Direct hydrogenation of nitroaromatics and one-pot amidation with carboxylic acids over platinum nanowires

Article abstract of DOI:10.1002/chem.201002801

A novel ultrathin platinum nanowire with uniform length and a diameter of 1.5 nm was synthesized by acidic etching of FePt nanowire in methanol. This nanowire was characterized by high-resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD) data indicated that the main plane is (111). The ability of this nanowire to catalyze the heterogeneous hydrogenation of nitroaromatics to give the corresponding amines has been investigated. The catalyst showed satisfactory activity in various solvents under mild conditions and showed excellent stability. The catalytic performance was also evaluated in the one-pot reduction of nitroaromatics and amidation with carboxylic acids under a hydrogen atmosphere at 100°C. These methods for the hydrogenation of nitroaromatics and the direct amidation of nitroaromatics with carboxylic acids are simple, economical, and environmentally benign, and have practical advantages for the synthesis of amines and amides without the production of toxic byproducts.

Full text of DOI:10.1002/chem.201002801

FULL PAPER
DOI: 10.1002/chem.201002801
Direct Hydrogenation of Nitroaromatics and One-Pot Amidation with
Carboxylic Acids over Platinum Nanowires
[
a]
Min Li, Lei Hu, Xueqin Cao, Haiyan Hong, Jianmei Lu,* and Hongwei Gu*
Abstract: A novel ultrathin platinum
nanowire with uniform length and a di-
ameter of 1.5 nm was synthesized by
acidic etching of FePt nanowire in
methanol. This nanowire was charac-
terized by high-resolution transmission
electron microscopy (HRTEM). X-ray
diffraction (XRD) data indicated that
the main plane is (111). The ability of
this nanowire to catalyze the heteroge-
neous hydrogenation of nitroaromatics
to give the corresponding amines has
been investigated. The catalyst showed
satisfactory activity in various solvents
under mild conditions and showed ex-
cellent stability. The catalytic perfor-
mance was also evaluated in the one-
pot reduction of nitroaromatics and
amidation with carboxylic acids under
a
hydrogen atmosphere at 1008C.
These methods for the hydrogenation
of nitroaromatics and the direct amida-
tion of nitroaromatics with carboxylic
acids are simple, economical, and envi-
ronmentally benign, and have practical
advantages for the synthesis of amines
and amides without the production of
toxic byproducts.
Keywords: amides · heterogeneous
catalysis · hydrogenation · nanopar-
ticles · platinum
Introduction
drawbacks, such as toxic reactive reagents, shock sensitivity,
poor atom economy, or complex purification procedures.
[5]
The selective reduction of nitrobenzene and its derivatives
is one of the most important industrial reactions used for
the synthesis of the corresponding amines. These amines are
important intermediates in the production of many pharma-
ceuticals, agrochemicals, dyes, polymers, and rubber materi-
The most desirable solution method for amide synthesis is
direct condensation between an amine and a carboxylic
[6]
acid, which has been known since 1858. The amine used in
this process is often obtained by hydrogenation of the corre-
sponding nitro-compound with a catalyst. However, this pro-
cedure requires elevated temperatures owing to the forma-
tion of unreactive carboxylate-ammonium salts as the inter-
[
1]
als. Although numerous methods have been developed for
amine synthesis, the search for new, facile, chemoselective,
cost-effective, and environmentally friendly procedures that
avoid the use of expensive and hazardous stoichiometric re-
ducing agents in large excess has still attracted extensive in-
[7,8]
[8]
mediates.
Recently, Whiting and co-workers reviewed
the use of efficient boron-based catalysts for this transfor-
mation. However, these catalysts also display some disad-
vantages: synthesis of the boron complex catalysts is not
trivial, and separation of the products from the reaction
mixture can be difficult because they are homogeneous cata-
lysts. Therefore, it is desirable to perform direct amide con-
densation reactions between carboxylic acids and amines
under mild, catalytic conditions.
[2]
terest. Amides are one of the most prevalent functional
groups in both small and complex synthetic or naturally oc-
curring molecules, and they are also used widely by medici-
[3]
nal chemists. Traditional synthetic procedures involve the
reaction of amines with pre-activated carboxylic acid deriva-
tives, such as acyl halides, anhydrides, esters, acyl azides, or
by dicyclohexylcarbodiimide (DCC)/N,N’-carbonyldiimida-
Additionally, one-pot reactions have been developed as
economical, environmentally friendly, and efficient new syn-
[4]
zole type activation. Each of these methods has significant
[9]
thetic processes in organic chemistry. The reductive amida-
tion process is also one of the most powerful transforma-
tions for the direct conversion of carboxylic acids into
+
+
[
a] M. Li, L. Hu, X. Cao, H. Hong, Prof. Dr. J. Lu, Prof. Dr. H. Gu
Key Laboratory of Organic Synthesis of Jiangsu Province
Key Laboratory of Absorbent Materials
and Techniques for Environment
[10]
amides using simple operations.
In the present work, we describe a highly effective plati-
num nanowire (NW) catalyst for hydrogenation of nitroaro-
matics to the corresponding amines, and report a one-pot
amidation of nitroaromatics with carboxylic acids under a
hydrogen atmosphere (1 atm) at 1008C. This catalyst shows
excellent activity and stability for both hydrogenation of ni-
troaromatics and one-pot amidation reactions under mild
conditions. The latter offers compelling advantages over
other amide syntheses, because it does not require isolation
of the amine intermediate.
College of Chemistry
Chemical Engineering and Materials Science
Soochow University
Suzhou, 215123 (P.R. China)
Fax : (+86)6588-0905
E-mail: hongwei@suda.edu.cn
lujm@suda.edu.cn
+
[
] These authors contributed equally to this work.
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201002801.
Chem. Eur. J. 2011, 17, 2763 – 2768
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2763

Results and Discussion
Table 1. Hydrogenation of nitrobenzene over Pt NW in different
solvents.
[
a]
Pt NWs with uniform length and a diameter of 1.5 nm were
synthesized by acidic etching of FePt NWs, which were pre-
pared by following the methodology described by Sun and
[b]
Solvent
CH OH
OH
T [8C]
t [h]
Yield [%]
1
2
3
4
5
6
7
8
3
40
40
40
40
40
40
80
80
1
3
3
99
98
99
98
93
99
99
99
C
2
H
5
[11]
co-workers.
Transmission electron microscope (TEM)
H O
2
images of the representative FePt and Pt NWs, and high-res-
olution TEM (HRTEM) images of Pt NWs are shown in
Figure 1. The images in Figure 1A and B show NWs approx-
A
H
U
G
R
N
N
2
H
5
)
3
N
5
17
17
19
19
2
2
toluene
n-heptane
[
a] Reaction conditions: nitrobenzene (1 mmol) and solvent (2 mL) were
stirred magnetically under H (1 atm) in a reaction tube in the presence
2
of Pt NW catalyst (0.01 mmol). [b] Determined by GC and GC-MS anal-
ysis using 1-tert-butylbenzene as internal standard.
Table 1 shows the hydrogenation of nitrobenzene in differ-
ent solvents. Methanol (Table 1, entry 1) was found to be
the best solvent for this reaction, requiring lower tempera-
ture (408C) and shorter reaction time (1 h) than reactions
performed in other solvents. Water, which is clearly an envi-
ronmentally benign solvent, can also be used for this reac-
tion; in this case, a high yield (99%) was obtained in 3 h at
408C (Table 1, entry 3). Use of Pt NWs as catalyst gave
good activity with a high yield of aniline regardless of
whether the solvent was polar (Table 1, entries 1–3) or non-
polar (Table 1, entry 8). However, when acetic acid was
used as the solvent in the hydrogenation of nitrobenzene at
1008C, N-phenylacetamide (A) was detected as the main
product, with a small quantity of aniline (C) and N-acetyl-
N-phenylacetamide (B) (Scheme 1) being observed as minor
Figure 1. TEM images of A) FePt NWs; B) Pt NWs, and c) HRTEM
image of Pt NWs.
imately 200 nm in length. The diameters of the FePt and Pt
NWs are 1–2 nm. Figure 1C shows the HRTEM image of Pt
NWs. The interplanar distance between the (111) planes is
[12]
0
.218 nm, which matches that observed in Pt crystals. The
X-ray diffraction (XRD) spectrum (Figure 2) also shows
that the main plane is (111). An energy dispersive spectrum
(
EDS) (see Figure S1 in the Supporting Information), col-
lected in different regions, showed that Pt is the main com-
ponent, with trace amounts of Fe, after acidic etching of
FePt NWs.
Initially, the catalytic efficiency and stability of the Pt
NWs were tested in the hydrogenation of nitroaromatics to
their corresponding amines. Nitrobenzene was chosen as a
model substrate for optimization of the reaction conditions.
Scheme 1. One-pot reductive amidation of acetic acid with nitrobenzene.
products. N-Phenylacetamide and N-acetyl-N-phenylaceta-
mide may be obtained through a two-step reaction: 1) the
reduction of nitrobenzene to aniline over the Pt NWs, and
2
) the amidation of acetic acid with aniline over the Pt NWs
under the same reaction conditions. The acetic acid was thus
used as both reactant and solvent.
To elucidate the reaction mechanism, the reaction of ni-
trobenzene and acetic acid was monitored by GC analysis
using 1-tert-butylbenzene as internal standard (Figure 3). Ni-
trobenzene was first reduced to aniline as the reaction inter-
mediate. Amidation proceeded through the reduction of ni-
trobenzene. Upon completion of the reduction, a small
quantity of N-acetyl-N-phenylacetamide was detected as a
byproduct (see Figure S2 in the Supporting Information). In-
creasing the reaction time did not increase the yield of
N-acetyl-N-phenylacetamide.
Figure 2. XRD spectrum of Pt NW and the standard powder pattern for
Pt.
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Hydrogenation/Amidation with Pt Nanowire
FULL PAPER
Table 3. Hydrogenation of nitrobenzene on Pt NW in acetic acid at dif-
[
a]
ferent temperatures.
[
b]
T [8C]
Conversion [%]
Selectivity (A/B/C) [%]
1
2
3
4
40
60
80
11
100
100
100
0:0:100
6:3:91
81:6:13
99:1:0
100
[
(
a] Reaction conditions: nitrobenzene (1 mmol), acetic acid (2 mL), H
1 atm), Pt NW catalyst (0.01 mmol), 24 h. [b] Determined by GC and
GC-MS analysis using 1-tert-butylbenzene as internal standard.
2
Conditions for the hydrogenation of nitrobenzene to ani-
line were optimized with methanol as solvent. Using a reac-
tion temperature of 408C, the effect of substrate type was
investigated; Table 4 summarizes the main products and
yields under these conditions. Nitroaromatics containing
functional groups were also successfully reduced under
these reaction conditions. High yields from o-, m-, and p-
methyl nitrobenzene (Table 4, entries 1–3) showed the good
regioselectivity obtained with the Pt NWs as catalysts, and
the yields of the corresponding anilines were higher than
Figure 3. Reaction of nitrobenzene and acetic acid at 1008C under a hy-
drogen atmosphere over Pt NW (the structures of A, B, C are shown in
Scheme 1).
Water was considered to be an excellent solvent for the
reduction of nitrobenzene to aniline (Table 1, entry 3);
therefore, several experiments were conducted using various
amounts of water in acetic acid as the solvent for the one-
pot reduction and amidation of nitrobenzene to N-phenyl-
acetamide (Table 2). The addition of water generated aniline
[
a]
Table 4. Hydrogenation of nitroaromatics on Pt NW in methanol.
Substrate
Product
t
[
Yield
[%]
[
b]
h]
5
[
a]
Table 2. Hydrogenation of nitrobenzene on Pt NW in acetic acid.
[b]
[b]
Acetic acid [mmol] Conversion [%]
Selectivity (A/B/C) [%]
1
2
99
1
2
3
4
5
6
7
35
23
17
7
1
1
100
100
100
100
98
99:1:0
86:1:13
87:1:12
61:1:38
21:0:77
19 (A)
trace
5
97
3
4
5
5
5
5
5
5
5
5
99
78
98
98
99
98
96
99
[
[
c]
95
trace
d]
1
[
a] Reaction conditions: nitrobenzene (1 mmol) and solvent (acetic acid
and water 2 mL), H (1 atm), Pt NW catalyst (0.01 mmol), 1008C, 24 h.
b] Determined by GC and GC-MS analysis using 1-tert-butylbenzene as
an internal standard. [c] Aniline (1 mmol) was used as the substrate.
d] Aniline (1 mmol) was used as the substrate without Pt nanowire cata-
5
2
[
6
[
7
lyst.
8
9
as a byproduct but did not deactivate the hydrogenation of
nitrobenzene. Acetic acid was found to be the most suitable
solvent for high selectivity of N-phenylacetamide (Table 2,
entry 1). When the molar ratio of acetic acid and nitroben-
zene was 1:1 in water, 21% of N-phenylacetamide was ob-
tained as the product (Table 2, entry 5).
10
1
1
1
2
5
5
98
99
Nitrobenzene and acetic acid were used to probe the ac-
tivity of the Pt NW catalyst at different temperatures. It was
found that the reaction temperature is critical in the range
of 40–1008C (Table 3) with higher temperatures favoring the
one-pot amidation of nitrobenzene. A reaction temperature
of 1008C resulted in a yield of 99% N-phenylacetamide. At
13
5
5
97
1
4
99
88
[c]
15
24
4
08C, the main product was aniline. The selectivity of
[
(
a] Reaction conditions: nitroaromatics (1 mmol), methanol (2 mL), H
1 atm), Pt NW catalyst (0.01 mmol), 408C. [b] Determined by GC and
2
N-phenylacetamide increased with increasing temperature.
Temperature thus mainly influences the later amidation step
rather than the former hydrogenation step.
GC-MS analysis using 1-tert-butylbenzene as internal standard. [c] Re-
action conducted at 9 atm.
Chem. Eur. J. 2011, 17, 2763 – 2768
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www.chemeurj.org
2765

J. Lu, H. Gu et al.
9
7%. Functional groups did not influence the reduction of
Table 6. One-pot reductive amidation of nitrobenzene with carboxylic
[
a]
acid over Pt NW.
Carboxylic
acid (pK
the nitroaromatics significantly because good chemoselectiv-
ity was observed for substrates containing electron-donating
or electron-withdrawing groups (Table 4, entries 4–10). Hy-
drogenation of m- and p-dinitrobenzene also gave excellent
yields and produced the corresponding dianilines (Table 4,
entries 11 and 12) with yields of 98 and 99%, respectively.
Nitroaromatics with a sterically bulky group also produced
high yields (Table 4, entries 13 and 14). Moreover, hydroge-
nation was possible using unactivated aliphatic nitro com-
pounds, with the corresponding amine being obtained with
an excellent yield of 88% (Table 4, entry 15).
Product
Conv-
ersion [%]
Yield
[%]
[
b]
a
)
1
2
CH
CH
3
COOH (4.76)
100
98
99 (95)
90 (88)
3
2
CH COOH (4.88)
3
4
5
CH
CH
3
A
T
N
T
E
N
N
(CH
2
2
)
)
2
COOH (4.82)
3
COOH (4.82)
2
COOH (4.84)
100
97
95
Use of the Pt NWs as catalyst also showed good regiose-
lectivity in the one-pot amidation, and the yield of the cor-
responding amide was higher than 92% (Table 5, entries 1–
3
A
H
U
G
R
N
U
G
96
3). Nitroaromatics containing both electron-donating and
A( CH
H
U
G
R
N
U
G
3
)
2
CH
100
84 (82)
electron-withdrawing groups were converted into the corre-
sponding amides in good to high yields (Table 5, entries 4–
8
).
[
c]
6
7
HCOOH (3.77)
99
99
70
41
Table 5. One-pot reductive amidation of nitroaromatics with acetic acid
over Pt NW.
[
a]
[d]
3
CF COOH (0.23)
Substrate
Product
Conv-
ersion [%]
Yield
[%]
[
b]
[a] Reaction conditions: nitrobenzene (1 mmol), carboxylic acid (2 mL),
(1 atm), Pt NW catalyst (0.01 mmol), 1008C, 24 h. [b] Determined by
H
2
GC and GC-MS analysis using 1-tert-butylbenzene as internal standard.
The values within parentheses are the yields of the isolated products.
[
c]
1
2
99
94
[
c] Reaction conducted at 808C. [d] Reaction conducted at 608C.
100
96
92
inactive carboxylate salt or unreacted nitrobenzene. Howev-
3
4
5
100
100
99
er, acids with lower pK values, such as formic acid (3.77)
a
and trifluoroacetic acid (0.23), gave lower yields of the cor-
responding amides; this is because the stronger acids easily
formed inactive carboxylate salts with anilines. The lower
reaction temperatures, which were determined according to
the boiling points of the acids used, may also have influ-
enced the yield of the amide.
We attempted to use nitrobenzene with different function-
al groups (including 1-methoxy-4-nitrobenzene and 1-
chloro-4-nitrobenzene) as the substrate in a range of carbox-
ylic acids under the same reaction conditions. Good yields
were obtained from 1-methoxy-4-nitrobenzene (88–98%;
see Table S1 in the Supporting Information). However, the
yields were lower for the 1-chloro-4-nitrobenzene (47–91%;
see Table S2 in the Supporting Information), especially
when 2-methylpropanoic acid was used in the reaction, and
91 (88)
94 (94)
82
6
7
8
100
82
– (78)
98
100
[
(
[
a] Reaction conditions: nitroaromatic (1 mmol), acetic acid (2 mL), H
1 atm), Pt NW catalyst (metal/nitrobenzene mol ratio 1%), 1008C, 24 h.
b] Determined by GC and GC-MS analysis using 1-tert-butylbenzene as
internal standard. The values within parentheses are the yields of the iso-
lated products. [c] Reaction time: 40 h.
2
4
7% amide was obtained with a higher quantity of amine.
To demonstrate the unique reactivity and selectivity of
To determine the scope and limitations of the use of car-
boxylic acids in the reduction of nitrobenzene and the one-
pot amidation under a hydrogen atmosphere over Pt NW
catalyst, some of the liquid acids were chosen as substrates
this Pt NW catalyst, two alternative types of Pt nanomateri-
als, nanoparticles and nanorods were synthesized as control
catalysts for the amide formation using nitrobenzene and
acetic acid as the reactants (see Figure S3 and S4 in the Sup-
porting Information). The amide yield was 72% in the
nanoparticle system (ca. 2 nm in diameter ), and 87% in
the nanorod system (ca. 2 nm in diameter and ca. 20 nm in
length; see Table S3 in the Supporting Information). When
acetic acid was used as the solvent and substrate without the
(
Table 6). The Pt NW catalyst showed excellent activity
when acetic acid, propanoic acid, n-butyric acid, or n-penta-
noic acid were used, and high yields of the corresponding
amides (>90%) were obtained (Table 6, entries 1–4).
[13]
2-Methylpropanoic acid gave a yield of 84% (Table 6, en-
tries 5). Aniline was formed as a byproduct instead of the
2766
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Hydrogenation/Amidation with Pt Nanowire
FULL PAPER
Pt NW catalyst, the amide was also obtained as the main
product (see Table S4, entry 3 in the Supporting Informa-
tion). When n-butyric acid was used as the solvent and sub-
strate without the Pt NW catalyst, the yield of amide was
decreased and only 70% amide was obtained (see Table S4,
entry 6 in the Supporting Information). However, when the
molar ratio of aniline and acetic acid was 1:1 in water
under very mild conditions. Moreover, the reduction of ni-
troaromatics to the corresponding amines and the one-pot
amidation of nitroaromatics with carboxylic acids under a
hydrogen atmosphere were carried out in one-pot without
isolating the amine intermediates. Further studies on the re-
action process have revealed that the reduction of nitroaro-
matics was faster than the amidation and resulted in high
yields of the corresponding amides.
(
Table 2, entries 6 and 7), aniline could react with the car-
boxylic acid over Pt NW catalyst with a 19% yield, but no
amide was detected by GC analysis without Pt NW catalyst.
Aniline was also used as the substrate in the reaction. When
aniline (the intermediate) was used as the substrate instead
of nitrobenzene in acetic acid (or n-butyric acid; see
Table S4, entries 2 and 5 in the Supporting Information), the
amides were also formed as the main product with yields of
Experimental Section
Typical procedure for reductive amidation of carboxylic acids with nitro-
aromatics: Catalyst testing was carried out in a sealed tube. Pt NWs in
hexane were added and the hexane was evacuated by pressure reduction.
Nitroaromatics, carboxylic acid and 1-tert-butylbenzene were added to
the reaction tube and the tube was sealed. The reaction tube was thrice
evacuated and flushed with hydrogen and the reaction was carried out at
the appropriate temperature under a hydrogen atmosphere. The resulting
product mixtures were analyzed by gas chromatography (GC) (VARIAN
CP-3800 GC, HP-5 capillary column, FID detector) and gas chromatog-
raphy mass spectrometry (GC-MS) (VARIAN 450-GC and VARIAN
240-GC) equipped with a CP8944 capillary column (30 m ꢁ 0.25 mm)
and an FID detector. Some amides were purified by flash chromatogra-
96% (90%), which is slightly lower than observed when ni-
trobenzene was used (see Table S4, entries 1 and 4 in the
Supporting Information). These results demonstrate that the
nitroaromatics are first reduced to amines and then to
amides as the final product over Pt NW catalyst in one-pot,
without isolation of the amine intermediates.
The catalyst could be recovered by simple centrifugation
and washing with methanol. It could be reused at least six
times without significant loss of activity (98%) and there
were no measurable amounts of Pt in the reaction solution
as determined by atomic absorption spectrometry
1
13
phy and characterized by H NMR and C NMR spectroscopy and TOF-
MS.
(
Figure 4).
Acknowledgements
H.W.G. acknowledges financial support from the National Natural Sci-
ence Foundation of China ACHUNTGRNENUG( 21003092), the National Science Foundation
of Jiangsu Province (BK2008158), and the New Faculty Start Foundation
of Soochow University; J.M.L. acknowledges financial support from the
National Natural Science Foundation of China (20876101).
[
1] a) F. Zhao, Y. Ikushima, M. Arai, J. Catal. 2004, 224, 479–483;
b) C. H. Lia, Z. X. Yua, K. F. Yao, S. F Ji, J. Liang, J. Mol. Catal. A
2
005, 226, 101–105; c) A. Corma, P. Serna, Nat. Protoc. 2007, 1,
2
590–2595; d) J. F. Knifton, J. Org. Chem. 1976, 41, 1200–1206.
[
2] a) L. Liu, B. Qiao, Z. Chen, J. Zhang, Y. Deng, Chem. Commun.
009, 653–655; b) S. Fꢂldner, R. Mild, H. I. Siegmund, J. A.
2
Schroeder, M. Gruber, B. Kçnig, Green Chem. 2010, 12, 400–406;
c) R. G. de Noronha, C. C. Rom¼o, A. C. Fernandes, J. Org. Chem.
2
009, 74, 6960–6964; d) L. He, L. C. Wang, H. Sun, J. Ni, Y. Cao,
H. Y. He, K. N. Fan, Angew. Chem. 2009, 121, 9702–9705; Angew.
Chem. Int. Ed. 2009, 48, 9538–9541; e) F. Zhao, R. Zhang, M. Chat-
teriee, Y. Ikushima, M. Arai, Adv. Synth. Catal. 2004, 346, 661-668;
f) M. Boronat, P. Concepciꢃn, A. Corma, S. Gonzꢄlez, F. Illas, P.
Serna, J. Am. Chem. Soc. 2007, 129, 16230–16237; g) B. Li, Z. Xu, J.
Am. Chem. Soc. 2009, 131, 16380–16382.
Figure 4. Cycling of Pt NWs from the one-pot reaction. Reaction condi-
tions: Pt NWs (0.01 mmol), nitrobenzene (1 mmol), acetic acid (2 mL),
1
008C; reaction time of each cycle: 24 h.
[
3] a) C. A. G. N. Montalbetti, V. Falque, Tetrahedron 2005, 61, 10827–
1
2
2
0852; b) J. M. Humphrey, A. R. Chamberlin, Chem. Rev. 1997, 97,
243–2266; c) F. Albericio, Curr. Opin. Chem. Biol. 2004, 8, 211–
21; d) A. Rimola, S. Tosoni, M. Sodupe, P. Ugliengo, Chem. Phys.
Conclusion
The Pt NW developed here was found to be a useful hetero-
geneous catalyst for the hydrogenation of nitroaromatics
and direct amide synthesis from nitroaromatics and carbox-
ylic acids in a one-pot reaction. Whereas most of the report-
ed direct amidation reactions of amines and acids require
harsh conditions, such as high temperature, it is worth
noting that the reactions in this new approach proceeded
Lett. 2005, 408, 295–301.
[4] a) E. Bouron, G. Goussard, C. Marchand, M. Bonin, X. Panne-
coucke, J. C. Quirion, H. P. Husson, Tetrahedron Lett. 1999, 40,
7
4
1
227–7230; b) U. Ragnarsson, L. Grehn, Acc. Chem. Res. 1998, 31,
94–501; c) B. Belleau, G. Malek, J. Am. Chem. Soc. 1968, 90,
651–1652; d) R. Chicharro, S. Castro, J. L. Reino, V. J. Aran, Eur.
J. Org. Chem. 2003, 2314–2326; e) F. Fazio, C. H. Wong, Tetrahe-
dron Lett. 2003, 44, 9083–9085; f) M. Mikolajczyk, P. Kielbasinski,
Chem. Eur. J. 2011, 17, 2763 – 2768
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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2767

J. Lu, H. Gu et al.
Tetrahedron 1981, 37, 233–284; g) R. Paul, W. Anderson, J. Am.
Chem. Soc. 1960, 82, 4596–4600.
5] J. W. Comerford, J. H. Clark, D. J. Macquarrie, S. W. Breeden,
Chem. Commun. 2009, 2562–2564.
6] J. A. Mitchell, E. E. Reid, J. Am. Chem. Soc. 1931, 53, 1879–1883.
7] a) B. S. Jursic, Z. Zdravkovski, Synth. Commun. 1993, 23, 2761–
Chem. 2010, 122, 1700–1704; Angew. Chem. Int. Ed. 2010, 49, 1656–
1660; d) B. Sreedhar, P. S. Reddy, D. K. Devi, J. Org. Chem. 2009,
74, 8806–8809; e) Y. Yamane, X. Liu, A. Hamasaki, T. Ishida, M.
Haruta, T. Yokoyama, M. Tokunaga, Org. Lett. 2009, 11, 5162–5165.
[10] T. L. Ho, J. Org. Chem. 1977, 42, 3755–3755.
[11] C. Wang, Y. L. Hou, J. Kim, S. H. Sun, Angew. Chem. 2007, 119,
6449–6451; Angew. Chem. Int. Ed. 2007, 46, 6333–6335.
[12] S. Sun, G. Zhang, Y. Zhong, H. Liu, R. Li, X. Zhou, X. Sun, Chem.
Commun. 2009, 7048–7050.
[
[
[
2770; b) L. J. Goossen, D. M. Ohlmann, P. P. Lange, Synthesis 2008,
160–164; c) L. Perreux, A. Loupy, F. Volatron, Tetrahedron 2002,
58, 2155–2162.
[
[
8] H. Charville, D. Jackson, G. Hodges, A. Whiting, Chem. Commun.
010, 46, 1813–1823.
9] a) K. Ekoue-Kovi, C. Wolf, Chem. Eur. J. 2008, 14, 6302–6315;
b) A. Corma, T. Rꢃdenas, M. J. Sabater, Chem. Eur. J. 2010, 16,
[13] C. Wang, H. Daimon, T. Onodera, O. Koda, S. Sun, Angew. Chem.
2008, 120, 3644–3647; Angew. Chem. Int. Ed. 2008, 47, 3588–3591.
2
Received: September 30, 2010
2
54–260; c) Y. Shiraishi, Y. Sugano, S. Tanaka, T. Hirai, Angew.
Published online: January 26, 2011
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