Synthesis of spiropyran derivatives over 1-(carboxymethyl) pyridinium iodide as nanostructured pyridinium salt under aqueous media

Article abstract of DOI:10.1139/cjc-2016-0374

In this work, acetic acid functionalized pyridinium salt, namely 1-(carboxymethyl)pyridinium iodide {[cmpy]I}, has been applied as reusable nanostructured catalyst for green, simple and efficient preparation of spiropyrans by the one-pot domino Knoevenagel-Michael-cyclization reaction of isatin derivatives or acenaphthenquinone, with malononitrile, and 1,3-dicarbonyl compounds under aqueous media. Moreover, 1H and 13C NMR, mass, CHN analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG), X-ray diffraction analysis (XRD), and calculation of crystallite size and interplaner distance of the catalyst have been studied.

Full text of DOI:10.1139/cjc-2016-0374

Page 1 of 20
Synthesis of spiropyran derivatives over 1-(carboxymethyl)
pyridinium iodide as nanostructured pyridinium salt under aqueous
media
Ahmad Reza Moosavi-Zare*, Mohammad Ali Zolfigol, Rasoul Salehi-Moratab, Ehsan
Noroozizadeh
Ahmad Reza Moosavi-Zare. Department of Chemistry, University of Sayyed Jamaleddin
Asadabadi, Asadabad, 6541835583, Iran.
Mohammad Ali Zolfigol, Rasoul Salehi-Moratab, Ehsan Noroozizadeh.
Faculty of Chemistry, BuꢀAli Sina University, Hamedan 6517838683, Iran.
1
Corresponding author (Fax: +98 81323237451; Tel: 9881323237450; Eꢀmail:
2
moosavizare@yahoo.com). Corresponding author (Fax: +98 8138257407. Eꢀmail addresses:
mzolfigol@yahoo.com).
1

Page 2 of 20
ABSTRACT
In this
ꢀ(carboxymethyl)pyridinium iodide {[cmpy]I}, has been applied as reusable nanostructured
work,
acetic
acid
functionalized
pyridinium
salt,
namely
1
catalyst for green, simple and efficient preparation of spiropyrans by the oneꢀpot domino
KnoevenagelꢀMichaelꢀcyclization reaction of isatin derivatives or acenaphthenquinone, with
1
13
malononitrile, and 1,3ꢀdicarbonyl compounds under aqueous media. Moreover, H and
C
NMR, mass, CHN analysis, fourier transform infrared spectroscopy (FTꢀIR), scanning electron
microscope (SEM), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG),
Xꢀray diffraction analysis (XRD), and calculation of crystallite size and inter planer distance of
the catalyst have been studied.
Keywords: Spiropyran, Multi component, 1ꢀ(carboxymethyl)pyridinium iodide, Nanostructured
pyridinium salt, Isatin.
2

Page 3 of 20
Graphical Abstract
Synthesis of spiropyran derivatives over
1
-(carboxymethyl) pyridinium iodide as
nanostructured pyridinium salt under
aqueous media
Ahmad Reza MoosaviꢀZare,* Mohammad Ali Zolfigol,* Rasool Salehi, Ehsan Noroozizadeh
3

Page 4 of 20
Introduction
Multiꢀcomponent reactions (MCRs) have a significant role in combinatorial chemistry because
of the ability to synthesis of target compounds with more atomic economy and efficiency by the
reaction of three or more compounds to provide single product. Also, MCRs improve simplicity
1
–5
and synthetic efficiency on the conventional organic transformations.
Spiropyrans containing oxindoles are an important class of attractive heterocyclic compounds
with useful biological properties such as spasmolitic, diuretic, anticoagulant, anticancer, and
6
ꢀ9
antiꢀanaphylactic activities. Several catalysts have been used for this transformation, including
9
10
11
sodium stearate, sulfated choline based heteropolyanion, Protic guanidinium ionic liquid,
1
2
13
14
15
4
ꢀdimethylaminopyridine, [BMIm]BF4, SBAꢀPrꢀSO H, (SBꢀDBU)Cl, carbonꢀsulfonic
3
1
6
17
18
acid,
polyethylene glycol (PEG)ꢀstabilized Ni nanoparticles,
alphaꢀAmylase,
ZnS
1
9
20
21
nanoparticles, triphenylphosphine and nickel oxide. Therefore, considerable attention has
been concentrated on the development of new protocols for the preparation of these compounds.
Recently, we have introduced a new category of ionic liquids and solid salts (with an organic
2
2ꢀ38
cation), namely sulfonic acid functionalized imidazolium salts (SAFIS).
In this class of salts,
SꢀN bond formation in imidazole ring, as five member’s heterocyclic compounds, was reported
for the first time. These compounds have been successfully applied as catalysts or reagent to
prepare of 6ꢀaminoꢀ4ꢀ(4ꢀmethoxyphenyl)ꢀ5ꢀcyanoꢀ3ꢀ methylꢀ1ꢀphenylꢀ1,4ꢀdihydropyrano[2,3ꢀ
2
2
23
24
25
c]pyrazoles, bis(indolyl)methanes, Nꢀsulfonyl imines, 1ꢀamidoalkylꢀ2ꢀnaphthols, various
2
6
27
xanthene derivatives, 1ꢀcarbamatoalkylꢀ2ꢀnaphthols, 4, 4′ꢀ(arylmethylene)ꢀbis (3ꢀmethylꢀ1ꢀ
2
8
29
30
phenylꢀ1 Hꢀpyrazolꢀ5ꢀol)s, Nꢀboc protected amines, hexahydroquinolines, nitroaromatic
3
1,32
33
34
compounds,
1,2,4,5ꢀtetrasubstituted imidazoles,
benzylated aromatic compounds,
3
5
36
3b
βꢀacetamido ketones, benzimidazoles and amidoꢀalkylꢀphenols. In continuation of our
4

Page 5 of 20
previous projects involving the applications of acidic ionic liquids and solid salts in organic
transformations, we have used 1ꢀ(carboxymethyl)pyridinium iodide {[cmpy]I} as nanostructured
acetic acid functionalized pyridinium salt for the synthesis of spiropyran derivatives by the oneꢀ
pot multiꢀcomponent condensation reaction of isatin derivatives or acenaphthenquinone, with
malononitrile, and 1,3ꢀdicarbonyl compounds under aqueous media (Scheme 1).
«
Scheme 1»
Results and discussion
ꢀ(carboxymethyl)pyridinium iodide {[cmpy]I} was synthesized by the reaction of pyridine with
ethyl iodoacetate at 70 °C and then the product was hydrolysed to give [cmpy]I (Scheme 2). The
1
1
13
structure of [cmpy]I was confirmed by HNMR, CNMR, IR and mass as well as elemental
3
7
analysis (Figures S1ꢀS5).
«
Scheme 2»
Xꢀray diffraction analysis (XRD) pattern of 1ꢀ(carboxymethyl)pyridinium iodide {[cmpy]I} was
studied in a domain of 0ꢀ90 degree (Figure 1). As it is shown at Figure 4, indicates that XRD
◦
◦
◦
patterns exhibited diffraction lines of a high crystalline nature at about 2θ ≈ 18.8 , 19.6 , 23.0 ,
◦
◦
◦
◦
2
4.0 , 26.0 , 27.4 and 28.8 . Crystallite size was obtained by DebyeꢀScherrer’s formula given by
equation: D=Kλ/ (βcosθ). The crystallite size obtained using this formula was at about 32.49 nm
◦
(
for the highest diffraction line at 24.0 ) and inter planer distance was calculated to be via the
Bragg equation: dhkl = λ/(2sinθ), which obtained 0.3703 nm (λ : Cu radiation 0.154178 nm).
Figure 1»
«
In another investigation, the scanning electron microscope (SEM) micrographs of the catalyst
showed three types of materials, large nanospheres, large amorphous regions and small
nanoparticles (Figure 2).
5

Page 6 of 20
«
Figure 2»
To optimize the reaction conditions, as a model reaction, the condensation between dimedone
2 mmol), isatin (2 mmol) and malononitrile (2 mmol) was tested in the presence of different
(
amounts of [cmpy]I at range of 25 to reflux temperature in water (Table 1). As it is shown in
Table 1 indicates that the reaction was efficiently performed using 5 mol% of the catalyst under
reflux conditions to obtain the desired product in high yield within short reaction time (Table 1,
entry 3). The reaction was also examined without catalyst under reflux conditions in which the
reaction did not significantly progress even after long reaction time (Table 1, entry 1).
«
Table 1»
In the next step, the model reaction was investigated in several solvents in the presence of
mol% of [cmpy]I under reflux conditions. The results are depicted in Table 2. As it is shown in
Table 2, indicates that the solventꢀfree conditions are more effective than solvent conditions.
Table 2»
To investigate the efficacy and generality of [cmpy]I in the preparation of spiropyran derivatives,
various 1,3ꢀdicarbonyl compounds including, dimedone, 1,3ꢀcyclohexanedione,
,3ꢀcyclopentanedione, 4ꢀhydroxyꢀ2Hꢀchromenꢀ2ꢀone and 1ꢀphenylꢀ3ꢀmethylpyrazolꢀ5ꢀone were
reacted with isatin derivatives such as 6ꢀbromoꢀisatin, 6ꢀiodoisatin, 6ꢀnitroisatin,
ꢀmethoxyisatin and 5,7ꢀdimethyindole and also with acenaphthenquinone under the optimal
5
«
1
6
reaction conditions to obtain the desired products in high yields and in short reaction times. The
results are depicted in Table 3.
«
Table 3»
In a plausible mechanism, in a typical domino reaction, initially, isatin, activated by [cmpy]I and
reacted with malononitrile via Knoevenagel condensation to give isatylidene malononitrile
6

Page 7 of 20
derivative I. Then, dimedone, in enol form, attacked to I via Michael addition to obtain the
intermediate II which followed by the cycloaddition reaction of hydroxyl group with cyano
group to prepare the desired product.
«
Scheme 3»
In another study, recyclability of the catalyst was tested upon the reaction of isatin (2 mmol) with
dimedone (2 mmol) and malononitrile (2 mmol) using [cmpy]I in water under reflux conditions.
After completion of the reaction, H O was added to the reaction mixture, stirred and refluxed for
2
5
min. Then the reaction mixture was filtered and the solvent of the filtrate (H O) was removed
2
under reduced pressure to separate the catalyst from crude product. Finally, the catalyst was used
for another reaction. We observed that the catalytic activity of the catalyst was restored within
the limits of the experimental errors for four successive runs (Figure 8).
«
Figure 3»
To compare the efficiency of our catalyst with some reported catalysts for the synthesis
of spiropyrans, we have tabulated the results of these catalysts to perform oneꢀpot threeꢀ
component condensation of dimedone, isatin and malononitrile, in Table 4. As Table 4 indicates,
[
cmpy]I has remarkably improved the synthesis of spiropyrans in different terms {reaction time,
yield and turnꢀover frequency (TOF)}. The reaction times were shorter, and the yields and TOFs
were higher when our catalysts were utilized.
Experimental
General
All chemicals were purchased from Merck or Fluka Chemical Companies. The known
products were identified by comparison of their melting points and spectral data with those
reported in the literature. Progress of the reactions was monitored by TLC using silica gel SIL
7

Page 8 of 20
1
13
G/UV 254 plates. The H NMR (400 MHz) and C NMR (100 MHz) were run on a Bruker
Avance DPXꢀ250 FTꢀNMR spectrometer (δ in ppm). Infrared spectrum of products is recorded
by Perkin Elmer PEꢀ1600ꢀFTIR. Melting points were recorded on a Büchi Bꢀ545 apparatus in
open capillary tubes.
General procedure for the synthesis of spirooxindole derivatives
A mixture of isatin derivatives or acenaphthenquinone (2 mmol), malononitrile (2 mmol),
1,3ꢀdicarbonyl compounds ( 2 mmol) hydrazine hydrate (2.5 mmol), {[cmpy]I (5 mol%) and
H O (10 ml) was added to a in a 10 mL roundꢀbottomed flask connected to a reflux condenser,
2
and stirred under reflux conditions. After completion of the reaction, as monitored by TLC, the
reaction mixture was filtered and the solvent of the filtrate (H O) was removed under reduced
2
pressure to separate the catalyst from crude product and used for another reaction. The solid
residue (crude product) was triturated by a mixture of ethanol and water (9/1) to give the pure
product.
Conclusions
In summary, we have reported the efficient synthesis of spiropyran derivatives using
1ꢀ(carboxymethyl)pyridinium iodide {[cmpy]I} as an acetic acid functionalized pyridinium salt
and reusable nanostructured catalyst in aqueous media under reflux conditions. The promising
points for the presented methodology are efficiency, generality, high yield, relatively short
reaction time, low cost, cleaner reaction profile, ease of product isolation, simplicity, and finally
compliance with the green chemistry protocols.
Acknowledgements
We thank BuꢀAli Sina University and Iran National Science Foundation (INSF) (The Grant of
8

Page 9 of 20
Allameh Tabataba'i's Award, Grant Number BN093) and Sayyed Jamaleddin Asadabadi
University for providing support to this work.
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2

Page 13 of 20
Table 1. Effect of different amounts of the catalyst and temperature on the reaction of dimedone
2 mmol) isatin (2 mmol) and malononitrile (2 mmol) in the absence of solvent in water under
(
reflux conditions.
a
Entry
Mol% of
Catalyst
Temp.
(°C)
Time (min)
Yield (%)
1
2
ꢀ
3
Reflux
Reflux
480
45
15
86
3
4
5
6
7
5
7
Reflux
Reflux
Reflux
25
30
30
92
92
92
48
64
10
5
30
120
90
5
50
a
Isolated yield.
Table 2. The reaction of dimedone (2 mmol) isatin (2 mmol) and malononitrile (2 mmol) using
[
cmpy]I (5 mol%) in different solvents (5 mL) under reflux conditions.
a
Entry
Solvent
ꢀ
Time (min)
Yield (%)
1
2
120
30
43
92
2
H O
3
4
5
6
EtOH
60
60
81
64
Acetonitrile
C
2
H
2
Cl
2
120
120
trace
19
Ethylacetate
a
Isolated yield.
1
3

Page 14 of 20
Table 3. The preparation of spiropyran derivatives using [cmpy]I as catalyst in water under reflux conditions.
a
Entry
Product
Time (min)
Yield (%)
Mp. ºC (Lit.)
1
8a
30
92
290ꢀ292 (290ꢀ292) [19]
2
3
4
5
6
7
8
9
8
b
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
91
91
93
92
93
92
91
90
89
91
87
88
91
87
92
94
94
91
90
90
91
89
92
91
289ꢀ291 (297ꢀ299) [15]
>295 (>300) [9]
8
c
8d
305 (302ꢀ304) [19]
311 (305ꢀ307) [19]
283ꢀ284 (>360) [19]
282ꢀ283 (277ꢀ279) [20]
278ꢀ279 (279ꢀ280) [21]
Dec. 289 (Dec. 289) [15]
267ꢀ268 (268ꢀ269) [21]
>295 (>300) [9]
8
e
8
f
8
g
8h
8
i
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
8
j
9
a
9b
>320
9
c
275 (270ꢀ272) [9]
9d
278ꢀ279 (279ꢀ280) [21]
Dec. 257ꢀ258 (217ꢀ219) [9]
280 (283ꢀ285) [9]
9
e
1
0a
0b
0c
0d
1a
1b
1c
1d
1e
1f
1
Dec. 240 (>300) [7]
Dec. 315 (Dec. 310) [15]
280ꢀ281 (271ꢀ273) [18]
299 (285ꢀ286) [15]
>300 (>300) [20]
1
1
1
1
1
224 (226ꢀ228) [19]
228ꢀ230 (227ꢀ229) [15]
274ꢀ275 (282ꢀ283) [21]
223ꢀ224 (218ꢀ221) [19]
1
1
2
1
a
Isolated yield.
1
4

Page 15 of 20
Table 3. Countinued.
Entry Product
2a
2b
a
Time (min)
Yield (%)
Mp. ºC (Lit.)
266ꢀ267 (262ꢀ264) [6b]
2
2
2
2
6
7
8
9
1
30
93
91
93
89
1
30
30
30
262ꢀ263 (>300) [6b]
Dec. 287 (Dec. 289) [15]
271ꢀ272 (276ꢀ277) [6b]
13
14
a
Isolated yield.
1
5

Page 16 of 20
Table 4. Comparison of the results of the condensation of dimedone, isatin and malononitrile
catalyzed by our new catalyst with those obtained by the recently reported catalysts.
a
b
Catalyst
loading
Time Yield
TOF
Reaction Condition
ꢀ1
Ref.
38
(min)
(%)
(min )
InCl /SiO , CH CN, Reflux
20 mol%
90
75
0.041
3
2
3
βꢀcyclodextrin, Water, 60 ºC
Ethylenediamine, Water, 60 °C
TBAB, Water, Reflux
100 mol%
10 mol%
10 mol%
5
60
30
90
90
92
0.18
0.15
0.306
39
40
41
TBAB, Solventꢀfree, 100 °C
10 mol%
7 mol%
40
30
90
92
0.225
0.438
41
c
[
cmpy]I , Water, Reflux
ꢀ
a
b
c
Isolated yield. Turnꢀover frequency Our work.
.
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6

Page 17 of 20
Figure 1. The XRD pattern of 1ꢀ(carboxymethyl)pyridinium iodide [cmpy]I.
Figure 2. The SEM images of 1ꢀ(carboxymethyl)pyridinium iodide [cmpy]I.
1
7

Page 18 of 20
Figure 3. The reaction of isatin with dimedone and malononitrile in the presence of reused
catalyst after 30 minutes in aqueous media under reflux conditions.
1
8

Page 19 of 20
R
H
N
O
O
N
or
R1
O
O
1
2
N
3
OH
R2 R2
O
or
or
or
N
N
Ph
O
O
O
O
O
O
4
5
6
H O, Reflux
7
[
cmpy]I, 5 mol%
2
R
R
R
R
NH
NH
O
NH
R1
NH
R1
R1
O
R1
O
O
O
O
O
CN
CN
CN
O
CN
R2
N
O
NH2
R2
O
9
NH2
O
NH2
N
O
NH2
8
1
0
11
O
O
O
O
O
O
CN
O
CN
CN
R2
R2
O
NH2
O
NH2
O
NH2
12
13
14
R
R1
H
R2
R
H
R1
Br
R2
8a
H
H
H
H
CH3
H
9
d
1
2a
CH3
H
8b
H
9e
H
H
H
H
H
CH O
3
1
2b
8c
I
CH3
10a
10b
10c
10d
H
I
8d
8e
8f
NO2
CH3
H
Br
CH3
Br
CH3
H
CH3
I
CH O
CH3
H
3
8
g
h
11a
11b
11c
H
H
H
H
8
H
NO2
H
I
8i
H
H
Br
H
NO2
8j
CH O CH3
3
11d
11e
H
Br
9a
H
H
H
H
H
NO2
CH3
9b
I
CH3
11f
9c
NO2
Scheme 1. The preparation of spiropyran derivatives using [cmpy]I.
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9

Page 20 of 20
Scheme 2. The synthesis of 1ꢀ(carboxymethyl)pyridinium iodide {[cmpy]I}.
Scheme 3. The plausible mechanism of the synthesis of spiropyran derivatives.
2
0