Synthesis of a novel diol-functionalized poly(ethylene glycol)-bridged dicationic ionic liquid and its application in copper-catalyzed amination of aryl halides

Article abstract of DOI:10.1071/CH12487

A novel diol-functionalized poly(ethylene glycol)-bridged dicationic ionic liquid ([diol-PEG1000-DIL][PF6]) is prepared and used as an efficient and reusable ligand for copper-catalyzed amination. A variety of aryl iodides and aryl bromides reacted smoothly with aqueous ammonia to afford the corresponding aromatic primary amines in good to excellent yields. It is remarkable that aryl chlorides with a strong electron-withdrawing group exhibited a dramatically elevated activity in the presence of tetrabutylammonium bromide. Furthermore, the catalyst could be easily recovered and reused without obvious loss of catalytic activity after five recycling runs.

Full text of DOI:10.1071/CH12487

CSIRO PUBLISHING
Aust. J. Chem.
Full Paper
http://dx.doi.org/10.1071/CH12487
Synthesis of a Novel Diol-Functionalized Poly(ethylene
glycol)-Bridged Dicationic Ionic Liquid and its Application
in Copper-Catalyzed Amination of Aryl Halides
A
A
,
B
A
A
Yinglei Wang, Jun Luo,
Tianjiao Hou, and Zuliang Liu
A
School of Chemical Engineering, Nanjing University of Science and Technology,
Nanjing 210094, China.
B
Corresponding author. Email: luojun@njust.edu.cn
A novel diol-functionalized poly(ethylene glycol)-bridged dicationic ionic liquid ([diol-PEG1000-DIL][PF ]) is prepared
6
and used as an efficient and reusable ligand for copper-catalyzed amination. A variety of aryl iodides and aryl bromides
reacted smoothly with aqueous ammonia to afford the corresponding aromatic primary amines in good to excellent yields.
It is remarkable that aryl chlorides with a strong electron-withdrawing group exhibited a dramatically elevated activity in
the presence of tetrabutylammonium bromide. Furthermore, the catalyst could be easily recovered and reused without
obvious loss of catalytic activity after five recycling runs.
Manuscript received: 29 October 2012.
Manuscript accepted: 25 January 2013.
Published online: 27 March 2013.
Introduction
including excellent thermal and chemical stability, low vapour
pressure, large electrochemical window, potential recyclability,
Primary aromatic amines are important intermediates in the
synthesis of natural products, agrochemicals, pharmaceuticals,
dyes, pigments, polymers, and materials. Ammonia is one of
the most attractive sources of nitrogen in organic synthesis
because of its low cost and wide availability. The traditional
strategy for the preparation of primary aromatic amines by direct
coupling of aryl halides with ammonia often suffers from sev-
eral drawbacks such as high temperature, high pressure, and low
tolerance of substituted groups. Recently, the palladium-
catalyzed coupling reactions of aryl halides with ammonia have
[
7]
and highly designability. In particular, functionalized ionic
liquids (FIL), so-called task specific IL which incorporate
additional functional groups as a part of the cation and/or anion,
have been designed and synthesized for special purposes. Such
IL can be applied in a wide range of areas, including catalyst
recycling, supports for organic synthesis, catalysis, separation of
specific metal ions from aqueous solution, gas absorption, and
[
1]
[
2]
[
3]
[8]
construction of nanostructures and ion conductive materials.
In recent years, diol-functionalized IL (diol-FIL), containing
two vicinal hydroxy groups, have received great interest. Cai
and coworkers synthesized and used 1-(2,3-dihydroxypropyl)-
[
4]
been reported. More recently, the copper-catalyzed protocols
have been developed. The copper catalysts used include CuI/
[
5a]
[5b]
L-proline,
(
CuI/acac,
Cu O/H O/N-methyl-2-pyrrolidone
2
CuI/N,N-dimethylglycine/organic
3-methylimidazolium hexafluorophosphate ([2,3-dhpmim]
[9]
[PF ]) as a catalyst for Heck reactions. Bellina and coworkers
2
[
5c]
[5d]
NMP),
ionic base,
CuI/Cu/ethylene glycol,
copper/oxalohydrazide/ketone,
CuI/DMF,
6
[
5e]
[5f]
[5g]
CuBr/2-pyridinyl-b-ketone,
CuI/Fe O ,
2
reported a series of imidazolium-based IL functionalized by 2,3-
dihydroxypropyl groups and used as potential ligands and
3
[
5h]
[5i]
CuI/4-hydroxy-L-proline,
2
0
CuO/N ,N -diisopropylox-
[
5j]
2
[10a]
solvents for palladium(II)-catalyzed reactions,
recently, they synthesized a series of trialkyl(2,3-dihydroxypro-
and very
[
5k]
alohydrazide,
[5l]
N,N -ethylenebis(salicylimine)), CuI nanoparticles,
sulfonato–Cu(salen) complex (salen:
0
[5m]
CuI/
CuI/
pyl)phosphonium salts and used them as efficient additives in
[10b]
[
5n]
1
2
,4-bis(2-hydroxy-3,5-di-tert-butylbenzyl)piperazine,
[
typical Baylis–Hillman reactions.
reported a series of diol-functionalized imidazolium-based IL
Andrew and coworkers
5o]
-carboxylic acid-quinoline-N-oxide,
-dicationic ionic liquid (DIL)/
CuSO ꢀ 5H O/poly
4
2
(ethylene glycol (PEG)
methylcyclohexane,
with bis(trifluoromethanesulfonimide) anions that exhibited
[11]
1
000
[
5p]
[5q]
CuI/PEG400
,
Cs CO . Meanwhile, Fu and coworkers reported a copper-
and PEG3400/Cu O/
variable water miscibility.
Wang and coworkers reported a
copolymer of diol-FIL with styrene-supported Pd nanoparticles
2
[
5r]
2
3
[
12]
catalyzed amination coupling of aromatic boronic acids with
and used it as a catalyst for a Suzuki reaction.
coworkers reported a polymer-supported diol-FIL as catalyst for
Rahul and
[
6]
aqueous ammonia. Based on the significance of primary
aromatic amines, the search for an efficient, especially recy-
clable catalyst is still being actively pursued.
[
13a]
the synthesis of 5-aryl-2-oxazolidinones
ate from CO2.
and cyclic carbon-
[13b]
Ionic liquids (IL) are defined as a special class of molten salt
composed of organic cations and inorganic or organic anions
and melt at or below 1008C. IL have attracted considerable
attention during the past decades due to their peculiar properties
Recently, poly(ethylene glycol) (PEG) has been introduced
as a green reaction medium for organic synthesis and catalytic
processes, because of its particular advantages such as its low
cost, thermal stability, non-volatility, non-toxicity, and ease of
Journal compilation Ó CSIRO 2013
www.publish.csiro.au/journals/ajc

B
Y. Wang et al.
degradability. Moreover, it has also been extensively explored
[
as a support for the immobilization of reagents and catalysts.
thermal gravimetric analysis (TGA) depicted in Fig. 1, it can be
seen that the [diol-PEG1000-DIL][PF ] has good thermal sta-
14]
6
The combination of PEG with IL was realized by the synthesis of
PEG-functionalized IL. Owing to their special chemical and
physical properties, some functionalized PEG-supported IL
have been prepared and used in many reactions. Liu and
coworkers reported three PEG-functionalized imidazolium salts
bility. It has no melting point but has a glass transition tem-
perature of ꢁ288C derived from differential scanning
calorimetry (DSC) analysis (Fig. 2). In addition, the solubility of
[
15]
[diol-PEG1000-DIL][PF ] was determined at room temperature.
6
In general, it is soluble in acetonitrile, dimethoxyethane, pro-
pylene glycol monomethyl ether, dimethyl sulfoxide (DMSO)
and N,N-dimethylformamide, and insoluble in petroleum ether,
cyclohexane, ethyl ether, dichloromethane, ethyl acetate, tolu-
ene, acetone, and water.
To optimize reaction conditions, iodobenzene and aqueous
ammonia were used as model substrates for the amination
catalyzed by Cu(I)/3 and the results are listed in Table 1. Solvent
was an important factor for this amination. Among the solvents
used, DMSO was found to be the best (Table 1, entries 1–4).
When the [diol-PEG1000-DIL][Cl] was used as a ligand, only
74 % of aniline was afforded (Table 1, entry 5). However, a low
yield was obtained if no 3 was added (Table 1, entry 6). As
expected, no product formed under copper-free conditions
(Table 1, entry 7). Various copper catalysts were used and the
which served as N-heterocyclic carbene precursors for the
[
15m]
palladium-catalyzed Suzuki reaction.
developed a series of PEG-functionalized basic IL and used
Yang and coworkers
them as catalysts for the conversion of CO into organic
2
[
15n]
carbonates.
Tang and coworkers prepared a series of PEG-
functionalized IL comprising inexpensive alkylammonium or
piperidinium cations with acetate anions and selected some of
[15o]
them for cellulose dissolution and saccharification.
In this paper, a novel diol-functionalized PEG-bridged dica-
tionic IL ([diol-PEG1000-DIL][PF ]) is synthesized (Scheme 1)
6
and applied in the amination of aryl halides with aqueous
ammonia. The ethylene glycol moiety could act as an excellent
bi-dentate chelating ligand (O,O-ligands) for the metal without
[
16]
potential for oxidative destruction.
results indicated that CuBr, CuCl, and Cu(OAc) presented high
2
Results and Discussion
The synthetic pathway for the diol-functionalized PEG-bridged
dicationic IL is illustrated in Scheme 1. It was readily prepared
through a straightforward three-step procedure from commer-
cially available starting materials and reagents in good yields. In
the first step, PEG1000 was chlorinated with thionyl chloride in
the presence of pyridine in dichloromethane to afford PEG
dichloride 1. In the second step, sodium imidazole was prepared
from imidazole and sodium hydroxide in toluene, and then a
solution of 1 in acetonitrile was added and the mixture was
heated to reflux for 12 h to afford PEG-bridged di-imidazolium
compound 2 in 89 % yield. Thereafter, the quaternization
of compound 2 and 3-chloropropane-1,2-diol was conducted in
toluene under reflux for 72 h to give [diol-PEG1000-DIL][Cl],
and then the chloride was exchanged with potassium hexa-
fluorophosphate in dichloromethane at room temperature for
1
1
20
00
8
6
4
0
0
0
20
0
100
200
300
400
500
600
4
8 h to afford the target diol-functionalized PEG-bridged dica-
tionic IL containing a hexafluorophosphate anion [diol-
PEG -DIL][PF ] (3) in 86 % yield, which was identified by
T (ЊC)
Fig. 1. The thermogravimetric spectrum of the diol-functionalized poly
1
000
6
1
13
H NMR, C NMR, IR, and mass spectrometry analysis. From
6
(ethylene glycol)-bridged dicationic ionic liquid, [diol-PEG1000-DIL][PF ].
Cl
O
HO
O
SOCl2
O
Cl
O
OH
n
n
1
N
NH , NaOH
N
N
O
O
N
N
n
2
Cl
1)
OH
OH
(
OH
ϩ
Ϫ
6
HO
N
N
O
ϩ
2 PF
N
OH
O
N
(
2) KPF6
OH
n
3
[diol-PEG1000-DIL][PF6]
Scheme 1. Synthesis of the diol-functionalized poly(ethylene glycol)-bridged dicationic ionic liquid ([diol-
PEG1000-DIL][PF
]) (n ¼ 20–22).
6

CuI/[diol-PEG-DIL][PF
6
] Catalyzed Amination
C
activity (Table 1, entries 8–11). Base was another key factor.
Although ammonia itself could play the role of base in the
catalyst system, its basicity was not strong enough (Table 1,
entry 12). The following conditions’ screening results suggested
that Cs CO , K PO , and KOH were much better (Table 1,
long enough to ensure the completion of the reaction at 1008C
(Table 1, entries 3 and 21). So the following reactions were
performed with CuI/3 and K CO in DMSO at 1008C for 12 h.
2
3
In order to investigate the reusable properties of [diol-
PEG1000-DIL][PF ], a series of recycle experiments were con-
2
3
3
4
6
entries 13–18). Furthermore, low temperatures gave decreased
yields (Table 1, entries 19 and 20). The reaction time of 12 h was
ducted and the results are shown in Fig. 3. After the reaction was
complete, the reaction mixture was cooled to room temperature.
99
98
1
1
0
.5
.0
.5
0
100
80
60
40
20
0
96
95
95
Ϫ0.5
Ϫ1.0
Ϫ60 Ϫ40 Ϫ20
0
20
40
60
80
100 120
1
2
3
4
5
T [ЊC]
Run
Fig. 2. The differential scanning calorimetry spectrum of the diol-
Fig. 3. Recycling of the diol-functionalized poly(ethylene glycol)-bridged
functionalized poly(ethylene glycol)-bridged dicationic ionic liquid,
6
dicationic ionic liquid, [diol-PEG1000-DIL][PF ], in the amination of iodo-
benzene with aqueous ammonia.
6
[diol-PEG1000-DIL][PF ].
Table 1. Copper-catalyzed amination of iodobenzene with aqueous ammonia
Copper catalyst, 3
I ϩ NH (aq)
NH2
3
Base, solvent
A
B
Yield [%]
Entry
Copper catalyst
Base
Solvent
Time [h]
Temperature [8C]
1
2
3
4
CuI
CuI
CuI
CuI
CuI
CuI
—
K
K
K
K
K
K
K
K
K
K
K
2
2
2
2
2
2
2
2
2
2
2
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
3
3
3
3
3
3
3
3
3
3
3
DMF
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
6
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
80
29
22
99
80
87
32
0
NMP
DMSO
C
PM
D
5
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
E
6
7
8
9
CuBr
CuCl
97
98
98
91
10
33
98
97
98
79
13
82
68
62
10
11
12
13
14
15
16
17
18
19
20
21
Cu(OAc)
2
CuSO
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
CuI
4
—
Na
2
CO
CO
PO
KOH
Et
Pyridine
3
Cs
2
3
K
3
4
3
N
K
2
K
2
K
2
CO
CO
CO
3
3
3
60
100
A
Reaction conditions: iodobenzene (1.0 mmol), commercial 25 % aqueous ammonia (2 mL), copper catalyst (0.1 mmol), 3 (0.1 mmol), base (2 mmol),
DMSO (2 mL).
B
Gas chromatography yield.
C
PM, propylene glycol monomethyl ether.
D
With [diol-PEG1000-DIL][Cl].
E
6
Without [diol-PEG1000-DIL][PF ].

D
Y. Wang et al.
The product was extracted with diethyl ether. The remaining IL
phase, which contained CuI and KI, was dried to remove
ammonia and water under vacuum, extracted with diethyl ether
to remove residual DMSO, and then charged with fresh sub-
strates (iodobenzene, 1.0 mmol; commercial 25 % aqueous
ammonia, 2 mL; K CO , 2 mmol; DMSO, 2 mL) for the next
tetramethylsilane was used as a reference. Gas chromatography
analyses were performed on an Agilent 7890A instrument. IR
spectra were recorded in KBr disks with a Shimadzu IR Prestige-
21 FT-IR spectrometer. Mass spectra were taken on an Agilent
LC-MS 1100 series instrument in the electrospray ionization
(positive ESI) mode. The TGA was performed on a TGA/
SDTA851e thermal analyzer (Mettler Toledo). Samples were
loaded into an aluminium oxide crucible and heated at a rate of
2
3
run. The data listed in Fig. 3 indicated that [diol-PEG1000-DIL]
PF ] could be reused at least five times without visible loss of
catalytic activity.
[
6
208C ꢀ minꢁ from 50 to 6008C under N . The DSC was per-
1
2
In order to explore the scope of the application of this
catalytic system, a variety of substituted aryl halides were
applied and the results are presented in Table 2. It is obvious
that the substituted aryl iodides bearing either electron-
withdrawing or electron-donating substituents reacted smoothly
and afforded the corresponding anilines in high yields (Table 2,
entries 1 and 5). We were then intrigued by the possibility of
using aryl bromides, less reactive electrophiles compared with
iodides, as coupling partners. As expected, bromoarenes
required a longer reaction time and provided slightly decreased
yields. As shown in Table 2, the electronic effect exhibited
almost no influence on the amination of iodoarenes. As for
bromoarenes, however, electron-withdrawing substituents
seemed to be slightly beneficial compared with electron-
donating ones. For example, 4-nitrobromobenzene afforded a
higher yield (96 %) than 4-methylbromobenzene (87 %)
formed on a DSC 823e (Mettler Toledo), and heated at a rate of
ꢁ1
108C min from ꢁ50 to 1008C under N2.
Synthesis of [diol-PEG-DIL][PF6]
Synthesis of PEG Dichloride (1)
To a solution of PEG1000 (25 g, 0.025 mol) and pyridine
(4.0 mL, 0.05 mol) in CH Cl (100 mL) was added SOCl2
2
2
(4.0 mL, 0.055 mol) dropwise at ambient temperature. The
reaction mixture was stirred at ambient temperature for 12 h.
The solvent was evaporated under vacuum and the residue was
dissolved in ethyl acetate to allow the pyridine hydrochloride to
be precipitated and then filtered off. After evaporating the
solvent, the intermediate 1 was obtained and used directly for
the next reaction. dH (500 MHz, CDCl ) 3.77 (t, J 5.9, 4H),
3
3.73–3.60 (m, 78H).
(
Table 2, entries 15 and 7). Furthermore, the catalytic system
could tolerate a variety of functional groups including the nitro,
acetyl, amino, and ether groups. Owing to steric hindrance,
ortho-substituted aryl bromides gave lower yields than meta-
and para-substituted ones (Table 2, entries 9–11). At the same
time, heterocyclic bromides also showed high activity (Table 2,
entry 17). However, chloroarenes were inert under these condi-
tions. An attempt to use p-chloronitrobenzene as the substrate
gave no reaction at all even extending the time to 48 h. But if the
reaction temperature was elevated to 1208C, 4-nitroaniline
could be obtained in a very low yield. Surprisingly, a high
isolated yield of 84 % was achieved when tetrabutylammonium
bromide was added (Table 2, entry 18). In addition, it could act
as a phase-transfer catalyst, the most possible reason might be
the fact that a halogen-exchange reaction occurred to form some
Synthesis of PEG-Bridged Di-Imidazolium Compound (2)
Imidazole (8.2 g, 0.12 mol) was melted at around 1008C and
NaOH (4 g, 0.1 mol) was added. After the solid NaOH thawed,
toluene (50 mL) was added and heated to remove water by
azeotropy for 3 h. Toluene was then evaporated under reduced
pressure. Subsequently, the solution of intermediate 1 obtained
above in CH CN (80 mL) was added. The mixture was stirred at
3
708C for 12 h. The solvent was removed by distillation, the
residue was dissolved in CH Cl and washed with water several
2
2
times to remove inorganic salts and excess imidazole. After
removal of solvent, 20.5 g of the desired compound 2 was
obtained, yield 89 %. d (500 MHz, CDCl ) 7.47 (s, 2H), 6.96
H
3
(d, J 11.8, 4H), 4.05 (t, J 5.2, 4H), 3.68 (t, J 5.2, 4H), 3.65–3.48
(m, 87H).
[
17]
p-bromonitrobenzene first.
Conclusion
Synthesis of [diol-PEG1000-DIL][PF6]
In summary, a novel diol-functionalized PEG-bridged dica-
tionic IL ([diol-PEG1000-DIL][PF ]) was successfully prepared
A mixture of compound 2 (20.5 g) and 3-chloropropane-1,2-
diol (4.9 g) in toluene (50 mL) was heated to reflux for 72 h.
During the reaction, an oily liquid gradually precipitated from
the solution. Toluene was then evaporated under vacuum and the
residue was washed repeatedly with ethyl ether to remove
excess 3-chloropropane-1,2-diol, followed by evaporation
under reduced pressure to yield the yellow oily liquid. Subse-
quently, KPF (8.2 g) and CH Cl (50 mL) were added and the
6
and applied as the ligand in the cuprous catalyzed amination of
aryl halides with aqueous ammonia. A series of substituted aryl
iodides and aryl bromides could undergo amination with aque-
ous ammonia to afford corresponding aryl amines in good to
excellent yields. It is remarkable that an aryl chloride with a
strong electron-withdrawing group exhibited a dramatically
elevated activity in the presence of tetrabutylammonium bro-
6
2
2
mixture was stirred at ambient temperature for 48 h. [diol-
PEG1000-DIL][PF ] was finally obtained after filtration and
mide. Furthermore, the CuI/[diol-PEG1000-DIL][PF ] catalytic
6
6
system could maintain its catalytic activity even after being
recycled five times.
removal of solvent under reduced pressure, to yield 24.8 g
(86 %). dH (500 MHz, DMSO-d ) 9.27 (s, 2H), 7.80 (s, 4H),
6
5
7
1
1
.63 (s, 2H), 5.21 (s, 2H), 4.50–4.28 (m, 8H), 4.18 (dd, J 13.7,
.4, 2H), 3.86–3.71 (m, 8H), 3.66–3.32 (m, 110H), 3.23 (dd, J
0.9, 7.1, 2H). dC (126 MHz, DMSO-d ) 137.43, 123.58,
Experimental
6
General Remarks
22.69, 70.25, 70.05, 68.67, 62.92, 52.40, 49.16. n
(KBr)/
max
ꢁ
1
All of the reagents and solvents were commercially available
1
cm 3429, 2875, 1566, 1455, 1352, 1297, 1251, 1093, 953,
826, 740, 643. m/z (ESI-MS) 552.4 (M2þ/2, n ¼ 20), 574.3
(M þ/2, n ¼ 21), 596.5 (M2þ/2, n ¼ 22).
13
and were used without further purification. H and C NMR
spectra were recorded on a Bruker DRX 500 spectrometer and
2

CuI/[diol-PEG-DIL][PF
6
] Catalyzed Amination
E
Table 2. Copper-catalyzed amination of aryl halides with aqueous ammonia catalyzed by CuI/3
R
R
Cul, 3
X
ϩ
NH3 (aq)
NH2
K CO , DMSO
2
3
100ЊC
A
B
Entry
Aryl halide
Product
Time [h]
12
Yield [%]
96
l
NH2
1
2
H C
l
l
H3C
NH2
3
12
12
12
12
24
24
24
24
95
93
97
98
92
89
86
88
H N
H N
NH2
3
4
5
6
7
8
9
2
2
Br
l
Br
NH2
O N
l
O N
NH2
2
2
Br
NH2
H C
Br
Br
Br
H C
NH2
3
3
H N
H N
NH2
2
2
H CO
H CO
NH2
3
3
Br
NH2
10
24
87
H CO
H CO
3
3
Br
NH2
OCH3
1
1
1
2
24
24
85
94
OCH3
O
O
Br
Br
NH2
H C
H C
3
3
Cl
Cl
NH2
1
1
3
4
24
24
95
94
F
Br
F
NH2
(
Continued)

F
Y. Wang et al.
Table 2. (Continued)
A
B
Entry
Aryl halide
Product
Time [h]
24
Yield [%]
O N
Br
O N
NH2
1
5
6
2
2
96
86
1
24
Br
NH2
NH2
1
1
7
8
24
48
89
N
Br
N
C
trace 16 84
D
O N
Cl
O N
NH2
2
2
A
Reaction conditions: Aryl halide (1.0 mmol), commercial 25 % aqueous ammonia (2 mL), CuI (0.1 mmol), K
0.1 mmol), DMSO (2 mL), 1008C.
2 3 6
CO (2 mmol), [diol-PEG1000-DIL][PF ]
(
B
Isolated yield.
208C.
C
1
D
1
208C, 1 mmol tetrabutylammonium bromide.
[
5d,5g]
General Procedure for the Amination and Recycling
of the Catalyst System
4-Bromoaniline
(Table 2, entry 4)
White solid; d (500 MHz, CDCl ) 7.27–7.21 (m, 2H), 6.61–
H
3
Aryl halide (1.0 mmol), aqueous ammonia (2 mL), CuI (0.1 mmol),
K CO (2 mmol), [diol-PEG1000-DIL][PF ] (0.1 mmol), and
6.54 (m, 2H), 3.68 (s, 2H). dC (126 MHz, CDCl ) 145.44,
3
132.02, 116.72, 110.20.
2
3
6
DMSO (2 mL) were added into a tube and sealed. The reaction
mixture was stirred at 1008C for a certain time. After being
cooled to room temperature, the reaction mixture was extracted
with diethyl ether. The combined organic extracts were dried
over anhydrous Na SO and concentrated to give the crude
[
5d,5g,5l]
4-Nitroaniline
(Table 2, entries 5 and 15)
Yellow solid; dH (500 MHz, CDCl ) 8.12–8.06 (m, 2H),
3
6.67–6.61 (m, 2H), 4.41 (s, 2H). dC (126 MHz, CDCl3)
152.49, 139.18, 126.35, 113.38.
2
4
product, which was purified by column chromatography on
silica gel (200–300 mesh) using ethyl acetate/petroleum ether as
eluent. The products were identified by NMR, ESI-MS, and IR
analysis, all the data were compared with authentic standard
spectra.
[5d,5g,5l]
4
-Anisidine
(Table 2, entry 9)
Brown solid; dH (500 MHz, CDCl ) 6.79–6.75 (m, 2H),
3
6.69–6.64 (m, 2H), 3.76 (s, 3H), 3.44 (s, 2H). d (126 MHz,
C
CDCl ) 152.84, 139.95, 116.43, 114.84, 55.76.
3
The remaining liquid phase composed of CuI, [diol-PEG1000-
DIL][PF ], and KI formed in the reaction was dried to remove
6
[5l]
3
-Anisidine (Table 2, entry 10)
aqueous ammonia under vacuum and extracted with diethyl
ether to remove residual DMSO. The resultant residues were
reused directly without further treatment for the next run.
Yellow oil; d (500 MHz, CDCl ) 7.09 (t, J 8.0, 1H), 6.34
H
ddd, J 19.3, 8.0, 2.2, 2H), 6.27 (t, J 2.2, 1H), 3.79 (s, 3H), 3.69
3
(
(
s, 2H). d (126 MHz, CDCl ) 160.79, 147.82, 130.12, 107.95,
C
3
1
03.99, 101.12, 55.09.
Characterization Data of Products
[
5d,5g,5l]
[5g,5l]
Aniline
(Table 2, entries 1 and 6)
2-Anisidine
(Table 2, entry 11)
Yellow oil; d (500 MHz, CDCl ) 7.25–7.18 (m, 2H), 6.82
3
Yellow oil; d (500 MHz, CDCl ) 6.85 (ddd, J 6.5, 3.7, 1.3,
H
H
3
(
(
tt, J 7.4, 1.0, 1H), 6.73 (ddd, J 4.1, 3.1, 1.6, 2H), 3.67 (s, 2H). dC
126 MHz, CDCl ) 146.46, 129.34, 118.58, 115.16.
2H), 6.81–6.74 (m, 2H), 3.89 (s, 3H), 3.83 (s, 2H). d (126 MHz,
C
CDCl ) 147.38, 136.23, 121.13, 118.50, 115.08, 110.52, 55.46.
3
3
[
5d,5g,5l]
[
5d,5g,5l]
4-Acetylaniline
(Table 2, entry 12)
p-Toluidine
(Table 2, entries 2 and 7)
White solid; d (500 MHz, CDCl ) 7.84–7.79 (m, 2H), 6.67–
H
3
Yellow solid; d (500 MHz, CDCl ) 7.00 (d, J 8.1, 2H), 6.64
3
d, J 8.3, 2H), 3.55 (s, 2H), 2.28 (s, 3H). d (126 MHz, CDCl )
C
43.84, 129.77, 127.79, 115.28, 20.46.
H
6
1
.63 (m, 2H), 4.21 (s, 2H), 2.51 (s, 3H). d (126 MHz, CDCl ) d
C
3
(
1
3
96.53, 151.24, 130.80, 127.81, 113.71, 26.06.
[
5d,5l]
4-Chloroaniline
(Table 2, entry 13)
[
5g]
p-Phenylene Diamine
(Table 2, entries 3 and 8)
White solid; d (500 MHz, CDCl ) 7.16–7.08 (m, 2H), 6.67–
H
3
White solid; d (500 MHz, CDCl ) 6.59 (s, 4H), 3.35 (s, 4H).
H
6.57 (m, 2H), 3.67 (s, 2H). dC (126 MHz, CDCl ) 144.99,
3
3
d (126 MHz, CDCl ) 138.60, 116.74.
C
129.12, 123.16, 116.25.
3

CuI/[diol-PEG-DIL][PF
6
] Catalyzed Amination
G
[
5l]
4
-Fluoroaniline (Table 2, entry 14)
(g) X. F. Wu, D. Christophe, Eur. J. Org. Chem. 2009, 4753.
doi:10.1002/EJOC.200900588
Yellow oil; d (500 MHz, CDCl ) 6.92–6.85 (m, 2H), 6.66–
H
.59 (m, 2H), 3.57 (s, 2H). dC (126 MHz, CDCl ) 157.37,
3
55.50, 142.51, 116.12, 116.09, 115.76, 115.58.
3
(
h) Z. N. Guo, J. Y. Guo, Y. Song, L. M. Wang, G. Zou, Appl.
6
1
Organomet. Chem. 2009, 23, 150. doi:10.1002/AOC.1485
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[
[
[
5l]
1
-Aminonaphthalene (Table 2, entry 16)
7] F. Meng, X. H. Zhu, Y. Li, J. W. Xie, B. Wang, J. H. Yao, Y. Q. Wan,
White solid; d (500 MHz, CDCl ) 7.90–7.83 (m, 2H), 7.56–
H
Eur. J. Org. Chem. 2010, 6149.
3
7
(
.48 (m, 2H), 7.42–7.33 (m, 2H), 6.82 (dd, J 7.1, 1.2, 1H), 4.16
d, J 29.4, 2H). d (126 MHz, CDCl ) 142.16, 134.48, 128.62,
[8] Z. Q. Wu, Z. Q. Jiang, D. Wu, H. F. Xiang, X. G. Zhou, Eur. J. Org.
Chem. 2010, 1854.
[9] Y. Li, X. H. Zhu, F. Meng, Y. Q. Wan, Tetrahedron 2011, 67, 5450.
10] H. J. Xu, Y. F. Liang, Z. Y. Cai, H. X. Qi, C. Y. Yang, Y. S. Feng,
C 3
1
26.42, 125.91, 124.91, 123.74, 120.88, 119.03, 109.76.
[
[
5l]
J. Org. Chem. 2011, 76, 2296. doi:10.1021/JO102506X
11] Y. F. Zhu, Y. Y. Wei, Can. J. Chem. 2011, 89, 645. doi:10.1139/V11-051
12] (a) X. Zeng, W. M. Huang, Y. T. Qiu, J. Sheng, Org. Biomol. Chem.
2
-Aminopyridine (Table 2, entry 17)
[
Brown solid; d (500 MHz, CDCl ) 8.04 (d, J 4.8, 1H), 7.42–
H
3
[
7.35 (m, 1H), 6.64–6.57 (m, 1H), 6.46 (d, J 8.3, 1H), 4.62 (s, 2H).
d (126 MHz, CDCl ) 158.57, 148.04, 137.70, 113.86, 108.62.
2
011, 9, 8224. doi:10.1039/C1OB06208E
(b) Y. L. Hu, P. C. Wang, T. Chen, M. Lu, J. Chin. Chem. Soc. 2010,
7, 604.
C
3
5
Supplementary Material
[
[
[
[
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1
13
52, 3710. doi:10.1016/J.TETLET.2011.02.096
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The Supplementary Material contains H-NMR and C-NMR
spectra and is available on the Journal’s website.
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Acknowledgements
4
The authors are grateful for financial support by the National Natural Sci-
ence Foundation of China (No. 21002050), Doctoral Fund of Ministry of
Education of China for New Teacher (No. 200802881029), the ‘Zijin Star
Project’ and the ‘Excellence Initiative Project’ of NUST.
(
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