Copper(I) oxide catalyzed N-arylation of azoles and amines with arylboronic acid at room temperature under base-free conditions

Article abstract of DOI:10.1055/s-2008-1032184

N-Arylation of azoles and amines with arylboronic acids was efficiently carried out with heterogeneous copper(I) oxide in methanol at room temperature under base-free conditions. The products N-arylazoles and N-arylamines were isolated in good to excellent yields. A variety of arylboronic acids and amines were converted to the corresponding N-arylazoles and N-arylamines, demonstrating the versatality of the reaction. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2008-1032184

PAPER
795
Copper(I) Oxide Catalyzed N-Arylation of Azoles and Amines with
Arylboronic Acid at Room Temperature under Base-Free Conditions
C
u
O
-Catalyze
d
o-Arylation
j
of
A
zo
j
le
s
and
a
A
mines Sreedhar,* Gopaladasu T. Venkanna, Kota Balaji Shiva Kumar, Vura Balasubrahmanyam
2
Inorganic and Physical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad 500 007, India
Fax +91(40)27160921; E-mail: sreedharb@iict.res.in
Received 17 October 2007
of products with the use of a small amount of catalyst. Re-
cently, we reported the preparation of recyclable hetero-
geneous Cu-exchanged fluoroapatite and tert-
butoxyapatite catalysts, by incorporating basic species
Abstract: N-Arylation of azoles and amines with arylboronic acids
was efficiently carried out with heterogeneous copper(I) oxide in
methanol at room temperature under base-free conditions. The
products N-arylazoles and N-arylamines were isolated in good to
excellent yields. A variety of arylboronic acids and amines were F–/t-BuO– in apatite in situ by co-precipitation and subse-
converted to the corresponding N-arylazoles and N-arylamines,
demonstrating the versatality of the reaction.
quent exchange with Cu(II) for N-arylation of imidazoles
and other heterocycles with chloroarenes and fluoroarenes
(EW) with good to excellent yields for the first time.10a
Key words: copper(I) oxide, N-arylimidazoles, N-arylamines, N-
arylation, heterogeneous catalyst
We also explored bromo and iodoarenes for such cou-
pling.10b
Thus, in continuation of our work on N-arylation, we
N-Arylated azoles and amines are found in many biologi-
herein report mild and efficient N-arylation of azoles such
cally active compounds.1,2 The standard practice for N-
as imidazole, substituted imidazole, pyrazole, benzimida-
arylation reactions involves nucleophilic aromatic substi-
zole, and amines catalyzed by heterogeneous Cu2O
tution 3 and traditional Ullmann reactions 4 as well as the
(Scheme1) at room temperature under base-free condi-
coupling of imidazoles with aryllead, arylbismuth, aryl-
tions. To the best of our knowledge, N-arylation of substi-
tuted imidazole and pyrazole at room temperature has not
borane, and arylsilane reagantes.5
Previously the Chan and Lam group have developed an been explored previously. Very recently, we were the first
efficient method for coupling of azoles and arylboronic to report N-arylation of imidazole, benzimidazole, and
acids for the synthesis of N-arylated azoles using stoichio- amines with arylboronic acids at room temperature under
metric Cu(OAc)2 and pyridine as base.6 Later, Collman base-free conditions using CuFAP as catalyst.10c
and co-workers has demonstrated the use of diamine cop-
To identify the best catalytic system for N-arylation of im-
per complex for the coupling of arylboronic acid with im-
idazole and aniline with phenylboronic acid, a variety of
idazole in dichloromethane and water at room
solvents were screened and it was found that the methanol
temperature.7 Very recently, Xie and co-workers have
is the best solvent. A control reaction conducted under
shown simple copper salt catalyzed coupling of imida-
identical conditions devoid of Cu2O gave no coupled
zoles with arylboronic acids in protic solvent under reflux
product despite prolong reaction time. Cu2O was recov-
condition without any base.8 Thus, the development of
ered quantitatively by simple centrifugation and reused
mild and cost effective catalytic procedures for N-aryla-
for four cycles with consistent activity (Table1, entry 1).
tion of imidazoles and amines still remains an active re-
We chose a variety of structurally divergent arylboronic
acids possessing a wide range of functional groups to un-
derstand the scope and the generality of the Cu2O promot-
ed N-arylation of azoles to afford N-arylated azoles and
search area.9
Heterogeneous catalysis is particularly attractive as it al-
lows production and ready separation of large quantities
B(OH)2
N-azoles
HN-azoles
azoles = imidazole,
2-methylimidazole,
R1
R1
pyrazole, benzimidazole
Cu2O
NHR2
R2NH2
MeOH
r.t., air
R1
Scheme 1 N-Arylation of azoles and amine catalyzed by Cu2O
SYNTHESIS 2008, No. 5, pp 0795–0799
x
x
.
x
x
.2
0
0
8
Advanced online publication: 18.02.2008
DOI: 10.1055/s-2008-1032184; Art ID: P12007SS
© Georg Thieme Verlag Stuttgart · New York

796
B. Sreedhar et al.
PAPER
Table 1 N-Arylation of Imidazoles with Arylboronic Acidsa
Table 2 N-Arylation of Amines with Phenylboronic Acida
Cu2O
H
B(OH)2
+
Cu2O
N
R1
NH-azole
+
ArB(OH)2
Ar-N-azole
MeOH, r.t., air
R1NH2
MeOH, r.t., air
Entry
Arylboronic acid
NH-Azole
Time Yield
(h)
(%)b
Entry
1
Amines
Time (h) Yield (%)b
N
NH2
B(OH)2
4
4
92
90
1
2
3
5
95, 92c
N
H
2a
1a
1a
NH2
2
3
4
B(OH)2
5
6
95
95
NH2
Me
5
6
90
80
2b
B(OH)2
NH
1a
MeO
2c
NH
5
6
6
4
85
95
B(OH)2
O
4
5
6
1a
1a
1a
5
6
5
90
85
92
Me
NH2
O2N
B(OH)2
B(OH)2
a Conditions: amine (1.5 mmol), arylboronic acid (1 mmol), Cu2O
(0.055 mmol), MeOH (4 mL), r.t., under air.
b Isolated yields.
the results are summarized in Table1. Arylboronic acids
with electron-donating groups such as p-tolylboronic ac-
id, 4-methoxyphenylboronic acid afforded better yields
(Table1, entries 2 and 3) than with electron-withdrawing
group such as 3-nitrophenylboronic acid and 4-fluorophe-
nylboronic acid (Table1, entries 5 and 7). 2-Bromo and 4-
bromophenylboronic acid react similarly to provide the
corresponding N-arylated imidazole which shows that
there is not much effect of ortho- and para-substitution on
phenylboronic acid (Table1, entries 6 and 8). No side
products such as anisole or deboronation of phenylboron-
ic acid was observed in N-arylation of imidazole with
phenylboronic acid and the selectivity of 1-phenyl-1H-
imidazole is >99%. It is noteworthy to observe that when
the reaction conducted in the absence of air their was no
coupled product, which clearly emphasizes that the pro-
cess is redox.
Br
F
B(OH)2
7
8
1a
1a
5
5
90
95
B(OH)2
Br
N
9
2a
12
95
Me
N
H
1b
1b
10
11
2b
2c
12
12
90
92
1b
N
12
2a
12
90
N
H
1c
1c
Various other azoles such as 2-methylimidazoles, pyra-
zoles, and benzimidazoles were also successfully coupled
with arylboronic acids to give N-arylated products in good
yields. Among these azoles, 2-methylimidazoles, and
pyrazoles reacted equally good with boronic acids to af-
ford the corresponding N-arylated products, but the reac-
tions took longer when compared to imidazoles (Table1,
entries 9–15).
13
14
2b
2c
12
12
92
94
1c
N
15
2a
15
90
N
H
1d
1d
16
17
2b
2c
15
15
85
88
After achieving excellent results with azoles, we further
applied this catalytic system for the N-arylation of amines
with phenylboronic acid to afford corresponding N-ary-
lated amines in good yields and the results are summa-
rized in Table2.
1d
a Reaction conditions: azole (1.2 mmol), arylboronic acid (1 mmol),
Cu2O (0.055 mmol), MeOH (4 mL), r.t, under air.
b Isolated yields.
c Yield after fourth cycle.
Synthesis 2008, No. 5, 795–799 © Thieme Stuttgart · New York

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Cu2O-Catalyzed N-Arylation of Azoles and Amines
797
1H NMR (300 MHz, CDCl3): δ = 7.71 (s, 1 H), 7.28 (d, J = 9.0 Hz,
2 H), 7.15 (br s, 1 H), 7.11 (br s, 1 H), 6.94 (d, J = 9.0 Hz, 2 H), 3.83
(s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 159.0, 135.8, 130, 130.8, 123 (2
C), 118.5, 114.6, (2 C), 55.2.
We chose a variety of structurally divergent amines to un-
derstand the scope and generality of N-arylation of
amines. Among the aliphatic amines tested n-butylamine
provided excellent yields of N-butylaniline in short dura-
tion of time (Table2, entry 6), whereas amines such as pi-
peridine and morpholine took long duration of time with
moderate yields (Table2, entries 4 and 5). Aromatic
amine such as aniline reacted very fast to afford diphenyl-
amine with excellent yields in short duration (Table2, en-
try 1). It was interesting to note that the formation of the
conceivable diarylated product is not observed in our con-
ditions.
EI-MS: m/z = 174 (100%), 159, 147, 132, 120, 77.
HRMS: m/z calcd for C10H10N2O (M+): 174.079; found: 174.078.
1-(2-Methylphenyl)-1H-imidazole (Table 1, entry 4)
1H NMR (300 MHz, CDCl3): δ = 7.59 (br s, 1 H), 7.37–7.28 (m, 3
H), 7.23–7.20 (m, 2 H), 7.06 (br s, 1 H), 2.19 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 148.2, 138.4, 135.6, 130.7, 130.1,
118.4, 114.0, 111.1, 107.7.
In conclusion, N-arylation of imidazoles and amines was
performed using Cu2O catalyst under mild conditions.
The following features make this process attractive: (1)
base-free N-arylation, (2) the reaction is carried out at
room temperature, (3) the procedure works well with a va-
riety of azoles and amines, affording good to excellent
yields, (4) ready availability of Cu2O catalyst, and (5) re-
usability of the catalyst.
HRMS: m/z calcd for C10H10N2 (M+): 158.084; found: 158.084.
1-(3-Nitrophenyl)-1H-imidazole (Table 1, entry 5)
1H NMR (200 MHz, DMSO-d6): δ = 8.36 (s, 1 H), 8.24–8.02 (m, 2
H), 7.91 (d, J = 9.4 Hz, 1 H), 7.74 (t, J = 8.6 Hz, 1 H), 7.52 (br s, 1
H), 7.18 (br s, 1 H).
13C NMR (75 MHz, CDCl3): δ = 149.1, 138.3, 125.5, 131.5, 131.2,
126.9, 122.1, 118.0, 16.2.
EI-MS: m/z = 189 (100%), 132, 116, 89, 76, 63, 50.
HRMS: m/z calcd for C9H8N3O2 (M + H+): 190.0611; found:
190.0600.
All chemicals were purchased from Aldrich and were used as re-
ceived. All solvents were of analytical grade from Merck India Pvt.
Ltd. and used as such. The 1H spectra of samples were recorded on
a Gemini 200 MHz and Bruker Avance 300 MHz spectrometer us-
ing TMS as an internal standard in CDCl3.
1-(4-Bromophenyl)-1H-imidazole (Table 1, entry 6)
1H NMR (300 MHz, CDCl3): δ = 7.83 (br s, 1 H), 7.63 (m, 2 H),
7.32–7.20 (m, 4 H).
13C NMR (75 MHz, CDCl3): δ = 136.3, 135.4, 132.9, 130.7, 122.9,
120.8, 118.0.
N-Arylation of Azoles with Arylboronic Acid at Ambient
Conditions; General Procedure
Cu2O (0.055 mmol) was added to a mixture of azole (1.2 mmol) and
arylboronic acid (1 mmol) in MeOH (3 mL) at r.t., and the mixture
was stirred for 5 h under an atmosphere of air. The progress of the
reaction was monitored by TLC and on completion of the reaction,
the mixture was centrifuged and the centrifugate was concentrated
under reduced pressure to give the crude product. The crude product
was purified by column chromatography on silica gel (hexane–
EtOAc, 70:30) to afford the N-arylated azoles.
EI-MS: m/z = 222 (M+).
Anal. Calcd for C9H7BrN2: C, 48.46; H, 3.16; N, 12.56. Found: C,
48.41; H, 3.11; N, 12.53.
1-(4-Fluorophenyl)-1H-imidazole (Table 1, entry 7)
1H NMR (300 MHz, CDCl3): δ = 7.79 (br s, 1 H), 7.33–7.36 (m, 2
H), 7.14–7.21 (m, 4 H).
13C NMR (75 MHz, CDCl3): δ = 163.4, 160, 133.5, 130.4, 123.2 (2
1-Phenyl-1H-imidazole (Table 1, entry 1)
IR (film): 3424, 3117, 1600, 1509, 1304, 1253, 1110, 1058, 908,
760, 690, 659, 520 cm–1.
1H NMR (300 MHz, CDCl3): δ = 7.83 (s, 1 H), 7.50–7.30 (m, 5 H),
7.25 (br s, 1 H), 7.18 (br s, 1 H).
C), 118.2, 116.5 (2 C).
EI-MS: m/z = 162 (100%), 141, 135, 129, 108, 95, 83, 71, 57.
HRMS: m/z calcd for C9H7FN2 (M+): 162.059; found: 162.059.
13C NMR (75 MHz, CDCl3): δ = 137.3, 135.7, 130.3, 129.9, 127.5,
1-(2-Bromophenyl)-1H-imidazole (Table 1, entry 8)
1H NMR (300 MHz, CDCl3): δ = 7.71 (d, J = 8.3 Hz, 1 H), 7.59 (br
s, 1 H), 7.47–7.26 (m, 3 H), 7.13 (br s, 1 H), 7.01 (br s, 1 H).
121.5, 118.3.
EI-MS: m/z = 144 (100%), 117, 77, 51.
HRMS: m/z calcd for C9H8N2 (M+): 144.069; found: 144.069.
13C NMR (75 MHz, CDCl3): δ = 137.1, 136.3, 133.5, 129.7, 128.9,
128.1, 127.1, 120.1, 119.5.
EI-MS: m/z = 222 (M+).
1-(4-Methylphenyl)-1H-imidazole (Table 1, entry 2)
IR (film): 3391, 3115, 2924, 1612, 1522, 1488, 1304, 1249, 1112,
1058, 964, 908, 816, 735, 661, 616, 523 cm–1.
Anal. Calcd for C9H7BrN2: C, 48.46; H, 3.16; N, 12.56. Found: C,
48.42; H, 3.10; N, 12.51.
1H NMR (300 MHz, CDCl3): δ = 7.76 (s, 1 H), 7.24 (m, 4 H), 7.19
2-Methyl-1-phenyl-1H-imidazole (Table 1, entry 9)
1H NMR (300 MHz, CDCl3): δ = 7.49–7.36 (m, 3 H), 7.30–7.26 (m,
2 H), 6.98–6.93 (m, 2 H), 3.35 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 144.0, 137.4, 128.9, 127.5, 126.9,
124.9, 120.6, 13.0.
(br s, 1 H), 7.13 (br s, 1 H), 2.39 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 137.4, 135.5, 134.9, 130.3, 130.1,
121.3, 118.3, 20.9.
EI-MS: m/z = 158 (100%), 131, 104, 91, 50.
Anal. Calcd for C10H10N2: C, 75.92; H, 6.37; N, 17.71. Found: C,
75.88; H, 6.31; N, 17.68.
1-(4-Methoxyphenyl)-1H-imidazole (Table 1, entry 3)
IR (film): 3415, 2928, 1675, 1520, 1464, 1302, 1250, 1181, 1113,
1059, 1029, 833, 764, 661, 614, 536 cm–1.
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798
B. Sreedhar et al.
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2-Methyl-1-p-tolyl-1H-imidazole (Table 1, entry 10)
1H NMR (300 MHz, CDCl3): δ = 7.31–7.12 (m, 5 H), 7.03 (s, 1 H),
2.42 (s, 3 H), 2.30 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 138.0, 135.3, 129.7, 126.8, 125.0,
20.7, 13.3.
13C NMR (75 MHz, CDCl3): δ = 144, 142, 138, 134 (2 C), 130.5,
124, 123.6, 122.8 (2 C), 120.3, 110.1 (2 C), 21.
EI-MS: m/z = 209 (M+ + 1), 208 (M+), 192, 179, 151, 91, 65.
Anal. Calcd for C14H12N2: C, 80.74; H, 5.81; N, 13.45. Found: C,
80.70; H, 5.80; N, 13.40
Anal. Calcd for C11H12N2: C, 76.71; H, 7.02; N, 16.27. Found: C,
76.67; H, 6.97; N, 16.19.
1-(4-Methoxyphenyl)-1H-benzimidazole (Table 1, entry 17)
1H NMR (300 MHz, CDCl3): δ = 8.06 (br s, 1 H), 7.86–7.88 (m, 1
H), 7.45–7.47(m, 1 H), 7.41 (d, J = 9.0 Hz, 2 H), 7.30–7.33 (m, 2
H), 7.06 (d, J = 9.0 Hz, 2 H), 3.88 (s, 3 H).
1-(4-Methoxyphenyl)-2-methyl-1H-imidazole (Table 1, entry
11)
1H NMR (300 MHz, CDCl3): δ = 7.22–7.15 (m, 2 H), 6.97–6.88 (m,
4 H), 3.84 (s, 3 H), 2.31 (s, 3 H).
EI-MS: m/z = 224 (100%), 209, 192, 181, 141, 121, 117, 82, 77, 55,
47.
13C NMR (75 MHz, CDCl3): δ = 144.5, 137.8, 129.3, 128.0, 127.3,
125.3, 120.4, 13.4.
HRMS: m/z calcd for C14H13N2O (M + H): 225.102245; found:
225.10241.
Anal. Calcd for C11H12N2O: C, 70.19; H, 6.43; N, 14.88. Found: C,
70.18; H, 6.40; N, 14.86
N-Arylation of Phenylboronic Acid with Amines; General Pro-
cedure
1-Phenyl-1H-pyrazole (Table 1, entry 12)
In a typical experimental procedure, Cu2O (0.055 mmol) was added
to a mixture of amine (1.5 mmol) and phenylboronic acid (1 mmol)
in MeOH (3 mL) at r.t., and the mixture was stirred for 3 h under an
atmosphere of air. The progress of the reaction was monitored by
TLC and on completion of the reaction, the mixture was centrifuged
and the centrifugate was concentrated under reduced pressure to
give the crude product. The crude product was purified by column
chromatography on silica gel (hexane–EtOAc, 20:1) to afford the
diphenylamine.
IR (KBr): 3142, 3121, 3150, 1601, 1521, 1501, 1464, 1393, 1332,
1253, 1198, 1120, 1074, 1046, 1036, 936, 915, 756 cm–1.
1H NMR (300 MHz, CDCl3): δ = 7.84 (s, 1 H), 7.65 (d, J = 8.3 Hz,
3 H), 7.23 (t, J = 8.3 Hz, 2 H), 7.20 (t, J = 7.1 Hz, 1 H), 6.37 (s, 1
H).
13C NMR (75 MHz, CDCl3): δ = 141.1, 140.2, 129.4, 126.8, 126.4,
119.2, 107.6.
EI-MS: m/z = 144.
Diphenylamine (Table 2, entry 1)
Anal. Calcd for C9H8N2: C, 74.98; H, 5.59; N, 19.43. Found: C,
74.96, H, 5.54; N, 19.39.
1H NMR (300 MHz, CDCl3): δ = 7.23–7.16 (m, 4 H), 7.02–6.97 (m,
4 H), 6.89–6.82 (m, 2 H), 5.56 (br s, 1 H).
EI-MS: m/z = 168 (100%), 96, 81, 67, 54, 45.
1-(4-Methylphenyl)-1H-pyrazole (Table 1, entry 13)
1H NMR (300 MHz, CDCl3): δ = 7.82 (d, J = 2.26 Hz, 1 H,), 7.63
(s, 1 H), 7.53 (d, J = 8.3 Hz, 2 H), 7.19 (d, J = 8.3 Hz, 2 H), 6.37
(s, 1 H), 2.33 (s, 3 H).
Anal. Calcd for C12H11N: C, 85.17; H, 6.55; N, 8.28. Found: C,
85.13; H, 6.52; N, 8.26.
13C NMR (75 MHz, CDCl3): δ = 140.7, 138.02, 136.1, 126.66,
N-Phenylbenzylamine (Table 2, entry 2)
1H NMR (300 MHz, CDCl3): δ = 7.37–7.16 (m, 5 H), 7.27–7.20 (m,
1 H), 7.15–7.04 (m, 1 H), 6.70–6.60 (m, 1 H), 6.55 (d, J = 7.81 Hz,
2 H), 4.29 (s, 2 H), 3.90 (br s, 1 H).
129.93, 119.15, 107.3, 20.90.
EI-MS: m/z = 158 (100%).
Anal. Calcd for C10H10N2: C, 75.92; H, 6.37; N, 17.71. Found: C,
75.90; H, 6.33; N, 17.68.
EI-MS: m/z = 183, 135, 91 (100%), 77, 55.
HRMS: m/z calcd for C13H14N (M + H+): 184.1121; found:
184.1129.
1-(4-Methoxyphenyl)-1H-pyrazole (Table 1, entry 14)
1H NMR (300 MHz, CDCl3): δ = 7.77 (d, J = 2.26 Hz, 1 H), 7.62
(s, 1 H), 7.54 (d, J = 8.3 Hz, 2 H), 6.90 (d, J = 8.3 Hz, 2 H), 6.37 (s,
1 H), 3.70 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 157.52, 140.2, 133.4, 127.31,
119.90, 114.46, 107.2, 55.29.
N-Cyclohexylaniline (Table 2, entry 3)
1H NMR (300 MHz, CDCl3): δ = 7.07 (t, J = 8.3 Hz, 2 H), 6.58 (t,
J = 7.55 Hz, 1 H), 6.5 (d, J = 7.5 Hz, 2 H), 3.28–3.18 (m, 1 H),
2.11–2.02 (m, 2 H), 1.82–1.71 (m, 2 H), 1.70–1.60 (m, 1 H), 1.45–
1.06 (m, 5 H).
EI-MS: m/z = 174 (100%).
EI-MS: m/z = 174 (100%), 148, 132, 119, 97, 83, 71, 57.
Anal. Calcd for C10H10N2O: C, 68.95; H, 5.79; N, 16.08. Found: C,
68.91; H, 5.74; N, 16.01.
13C NMR (75 MHz, CDCl3): δ = 147.3, 129.2, 116.7, 113.3, 51.6,
33.4, 25.9, 25.0.
HRMS: m/z calcd for C12H18N (M + H+): 176.1434; found:
176.1430.
1-Phenyl-1H-benzimidazole (Table 2, entry 15)
1H NMR (300 MHz, CDCl3): δ = 8.09 (s, 1 H), 7.81–7.87 (m, 1 H),
7.43–7.60 (m, 6 H), 7.5–7.3 (m, 2 H).
13C NMR (75 MHz, CDCl3): δ = 144, 142.2, 136.5, 133.7, 130,
127.9, 124, 123.5, 122.8 (2 C), 120.6, 110.5 (2 C).
N-Phenylpiperidine (Table 2, entry 4)
1H NMR (300 MHz, CDCl3): δ = 7.25–7.18 (m, 2 H), 6.93 (d,
J = 8.0 Hz, 2 H), 6.82–6.79 (m, 1 H), 3.13 (t, J = 8.0 Hz, 4 H),
1.72–1.66 (m, 4 H), 1.58–1.52 (m, 2 H).
EI MS: m/z = 194 (100%), 165, 138, 77, 50.
HRMS: m/z calcd for C11H16N (M + H+): 162.1277; found:
162.1271.
Anal. Calcd for C13H10N2: C, 80.39; H, 5.19; N, 14.42. Found: C,
80.30; H, 5.12; N, 14.40.
1-(4-Methylphenyl)-1H-benzimidazole (Table 1, entry 16)
1H NMR (300 MHz, CDCl3): δ = 8.01 (br s, 1 H), 7.78–7.84 (m, 1
H), 7.39–7.45 (m, 1 H), 7.20–7.31 (m, 6 H), 2.42 (s, 3 H).
4-Phenylmorpholine (Table 2, entry 5)
1H NMR (300 MHz, CDCl3): δ = 7.28 (t, J = 7.20 Hz, 2 H), 6.89–
6.94 (m, 3 H), 3.86 (t, J = 4.47 Hz, 4 H), 3.17 (t, J = 4.47 Hz, 4 H).
Synthesis 2008, No. 5, 795–799 © Thieme Stuttgart · New York

PAPER
Cu2O-Catalyzed N-Arylation of Azoles and Amines
799
13C NMR (75 MHz, CDCl3): δ = 155.8, 129.8, 120.3, 115.4, 67.0,
49.6.
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HRMS: m/z calcd for C10H14NO (M + H+): 164.0997; found:
164.1001.
N-Butylaniline (Table 2, entry 6)
1H NMR (300 MHz, CDCl3): δ = 7.10 (t, J = 7.55 Hz, 1 H), 6.61 (t,
J = 7.55 Hz, 1 H), 6.55–6.48 (m, 2 H), 3.10 (t, J = 6.79 Hz, 3 H),
1.67–1.55 (m, 2 H), 1.51–1.37 (m, 2 H), 0.97 (t, J = 7.55 Hz, 3 H).
EI-MS: m/z = 149, 119, 106 (100), 77, 51, 43.
HRMS: m/z calcd for C10H16N (M + H+): 150.1277; found:
150.1268.
Acknowledgment
K.B.S.K, G.T.V, and V.B. thank UGC and CSIR, India for their fel-
lowships.
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Synthesis 2008, No. 5, 795–799 © Thieme Stuttgart · New York