Catalytic synthesis of benzimidazoles and organic carbamates using a polymer supported zinc catalyst through CO2 fixation

Article abstract of DOI:10.1039/c9nj03015h

Utilization of carbon dioxide in chemical fixation for synthesis of fine chemicals like benzimidazoles, organic carbamates, etc. is in high demand in recent years as carbon dioxide is a cost effective, sustainable, and green renewable C1 source. In this article we present the design and synthesis of an organically modified polystyrene bound heterogeneous [PS-Zn(ii)-SALTETA] catalyst. The catalyst has been characterized thoroughly by Fourier transform infrared spectroscopy, atomic absorption spectroscopy, thermo gravimetric analysis, PXRD, SEM and EDAX studies. The catalyst was used for cyclization of o-phenylenediamines through insertion of carbon dioxide in order to produce benzimidazoles in the presence of dimethylamine borane (DMAB). The developed catalytic procedure is sustainable, economical and efficient owing to the utilization of ethanol/water as a biodegradable and environment friendly solvent system. Besides benzimidazole production the catalyst was also very active for manufacture of organic carbamates from anilines and n-butyl bromide under atmospheric CO₂ pressure under solvent free conditions at room temperature and the catalytic protocol showed outstanding functional group tolerance. Moreover the catalyst is highly recyclable and reusable.

Full text of DOI:10.1039/c9nj03015h

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0.1039/C9NJ03015H.
Volume 42
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March 2018
Pages 3963-4776
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Yellowish and blue luminescent graphene oxide quantum dots
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DOI: 10.1039/C9NJ03015H
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Received 00th January 20xx,
Accepted 00th January 20xx
Catalytic Synthesis of Benzimidazoles and Organic Carbamates by
Polymer Supported Zinc Catalyst through CO Fixation
2
DOI: 10.1039/x0xx0
a,#
a,#
a
b
a
www.rsc.org/
Imdadul Haque Biswas, Surajit Biswas, Md Sarikul Islam, Sk Riyajuddin, Priyanka Sarkar,
b
a
Kaushik Ghosh, Sk Manirul Islam*
Abstract
Utilization of carbon dioxide in chemical fixations for synthesis of fine chemicals like benzimidazoles, organic carbamates
etc. is very demanding in recent era as carbon dioxide is cost effective, sustainable, and green renewable C1 sourse. In this
article we represent the design and synthesis of organically modified polystyrene bounded heterogeneous [PS-Zn(II)-
SALTETA] catalyst. The catalyst has been characterized thoroughly by Fourier Transformed Infrared spectroscopy, Atomic
Absorption Spectroscopy, thermo gravimetric analysis, PXRD, SEM and EDAX studies. The catalyst was used for cyclization
of o-phenylenediamines through insertion of carbon dioxide in order to produce benzimidazoles in presence of
dimethylamine borane (DMAB). The developed catalytic procedure is sustainable, economical and efficient owing to
utilization of ethanol/water as a biodegradable and environment friendly solvent system. Besides benzimidazoles
production the catalyst was also very active for manufacture of organic carbamates from anilines and n-butyl bromide
2
under atmospheric CO pressure in solvent free condition at room temperature and the catalytic protocol shows
outstanding functional group tolerance. Moreover the catalyst is highly recyclable and reusable.
types of pharmacodynamic as well as pharmacokinetic properties
and is one of the most biologically active heterocyclic compounds.
Introduction
1
3
This benzimidazoles nucleus is present in vitamin B12 and various
types of important drugs such as Rabeprazole, Omeprazole,
Mebendazole, Albendazole, and Thiabendazole etc .
Carbon dioxide (CO
global warming, ocean acidification, and many more environmental
hazardness. Again CO is an abundant, low cost, renewable carbon
source and can be used in place of harmful toxic reagents such as
CO, isocyanates, or phosgene, to make the protocol greener and
eco-friendly. Hence, chemical fixation of carbon dioxide has been
2
) is the chief greenhouse gas responsible for
1
4
2
The previously reported protocols utilize DMF derivatives, carbon
monoxide, formic acid, aldehydes, esters, methanol and nitro
1
5
methane for the synthesis of benzimidazoles . But all these
reported protocols have certain difficulties like harsh reaction
conditions (high reaction temperature), toxicity, strong basic or
acidic medium etc. Our strategy is the use of carbon dioxide to
prepare benzimidazoles from o-phenelenediamines in order to
make the method greener and cost-effective. Although there are
few catalytic systems already reported where benzimidazoles is
1
gaining a lot of attention in green and sustainable chemistry .
However, due to thermo dynamical stability of CO
reactivity is much less than phosgene and hence CO
requires a huge energy input (high CO pressures), highly reactive
reagents, stoichiometric amount of bases or acids. Therefore low-
energy consuming and cost-effective catalytic fixation of carbon
2
, its chemical
2
fixation
2
1
6
synthesized using CO
2
from o-phenelenediamine . But these
2
dioxide is very demandable in current years .
systems also have some limitations such as homogeneous and non-
recyclable catalyst system, toxic solvents, hydrogen or silane as
reducing agents and harsh reaction conditions. Recently Bhanage
and co-workers have published two articles where heterogeneous
and recyclable catalyst was used for manufacturing benzimidazoles
Recently catalytic fixation of CO
of valuable fine chemicals such as oxazolidinones , benzimidazoles ,
2
is widely used for the production
3
4
5
6
7
8
cyclic carbonates , carbamates , methanol , formamides , formic
9
10
11
acid , urea , quinazoline-2,4(1H,3H)-diones etc. Carbon dioxide is
generally utilized for the formation of C–H, C–O, C–C, and C–N
bonds, which affords an eco-friendly pathway for the manufactures
of value-added chemicals. The catalytic productions of C–N bond
through the reaction between nitrogen-containing compounds and
carbon dioxide are important in both academic and industrial
from o-phenylenediamines and CO
borane (DMAB) as reducing agent . Again the drawback is that
2
1
in presence of dimethylamine
7
2
both the catalytic systems required high CO pressure (≥ 2 Mpa).
Here we have designed and successfully synthesized a modified
polystyrene supported zinc metal catalyst which can produce
benzimidazoles from o-phenylenediamines through fixation of
atmospheric CO in presence of green solvent mixture (ethanol-
2
water) and DMAB as reducing agent.
1
2
aspects . Benzimidazoles and its derivatives are linked with diverse
aDepartment of Chemistry, University of Kalyani, Kalyani, Nadia 741235, West Bengal,
India
Institute of Nano Science and Technology, Mohali, Punjab-160062, India
Organic carbamates are an essential class of organic compounds
which are exclusively found in agrochemicals (pesticides, fungicides,
b
#
18
19
These authors contributed equally.
herbicides, insecticides, etc.) , natural products , and
This journal is © The Royal Society of Chemistry 20xx
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pharmaceutical compounds . Due to the chemical stability and cell Preparation
membranes permeability; these compounds are extensively used in [PS-Zn(II)SALTETA]
many currently marketed drugs. For examples Felbamate (Felbatol),
an anti-convulsant drug, used for the epilepsy treatment .
Tedizolid (brand name is Sivextro), a five-membered cyclic
carbamate, worldwide marketed for skin infections treatment in
adults, including “MRSA” staph infections . Toloxatone, an anti-
depressant drug is utilized as a monoamine oxidase A (MAOA)
of
polymer
supported
Zn(II)
complex
View Article Online
DOI: 10.1039/C9NJ03015H
0.5 g of polymer bound Schiff base ligand was taken in 20 mL EtOH
in a rb flask. It was allowed to stir for 20 minutes. Next 5 mL 1%
(w/v) ethanolic solution of zinc (II) chloride was added drop by drop
over 30 minutes under continuous stirring. Then 2 drops of
triethylamine was added. The resulting mixture was then refluxed
for 24h. The complex was filtered, washed thoroughly with EtOH
and dried under vacuum at room temperature.
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inhibitor, marketed as Humoryl . Ritonavir (trade name Norvir) is a
potential anti-retroviral drug, in combination with other drugs; it is
used for HIV infection treatment .
2
4
Traditionally, Organic carbamates have been synthesized from
amines using isocyanate derivatives or phosgene which are very
toxic and may cause serious health problems and environmental
2
5
2
hazards . Over the last couple of decades, use of CO in place of
phosgene have been explored extensively due to the inexpensive,
non-toxic, abundant, non-flammable, and renewable nature of
2
6
CO
2
. A number of metal (Al, Sn, Ru, Co and Au etc.) based catalytic
systems have been reported for the manufacture of organic
carbamates using CO as the carbon source . Besides these
2
2
7
catalytic systems, various organic, inorganic based catalysts or
mediated transition metal-free catalysts have been explored
2
8
recently . But all the catalytic systems involved some drawbacks
such as requirement of harsh reaction conditions like high pressure
and temperature, or additional reagents and exhibit poor atom-
economy and functional group tolerance. Therefore, a suitable
catalytic system is necessary to produce organic carbamates under
ambient reaction conditions through cost effective, chemo-selective
and eco-friendly pathway.
Scheme 1 Scheme for synthesis of [PS-Zn(II)-SALTETA] catalyst.
General Procedure for catalytic synthesis of benzimidazoles
This paper demonstrates design, synthesis and characterizations of
through CO
2
fixation
[
PS-Zn(II)TETA] catalyst and its dual tasking catalytic action on the
syntheses of benzimidazoles and organic carbamates through CO
fixation path way under green and mild reaction conditions.
2
Catalytic synthesis of benzimidazoles from o-phenylenediamine
through CO fixation in presence of DMAB as reducing agent and
PS-Zn(II)SALTETA] catalyst was carried out in a 25 ml round bottom
flask under 1 bar carbon dioxide pressure. In a 25 ml flask, 1 mmol
of o-phenylenediamine, 3 mmol of DMAB were dissolved in
ethanol:water (2 mL:1 mL) mixture and 50 mg of [PS-Zn(II)SALTETA]
catalyst was purged into the mixture. Then the whole reaction
2
[
Experimental
Preparation of Schiff base [SALTETA]
2
mixture was allowed to stir at 100 °C under 1 bar CO pressure
In a 50 mL round-bottom flask triethylenetetradiamine (TETA) and
salicyldehyde (1:2 molar ratio) were dissolved in 20 mL Methanol.
The mixture was refluxed under stirring condition for 24h. Then the
reaction mixture was cooled at room temperature and solid
product was isolated by filtration. The obtained product was
washed properly with EtOH. The yellow colored Schiff Base material
using balloon set up. Reaction advancement was checked by Thin
Layer Chromatography. Finally the mixture was cooled to room
temperature. Then the catalyst was separated by filtration and the
product mixture was diluted with ethyl acetate and washed with
brine water. The combined mixture was dried over sodium sulphate
and concentrated under rotary evaporator. Through column
was dried under vacuum. Finally it was re-crystallized from MeOH
for spectroscopy. H NMR (400 MHz, CDCl
chromatography (mesh size of silica gel 100–200) using Et
CH COOEt as eluent pure product was isolated and confirmed by
proton NMR.
2
O-
1
3
) δ 1.623 (s, –2NH),
3
2
6
.611-2.745 (m, 4H), 2.962-3.025 (m, 4H), 3.607 (t, J = 6.4, 3H),
.809-7.333 (m, 8H), 8.279 (s, –2OH), 13C NMR (100 MHz, CDCl
)
3
δ51.1, 52.8, 58.3, 117.0, 118.8, 120.8, 132.2, 132.3, 157.2, 161.1 General Procedure for the formation of carbamates through CO
ppm (Fig.S1), M. W. = 354.21, MS : m/z = 242.2841, 355.2397, fixation
408.1243, 512.1502 (Fig. S2).
2
+
In a 25 mL round bottom flask 5 mmol of amine, 5 mmol of n-butyl
bromide and 50 mg [PS-Zn(II)-SALTETA] catalyst were taken. The
round bottom flask was then equipped with a magnetic stirrer. The
Preparation of polymer bound-ligand [PS-SALTETA]
g of Schiff base was added to 20 mL methanol. To that methanolic
1
2
mixture was stirred for 3h under 1 atm CO pressure using balloon
solution, 1.2 g of Chloromethylated polystyrene was added. Then
the mixture was refluxed for 24h under continuous stirring. The
obtained reaction mixture was cooled at room temperature and
filtered. The yellow beds were washed with ethanol until filtrate
became colorless. Finally the product was dried under vacuum.
set up. Thin layer chromatographic technique was used to check the
progress of the reaction. Next the mixture was diluted with ethyl
acetate and worked up with brine solution. The organic layer was
filtered over sodium sulphate. Using column chromatography, pure
product was separated and identified by proton NMR spectra.
2
| J. Name., 2012, 00, 1-3
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We have done FE-SEM analysis to explain the mVoierwpAhroticlolegOynlionef
PS-SALTETA] ligand and [PS-Zn(II)-SALTETA]DcOaIt:a1l0y.s1t0.3S9E/CM9NimJ0a3g0e15oHf
[PS-SALTETA] ligand showed a sponge like appearance whereas that
of [PS-Zn(II)-SALTETA] catalyst demonstrated tiny particles
deposition on the spongy surface (Fig. 3). So a clear morphological
change from ligand to catalyst assures the incorporation of zinc
metal onto the ligand surface.
Results and discussion
[
Characterization
Table 1 represents elemental analysis data of [PS-SALTETA] ligand
and [PS-Zn(II)-SALTETA] catalyst. Zinc metal loading on [PS-Zn(II)-
SALTETA] catalyst surface was determined by atomic absorption
spectroscopy (AAS).
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Table 1 Elemental composition of [PS-SALTETA] ligand and [PS-Zn(II)-
SALTETA] catalyst (in weight percentage)
Compound
PS-TETA]
Color
Yellow
C
H
N
O
Zn
[
81.53 8.14 3.53 1.98 ------
ligand
[PS-TETA]
catalyst
a
Pale
yellow
77.68 7.76 3.48 1.96 3.9136
3.9112
a
Zinc loading on used catalyst (after 4th cycle)
Fig. 1 depicts the FT-IR spectra of both [PS-SALTETA] ligand and
PS-Zn(II)-SALTETA] catalyst. Pure chloromethylated polystyrene
[
−1
gives a sharp characteristics IR active band for ν(C-Cl) at 1262 cm .
This characteristics band was absent in IR spectrum of [PS-SALTETA]
which clearly indicates successful bonding between Schiff base and
the polystyrene support. IR spectrum of [PS-SALTETA] catalyst
showed a broad band in between range of 3100–3700 cm is due
to ν(O-H) and sharp bands at 1627 cm is due to ν(C=N). The
−1
−
1
Fig. 2 Powder X-ray diffraction pattern of [PS-SALTETA] ligand and
−1
decrease of intensity of the broad band (3100–3700 cm ) in
PS-Zn(II)-SALTETA] catalyst specifies the effective bonding between
phenolic hydroxy group and zinc metal. The shifting of ν(C=N) band
[PS-Zn(II)-SALTETA] catalyst.
[
−1
−1
from 1627 cm to 1632 cm further confirms the bonding of Zn
metal with [PS-SALTETA] ligand through nitrogen of azomethine
moiety. Moreover two new bands was appeared in catalyst at 560
-1
6a
and 461 cm due to ν(Zn-N), ν(Zn-O) respectively .
Fig. 3 FE-SEM images of [PS-SALTETA] ligand (a) and [PS-Zn(II)-SALTETA]
catalyst (b).
EDAX analysis of ligand indicates the presence of carbon, nitrogen
and oxygen elements and that of catalyst contains zinc metal along
with the same elements (Fig.S2). Thus the result further mentions
the insertion of Zn metal on [PS-SALTETA] surface.
Fig. 1 Fourier Transformed Infrared spectra of [PS-SALTETA] ligand and [PS-
Zn(II)-SALTETA] catalyst.
Powder X-Ray diffraction pattern of [PS-SALTETA] ligand and
[
PS-Zn(II)-SALTETA] catalyst is expressed in Fig. 2. A broad band
appeared at the range of 2θ (10–35) for both ligand as well as
catalyst. From the figure it is clear that after loading of Zn metal on
[
PS-SALTETA] ligand surface, amorphous nature of the material did
not changed and there was no formation of nano-crystalline
Fig. 4 TGA graph of [PS-SALTETA] ligand and [PS-Zn(II)-SALTETA] catalyst.
2
9
particles of ZnO further took place .
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To check the thermal stability of [PS-SALTETA] ligand and
PS-Zn(II)-SALTETA] catalyst TGA study were monitored under N
Under optimized reaction conditions we explored Vtihewe AsrtuicblesOtrnalitnee
scopes of different derivatives of o-phenyDleOnIe: d10ia.1m03in9e/Cs9tNoJ0g3i0v1e5Ha
[
2
atmosphere involving temperature gradient from 20 to 800°C with series of benzimidazoles (Table 3). Both electron donating and
−1
1
0°C min heating rate. The thermogram of [PS-SALTETA] ligand withdrawing derivatives were well tolerable to furnish good yield of
showed that the ligand is stable up to 150°C and above 150°C corresponding benzimidazoles product under optimized reaction
temperature decomposition occurs (Fig. 4). In case of conditions. 3-methyl, 4-methyl and 4,5-dimethyl substituted
[
PS-Zn(II)-SALTETA] catalyst, the thermogram depicted that the diamine produced 94%, 95%, 93% of corresponding benzimidazoles
catalyst is thermally more stable than that of the ligand. The product 2b, 2c, 2d respectively (Table 3 entry 2-4).
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catalyst provided two-step decomposition. First decomposition
occurred in between 200–450°C temperature range due to Table
decompose of salen group of catalyst and final decomposition of
the catalyst was noticed beyond 450°C.
2
optimization of catalytic benzimidazoles formation reaction
a
[
5b]
conditions
Entry
Catalyst
mg)
DMAB
(mmol)
Solvent
T
(°C)
Time
(h)
Isolated
Yield (%)
(
1
2
20
-
3
3
DMF
DMF
100
100
24
24
73
-
Catalytic activity of [PS-Zn(II)-SALTETA] catalyst
3
4
5
6
7
8
9
20
20
20
20
20
20
30
40
50
60
50
50
50
50
50
20
3
3
3
3
3
3
3
3
3
3
3
3
3
3
2
2
Toluene
100
100
100
100
100
100
100
100
100
100
90
110
100
100
100
100
24
24
24
24
24
24
24
24
24
24
24
24
16
28
24
24
13
52
56
60
78
82
86
90
93
93
75
93
67
93
62
28
2
Catalytic synthesis of benzimidazoles through CO fixation reaction
Acetonitrile
Chloroform
1,4-Dioxane
EtOH
To optimize the reaction conditions, initially we carried out the
reaction by taking o-phenylenediamines (1 mmol) as model
substrate in presence of our synthesized [PS-Zn(II)-SALTETA]
catalyst (20 mg) and dimethylamine borane (DMAB) (3.0 mmol)
under 1 atm CO pressure in DMF solvent at 100 °C for 24 h, we got
2
73% yield of benzimidazoles (2a) (Table 2, entry 1). In absence of
2
H O:EtOH
2
H O:EtOH
2
H O:EtOH
2
H O:EtOH
2
H O:EtOH
1
1
1
0
1
2
catalyst, no desired product was formed, it implies that for the
synthesis of benzimidazoles trough the same reaction pathway, 13
catalyst is essential (Table 2, entry 2). In order to explore the 14
solvent effects on this reaction, the reaction was performed in 15
2
H O:EtOH
2
H O:EtOH
2
H O:EtOH
2
H O:EtOH
2
H O:EtOH
2
H O:EtOH
1
1
6
7
different solvents. In non polar solvent like toluene, very poor yield
13%) of desired product (2a) was obtained (Table 2, entry 3). We
(
b
18
got relatively better yield of product (52-60%) in use of polar
solvents such as acetonitrile, chloroform, 1,4- dioxane (Table 2,
entry 4-6). When the reaction is monitored in green solvent ethanol
a
o-phenylenediamines (1.0 mmol), DMAB (3.0 mmol), [PS-Zn(II)-SALTETA]
b
catalyst, Solvent, CO
2
(1 atm), 100 °C, 24 h; ZnCl
2
catalyst.
(
EtOH), it gave 78% yield of benzimidazoles (2a) (Table 2, entry 7). Table 3. Substrate scope
a
2
Since the solubility of DMAB is more in water, we used H O and
EtOH (1:2 v/v ratio) mixture for the reaction, as our expectation we
got 82% yield of desired product (Table 2, entry 8). Next we
screened the effect of amount of catalyst loading on the reaction.
With increasing catalyst amount the reaction proceed smoothly
furnishing better yield of product (Table 2, entry 9-12). Same
amount yield of product (92%) was obtained by the use of both 50
mg and 60 mg catalyst. Thus 50 mg catalyst loading is enough to get
the maximum quantity product yield. Then we slightly decreased
the reaction temperature from 100 to 90 °C, but the product yield
was also decreased (Table 2, entry 13). When we raised the
reaction temperature from 100 to 110 °C, the yield of desired
product did not altered from its maximum value (93%) (Table 2,
entry 14). Hence 100 °C is the optimum temperature for efficient
conversion of 2a. The time effect observations imply that 24 h is
sufficient to get the maximum yield of product. When the reaction
is carried out for shorter duration the yield of 2a decreased
significantly (Table 2, entry 15) but the performance of reaction in
longer duration has no effect on product yield (Table 2, entry 16).
Finally while we decreased the amount of DMAB (2 mmol),
reduction of product yield is also observed here (Table 2, entry 17).
Therefore the optimized conditions for the benzimidazole
formation reaction is o-phenylenediamines (1 mmol),
dimethylamine borane (3 mmol), [PS-Zn(II)-SALTETA] catalyst (50
Entry
1
Substrate
Product
Time
h)
Isolated
Yield
(
(%)
NH2
NH2
H
N
2
4
93
N
1
a
b
2a
H
N
NH2
2
24
94
N
NH2
2
b
1
NH2
H
N
3
4
5
6
24
24
24
24
95
93
83
85
NH2
N
1c
1d
2c
2d
2e
NH2
H
N
NH2
N
NH2
NH2
H
N
F
N
F
1
e
mg), Solvent-H
pressure for 24 h. The cyclization reaction of o-phenelenediamines
was also carried out in presence of 20 mg ZnCl salt catalyst under
optimized reaction condition, the isolated yield of corresponding
product was obtained only 28%.
2 2
O:EtOH (1 ml:2 ml), at 100 °C under 1 atm CO
NH2
H
N
2
Cl
NH2
N
Cl
1f
2
f
4
| J. Name., 2012, 00, 1-3
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Journal Name
ARTICLE
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
NH2
O
N
conditions. So the catalyst separation and reVcieywclAartbicilleitOynlinies
problematic in these methods. Again noDnO-eIn: 1v0ir.1o0n3m9/eCn9tNJf0ri3e0n1d5lHy
solvent was used in those reports. Recently Bhanage and his
group reports the synthesis of benzimidazoles under
heterogeneous catalytic conditions with high product yield but used
CO pressure is very high (2 MPa) in their protocols. Moreover those
catalytic systems were very costly. In our system low cost
heterogeneous [PS-Zn(II)TETA] catalyst is utilized for the production
of benzimidazoles under 1 bar CO pressure and mild reaction
2
7
8
24
24
78
35
OH
2
g
1
g
h
17
NH2
S
N
2
SH
2h
1
9
NO2
NO2
24
68
H
N
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
NH2
NH2
conditions in green solvent mixture to furnish 93% yield of desired
product.
N
2
i
1i
aReaction conditions: Substrate (1.0 mmol), DMAB (3.0 mmol),
Table 4 Comparison table for catalytic formation of benzimidazole from
o-phenelenediamines with previously reported systems
[
(
PS-Zn(II)-SALTETA] catalyst (50 mg), Solvent: H
1 atm), 100 °C, 24 h.
2 2
O-EtOH (1ml:2 ml), CO
Sl.
No.
Catalyst
Reaction conditions
Catalytic nature
T
(h)
Yield
(%)
Ref
Mono substituted moderate electron withdrawing groups like
-fluoro and 4-chloro substituted 1,2-diamine gave very good yield
1
RuCl
2
(dppe)
2
Substrate(5 mmol),
catalyst (0.2 mol%),
Homogeneous
40
92
16a
4
CO
pressure 15 MPa),
20 °C
2 2
and H (mixture
of 2e (83%) and 2f (85%) respectively (Table 3, entries 5 and 6).
Beside diamine derivatives, we checked the substrate tolerance of
2-aminophenol and 2-aminothiol for this same reaction under
optimized conditions. 2-aminophenol formed benzoxazole (2g) with
good yield (78%) (Table 3, entry 7) but 2-aminothiol furnish low
amount (35%) of benzothiazole (2h). Again strong electron
1
2
IPr
Substrate(5 mmol),
catalyst (9.7 mg,
Homogeneous
24
90
16b
0.025
mmol,
5
mol%), PMHS (90µL,
1.5 mmol, 3 eq), THF
withdrawing group like -NO
gave greater than moderate yield (68%) of the corresponding
desired product (Table 3, entry 9).
In addition, a plausible mechanistic pathway for the formation of
benzimidazoles from o-phenylenediamines and dimethylamine
2
borane through CO fixation has been expressed here on the
support of previously reported literature . [PS-Zn(II)-SALTETA]
catalyst activates dimethylamine borane in order to form
intermediate II and catalyzes the insertion of carbon dioxide into
B–H bond to form intermediate III. Then formamide intermediate IV
is formed through the combination of diamine with intermediate III.
Finally, intermediate IV afford benzimidazoles product through
cyclization followed by release of water molecule (Scheme 2).
2
substituted o-phenelenediamine also
(0.5 mL), CO
70 °C
2
(1 bar),
3
4
5
6
B(C
6
F
5
)
3
Substrate(0.2
mmol), catalyst (0.02
mmol, 10 mo %),
Homogeneous
Heterogeneous
Heterogeneous
Heterogeneous
24
18
24
24
83
96
92
93
16c
17a
17b
3
PhSiH (0.8 mmol),
17
THF (2 ml), CO
2
(1
MPa), 120 °C
Ru@PsIL
Substrate(1 mmol),
catalyst (5 mg),
DMAB (3 mmol),
water/EtOH
mL), CO
mmol), CO
(3:3
(0.5
(2 MPa)
K
2
3
2
Cu@U-g-C
3
N
4
Substrate(1 mmol),
catalyst (20 mg),
DMAB (3 mmol),
PC:H
mL), CO
100 °C
2
O
(3 mL:1.5
2
(2 MPa),
[PS-Zn(II)-
SALTETA]
Substrate (1 mmol),
catalyst (50 mg),
DMAB (3 mmol),
This
work
2
H O:EtOH (1 mL:2
mL), CO
100 °C
2
(1 bar),
Catalytic production of organic carbamates through CO
reaction
2
fixation
Organic carbamates hold a unique position in agricultural as well as
medicinal chemistry. There are various protocols reported earlier
for the formation of such compounds. Through classical method,
carbamates are synthesized between the reaction of amines and
alcohols in presence of phosgene but the route is highly toxic in
nature. Thus to overcome the phosgene containing route and make
it sustainable, researchers have developed different methodologies
afterward. Use of diethyl carbonate, dimethyl carbonate etc. by
replacing phosgene for carbamates preparation from amines is
Scheme
benzimidazoles from o-phenylenediamines and dimethylamine borane
through CO fixation.
2
Proposed mechanistic pathway for the synthesis of
2
Table 4 shows the comparison between the previously reported
catalytic systems with this catalyst system for benzimidazoles
production from o-phenylenediamines through CO fixation. Three
2
catalytic systems [16] were published where high yield (83-92%) of
benzimidazoles was obtained under homogeneous catalytic
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
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ARTICLE
Journal Name
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
3
0
more promising and eco-friendly . Nowadays the catalytic
synthesis of carbamates using CO as a C1 feedstock from amines donating and withdrawing derivatives wDeOreI: 1w0.e10ll39t/oCl9eNraJn0c3e015tHo
and alcohols or metal alkoxide/alkoxy silanes or aryl / alkyl halides furnish good yield of corresponding carbamates product under the
is the most demandable and suitable route . Earlier He and his same reaction conditions.
group described base catalyzed organic carbamates production
from amines and alkyl halides through CO fixation . Recently Das
2
et al. also published
carbamates synthesis from amines and alkyl bromide using carbon
dioxide as a carbon source (Scheme 3).
the obtained results are summarized in table 6. BVioewthArteiclleecOtnrloinne
2
3
1
31a
Table 6. Substrate scope for catalytic formation of organic
31d
base (Cs
2
CO
3
)
catalyzed route for
a
carbamates
%
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Entry
Amines
Halide
Product
b
Yield (c)
To improve the above methods we have developed and synthesized
a cost effective, eco-feiendly amine functionalized polystyrene
embedded zinc catalyst ([PS-Zn(II)-SALTETA]) which can efficiently
manufacture organic carbamates from amines and alky halide
under 1 bar carbon dioxide pressure in solvent free conditions at
room temperature. Furthermore, our catalyst can be recycled and
reused, even after consecutive six catalytic cycles, the catalytic
efficiency of catalyst remains intact.
O
NH2
nBu
HN
HN
O
1
.
n-BuBr
95 (91)
97 (94)
O
O
NH2
nBu
2.
3.
4.
5
n-BuBr
n-BuBr
n-BuBr
In order to optimize the catalytic reaction conditions, primarily we
have checked catalyst amount and reaction time by taking aniline (2
mmol) and n-butyl bromide (n-BuBr) (2 mmol) in presence of our
catalyst under CO (1 bar) pressure at room temperature for the
2
formation of butyl phenylcarbamate as model reaction. In absence
of catalyst no desired product was formed after 24 h of reaction
OMe
NH2
OMe
O
nBu
HN
O
(
Table 5, entry 1). When the reaction was monitored under same
89 (86)
88 (84)
reaction environment in presence of 20 mg [PS-Zn(II)-SALTETA]
catalyst furnished 58% substrate conversion after 6 h (Table 5, entry
Br
2
). By increasing catalyst amount we got better conversion (65-88%)
Br
O
after 3 h (Table 5, entries 3-4). By using 50 mg of catalyst 100%
conversion of substrate was observed in 3 h (Table 5, entry 5). Then
time period of reaction was decreased but the resultant conversion
was also decreased (Table 5, entry 6). Thus the optimized reaction
conditions is; aniline (2 mmol), n-butyl bromide (2 mmol), catalyst
(50 mg), no solvent, room temperature under one bar carbon
dioxide pressure and reaction interval is 3 h.
NH2
nBu
HN
O
Cl
Cl
O
NH2
nBu
HN
O
I
I
n-BuBr
n-BuBr
85 (82)
74 (70)
O
NH2
nBu
I
HN
O
I
6
.
F
Scheme 3 Comparisons with previous protocols for the synthesis of organic
carbamates from amines and organo-halides using CO .
2
F
O
NH2
nBu
Table 5. Reaction optimization table of catalytic organic carbamates
HN
O
I
I
a
synthesis
7.
8.
n-BuBr
n-BuBr
76 (73)
90 (87)
b
Entry Amount of [PS-Zn(II)-SALTETA] (mg)
Time (h) Conversion (%)
Cl
1
2
3
4
5
6
0
24
6
3
3
3
No conversion
Cl
N
20
30
40
50
50
58
65
88
100
78
O
NH
nBu
O
2
a
Aniline (2 mmol), n-butyl bromide (2 mmol), room temperature; bGC
conversion.
Under optimized reaction conditions we explore the substrate
scopes of different derivatives of anilines with n-butyl bromide and
6
| J. Name., 2012, 00, 1-3
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ARTICLE
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
O
O
NH2
View Article Online
DOI: 10.1039/C9NJ03015H
nBu
OH
HN
HN
O
9
.
n-BuBr
n-BuBr
88 (85)
93 (90)
OH
NH2
nBu
O
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
0.
CH3
CH3
aReaction conditions: substrate (2 mmol), n-butyl bromide/benzyl
bromide (2 mmol), [PS-Zn(II)-SALTETA] (50 mg), room temperature, CO
Fig. 5 Recyclability of [PS-Zn(II)-SALTETA] catalyst for formation of organic
2
carbamates from aniline under optimized reaction conditions.
b
c
(
1 bar); GC conversion; isolated yield.
Heterogeneity Test of Catalyst [PS-Zn(II)-SALTETA]
Conclusion
To find the heterogeneity nature of [PS-Zn(II)-SALTETA] catalyst, hot
filtration test was carried out for organic carbamates synthesis
reaction in presence of our catalyst by taking aniline (2 mol) and
n-butyl bromide (2 mmol). The catalytic reaction was performed
through the developed optimized reaction conditions for 1 h. We
got 52% conversion of amine in 1 h. Then by simple filtration
A recyclable, cost-effective polymer bound heterogeneous catalyst,
PS-Zn(II)-SALTETA] has been designed and synthesized from
organically modified Merrifield resin. The catalyst was characterized
thoroughly by Fourier-transform infrared spectroscopy, Power X-ray
diffraction analysis, Atomic Absorption Spectroscopy, Field Emission
Scanning electron microscopy, EDX and thermal analysis. Fixation of
[
[
PS-Zn(II)-SALTETA] catalyst was separated and the filtrate was
2
CO is very demanding field in current research for the synthesis of
allow to stir for further 1 h under same reaction conditions. But no
extra conversion of substrate was seen from Gas Chromatography
analysis.Thus it indicates that the catalytic reaction was not occured
without catalyst. For further clarification we have checked AAS
analysis of recovered catalyst and filtrate. The results of the analysis
cleared that used catalyst contains same amount of metal
percentage as that of fresh catalyst (3.9136 %) but filtrate did not
contained any trace of metal percentage. Again FT-IR spectra and
PXRD analysis of used and fresh catalyst have been carried out for
more confirmation of no leaching of zinc metal from polymer
support. Both used and fresh catalyst showed similar spectrum
pattern in FT-IR spectra (Fig. S20). Also PXRD pattern of fresh and
reused catalyst gave a broad peak in same region (Fig. S21). Loading
of Zn metal in fresh catalyst and that of used catalyst after fourth
cycle was found almost same by AAS analysis (3.9112 %). Moreover
product mixture AAS analysis of organic carbamates formation
reaction after catalyst separation also demonstrates the absence of
Zn metal in that mixture. Therefore all these experimental
value based product. Our synthesized catalyst is very efficient for
chemical fixation of carbon dioxide in formation of benzimidazoles
from o-phenylenediamines and organic carbamates from anilines.
The developed protocol for production of benzimidazoles from
o-phenylenediamines is highly proficient and sustainable due to the
utilization of dimethylamine borane as a non-hazardous and
inexpensive hydrogen source, atmospheric carbon dioxide pressure,
mild temperature, and use of ethanol/water green solvent mixture.
Additionally, the catalyst is able to form organic carbamates from
aniline/derivatives of anilines and n-butyl bromide under 1 bar CO
2
pressure at room temperature and solvent free condition. Here, the
established process of carbamates formation is safe, low cost and
phosgene free. More over the catalyst is enough stable, it preserved
its catalytic efficiency even after use of seven successive catalytic
cycles.
information evidently established the heterogeneous character of Acknowledgments
[PS-Zn(II)-SALTETA] catalyst.
SMI gratefully acknowledges the Department of Science and
Technology, DST-SERB (Project sanction No. EMR/2016/004956),
New Delhi, Govt. of India, Board of Research in Nuclear Science,
Recycling of catalyst
Easy separation, recoverability and recyclability are the most BRNS (Project sanction No. 37(2)/14/03/2018-BRNS/37003), Govt.
important characteristics features of a heterogeneous catalyst. The of India and the Council of Scientific and Industrial Research, CSIR
recoverability and recyclability of [PS-Zn(II)-SALTETA] catalyst was (Project sanction No. 02(0284)/16/EMR-II, Dated 06-12-2016), New
monitored in formation of carbamates from aniline through carbon Delhi, Govt. of India for financial support. SB acknowledges
dioxide fixation reactions. By simple filtration method the catalyst University Grants Commission for D. S. Kothari Post Doctoral
was separated from reaction mixture and washed properly by Fellowship (Award letter no. F.4-2/2006 (BSR)/CH/16-17/0026). MSI
distilled water followed by methanol (hot) and diethyl ether after gratefully acknowledges the Department of Science and
every catalytic round. Then recovered [PS-Zn(II)-SALTETA] catalyst Technology;
DST-INSPIRE for financial support (INSPIRE fellow
was further used for another cycle after drying the catalyst under Registration No. IF170931). We acknowledge Department of
vacuum desiccators. Figure 6 depicted the recyclability cycles of our Science and Technology (DST) and University Grant Commission
synthesized catalyst and from the graph it is very clear that the (UGC) New Delhi, India for providing support to the Department of
heterogeneous catalyst was well enough stable and efficient after Chemistry, University of Kalyani under PURSE, FIST and SAP
successive use of seven cycles.
program.
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*
Author to whom correspondence should be addressed.
11.
(a) W.-Z. Zhang, H. Li, Y. Zeng, X. Tao and X. Lua, Chin. J.
View Article Online
Chem., 2018, 36, 112-118; (b) P. MaDmOIp:u10y.s1,0H39. /NCe9uNmJ0a3n0n15, H
S. Sergeyev, R. V. A. Orru, H. Jiao, A. Spannenberg, B. U.
W. Maes and M. Beller, ACS Catal., 2017, 7, 5549-5556;
Dr. Sk. Manirul Islam, Department of Chemistry, University of
Kalyani, Kalyani, Nadia, 741235, W.B., India. Phone: + 91- 33-2582-
8
750, Fax: 91-33-2582-8282, E-mail: manir65@rediffmail.com
(
c) P. Xu, F. Wang, T.-Q. Wei, L. Yin, S.-Y.Wang and S.-J. Ji,
Org. Lett., 2017, 19, 4484-4487.
Notes and references
1
2.
(a) T. Kimura, K. Kamata and N. Mizuno, Angew. Chem.,
Int. Ed. 2012, 51, 6700-6703; (b) Y. Li, X. Cui, K. Dong, K.
Junge, and M. Beller, ACS Catal., 2017, 7, 1077–1086.
M.J. O’Neil, M. Smith and P. E. Heckelman, The Merck
Index, 13th ed. Merck & Co Inc., 2001, P-1785, 10074.
(a) R. S. Keri, A. Hiremathad, S. Budagumpi and B. M.
Nagaraja Chem Biol Drug Des., 2015, 86, 19–65; (b) N.
Vojčić, N. Bregović, N. Cindro, J. Požar, G. Horvat, K.
Pičuljan, E. Meštrović andV. Tomišić, ChemistrySelect,
017, 2, 4899–4905; (c) J. Zhang, J.-L. Wang, Z –M. Zhou,
Z. H. Li, W. Z. Xue, D. Xu, L. P. Hao, X. F. Han, F. Fei, T. Liu
and A. H. Liang, Bioorg. Med. Chem., 2012, 20, 4208–
216; (d) R. Zhou and E. B. Skibo, J. Med. Chem., 1996,
39, 4321–4331; (e) P. Kohler, Int. J. Parasitol., 2001, 31,
336-345.
(a) D. Nale and B. Bhanage, Synlett., 2015, 26, 2835–
842; (b) P. P. Kattimani, R. R. Kamble and G. Y. Meti,
RSC Adv., 2015, 5, 29447–29455; (c) J. Mann, A. Baron
and Y. Opoku-Boahen, J. Med. Chem., 2001, 44, 138–
1
.
(a) X. Wang, W. -Y. Gao, Z. Niu, L. Wojtas, J. A. Perman,
Y.-S. Chen, Z. Li, B. Aguila and S. Ma, Chem. Commun.,
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
13.
4.
2
018, 54, 1170-1173; (b) J. Jia, C. Qian, Y. Dong, Y. F. Li,
H. Wang, M. Ghoussoub, K. T. Butler, A. Walsh and G. A.
Ozin, Chem. Soc.Rev., 2017, 46, 4631-4644; (c) Q.-W.
Song, Z.-H. Zhoua, L.-N. He, Green Chem., 2017, 19,
3707-3728; (d) J. Albo, M. Alvarez- Guerra, P. Castaño
and A. Irabien, Green Chem., 2015, 17, 2304- 2324; (e) P.
Lanzafame, G. Centi and S. Perathoner, Chem. Soc.Rev.,
1
2
2
014, 43, 7562-7580.
(a) S. Wanga and C. Xi, Chem. Soc. Rev., 2019, 48, 382-
04; (b) T. Biswas and Mahalingam, Sustainable Energy
2
.
4
4
Fuels, 2019, 3, 935-941; (c) M. M.-J. Li and S. C. E. Tsang,
Catal. Sci. Technol., 2018, 8, 3450-3464; (d) J. Hu, J. Ma,
Q. Zhu, Q. Qian, H. Han, Q. Mei and B. Han, Green Chem.,
15.
2
2
016, 18, 382-385; (e) M. Ahamed, J. Verbeek, U. Funke,
J. Lecina, A. Verbruggen and G. Bormans, ChemCatChem,
2016, 8, 3692 –3700.
1
4
44; (d) S. Lin and L. Yang, Tetrahedron Lett., 2005, 46,
315–4319; (e) R. Fu, Y. Yang, Y. Ma, F. Yang, J. Li, W.
3.
(a) F. Chen, M. Li, J. Wang, B. Dai and N. Liu,J. CO₂ Util.,
2018, 28, 181–188; (b) X.-D. Li, Y. Cao, R. Ma and L.-N.
He, J. CO₂ Util., 2018, 25, 338–345; (c) M.-Y. Wang, Q.-W.
Song, R. Ma, J.-N. Xie and L.-N. He, Green Chem., 2016,
Chai, Q. Wang and R. Yuan,Tetrahedron Lett., 2015, 5,
527–4531; (f) F. Feng, J. Ye, Z. Cheng, X. Xu, Q.
Zhang, L. Ma and C. Lu, X. Li, RSC Adv., 2016, 6, 72750–
2755; (g) A. V. Aksenov, A. N. Smirnov, N. A. Aksenov,
A. S. Bijieva, I. V. Aksenovaa and M. Rubin, Org. Biomol.
Chem., 2015, 13, 4289–4295.
(a) B. Yu, H. Zhang, Y. Zhao, S. Chen, J. Xu, C. Huang and
Z. Liu, Green Chem., 2013, 15, 95–99; (b) O. Jacquet, C.
Das Neves Gomes C, M. Ephritikhine and T. Cantat
ChemCatChem, 2013, 5, 117–120; (c) Z. Zhang, Q. Sun, C.
Xia and W. Sun Org Lett., 2016, 18, 6316–6319.
(a) V. B. Saptal, T. Sasaki and B. M. Bhanage,
ChemCatChem, 2018, 10, 2593-2600; (b) V. V. Phatake
and B. M. Bhanage, Catal. Lett., 2019, 149, 347–359.
(a) L. H. Machemer and M. Pickel, Toxicology, 1994, 91,
4
1
8, 282-287; (d) Q. Liu, L. Wu, R. Jackstell and M. Beller,
7
Nat Commun., 2015, 6, 5933.
4
5
.
.
(a) V. B. Saptal, T. Sasaki and B. M. Bhanage,
ChemCatChem, 2018, 10, 2593-2600; (b) E. Vessally, K.
Didehban, M. Babazadeh, A. Hosseinian and L. Edjlali, J.
CO₂ Util., 2017, 21, 480-490.
(a) R. K. Mondal, S. Riyajuddin, A. Ghosh, S. Ghosh, K.
Ghosh and S. M. Islam, J. Organomet. Chem., 2019, 880,
322-332; (b) S. Biswas, R. Khatun, M. Sengupta and S. M.
Islam, Mol. Catal., 2018, 452, 129-137; (c) S. Ghosh, P.
Mondal, D. Das, K. Tuhina and S. M. Islam, J. Organomet.
Chem., 2018, 866, 1-12; (d) V. B. Saptal and B. M.
Bhanage, ChemCatChem, 2016, 8, 244-250; (e) W. Chen,
L. Zhong, X. Peng, R. Sun, F. Lu, ACS Sus. Chem. Eng.,
16.
1
1
7.
8.
1
05–109; (b) R. C. Gupta, J. Toxicol. Environ. Health A,
1994, 43, 383–418; (c) T. Goto, Y. Ito, S. Yamada, H.
Matsumoto, H. Oka and H. Nagase, Anal. Chim. Acta,
2006, 555, 225–232; (d) J. Ma, N. Lu, W. Qin, R. Xu, Y.
Wang and X. Chen, Ecotoxicol. Environ. Saf., 2006, 6,
2
015, 3, 147-152.
6
.
(a) R. Khatun, S. Biswas, M. S. Islam, I. H. Biswas, S.
Riyajuddin, K. Ghosh and S. M. Islam, ChemCatChem,
2
019, 11, 1303–1312; (b) S. Arshadi, E. Vessally, A.
2
68–274.
Hosseinian, S. Soleimani-amiri and L. Edjlali, J. CO₂ Util.,
2017, 21, 108-118.
1
9.
(a) W. Aida, T. Ohtsuki, X. Li and M. Ishibashi,
Tetrahedron, 2009 65, 369–373; (b) X. Xu, Y. Wu, M. Hu,
X. Li, Q. Bao, J. Bian, Q. You and X. Zhang, Sci. Rep., 2016,
, 35771.
A. K. Ghosh and M. Brindisi, J. Med. Chem., 2015, 58,
895–2940.
K. J. Palmer and D. McTavish, Drugs, 1993, 45, 1041–
1065.
J. J. Kisgen, H. Mansour, N. R. Unger and L. M. Childs,
Am. J. Health Syst. Pharm., 2014, 71, 621–633.
I. Berlin, R. Zimmer, H. M. Thiede, C. Payan, T.
Hergueta, L. Robin and A. J. Puech,Br. J. Clin. Pharmacol.,
7.
(a) W. Geng, H. Han, F. Liu, X. Liu, L. Xiao and W. Wu, J.
CO₂ Util., 2017, 21, 64-71; (b) S, Wesselbaum, T. vom
Stein, J. Klankermayer and W. Leitner, Angew Chemie.
Int. Ed., 2012, 51, 7499-7502.
6
2
2
0.
1.
2
8
.
a) H. Niu, L. Lu, R. Shi, C. -W. Chiang and A. Lei, Chem.
Commun.,2017, 53, 1148-1151; (b) V. B. Saptal, T. Sasaki,
K. Harada, D. N.-Hamane and B. M. Bhanage,
ChemSusChem, 2016, 9, 644–650.
22.
3.
9
.
S. Moret, P. J. Dyson and G. Laurenczy, Nat Commun.,
2
2
014, 5, 4017.
10.
T. Jiang, X. Ma, Y. Zhou, S. Liang, J. Zhang and B. Han,
Green Chem., 2008, 10, 465.
1
990, 30, 805–816; (b) F. Moureau, J. Wouters, D.
Vercauteren, S. Collin, G. Evrard, F. Durant, F. Ducrey, J.
8
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 9 of 10
Ple Na es we dJ oo u nr no at l ao df jCu hs et mm i as tr rgy ins
Journal Name
ARTICLE
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Koenig, F. Jarreau, Eur. J. Med. Chem., 1994, 29, 269–
77.
S. Walmsley, B. Bernstein, M. King, J. Arribas, G. Beall, P.
Ruane, M. Johnson, D. Johnson, R. Lalonde and A.
Japour, N. Engl. J. Med. 2002, 346, 2039–2046.
(a) D. Chaturvedi, N. Mishra and V. Mishra, Curr. Org.
Synth., 2007, 4, 308–320; (b) D. Chaturvedi, Curr. Org.
Chem., 2011, 15, 1593–1624; (c) D. Chaturvedi,
Tetrahedron, 2012, 68, 15–45.
Chem., 2017, 19, 5614–5624.
View Article Online
DOI: 10.1039/C9NJ03015H
2
2
2
4.
5.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
26.
(a) S. Arshadi, E. Vessally, A. Hosseinian, S. Soleimani-
amiri and L. Edjlali, J. CO2 Util., 2017, 21, 108–118; (b) E.
Vessally, R. Mohammadi, A. Hosseinian, L. Edjlali and M.
Babazadeh, J. CO2 Util., 2018, 24, 361–368.
2
7.
(a) F. Kojima, T. Aida and S. Inoue, J. Am. Chem. Soc.,
1
986, 108, 391-395; (b) R. Mahe, Y. Sasaki, C. Bruneau
and P. H. Dixneuf, J. Org. Chem. 1989, 54, 1518-1523; (c)
M. Abla, J. Choi and T. Sakakura, Chem. Commun.,
2
001,2238-2239; (d) Y. Sasaki and P. H. Dixneuf, J. Chem.
Soc. Chem. Commun., 1986, 790-791; (e) J. Shang, X.
Guo, Z. Li and Y. Deng, Green Chem. 2016, 18, 3082-
3088; (f) Y. Liu, W.-M. Ren, K.-K. He, W.-Z. Zhang, W.-B.
Li, M. Wang, and X.-B. Lu, J. Org. Chem. 2016, 81, 8959-
8
966.
2
8.
(a) W. Xiong, C. Qi, H. He, L. Ouyang, M. Zhang and H.
Jiang, Angew. Chem. Int. Ed., 2015, 54, 3084-3087;
Angew. Chem., 2015, 127, 3127-3130; (b) A. Ion, V.
Parvulescu, P. Jacobs and D. De Vos, Green Chem., 2007,
9
, 158-161; (c) A. Ion, C. V. Doorslaer, P. Jacobs and D.
De Vos, Green Chem., 2008, 10, 111-116; (d) S. L.
Peterson, S. M. Stucka and C. J. Dinsmore, Org. Lett.,
2
010, 12, 1340-1343; (e) R. N. Salvatore, S. Shin, A. S.
Nagle and K. W. Jung, J. Org. Chem. 2001, 66, 1035-
1037; (f) W. McGhee, D. Riley, K. Christ, Y. Pan and B.
Parnas, J. Org. Chem., 1995, 60, 2820-2830; (g) W. Xiong,
C. Qi, Y. Peng, T. Guo, M. Zhang and H. Jiang, Chem. Eur.
J.. 2015, 21, 14314-14318; (h) Q. Zhang, H. -Y. Yuan, N.
Fukaya, H. Yasuda and J. -C. Choi, Green Chem., 2017, 19,
5
614-5624.
2
3
9.
0.
R. Khatun, S. Biswas, S. Ghosh and S. M. Islam, J.
Organomet. Chem., 2018, 858, 37–46.
(a) S. Huang, B. Yan, S. Wang, X. Ma, Chem. Soc.
Rev.,2015, 44, 3079–3116; (b) M. Honda, M. Tamura, Y.
Nakagawa and K. Tomishige, Catal. Sci.Technol., 2014, 4,
2830–2845; (c) B. Schäffner, F. Schäffner, S. P. Verevkin
and A. Börner, Chem. Rev., 2010, 110, 4554–4581; (d) T.
Sakakura and K. Kohno, Chem. Commun., 2009, 11,
1
312–1330.
a) D.-L. Kong, L.-N. He and J.-Q. Wang, Synth. Commun.,
011, 41, 3298–3307; (b) R. Zhang, L. Guo, C. Chen, J.
3
1.
2
Chen, A. Chen, X. Zhao, X. Liu, Y. Xiu and Z. Hou, Catal.
Sci. Technol., 2015, 5, 2959–2972; (c) G. Fan, S. Luo, T.
Fang, Q. Wu, G. Song and J. Li, J. Mol. Catal. A, 2015,
4
04–405, 92–97; (d) D. Riemer, P. Hirapara and S. Das,
ChemSusChem, 2016, 9, 1916–1920; (e) M. Zhang, X.
Zhao and S. Zheng, Chem. Commun., 2014, 50, 4455–
4458; (f) J.-C. Choi, H.-Y. Yuan, N. Fukaya, S.-Y. Onozawa,
Q. Zhang, S. J. Choi and H. Yasuda, Chem. Asian J., 2017,
12, 1297–1300; (g) N. Germain, M. Hermsen, T. Schaub
and O. Trapp, Appl. Organomet. Chem., 2017, 31, e3733;
(
h) Q. Zhang, H.-Y. Yuan, N. Fukaya, H. Yasuda and J.-C.
Choi, ChemSusChem, 2017, 10, 1501–1508; (i) Q. Zhang,
H.-Y. Yuan, N. Fukaya, H. Yasuda and J.-C Choi, Green
This journal is © The Royal Society of Chemistry 20xx
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Graphical Abstract
Catalytic Synthesis of Benzimidazoles and Organic Carbamates by
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Polymer Supported Zinc Catalyst through CO Fixation
2
Imdadul Haque Biswas,a,# Surajit Biswas,a, # Md Sarikul Islam, Sk Riyajuddin, Kaushik
a
b
b
a
Ghosh, Sk Manirul Islam*
aDepartment of Chemistry, University of Kalyani, Kalyani, Nadia, 741235, W.B., India
bRefinery Technology Division, CSIR-Indian Institute of Petroleum, Dehradun, 248005,
Uttarakhand, India.
Zinc metal is attached to the organically modified polystyrene and the obtained catalyst is well
characterized. The catalyst is very efficient for the formation benzimidazoles and organic carbamates
through carbon dioxide fixation.