G. Mansouri and S. Miraninezhad, Asian J. Nanosci. Mater.,
2018, 11.
Z.Z. Chen, S.Q. Li, W.L. Liao, Z.G. Xie, M.S. Wang, Y. Cao, J. Zhang and
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Med. Chem., 1998, 41, 1252.
13
H) ppm; C NMR (75 MHz, DMSO-d ): δ 145.8, 144.9, 143.6, 138.3,
6
22.6, 116.3, 112.7, 111.4 ppm.
2
-Styryl-1H-benzo[d]imidazole (3d): Yield 82%; m.p. 200–202 °C
43
1
(
7
lit. 201–203 °C); H NMR (300 MHz, DMSO-d ): δ 12.50 (s, 1H),
6
.60 (t, 3H, J = 8.5 Hz), 7.49 (s, 2H), 7.41 (t, 2H, J = 7.53 Hz), 7.35
13
(t, 1H, J = 7.28 Hz), 7.20–7.14 (m, 3H) ppm; C NMR (75 MHz,
DMSO-d ): δ 140, 138, 136, 132, 128, 126, 124, 122, 113 ppm.
6
2
-(3-Nitrophenyl)-1H-benzo[d]imidazole (3e): Yield 73%; m.p.
4
4
1
2
1
1
04–206 °C (lit. 203–205 °C); H NMR (300 MHz, DMSO-d ): δ
6
2.27 (s, 1H), 8.97 (s, 1H), 8.50 (d, J = 7.6 Hz, 1H), 8.30 (d, J = 7.9 Hz,
H), 7.82 (t, J = 7.9 Hz, 1H), 7.74 (d, J = 7.3 Hz, 1H), 7.60 (d, J = 7.4
10
M.T. Migawa, J.L. Giradet, J.A. Walker, G.W. Koszalka, S.D. Chamberlain,
J.C. Drach and L.B. Townsend, J. Med. Chem., 1998, 41, 1242.
13
Hz, 1H), 7.26 (t, J = 6.7 Hz, 2H) ppm; C NMR (75 MHz, DMSO-d ):
11 L.M. Dudd, E. Venardou, E. Garcia-Verdugo, P. Licence, A.J. Blake, C.
6
Wilson and M. Poliakoff, Green Chem., 2003, 5, 187.
δ 150, 147.3, 144.8, 135, 133.1, 131.6, 130.7, 126.0, 123.0, 122.4, 120.8,
1
1
2
3
J. Zhu, Z. Zhang, C. Miao, W. Liu and W. Sun, Tetrahedron, 2017, 73, 3458.
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1999, 1, 1153.
118.0, 112.5 ppm.
2
-(4-Cholorophenyl)-1H-benzo[d]imidazole (3f): Yield 81%; m.p.
14
45
1
2
86–288 °C (lit. 290–292 °C); H NMR (300 MHz, DMSO-d ):
6
δ 12.26 (s, 1H), 8.22 (d, J = 8.2 Hz, 2H), 7.61 (d, J = 8.5 Hz, 2H),
15 D. Anastasiou, E.M. Campi, H. Chaouk and W.R. Jackson, Tetrahedron,
1992, 48, 7467.
13
7
.54–7.48 (m, 2H), 7.25–7.19 (m, 2H); C NMR (75 MHz, DMSO-d ):
6
1
6
C.T. Brain and S.A. Brunton, Tetrahedron Lett., 2002, 43, 1893.
S. Perumal, S. Mariappan and S. Selvaraj, Arkivoc, 2004, 8, 46.
8 R. Morton, C. Hu, C. Leslie and H. Edwin, J. Org. Chem., 1985, 50, 2205.
δ 151.3, 143.6, 133.6, 129.2, 129.1, 128.4, 123.2, 120.1, 114.7 ppm.
,6-Dimethyl-2-phenyl-1H-benzo[d]imidazole (3g): Yield 69%;
1
7
5
1
1
m.p. 233–235 °C. H NMR (300 MHz, DMSO-d ): δ 12.83 (s, 1H),
.18–8.16 (m, 2H), 7.54–7.32 (m, 5H), 2.35 (s, 6H) ppm; C NMR
6
19 M. Rekha, A. Hamza, B.R. Venugopal and N. Nagaraju, Chin. J. Catal.,
012, 33, 439.
13
8
2
(
1
75 MHz, DMSO-d ): δ 154.6, 142.5, 133.1, 131.7, 130.9, 129.5, 126.9,
20 J.P. Robert and B.D. Wilson, J. Org. Chem., 1993, 58, 7016.
21 H. Göker, S. Ölgen, R. Ertan, H. Akgün, S. Özbey, E. Kendi and G. Topçu,
J. Heterocyclic. Chem., 1995, 32, 1767.
6
16.7, 19.5 ppm.
2
-(2,4-Dichlorophenyl)-1H-benzo[d]imidazole (3h): Yield 70%;
4
6
1
22 Z.H. Zhang, L. Yin and Y.M. Wang, Catal. Commun., 2007, 8, 1126.
m.p. 219–221 °C (lit. 220–223 °C); H NMR (300 MHz, DMSO-d ):
δ 12.52 (s, 1H), 8.12 (d, J = 8.8, 2H), 7.83 (s, 1H), 7.50–7.48 (m, 2H),
7
6
2
2
3
4
H. Sharghi, O. Asemani and R. Khalifeh, Synth. Commun., 2008, 38, 1128.
J. She, Z. Jiang and Y. Wang, Synlett, 2009, 12, 2023.
13
.20–7.18 (m, 2H) ppm; C NMR (75 MHz, DMSO-d ): δ 150.1, 139.7,
6
25 F. Bazi, H. El Badaoui, S. Tamani, S. Sokori, L. Oubella, M. Hamza, S.
Boulaajaj and S. Sebti, J. Mol. Catal. A-Chem., 2006, 256, 43.
26 H.B. Lazrek, B. Baddi, M. Smietana, J-J. Vasseur, S. Sebti and M. Zahouily,
Nucleos. Nucleot. Nucl., 2008, 27, 1107.
1
35.4, 133.8, 132.7, 130.6, 130.1, 128.2, 122.8, 115.5 ppm.
2
-(4-Fluorophenyl)-1H-benzo[d]diazole (3i): Yield 73%; m.p.
43
1
2
47–249 °C (lit. 248 °C); H NMR (300 MHz, DMSO-d ): δ 12.10
6
2
7
M. Zahouily, Y. Abrouki, B. Bahlaouan, A. Rayadh and S. Sebti, Catal.
Commun., 2003, 4, 521.
(s, 1H), 7.74–7.65 (m, 2H), 7.53–7.48 (m, 2H), 7.39–7.26 (m, 2H),
13
7
1
.23–7.11 (m, 2H) ppm; C NMR (75 MHz, DMSO-d ): δ 162.1, 151.2,
6
28 A. Hassine, S. Sebti, A. Solhy, M. Zahouily, C. Lenc, M.N. Hedhili and A.
Fihri, Appl. Catal. A Gen., 2013, 450, 13.
39.6, 134.1, 131.2, 128.1, 122.6, 116.0 ppm.
2
-(4-Boromophenyl)-1H-benzo[d]imidazole (3j): Yield 71%; m.p.
29 H.B. Lazrek, A. Rochdi, Y. Kabbaj, M. Taourirte and S. Sebti, Synth.
Commun., 1999, 29, 1057.
47
1
2
51–253 °C (lit. 253–255 °C); H NMR (300 MHz, DMSO-d ):
δ 12.14 (s, 1H), 8.30 (d, J = 8.1 Hz, 2H), 7.90 (d, J = 8.3 Hz, 2H),
.77–7.52 (m, 2H), 7.50 (m, 2H) ppm; C NMR (75 MHz, DMSO-d ):
6
3
0
A. Alahiane, A. Rochdi, M. Taourirte, N. Redwane, S. Sebti and H.B.
Lazrek, Tetrahedron Lett., 2001, 42, 3579.
13
7
6
31
C. Gong, Q. Luo, Y. Li, M. Giotto, N.E. Cipollini, Z. Yang, R.A. Weiss and
D.A. Scola, J. Polym. Sci. A1, 2011, 49, 4476.
δ 153.4, 142.1, 137.2, 131.4, 128.5, 125, 121.7, 113.5 ppm.
3
2
H. Sharghi, O. Asemanib and S.M.H. Tabaei, J. Heterocyc. Chem., 2008,
Acknowledgement
4
5, 1293.
3
3
Y. Kim, M.R. Kumar, N. Park, Y. Heo and S. Lee, J. Org. Chem., 2011, 76, 9577.
X. Shi, J. Guo, J. Liu, M. Ye and Q. Xu, Chem. Eur. J., 2015, 21, 9988.
X. Li, R. Hu, Y. Tong, Q. Pan, D. Miao and S. Han, Tetrahedron Lett.,
The authors would like to acknowledge the technical staff
of the Centre of Analysis and Characterisation, University
Cadi Ayyad for the technical assistance and for running the
spectroscopic analysis.
3
3
4
5
2
016, 57, 4645.
36 M. Shen and T.G. Driver, Org. Lett., 2008, 10, 3367.
3
3
7
8
S.D. Sharma and D. Konwar. Synth. Commun., 2009, 39, 980.
M.R. Marri, S. Peraka, A.K. Macharla, N. Mameda, S. Kodumuri and N.
Nama, Tetrahedron Lett., 2014, 55, 6520.
R. Valara, A. Nasreen, R. Enugala and S.R. Adapa, Tetrahedron Lett.,
2007, 48, 69.
R. Trivedi, S.K. De and R.A. Gibbs, J. Mol. Catal. A-Chem., 2006, 245, 8.
M. Zahouily, M. Salah, B. Bahlaouane, A. Rayadh, A. Houmam, E.A.
Hamed and S. Sebti, Tetrahedron, 2004, 60, 1631.
Electronic Supplementary Information
3
9
0
The ESI, FTIR and IR spectra, X-ray diffractions and scanning
electron microscopy images, is available through:
4
41
stl.publisher.ingentaconnect.com/content/stl/jcr/2018/supp-data/00000042/00000012/art00008
4
2
V.Y.A. Sontakke, S. Ghosh, P.P. Lawande, B.A. Chopade and V.S.
Shinde, ISRN Org. Chem., 2013, Article ID 453682, https://doi.
org/10.1155/2013/453682.
Received 26 September 2018; accepted 3 November 2018
Paper 1805693
https://doi.org/10.3184/174751918X15420201703363
Published online: 22 November 2018
43
44
45
Y. Venkateswarlu, S.R. Kumar and P. Leelavathi, Org. Med. Chem. Lett.,
2
013, 3, 1.
R. Srinivasulu, K.R. Kumar and P.V.V. Satyanarayana, Green Sus. Chem.,
014, 4, 33.
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