Copper-catalyzed amination of aryl halides with aqueous ammonia under mild conditions

Article abstract of DOI:10.1002/cjoc.201201240

A Cu(I) generated in situ from CuSO₄·5H ₂O/sodium ascorbate catalyzed cross-coupling reaction of aryl halides with aqueous ammonia for the synthesis of primary aromatic amines has been developed. Key to the success included the application of aqueous ammonia under a homogeneous condition. A Cu(I) generated in situ from CuSO₄· 5H₂O/sodium ascorbate catalyzed cross-coupling reaction of aryl halides with aqueous ammonia for the synsthesis of primary aromatic amines has been developed. Key to the success included the application of aqueous ammonia under a homogeneous condition.

Full text of DOI:10.1002/cjoc.201201240

FULL PAPER
DOI: 10.1002/cjoc.201201240
Copper-Catalyzed Amination of Aryl Halides with Aqueous
Ammonia under Mild Conditions
Zhengjun Quan, Haidong Xia, Zhang Zhang, Yuxia Da, and Xicun Wang*
Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education,
Lanzhou, Gansu 730070, China
Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal
University, Anning East Road 967#, Lanzhou, Gansu 730070, China
A Cu(I) generated in situ from CuSO4•5H2O/sodium ascorbate catalyzed cross-coupling reaction of aryl halides
with aqueous ammonia for the synthesis of primary aromatic amines has been developed. Key to the success in-
cluded the application of aqueous ammonia under a homogeneous condition.
Keywords amination, aqueous ammonia, copper catalysis, aryl halides, primary anilines
Introduction
herein we present the CuSO4•5H2O/sodium ascorbate-
catalyst systems for the amination of aryl halides with
aqueous ammonia under mild conditions.
Ammonia is one of the most attractive sources of ni-
trogen for synthesis due to its great abundance and ex-
tremely low cost.[1] Direct synthesis of nitro-
gen-containing compounds from ammonia is the most
desirable synthetic route, and recent achievements re-
garding the direct use of ammonia have been reported.[2]
Among nitrogen-containing compounds, primary ani-
lines are widely used in the synthesis of natural products,
pharmaceuticals, agrochemicals as well as polymers and
materials.[3] Hence, the development of synthetic strate-
gies towards primary aromatic amines has attracted the
interest of chemists. The traditional preparation of pri-
mary aromatic amines by coupling of aryl halides with
ammonia suffers from several drawbacks such as high
temperature and high pressure or involves the use of
additives, which make those methodologies less attrac-
tive.[4] Recently, transition metal-catalyzed (such as
palladium and copper) coupling reactions of aryl halides
with ammonia or ammonia surrogates have made big
improvements for the preparation of parent anilines.[5,6]
Very recently, a simple and efficient protocol for cou-
pling aryl halides with aqueous ammonia under mild
conditions has been developed by Zhu and
co-workers.[6b] Apparently, no further methodological
advancements are needed in this area. Moreover, when
using Cu(I) (such as CuI) as the catalyst the reactions
have to be carried out in a heterogeneous system, low-
ering the overall efficiency of a given synthesis. More
recently, we have reported the Cu(I) generated in situ
from Cu(OAc)2•H2O/sodium ascorbate catalyzed the
click reaction of azide with acetylene.[7] Therefore,
Results and Discussion
To optimize the reaction conditions, amination of
m-bromonitrobenzene with aqueous ammonia was cho-
sen as the model substrate considering easy monitoring
and handling of the reaction (Table 1). In our prelimi-
nary studies we were pleased to find that, with DMSO
as the solvent, this m-bromonitrobenzene can be suc-
cessfully coupled with NH3•H2O at 100 ℃ in the pres-
ence of catalytic amounts of CuSO4•5H2O and
L-ascorbic acid sodium salt (L1) to afford m-nitro-
aniline in a yield of 65% (Table 1, Entry 1).
NH2
OH
O
OH
O
HO
O
O
-
+
O
N
H
ONa
HO
L1
L2
L3
S
O
HN
NH2
N
S
H2N
O
L4
L5
L6
Figure 1 Amination additives.
*
E-mail: wangxicun@nwnu.edu.cn; Tel./Fax: 0086-931-7972626
Received December 20, 2012; accepted March 19, 2013; published online April 3, 2013.
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/cjoc.201201240 or from the author.
Chin. J. Chem. 2013, 31, 501—506
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Quan et al.
FULL PAPER
It is important to note that the reaction is carried out
at approximately atmospheric pressure, which permits
the use of common glass reactors. We then tested other
additives. L2 yielded a lower yield (25%) of m-nitro-
aniline (Table 1, Entry 2). No product was detected in
the presence of additives L3－L6 or in the absence of
L-ascorbic acid sodium salt, verifying the importance of
L-ascorbic acid sodium salt (Table 1, Entry 3). To fur-
ther optimize the reaction conditions, copper sources,
bases, and solvents were screened using the same model
substrate and additive L1. As expected, no product
could be detected in the absence of a copper catalyst
(Table 1, Entry 4). All copper sources examined were
effective in accelerating the reactions (Table 1, Entries 1,
5 and 7－9) and CuI provided the best catalytic effect.
Concerning the unstabitily and cost of CuI, CuSO4•
5H2O was finally chosen as the desired catalyst. Among
various solvents tested, DMSO and glycerol were both
effective for the reaction (Table 1, Entries 1 and 13). In
1,4-dioxane, no reaction occurred because of the bi-
phasic reaction mixture (Table 1, Entry 11). It is in-
triguing that the mixed solvent systems of aqueous am-
monia, DMSO, and glycerol in a 2∶2∶1 (V/V/V) ratio
provided a good yield (Table 1, Entry 17). This is be-
cause the reaction was carried out in a homogeneous
system and glycerol could form hydrogen bonds with
ammonia so as to prevent the release of ammonia from
solution. At the same time, glycerol is also a good green
solvent.[8] Base is another important factor to affect the
catalysis. All kinds of bases examined were all effective
for the catalysis (Table 1, Entries 17 and 21－23). When
the amount of base was reduced to 2 equiv., the yield of
m-nitroaniline did not have any change (Table 1, Entry
24). However, 1.5 equiv. of K2CO3 led to the lower
yield of 60% (Table 1, Entry 25). We then examined the
reaction temperature and found that low temperatures
decelerated the reaction rate. For example, only 50%
yield was obtained when the reaction was carried out at
80 ℃ (Table 1, Entry 26). Meanwhile, increasing the
reaction temperature to 120 ℃ did not improve the
yield (Table 1, Entry 27). Under these optimized condi-
tions, the amounts of CuSO4•5H2O and L-ascorbic acid
sodium salt were separately reduced to 0.1 equiv. and
0.2 equiv. and the yield of m-nitroaniline was decreased
to 69% (Table 1, Entry 28).
Table 1 Amination of m-bromonitrobenzene: optimization of the catalytic conditionsa
0.2 equiv. [Cu],
0.4 equiv. additive
.
NH3 H2O
NH2
Br
base, solvent, 8 h
O2N
O2N
Entry
1
Catalyst
Additive
Solvent
DMSO
aq. NH3/Solvent
1∶2
Base
Yieldb/%
65
25
0
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
－
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K3PO4
L1
L2
－
2
DMSO
1∶2
3
DMSO
1∶2
4
DMSO
0
L1
L1
－
1∶2
5
CuI
DMSO
67
0
1∶2
6
CuI
DMSO
1∶2
7
CuCl2
DMSO
60
61
59
23
0
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
1∶2
8
Cu(OAc)2
CuO
DMSO
1∶2
9
DMSO
1∶2
10
11
12
13
14
15
16
17
18
19
20
21
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
MeOH
1∶2
1,4-Dioxane
EtOH
1∶2
28
45
40
42
76
80
77
50
35
75
1∶2
Glycerol
1∶2
DMSO/MeOH
DMSO/EtOH
DMSO/Glycerol
DMSO/Glycerol
DMSO/Glycerol
DMSO
1∶2∶1
1∶2∶1
1∶2∶1
2∶2∶1
3∶2∶1
2∶1
Glycerol
2∶1
DMSO/Glycerol
2∶2∶1
502
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Chin. J. Chem. 2013, 31, 501—506

Copper-Catalyzed Amination of Aryl Halides with Aqueous Ammonia under Mild Conditions
Continued
Yieldb/%
Entry
22
Catalyst
Additive
L1
Solvent
aq. NH3/solvent
2∶2∶1
2∶2∶1
2∶2∶1
2∶2∶1
2∶2∶1
2∶2∶1
2∶2∶1
Base
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
CuSO4•5H2O
DMSO/Glycerol
DMSO/Glycerol
DMSO/Glycerol
DMSO/Glycerol
DMSO/Glycerol
DMSO/Glycerol
DMSO/Glycerol
Na3PO4
Et3N
70
65
23
L1
24
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
80c
60d
50e
79f
69g
L1
25
L1
26
L1
27
L1
28
L1
a
Reaction conditions: m-bromonitrobenzene (1.0 mmol), commercial 28% aqueous NH3, [Cu]-catalyst (0.2 mmol), additive (0.4 mmol),
base (3 mmol), reaction temperature (100 ℃), reaction time (8 h). b Isolated yield. c K2CO3 (2 mmol). d K2CO3 (1.5 mmol). e The reaction
temperature was 80 ℃. f The reaction temperature was 120 ℃. g CuSO4•5H2O (0.1 mmol), L1 (0.2 mmol).
Next we investigated the scope of substrates (Table
2). Although the aryl iodides are interesting substrates,
we focused our attention on arylation with aryl bro-
mides and chlorides, which are less reactive electro-
philes but of much greater interest for industrial appli-
cations. It was observed that aryl bromides bearing
electron-withdrawing or electron-donating groups were
viable substrates, most of the substrates afforded good
to excellent yields under the previously optimized reac-
tion conditions (100 ℃, 8 h) as shown in Table 2. The
electronic effects on the reactivity were limited. It
should be pointed out that the yield obtained for the re-
action of aryl bromides substituted by electron-donating
substituents with aqueous ammonia became low (Table
2, Eentries 7－11). In contrast, aryl iodides substituted
by electron-donating substituents such as Me or OMe
afforded the desired aniline derivatives in good yields
(70%, 58%; Table 2, Entries 24 and 26). To broaden the
scope of substrates used, we carried out the reaction of
heterocyclic bromide with aqueous ammonia, and the
corresponding primary arylamine was afforded in a
good yield (Table 2, Entry 13). Furthermore, aryl chlo-
rides with electron-withdrawing substituents such as
NO2 could be successfully coupled with NH3•H2O to
afford primary aromatic amines in good yields (Table 2,
Entries 14－17).
Table 2 Copper-catalyzed amination of aryl halides with
aqueous ammoniaa
.
20 mol% CuSO4 5H2O
.
NH3 H2O
40 mol% L-ascorbic acid sodium salt ( L1)
+
NH2
2 equiv. K2CO3, DMSO/glycerol
R
X
60 100 oC, 2 8 h
－
－
R
X = Br, Cl, I
Entry
Aryl halide
Product
Yieldb/%
83
Br
Br
Br
Cl
NH2
NH2
1
2
Cl
Br
78
50
88
80
NH2
Br
3
4
5
Cl
Cl
O
O
Br
NH2
NH2
Me
Me
Br
O2N
O2N
We were pleased to find that all the aryl iodides, es-
pecially those with electron-withdrawing substituents,
provided good to excellent yields at 60 ℃ for 2 h in
contrast with aryl bromides. Aryl iodides could be
selectively coupled with aqueous ammonia in the pres-
ence of a competing aryl bromide (Table 2, Entry 20).
The reaction is even possible at lower temperatures (r.t.)
with activated substrates such as 4-iodoacetophenone
(Table 2, Entry 21). Notably, the sterically demanding
ortho substituents hampered the reaction (Table 2, En-
tries 22 and 25). As shown in Figure 2, the yield of pri-
mary aromatic amines by using aryl bromides was al-
most same as that by using aryl iodides. Therefore, it
was more favorable to industrial applications.
Br
NH2
6
7
72
47
Me
Br
Me
NH2
Br
NH2
8
9
45
37
40
Me
Me
MeO
Br
MeO
NH2
Br
NH2
10
Finally, we demonstrated the utility of this protocol
in the synthesis of 4-amino-N-phenylbenzamide derivatives
MeO
MeO
Chin. J. Chem. 2013, 31, 501—506
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503

Quan et al.
FULL PAPER
Continued
Yieldb/%
Entry
11
Aryl halide
Product
H2N
Br
H2N
NH2
NH2
15
85
Br
12
80
69
13
14
N
NH2
NH2
N
Br
O2N
Cl
O2N
Figure 2 The yield of primary anilines by employing aryl io-
dides (60 ℃, 2 h) and aryl bromides (100 ℃, 8 h) with the same
substituents.
Cl
NO2
NH2
NO2
15
16
65
67
(Scheme 1). To our delight, the amination of
4-iodo-N-phenylbenzamide and 4-iodo-N-m-tolylben-
zamide with ammonia afforded the desired 4-amino-
N-phenylbenzamide (84%) and 4-amino-N-m-tolylben-
zamide (82%) in high yields.
Cl
NH2
O2N
O2N
O2N
Cl
NO2
O2N
NH2
NO2
Scheme 1 Synthesis of 4-amino-N-phenylbenzamide
17
18
19
20
21
75, 43c
.
20 mol% CuSO4 5H2O
HN
O
40 mol% L1
.
+
NH3 H2O
R
I
Cl
NH2
0
0
2 equiv. K2CO3
DMSO/glycerol, 60 oC, 3 h
Me
Br
Cl
I
Me
Br
NH2
HN
O
R
H2N
85, 37c
90, 50c
NH2
NH2
R = H, 84%; 3-CH3, 82%
O
O
I
Me
Me
Glycerol could form hydrogen bonds with ammonia
so as to prevent the release of ammonia from solution.
On the basis of the observations described above and
reported previously,[6m,6p] a possible rationale for the
copper-promoted amination of aryl halides in aqueous
ammonia lies in the formation of [Cu(NH3)2]＋ (Scheme
2). In aqueous ammonia solution, the linear diamine-
copper(I) complex, [Cu(NH3)2]＋, may be the dominant
species.[9,10]
I
I
NH2
54
22
23
24
Cl
Cl
83, 35c
70
NH2
Me
I
Me
NH2
Conclusions
I
NH2
45
58
25
26
In summary, we have developed a simple, homoge-
neous and efficient method for transforming aryl halides
into aniline derivatives by using a copper/L-ascorbic
acid sodium salt catalyst system. The easy use of aque-
ous ammonia, the use of nontoxic L-ascorbic acid so-
dium salt as a reductant, and the low cost and environ-
mentally benign character of the catalytic system
(CuSO4•5H2O/L-ascorbic acid sodium salt) are great
advantages in terms of industrial scale and green chem-
istry.
Me
Me
MeO
I
MeO
NH2
a Reaction conditions: Aryl halide (1 mmol), CuSO4•5H2O (0.2
mmol), L-ascorbic acid sodium salt (0.4 mmol), K2CO3 (2.0
mmol), commercial 28% aqueous NH3, DMSO and glycerol (2∶
2∶1, total volume 5.0 mL), aryl bromides and chlorides (100 ℃,
8 h), aryl iodides (60 ℃, 2 h). Isolated yield. At room tem-
perature (25 ℃), overnight.
b
c
504
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Chin. J. Chem. 2013, 31, 501—506

Copper-Catalyzed Amination of Aryl Halides with Aqueous Ammonia under Mild Conditions
Scheme 2 A possible rationale for the copper-promoted amina-
2H, ArH); 13C NMR (CDCl3, 100 MHz) δ: 114.88,
tion of aryl halides in aqueous ammonia
118.23, 129.06, 146.25.
4-Toluidine:[6a] 1H NMR (CDCl3, 400 MHz) δ: 2.23
(s, 3H, CH3), 3.48 (s, 2H, NH2), 6.59 (d, J＝8.4 Hz, 2H,
ArH), 6.96 (d, J＝8 Hz, 2H, ArH); 13C NMR (CDCl3,
100 MHz) δ: 20.36, 115.16, 127.64, 129.66, 143.77.
3-Toluidine:[6a] 1H NMR (CDCl3, 400 MHz) δ: 2.25
(s, 3H, CH3), 3.56 (s, 2H, NH2), 6.46－6.49 (m, 2H,
ArH), 6.56－6.58 (m, 1H, ArH), 7.03 (t, J＝7.6 Hz, 1H,
ArH); 13C NMR (CDCl3, 100 MHz) δ: 21.33, 112.14,
115.81, 119.32, 129.06, 139.00, 146.27.
Cu2+ (NH3)2
NH3
X
X
Cu2+(NH3)2
NH3X-
OH
HO
Cu+ (NH3)2
HO
H
O
NH2
4-Methoxyaniline:[6a] 1H NMR (CDCl3, 400 MHz) δ:
3.73 (s, 3H, CH3), 3.34 (s, 2H, NH2), 6.62－6.65 (m, 2H,
ArH), 6.73－6.75 (m, 2H, ArH); 13C NMR (CDCl3, 100
MHz) δ: 55.66, 114.71, 116.35, 139.87, 152.70.
3-Methoxyaniline:[6a] 1H NMR (CDCl3, 400 MHz) δ:
3.65 (s, 2H, NH2), 3.70 (s, 3H, CH3), 6.18－6.22 (m, 1H,
ArH), 6.22－6.31 (m, 2H, ArH), 7.02 (t, J＝8 Hz, 1H,
ArH); 13C NMR (CDCl3, 100 MHz) δ: 54.95, 100.89,
103.77, 107.78, 130.01, 147.71, 160.59.
NH3
O
H
Cu2+
H
Cu+
H
N
O H
H
L1
Experimental Section
Typical procedure for the catalysis
CuSO4•5H2O (0.2 mmol), L-ascorbic acid sodium
salt (0.4 mmol), aryl halide (1 mmol), K2CO3 (2 mmol),
aqueous ammonia (2 mL), and mixed solvent (3 mL,
DMSO/glycerol＝2∶1) were added to a flask bearing a
balloon to prevent gaseous ammonia from escaping. The
reaction mixture was stirred (aryl iodides at 60 ℃ for 2
h, aryl bromides and chlorides at 100 ℃ for 8 h) and
then cooled to room temperature and extracted with di-
ethyl ether (10 mL×3). The organic layer was then
dried over anhydrous Na2SO4, and the solvent was re-
moved under reduced pressure. The aniline product was
finally obtained by column chromatography on silica
4-Phenylenediamine:[6a] 1H NMR (CDCl3, 400 MHz)
δ: 3.33 (s, 4H, NH2), 6.56 (s, 4H, ArH); 13C NMR
(CDCl3, 100 MHz) δ: 116.64, 138.51.
1-Naphthylamine:[6a] 1H NMR (CDCl3, 400 MHz) δ:
4.02 (s, 2H, NH2), 6.74－7.25 (m, 1H, ArH), 7.27－
7.32 (m, 2H, ArH), 7.41－7.45 (m, 2H, ArH), 7.46－
7.79 (m, 2H, ArH); 13C NMR (CDCl3, 100 MHz) δ:
109.71, 118.95, 120.82, 123.65, 124.89, 125.75, 126.35,
128.55, 134.40, 142.08.
2-Aminopyridine:[6a] 1H NMR (CDCl3, 400 MHz) δ:
4.71 (s, 2H, NH2), 6.39 (d, J＝8.4 Hz, 1H, ArH), 6.51－
6.54 (m, 1H, ArH), 7.22－7.33 (m, 1H, ArH), 7.97 (d,
J＝5.2 Hz, 1H, ArH); 13C NMR (CDCl3, 100 MHz) δ:
108.72, 113.69, 137.76, 147.84, 158.74.
gel. All the products were confirmed by H and 13C
1
NMR spectroscopic analysis.
4-Bromoaniline:[6a] 1H NMR (CDCl3, 400 MHz) δ:
3.64 (s, 2H, NH2), 6.56 (d, J＝8.8 Hz, 2H, ArH), 7.23 (d,
J＝8.8 Hz, 2H, ArH); 13C NMR (CDCl3, 100 MHz) δ:
110.06, 116.63, 131.91, 145.36.
4-Nitroaniline:[6a] 1H NMR (CDCl3, 400 MHz) δ:
3.64 (s, 2H, NH2), 6.59－6.61 (m, 2H, ArH), 7.09－
7.10 (m, 2H, ArH); 13C NMR (CDCl3, 100 MHz) δ:
116.15, 123.02, 129.03, 144.88.
4-Chloroaniline:[6a] 1H NMR (CDCl3, 400 MHz) δ:
3.61 (s, 2H, NH2), 6.59 (d, J＝8.4 Hz, 2H, ArH), 7.09 (d,
J＝8.4 Hz, 2H, ArH); 13C NMR (CDCl3, 100 MHz) δ:
116.16, 123.05, 129.03, 144.90.
2-Nitroaniline:[6a] 1H NMR (CDCl3, 400 MHz) δ:
6.11 (s, 2H, NH2), 6.67－6.72 (m, 1H, ArH), 6.81－
6.83 (m, 1H, ArH), 7.33－7.38 (m, 1H, ArH), 8.09－
8.12 (m, 1H, ArH); 13C NMR (CDCl3, 100 MHz) δ:
116.85, 118.71, 126.07, 132.11, 135.60, 144.65.
2-Chloroaniline:[6a] 1H NMR (CDCl3, 400 MHz) δ:
3.96 (s, 2H, NH2), 6.62－6.69 (m, 2H, ArH), 6.99－
7.01 (m, 1H, ArH), 7.01－7.21 (m, 1H, ArH); 13C NMR
(CDCl3, 100 MHz) δ: 115.75, 118.87, 119.08, 127.52,
129.26, 142.78.
1
2,4-Dinitroaniline: H NMR (DMSO-d6, 400 MHz)
δ: 7.08 (d, J＝9.6 Hz, 1H, ArH), 8.12－8.15 (m, 1H,
ArH), 8.39 (s, 2H, NH2), 8.75 (d, J＝2.4 Hz, 1H, ArH);
13C NMR (DMSO-d6, 100 MHz) δ: 120.21, 123.80,
129.03, 129.70, 135.50, 150.27.
4'-Aminoacetophenone:[6a] 1H NMR (CDCl3, 400
MHz) δ: 2.50 (s, 3H, CH3), 4.22 (s, 2H, NH2), 6.64 (d,
J＝8.4 Hz, 2H, ArH), 7.80 (d, J＝8.8 Hz, 2H, ArH); 13C
NMR (CDCl3, 100 MHz) δ: 26.04, 113.57, 127.51,
130.72, 151.22, 196.60.
2-Toluidine:[6a] 1H NMR (CDCl3, 400 MHz) δ: 2.10
(s, 3H, CH3), 3.50 (s, 2H, NH2), 6.59－6.66 (m, 1H,
ArH), 6.68－6.72 (m, 1H, ArH), 6.99－7.09 (m, 2H,
ArH); 13C NMR (CDCl3, 100 MHz) δ: 17.53, 115.08,
118.73, 122.47, 127.14, 130.61, 144.79.
3-Nitroaniline:[6a] 1H NMR (CDCl3, 400MHz) δ:
4.03 (s, 2H, NH2), 6.94－6.96 (m, 1H, ArH), 7.27 (t,
J＝8 Hz, 1H, ArH), 7.48－7.55 (m, 1H, ArH), 7.56－
7.58 (m, 1H, ArH); 13C NMR (CDCl3, 100 MHz) δ:
108.96, 113.05, 120.58, 129.86, 147.43, 149.19.
Aniline:[6a] 1H NMR (CDCl3, 400 MHz) δ: 3.52 (s,
2H, NH2), 6.60－6.75 (m, 3H, ArH), 7.12 (t, J＝8 Hz,
1
4-Amino-N-phenylbenzamide: H NMR (DMSO-d6,
400 MHz) δ: 6.24 (s, 2H, NH2), 7.09 (t, J＝7.4 Hz, 1H,
ArH), 7.34 (t, J＝8.0 Hz, 2H, ArH), 7.73－7.76 (m, 4H,
ArH), 7.91 (d, J＝8.4 Hz, 2H, ArH), 10.29 (s, 1H, NH);
13C NMR (DMSO-d6, 100 MHz) δ: 99.30, 120.38,
Chin. J. Chem. 2013, 31, 501—506
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Quan et al.
FULL PAPER
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123.80, 128.62, 129.61, 134.29, 137.24, 138.95, 164.79;
HRMS [M＋H]＋ calcd for C13H12N2O 213.1022, found
213.1024.
4-Amino-N-m-tolylbenzamide: 1H NMR (DMSO-d6,
400 MHz) δ: 2.29 (s, 3H, CH3), 5.77 (s, 2H, NH2),
6.61－6.64 (m, 2H, ArH), 6.86 (d, J＝8.0 Hz, 1H, ArH),
7.19 (t, J＝7.8 Hz, 1H, ArH), 7.58 (t, J＝12.6 Hz, 2H,
ArH), 7.73－7.76 (m, 2H, ArH), 9.72 (d, J＝1.6 Hz, 1H,
NH); 13C NMR (DMSO-d6, 100 MHz) δ: 21.29, 112.59,
117.36, 120.73, 121.19, 123.65, 128.33, 129.37, 137.57,
139.70, 152.13, 165.30; HRMS [M＋H]＋ calcd for
C14H14N2O 227.1179, found 227.1182.
Acknowledgement
We are thankful for the financial support from the
National Natural Science Foundation of China (Nos.
20902073 and 21062017), and the Scientific and Tech-
nological Innovation Engineering Program of Northwest
Normal University (Nos. nwnukjcxgc-03-64, nwnulkqn-
10-15).
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© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2013, 31, 501—506