Direct Catalytic Synthesis of N-Arylcarbamates from CO2, Anilines and Alcohols

Article abstract of DOI:10.1002/cctc.201801443

The direct catalytic synthesis of carbamates from CO₂, amines and methanol was achieved by controlling both the reaction equilibrium and the reactivity of the three components. The combination of CeO₂ and 2-cyanopyridine was an effective catalyst, providing various carbamates including N-arylcarbamates in high selectivities.

Full text of DOI:10.1002/cctc.201801443

Accepted Article
Title: Direct catalytic synthesis of N-arylcarbamates from CO₂, anilines
and alcohols
Authors: Masazumi Tamura, Ayaka Miura, Masayoshi Honda, Yu Gu,
Yoshinao Nakagawa, and Keiichi Tomishige
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To be cited as: ChemCatChem 10.1002/cctc.201801443
Link to VoR: http://dx.doi.org/10.1002/cctc.201801443
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10.1002/cctc.201801443
ChemCatChem
COMMUNICATION
Direct catalytic synthesis of N-arylcarbamates from CO2, anilines
and alcohols
Masazumi Tamura,*[a][b] Ayaka Miura,[a] Masayoshi Honda,[a] Yu Gu,[a] Yoshinao Nakagawa,[a] and
Keiichi Tomishige*[a]
Dedication ((optional))
R1 OH
R2 NH2
: Alcohol
1
: Amine
CO2
Abstract: We achieved direct catalytic synthesis of carbamates from
CO2, amines and methanol by controlling both the reaction equilibrium
and reactivities of the three components. Combination of CeO2 and 2-
cyanopyridine was an effective catalyst, providing various carbamates
including N-arylcarbamates in high selectivities.
2
2
R
NH2
2
R
OH
R1 OH
R2 NH2
This work
H2O
R2 NH2 R1 OH
H2O
H2O
O
R2 NH2
R1 OH
R2
H
H
N
H
N
O
N
O
R1
R1
R2
R1
R2
Transformation of CO2 to valuable chemicals can contribute not
only to CO2 fixation but also to effective CO2 utilization as a C1
resource. Carbamates attract much attention because of their
many applications to pharmaceuticals, agrochemicals, protecting
groups and polyurethanes.[1] Carbamates are traditionally
produced by using toxic and hazardous reagents such as
phosgene or CO[2], and environmentally-friendly alternative
catalytic methods have been intensively investigated: aminolysis
of organic carbonates[3], alcoholysis of ureas[4], coupling reaction
of dimethyl carbonate (DMC) and N,N’-substituted urea[5] and so
on. Recently, carbamate syntheses with CO2 as a carbonyl
source have been demonstrated using reactive reagents such as
N-tosylhydrazones[6], alkylhalides[7], metal alkoxides[8] and silicate
esters[9]. Compared with these approaches, carbamate synthesis
from CO2, amines and alcohols will be ideal (Scheme 1) because
the by-product is theoretically only water and all substrates are
easily available.[10] N-Arylcarbamates are the most useful among
various carbamates[11], however there are no effective catalyst
systems for the arylcarbamate synthesis from CO2, arylamines
and alcohols (yield≤10%, Table S1) owing to the inert character
of CO2, equilibrium limitation and side reactions as well as the low
reactivity (low basicity and nucleophilicity) of arylamines.[6] The
prospective byproducts are organic carbonates from CO2 and
alcohols, and N,N’-disubstituted ureas from CO2 and amines
(Scheme 1). Therefore, development of catalyst systems which
can sophisticatedly control the reactivities of the three
components and overcome the equilibrium limitation is desirable.
Recently, we found that combination of CeO2 and 2-cyanopyridine
was an effective catalyst system for the synthesis of dimethyl
carbonate (DMC) from CO2 + CH3OH[12] and cyclic carbonates[13]
and polycarbonates[14] from CO2 + diols. Urakawa and co-workers
also applied the combination catalyst system to the DMC
synthesis at high CO2 pressure.[15] The severe equilibrium was
O
O
O
Carbamate
Organic carbonate
Disubstituted urea
Target
Scheme 1. Direct and indirect routes for carbamate formation from CO2, amine
and alcohol.
overcome by removal of H2O from the reaction media through the
nitrile hydration over CeO2. In addition, 2-cyanopyridine can be
recovered by dehydration of the produced 2-picolinamide over
alkali metal-supported SiO2 catalysts.[12a,d] We envisioned that the
combination catalyst was applicable to the one-pot carbamate
synthesis from CO2, amines and alcohols.
At first, we applied the catalyst of CeO2 and 2-cyanopyridine to
methyl N-phenylcarbamate (MPC) formation from CO2, aniline
and CH3OH as a model reaction (Figure 1 and Table S2).
Fortunately, the reaction with CeO2 and 2-cyanopyridine
proceeded smoothly to reach >99% conversion at 8 h. The
selectivity to diphenyl urea (DPU) was very high (~80%) at 0 h
and it decreased with reaction time, in contrast, the MPC
selectivity increased to reach 98% at 6 h. These results indicate
that DPU is the intermediate. The maximum MPC yield was 97%
at 8 h, which is much higher than the reported ones (Table S1).
On the other hand, only CeO2 provided almost no conversion
(<1%, Table S3), and only 2-cyanopyridine hardly provided the
carbamate, and N-phenyl-pyridine-2-carboxamidine (amidine)
was mainly produced from 2-cyanopyridine and aniline (Table S4).
These results indicate that combination of CeO2 and 2-
cyanpyridine is essential for the reaction. From the time-course,
MPC will be formed by two consecutive reactions (Scheme 2): (I)
DPU formation from CO2 and aniline, and (II) MPC formation from
DPU and methoxy source. To clarify the advantage of the present
reaction system, the consecutive reactions were conducted step
by step (Figure S1). At the first step, DPU formation from aniline
and CO2 was performed using CeO2 and 2-cyanopyridine. The
reaction proceeded smoothly at the initial stage and leveled off at
about 80% conversion. After the 8 h reaction time, the autoclave
reactor was cooled to room temperature, and then methanol was
added to the reaction mixture and heated to 423 K. At the second
step, the conversion gradually increased, however stopped at
about 90%. The DPU selectivity decreased and MPC selectivity
increased to reach 91% yield at 4 h of the second step (total 13
h), which is lower than that of the present reaction system (97%
at 8 h). These results demonstrate that direct synthesis of MPC
[a]
Dr. M. Tamura, A. Miura, Dr. M. Honda, Y. Gu, Dr. Y. Nakagawa,
Prof. K. Tomishige
Graduate School of Engineering, Tohoku University
Sendai 980-8579 (Japan)
E-mail: mtamura@erec.che.tohoku.ac.jp,
tomi@erec.che.tohoku.ac.jp
[b]
M. Tamura
PRESTO, JST, Saitama 332-0012 (Japan)
Supporting information for this article is given via a link at the end of
the document.((Please delete this text if not appropriate))
This article is protected by copyright. All rights reserved.

10.1002/cctc.201801443
ChemCatChem
COMMUNICATION
H
CeO2 (0.34 g)
+ nitrile (75 mmol)
NH2
N
O
100
80
60
40
20
CO2
+
+
CH3OH
O
403 K, 6 h
Methyl N-phenylcarbamate (MPC)
5 MPa 5 mmol
100
75 mmol
90
80
70
60
50
40
30
20
10
0
0
4
8
Time / h
Figure 1. Time-course of MPC formation from CO2, aniline and CH3OH using
CeO2 and 2-cyanopyridine (ꢀ: conversion; : selectivity to MPC; ꢁ: selectivity
to DPU; ꢂ: selectivity to amidine). Reaction conditions: CeO2 0.17 g, aniline 5.0
mmol, 2-cyanopyridine 75 mmol, CH3OH 75 mmol, CO2 5 MPa (at r.t.), 423 K.
0
N
CN
N
N
CN
CN
N
N
N
CN
O
CN
CH3CN
Step (II): Carbamate formation from DPU and methoxy source
CN
CN
Nitrile
NH2
Figure 3. Screening of nitriles with CeO2 in MPC formation from CO2, aniline
and methanol. : aniline conversion. The bars represent selectivity. black: MPC,
white: DPU, stripe: amidine, gray: others. Others include N-methylaniline, N,N-
dimethylaniline and methyl N-phenyl-pyridine-2-carboximidate.
CH3OH
H
H
H
N
O
N
N
NH2
CO2
CH3
2
O
O
Alkyl N-phenylcarbamate
DPU
combination with 2-cyanopyridine. Effect of nitriles was also
H2O
investigated using CeO2 (Figure
3 and Table S6). 2-
Cyanopyridine, cyanopyrazine and methoxyacetonitrile showed
high conversion of aniline and selectivity to MPC and DPU, and
among these nitriles, 2-cyanopyridine showed higher conversion
and selectivity. Therefore, it was confirmed that combination of
CeO2 and 2-cyanopyridine was the most effective for the reaction.
The effect of 2-cyanopyridine amount was investigated by
changing 2-cyanopyridine amount from 5 to 75 mmol (Table S7).
In the case of 5 mmol aniline as a substrate, 5 mmol 2-
cyanopyridine is essential for removal of the H2O produced by the
reaction. When 50 mmol 2-cyanopyridine was used, the
conversion of aniline was similar to that in the case of 75 mmol 2-
cyanopyridine. However, the conversion decreased with
decreasing the 2-cyanopyridine amount from 50 mmol to 5 mmol,
because 2-cyanopyridine was exhausted by hydration with the
H2O produced from DMC formation. Therefore, an excess amount
of 2-cyanopyridine is essential for the reaction system.
Step (I): DPU formation from CO2 and aniline
Scheme 2 Formation of MPC from CO2, aniline and CH3OH
from CO2, aniline and methanol using CeO2 and 2-cyanopyridine
is preferable reaction system.
The performance with combination of various metal oxides and
2-cyanopyridine was compared (Figure 2 and Table S5). CeO2
provided much higher total selectivity to MPC and DPU with
comparatively high conversion than other metal oxides. On the
other hand, other metal oxides provided mainly amidine. These
results indicate that CeO2 is the only effective metal oxide in
H
Metal oxide (0.34 g)
+ 2-Cyanopyridine (75 mmol)
NH2
N
O
CO2
+
+
CH3OH
O
403 K, 6 h
Methyl N-phenylcarbamate
5 MPa 5 mmol
100
75 mmol
(MPC)
The scope of amines was studied using CeO2 and 2-
cyanopyridine (Scheme 3(A) and Table S8). Various p-substituted
aniline derivatives with electron-withdrawing groups such as F, Cl,
Br, and I or electron-donating groups such as methoxy, methyl,
and ethyl reacted to afford the corresponding carbamates in high
conversions and selectivities. o- or m-Toluidines were also
converted to the carbamates. Furfurylamine and 2-
(aminomethyl)thiophene, amines with a five-membered ring,
morpholine and N-methylpentylamine, secondary amines, and
tert-butylamine were also converted to the corresponding
carbamates in high conversions and selectivities. Note that 2,4-
diaminotoluene was converted to the dicarbamate in moderate
selectivity (54%), which is an important intermediate for the
synthesis of toluene-2,4-diisocyanate (2,4-TDI), a main raw
material for polyurethane[16]. Next, the scope of alcohols was also
investigated (Scheme 3(B) and Table S9). Linear and branched
alcohols reacted to provide the carbamates effectively. Benzyl
alcohol was also transformed to the corresponding carbamate,
which is an important scaffold for prodrugs such as
90
80
70
60
50
40
30
20
10
0
Metal oxide
Figure 2. Screening of metal oxides with 2-cyanopyridine in MPC formation
from CO2, aniline and methanol. : aniline conversion. The bars represent
selectivity. black: MPC, white: DPU, stripe: amidine, gray: others. Others include
N-methylaniline, N,N-dimethylaniline and methyl N-phenyl-pyridine-2-
carboximidate.
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10.1002/cctc.201801443
ChemCatChem
COMMUNICATION
R2
N
(A)
CeO2+2-cyanopyridine provided DPU selectively, in contrast, only
CeO2 and only 2-cyanopyridine showed almost no formation of
DPU, indicating that both CeO2 and 2-cyanopyridine are essential
for DPU formation. In MPC formation (Figure 4(b) and Table S12),
only CeO2 showed almost no activity. Surprisingly, only 2-
cyanopyridine showed high activity for the reaction. The
conversion with CeO2+2-cyanopyridine was about twice higher
than that with only 2-cyanopyridine. 2-Cyanopyridine promotes
MPC formation and combination of CeO2 with 2-cyanopyridine
further promotes the reaction.
The role of 2-cyanopyridine is important in DPU formation from
CO2 and aniline (Step (I)), because this step is the rate-
determining one. The equilibrium yield is below 1% as shown in
Figure 1(b). The reaction rate of hydration of 2-cyanopyridine was
measured with various H2O amount in the presence of CO2 and
aniline (Figure 5(a)), providing linear relationship between
log(reaction rate) and log(H2O amount). The reaction rate at
almost zero amount of H2O was calculated by extrapolation of the
relationship to be 360 mmolꢃh-1ꢃg-1, which is about 5-fold higher
than that of the carbamate synthesis (76 mmolꢃh-1ꢃg-1). This result
is in good agreement with the fact that the produced amount of 2-
picolinamide was almost equal to the sum of MPC, DPU, and
DMC amount in the MPC synthesis (Table S2) because these
products were accompanied by the equimolar amount of water.
Therefore, water was efficiently removed by hydration of 2-
cyanopyridine over CeO2, enabling the smooth reaction by
shifting the equilibrium to the product side. Moreover, the reaction
rates over CeO2 and CeO2+2-cyanopyridine were estimated
under the conditions where the conversion is below the
equilibrium to be 4.4 and 76 mmolꢃh-1ꢃg-1, respectively, (Figure
5(b)), indicating that addition of 2-cyanopyridine increased the
reaction rate of CeO2 by a factor of about 17, and the combination
of CeO2 and 2-cyanopyridine catalyzed DPU formation.
O
R1
R2
+
CeO2 (2 mmol)
2-Cyanopyridine (75 mmol)
423 K, 4 h(c12 h)
R1
NH
CO2
+
CH3OH
O
(Conv., Sel.)
5 MPa
5 mmol
75 mmol
aamine : CH3OH : CeO2: 2-cyanopyridine = 5 mmol : 75 mmol, 6 mmol, 75 mmol
bamine : CH3OH : CeO2: 2-cyanopyridine = 5 mmol : 150 mmol, 2 mmol, 75 mmol
camine : CH3OH : CeO2: 2-cyanopyridine = 2.5 mmol : 75 mmol, 6 mmol, 120 mmol
H
H
H
H
N
O
N
O
N
O
N
O
O
O
O
O
F
Cl
Br
(99%, 98%)
H
(99%, >99%)
(98%, >99%)
H
(98%, >99%)
H
H
N
O
N
O
N
O
N
O
O
O
O
O
O
I
(98%, 95%)
H
(>99%, >99%)
H
(98%, >99%)
(>99%, 96%)
O
O
N
O
N
O
S
O
N
O
N
O
H
O
O
H
(87%, >99%)a
(95%, >99%)
O
(>99%, >99%)
(>99%, 70%)
O
H
N
N
O
N
O
O
O
O
(>99%, >99%)
H
(>99%, >99%)
(97%, 84%)b
Byproducts(13%c)
O
H
O
N
N
H
H
O
N
NH2 H2
N
N
O
O
O
O
O
(>99%, 54%)c
H
NH2
N
O
(B)
CeO2 (2 mmol)
2-Cyanopyridine (75 mmol)
423 K
R
CO2
+
+ R-OH
O
(Time, Conv., Sel.)
5 MPa 5 mmol
75 mmol
H
N
H
H
O
N
O
N
O
O
O
O
(4 h, 99%, 98%)
H
(6 h, >99%, >99%)
(6 h, >99%, 99%)
H
N
N
O
O
O
O
(6 h, >99%, 93%)
(12 h, 96%, 95%)
H
H
N
H
N
O
O
N
O
O
O
O
The reaction route of MPC formation from CO2, aniline, and
CH3OH using CeO2+2-cyanopyridine catalyst system was
proposed in Scheme 4. First, DPU and H2O are formed from CO2
and aniline by CeO2+2-cyanopyridine. Second, alkolysis of DPU
with CH3OH provided MPC and aniline, which is also catalyzed by
(8 h, >99%, >99%)
(6 h, >99%, >99%)
(12 h, >99%, 93%)
H
N
H
N
O
O
O
O
(8 h, >99%, >99%)
(12 h, >99%, 74%)
Scheme 3. Scope of substrates in carbamate synthesis from
CO2, amines and alcohols using CeO2 and 2-cyanopyridine. (A)
Scope of amines. (B) Scope of alcohols.
(a)
(b)
H
H
NH2
N
N
CO2 + 2
5 MPa
+
CH3OH
O
5 mmol
2.5 mmol
75 mmol
PEG-daunorubicin conjugates for anti-cancer
CeO2 (0.17 g) and/or
2-cyanopyridine (75 mmol)
H
H
H
CeO2 (0.17 g) and/or
2-cyanopyridine (75 mmol)
403 K, 1 h
drugs[17]
.
N
N
N
O
403 K, 1 h
O
To confirm the methoxy source at the step (II) in
Scheme 2, reactions of DPU with CH3OH or DMC
were investigated in the presence of CO2 (Figure S2
and Table S10), because DMC was actually formed
from CO2 and methanol in the present reaction. The
DPU conversion with methanol was much higher than
that with DMC, and the formed MPC amount with
methanol was about 4-fold larger than that with DMC,
indicating that the reaction of DPU with CH3OH is the
main route. Next, to clarify the catalyst system in each
step, various catalysts (CeO2+2-cyanopyridine, only
CeO2, and only 2-cyanopyridine) were applied to the
DPU formation from aniline and CO2, and MPC
formation from DPU and CH3OH in the presence of
CO2. In DPU formation (Figure 4(a) and Table S11),
O
MPC
60
50
40
30
20
10
0
100
80
60
40
20
0
60
DPU100
50
40
30
20
10
0
80
60
40
20
0
CeO2
CeO2
2-Cyanopyridine
CeO2
+ 2-Cyanopyridine
2-Cyanopyridine
CeO2
+ 2-Cyanopyridine
Catalyst system
Catalyst system
Figure 4. Comparison of catalysts. (a) reaction of aniline with CO2. (b) reaction of DPU with
CH3OH in the presence of CO2.
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10.1002/cctc.201801443
ChemCatChem
COMMUNICATION
[1]
a) M. Aresta, Carbon Dioxide as Chemical Feedstock,
NH2
(a)
(b)
OH
O
CO2
+
+
Wiley-VCH, 2010; b) A. K. Ghosh, M. Brindisi, J. Med. Chem.
2015, 58, 2895-2940; c) H. Wang, Z. Xin, Y. Li, Top. Curr. Chem.
2017, 375, 49.
N
CN
N
CeO2 (0.003 g)
NH2
2-Picolinamide
5 MPa 200 mmol
75 mmol
+
H2O
H
2-propanol (75 mmol)
aniline (200 mmol)
CO2 1 MPa
CeO2 (0.01 g) and/or
2-Cyanopyridine (10 mmol)
N
O
30 mmol
4
5-30 mmol
[2]
K. Weissermel, H.-J. Harpe, Industrial Organic Chemistry,
O
423 K, 0-1h
423 K, 0-0.5 h
4th ed., Wiley-VCH, 2003.
Isopropyl N-phenylcarbamate
0.5
0.4
0.3
0.2
0.1
0
[3]
a) S. Grego, F. Arico, P. Tundo, Org. Process Res. Dev.
2013, 17, 679-683; b) R. Juárez, P. Concepción, A. Corma, V.
Fornés, H. García, Angew. Chem. 2010, 122, 1308-1312; Angew.
Chem. Int. Ed. 2010, 49, 1286-1290; c) S. Laursen, D. Combita,
A. B. Hungría, M. Boronat, A. Corma, Angew. Chem. 2012, 124,
4266-4269; Angew. Chem. Int. Ed. 2012, 51, 4190-4193; d) W.
Guo, J. Gónzalez-Fabra, N. A. G. Bandeira, C. Bo, A. W. Kleij,
Angew. Chem. 2015, 127, 11852-11856; Angew. Chem. Int. Ed.
2015, 54, 11686-11690.
CeO2+2-cyanopyridine
y=0.449x+2.56
(R2>0.99)
V = 76 mmol h-1 g-1
3
CeO2
V = 4.4 mmol h-1 g-1
[4]
R. Juárez, A. Corma, H. García, Top. Catal. 2009, 52,
1688-1695.
2
0
0.5
1
1.5
0
0.5
1
[5]
a) X. Guo, J. Shang, J. Li, L. Wang, Y. Ma, F. Shi, Synth.
Log(Amount of H2O / mmol)
Reaction time / h
Commun. 2011, 41, 1102-1111. b) J. Gao, H. Li, Y. Zhang, Y.
Zhang, Green Chem. 2007, 9, 572-576.
Figure 5. (a) Comparison of reaction rates over CeO2 and CeO2+2-cyanopyridine. (b)
Relationship between the reaction rate and H2O amount.
[6]
W. Xiong, C. Qi, H. He, L. Ouyang, M. Zhang, H. Jiang,
NH2
Angew. Chem. 2015, 127, 3127-3130; Angew. Chem. Int. Ed.
2015, 54, 3084-3087.
CH3OH
CeO2
2-cyanopyridine
+
H
H
H
[7]
D. Riemer, P. Hirapara, S. Das, ChemSusChem 2016, 9,
N
O
NH2
CO2
N
N
1916-1920.
2
2-Cyanopyridine
+ CeO2
O
O
[8]
a) N. Germain, I. Müller, M. Hanauer, R. A. Paciello, R.
DPU
Methyl N-phenylcarbamate
Baumann, O. Trapp, T. Schaub, ChemSusChem 2016, 9, 1586-
1590; b) H.-Y. Yuan, J.-C. Choi, S.-Y. Onozawa, N. Fukaya, S. J.
Choi, H. Yasuda, T. Sakakura, J. CO2 Util. 2016, 16, 282-286; c)
J.-C. Choi, H.-Y. Yuan, N. Fukaya, S.-y. Onozawa, Q. Zhang, S.
j. Choi, H. Yasuda, Chem. Asian J. 2017, 12, 1297-1300.
(MPC)
H2O
CN
O
N
N
NH2
CeO2
2-Cyanopyridine
Picolinamide
[9]
a) N. Germain, M. Hermsen, T. Schaub, O. Trapp, Appl.
Scheme 4. Proposed reaction route of MPC formation from CO2, aniline and methanol using
CeO2 and 2-cyanopyridine.
Organomet. Chem. 2017, 31. b) Q. Zhang, H.-Y. Yuan, N. Fukaya,
H. Yasuda, J.-C. Choi, ChemSusChem 2017, 10, 1501-1508; c)
Q. Zhang, H.-Y. Yuan, N. Fukaya, J.-C. Choi, ACS Sustainable
Chem. Eng. 2018, 6, 6675-6681; d) Q. Zhang, H.-Y. Yuan, N. Fukaya, H.
Yasuda, J.-C. Choi, Green Chem. 2017, 19, 5614-5624.
combination of CeO2 and 2-cyanopyridine. CeO2-catalyzed
hydration of 2-cyanopyrdine effectively proceeded under the
same reaction conditions, which can remove the produced H2O
from the reaction media to shift the equilibrium of DPU formation
to the product side. The MPC formation from DPU and methanol
also plays a role in shifting the equilibrium by decreasing the DPU
amount in the reaction media. In addition, smooth MPC formation
also enabled high selectivity by maintaining the low concentration
of DPU and amidine.
A new one-pot selective synthesis of carbamates from CO2,
amines and alcohols was demonstrated by using the combination
catalyst of CeO2 and 2-cyanopyridine. This method enables
sequential formation of C-N and C-O bonds by the drastic shift of
the reaction equilibrium in N,N’-substituted urea formation and
remarkable catalytic function of CeO2 and 2-cyanopyridine in
exchange-reaction of C-N and C-O bonds, providing various
carbamates including N-arylcarbamates in high selectivities.
[10] a) M. Abla. J.-C. Choi, T. Sakakura, Chem. Commun. 2001, 2238-2239;
b) A. Ion, C. V. Doorslaer, V. Parvulescu, P. Jacobs, D. D. Vos, Green
Chem. 2008, 10, 111-116; c) M. Honda, S. Sonehara, H. Yasuda, Y.
Nakagawa, K. Tomishige, Green Chem. 2011, 13, 3406-3413.
[11] R. H. Heyn, I. Jacobs, R. H. Carr, Adv. Inorg. Chem. 2014, 66, 83-115.
[12] a) M. Honda, M. Tamura, Y. Nakagawa, S. Sonehara, K. Suzuki, K.-i.
Fujimoto, K. Tomishige, ChemSusChem 2013, 6, 1341-1344; b) M.
Honda, M. Tamura, Y. Nakagawa, K. Nakao, K. Suzuki, K. Tomishige, J.
Catal. 2014, 318, 95-107; d) M. Honda, M. Tamura, Y. Nakagawa, K.
Tomishige, Catal. Sci. Technol. 2014, 4, 2830-2845.
[13] M. Honda, M. Tamura, K. Nakao, K. Suzuki, Y. Nakagawa, K. Tomishige,
ACS Catal. 2014, 4, 1893-1896.
[14] M. Tamura, K. Ito, M. Honda, Y. Nakagawa, H. Sugimoto, K. Tomishige,
Sci. Rep. 2016, 6, 24038.
[15] a) A. Bansode, A. Urakawa, ACS Catal. 2014, 4, 3877-3880; b) D. Stoian,
A. Bansode, F. Medina, A. Urakawa, Catal. Today 2017, 283, 2-10.
[16] P. Król, Prog. Mater. Sci. 2007, 52, 915-1015.
[17] R. B. Greenwald, Y. H. Choe, J. McGuire, C. D. Conover, Adv. Drug
Delivery Rev. 2003, 55, 217-250.
Acknowledgements
This work was supported by JST PRESTO Grant Number
JPMJPR15S5, Japan.
Keywords: carbon dioxide • carbamate • ceria •heterogeneous
catalyst • arylamine
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10.1002/cctc.201801443
ChemCatChem
COMMUNICATION
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COMMUNICATION
One-pot selective syntheses of
carbamates directly from CO2,
alcohols and amines was
Masazumi Tamura,* Ayaka Miura,
Masayoshi Honda, Yu Gu, Yoshinao
Nakagawa, and Keiichi Tomishige*
substantiated by using the
Page No. – Page No.
combination catalyst of CeO2 and 2-
cyanopyridine. The catalyst was
applicable to various alcohols and
amines including arylamines,
providing the corresponding
carbamates, particularly N-
Direct catalytic synthesis of N-
arylcarbamates from CO2, anilines
and alcohols
arylcarbamates, in high selectivities.
This article is protected by copyright. All rights reserved.