Very fast, ligand-free and aerobic protocol for the synthesis of 4-aryl-substituted triphenylamine derivatives

Article abstract of DOI:10.1002/ejoc.201100072

A fast, convenient and ligand-free protocol for the synthesis of a series of 4-aryl-substituted triphenylamine derivatives by a palladium-catalysed aerobic Suzuki reaction of aryl halides with [4-(diphenylamino)phenyl]boronic acid in aqueousiPrOH is described. Importantly, both aryl bromides and heteroaryl halides afforded good to excellent yields under mild conditions. A facile, efficient and general ligand-free Suzuki reaction in aqueous iPrOH is described. Under the optimized conditions, both aryl bromides and heteroaryl halidesreacted rapidly with [4-(diphenylamino)phenyl]boronic acid, providing a series of 4-aryl-substituted triphenylamine derivatives in good to excellent yields.

Full text of DOI:10.1002/ejoc.201100072

FULL PAPER
DOI: 10.1002/ejoc.201100072
Very Fast, Ligand-Free and Aerobic Protocol for the Synthesis of 4-Aryl-
Substituted Triphenylamine Derivatives
Chun Liu,*[a] Qijian Ni,[a] and Jieshan Qiu*[a]
Keywords: Synthetic methods / Palladium / Boron / Cross coupling / Amines
A fast, convenient and ligand-free protocol for the synthesis
of a series of 4-aryl-substituted triphenylamine derivatives by
a palladium-catalysed aerobic Suzuki reaction of aryl halides
with [4-(diphenylamino)phenyl]boronic acid in aqueous
iPrOH is described. Importantly, both aryl bromides and het-
eroaryl halides afforded good to excellent yields under mild
conditions.
tuted triphenylamine derivatives by using two alternative
cross-coupling paths (Scheme 1). Path I is the cross-cou-
pling of (4-bromophenyl)diphenylamine with arylboronic
acids, and Path II employs aryl halides and [4-(di-
phenylamino)phenyl]boronic acid as the coupling partners.
However, as far as we know, these two reaction paths were
performed in the presence of phosphane ligands, resulting
in moderate yields over a long reaction period.[26–30] We re-
cently developed two ligand-free and aerobic protocols for
an efficient Pd(OAc)2-catalysed Suzuki reaction.[31,32] En-
couraged by this development, we report herein a fast and
ligand-free protocol for the construction of 4-substituted
triphenylamine derivatives in aqueous 2-propanol in air by
Path II.
Introduction
Triphenylamine (TPA) derivatives, due to the non-co-
planarity of the three phenyl substituents, strong electron-
donating nature, high light-to-electrical energy-conversion
efficiencies and good hole-transporting capability are im-
portant structural motifs in numerous dye-sensitized solar
cells (DSSCs)[1–4] and organic electroluminescence materi-
als.[5,6] 4-Aryl-substituted triphenylamine derivatives have
also attracted considerable attention due to their wide range
of applications in DSSCs and organic light-emitting diodes
(OLEDs). For example, Sun and co-workers synthesized a
series of novel organic dyes, which provided a high solar-
energy conversion efficiency (η) of up to 7.03%.[7] Bai et al.
introduced two triphenylamine chromophores at the 3,3Ј-
positions of binaphthyl moieties to afford a new hole-trans-
port material, TPA–BN–TPA, with a current efficiency of
3.85 cd/A and a maximum brightness of 10100 cd/m2.[8]
So far, numerous approaches to the construction of 4-
aryl-substituted triphenylamine derivatives have been devel-
oped.[9–13] However, these methods always involve the use
of toxic substrates, harsh conditions, long reaction times
and low yields. Therefore, there remains a need for more
effective methods that grant chemists facile access to this
important type of compounds.
Scheme 1. Alternative pathways for the synthesis of 4-aryl-substi-
tuted triphenylamine derivatives.
Results and Discussion
The palladium-catalysed Suzuki reaction is one of the
most versatile, powerful and convenient methods for the
synthesis of carbon–carbon bonds, in particular, for the for-
mation of biaryls.[14–19] Recent advances have enabled this
transformation to be performed without any additional li-
gand under mild conditions.[20–25] Consequently, the Suzuki
reaction can also be applied to the formation of 4-substi-
Optimization of Reaction Conditions
In our protocol, solvents play a crucial role in the palla-
dium(II)-catalysed ligand-free Suzuki reaction. Therefore,
we initially investigated the effect of different solvents on
the model cross-coupling reaction of 4-bromobenzonitrile
with [4-(diphenylamino)phenyl]boronic acid in air at room
temperature. The results are illustrated in Table 1. We chose
several solvents that were commonly used in the palladium-
catalysed ligand-free Suzuki reaction. Both 50% aq. EtOH
and 50% aq. iPrOH gave the cross-coupling products in
good to excellent yields in the presence of 0.5 mol-%
[a] State Key Laboratory of Fine Chemicals, Dalian University of
Technology,
Linggong Road 2, Dalian 116024, China
E-mail: chunliu70@yahoo.com
jqiu@dlut.edu.cn
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201100072.
Eur. J. Org. Chem. 2011, 3009–3015
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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C. Liu, Q. Ni, J. Qiu
Pd(OAc)2 in 10 min (Table 1, Entries 1 and 2). However, Table 2. Effect of base on the Suzuki reaction.[a]
FULL PAPER
other solvents, such as 50% aq. DMF, 50% aq. ethylene
glycol and 50% aq. PEG400, resulted in low yields (Table 1,
Entries 3–5). Although the Pd(OAc)2/PEG400 system could
strongly activate aryl chlorides for the Suzuki reaction at
room temperature,[31] an isolated yield of only 52% was ob-
tained (Table 1, Entry 6).
Entry
Base
Time [min]
Yield [%][b]
1
2
3
4
5
K2CO3
K3PO4·7H2O
NaOH
NaOCH3
Et3N
5
4
5
5
5
98
98
76
68
49
[a] Reaction conditions: 4-bromobenzonitrile (0.25 mmol), [4-(di-
phenylamino)phenyl]boronic acid (0.375 mmol), Pd(OAc)2
(0.5 mol-%), base (0.5 mmol), iPrOH/H2O (1.35 mL/0.65 mL),
room temperature, air. The reaction was monitored by TLC. [b]
Isolated yields.
Table 1. Effect of different solvents on the Suzuki reaction.[a]
control experiments were carried out in air and under nitro-
gen. Table 3 shows that the reactivity decreased sharply and
that low yields were obtained after addition of a phosphane
ligand, both under nitrogen and in air, in comparison to
the ligand-free conditions (Table 3, Entries 1–6). For exam-
ple, the water-soluble ligand TPPTS [3,3Ј,3ЈЈ-phosphinid-
ynetris(benzenesulfonic acid) trisodium salt] gave an iso-
lated yield of 35% under nitrogen (Table 3, Entry 5) with a
still smaller amount of the product obtained in air (Table 3,
Entry 6), whereas the reaction afforded excellent yields both
under nitrogen and in air in the absence of ligand (Table 3,
Entries 1 and 2). This is possibly because a complex is ini-
tially formed between TPPTS and the PdII salt, which de-
mands a long induction period for the active catalyst to
form. In the case of the ligand-free protocol, the zero-valent
palladium, the catalytic species in the reaction, is generated
in situ from PdII salts under the reaction conditions and
exhibits high activity.[31,32]
Entry
Solvent (v/v)
Time [min]
Yield [%][b]
1
2
3
4
5
6
7
8
9
iPrOH/H2O (1:1)
EtOH/H2O (1:1)
DMF/H2O (1:1)
ethylene glycol/H2O (1:1)
PEG400/H2O (1:1)
neat PEG400
10
10
10
10
10
10
10
10
5
91
80
48
19
8
52
37
98
98
34
18
neat iPrOH
iPrOH/H2O (3:1)
iPrOH/H2O (2:1)
iPrOH/H2O (1:2)
iPrOH/H2O (1:3)
10
11
10
10
[a] Reaction conditions: 4-bromobenzonitrile (0.25 mmol), [4-(di-
phenylamino)phenyl]boronic acid (0.375 mmol), Pd(OAc)2
(0.5 mol-%), K2CO3 (0.5 mmol), solvent (2 mL), room temperature,
air. The reaction was monitored by TLC. [b] Isolated yields.
We next optimized the volume ratio of iPrOH/H2O in
the Suzuki reaction of 4-bromobenzonitrile with [4-(di-
phenylamino)phenyl]boronic acid. In accordance with lit-
erature reports,[33,34] the amount of water had a strong in-
fluence on the reaction. Low yields were obtained when an
excess amount of water was present in the catalytic system
(Table 1, Entries 10 and 11). Inversely, increasing the vol-
ume ratio of iPrOH/H2O to 2:1 led to an isolated yield of
98% in 5 min (Table 1, Entry 9). By further increasing the
volume of iPrOH to 75%, the cross-coupling reaction still
gave a quantitative yield after 10 min (Table 1, Entry 8),
whereas a yield of only 37% was obtained in neat iPrOH
(Table 1, Entry 7). Thus, the best solvent was 66% aq.
iPrOH, which provided the highest cross-coupling yield of
98% in 5 min. We suppose that a suitable amount of water
as co-solvent could dissolve the inorganic base and thus
shorten the induction period.
Further investigations were carried out to examine the
influence of the base on the same model reaction. The ex-
perimental data presented in Table 2 shows that both
K3PO4·7H2O and K2CO3 induced high reactivity and that
K3PO4·7H2O was more effective than K2CO3 in terms of
rate (Table 2, Entries 1 and 2). In addition, the organic base
Et3N exhibited poor activity (Table 2, Entry 5). Therefore,
the results reveal that K3PO4·7H2O is the preferred base in
this catalytic system.
Table 3. Effect of the ligand on the Suzuki reaction.[a]
Entry
Ligand
Time [min]
Yield [%][b]
1
2
3
4
5
6
none
none
PPh3
PPh3
TPPTS
TPPTS
4
4
4
4
4
4
93
98[c]
trace
trace[c]
35
22[c]
[a] Reaction conditions: 4-bromobenzonitrile (0.25 mmol), [4-(di-
phenylamino)phenyl]boronic acid (0.375 mmol), Pd(OAc)2
(0.5 mol-%), K3PO4·7H2O (0.5 mmol), iPrOH/H2O (1.35 mL/
0.65 mL), ligand (2 mol-%), room temperature, nitrogen. The reac-
tion was monitored by TLC. [b] Isolated yields. [c] Performed in
air.
Scope and Limitations of Substrates
To explore the catalytic properties of the reaction under
With the optimized conditions in hand, we next investi-
ligand-free conditions and in the presence of phosphanes, gated the scope and limitations of this catalytic system for
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Synthesis of 4-Aryl-Substituted Triphenylamine Derivatives
various aryl bromides. As shown in Table 4, the electronic bearing electron-deficient or moderately electron-rich
nature of the substituent group has a small influence on groups exhibited high reactivity and furnished the products
the reactivity of the cross-coupling reactions. Aryl bromides in high yields in short reaction times (Table 4, Entries 1–9).
However, aryl bromides bearing strong electron-rich
groups, such as OH and NH2, led to lower reactivity and
Table 4. Suzuki reaction of aryl bromides with [4-(diphenylamino)-
afforded the desired products in good to excellent yields at
phenyl]boronic acid.[a]
an elevated temperature of 50 °C (Table 4, Entries 10–12).
Moreover, in this catalytic system ortho-substituted sub-
strates exhibited almost the same reactivity in terms of rate
and yield (Table 4, Entries 2, 4 and 11). Thus, in compari-
son with the reported method,[29] which employed aryl io-
dides in the presence of [Pd(PPh3)4] over 16 h for the 4-aryl-
substituted TPA derivatives, the present protocol is a much
more efficient and facile process.
To further extend the scope of this methodology, we tried
to carry out the Suzuki coupling of heteroaryl halides with
[4-(diphenylamino)phenyl]boronic acid in Pd(OAc)2/iPrOH/
H2O. First, the coupling reaction between 2-bromopyridine
and [4-(diphenylamino)phenyl]boronic acid was chosen as
the model reaction to optimize the reaction conditions. The
results are summarized in Table 5. Unfortunately, the stan-
dard conditions used for aryl bromides were not suitable for
2-bromopyridine, and a relatively low yield was delivered
in 1 h (Table 5, Entry 1), even at 50 °C (Table 5, Entry 2),
although a good yield was obtained by raising the tempera-
ture to 80 °C (Table 5, Entry 3). Moreover, increasing the
palladium loading to 1.5 mol-% led to the desired cross-
coupling product 13 in 92% isolated yield in 20 min with
the highest TOF value of 184 h–1 (Table 5, Entry 5). There-
fore, the cross-coupling reactions of heteroaryl halides with
[4-(diphenylamino)phenyl]boronic acid were carried out by
using 1.5 mol-% Pd(OAc)2 at 80 °C in air.
In addition to 2-bromopyridine, other 2-halopyridines as
one of the coupling partners also exhibited high reactivity
and afforded good to excellent yields of the desired prod-
ucts. As demonstrated in Table 6, the coupling reactions of
5- or 6-substituted 2-bromopyridines with [4-(di-
phenylamino)phenyl]boronic acid produced the desired
products in excellent yields (Table 6, Entries 1–9). 2,6-Di-
[a] Reaction conditions: aryl bromide (0.25 mmol), [4-(di-
bromopyridine delivered the double coupling product 22 in
67% yield in the presence of 3 mol-% Pd(OAc)2 and
4 equiv. of base (Table 6, Entry 10). Other 2-halogenated
phenylamino)phenyl]boronic acid (0.375 mmol), Pd(OAc)2
(0.5 mol-%), K3PO4·7H2O (0.5 mmol), iPrOH/H2O (1.35 mL/
0.65 mL), room temperature, air. The reaction was monitored by
TLC. [b] Isolated yields. [c] Performed at 50 °C.
Table 5. Optimization of the reaction conditions for the Suzuki reaction of 2-bromopyridine with [4-(diphenylamino)phenyl]boronic
acid.[a]
Entry
Pd loading [mol-%]
Temp. [°C]
Time [min]
Yield [%][b]
TOF [h–1]
1
2
3
4
5
0.5
0.5
0.5
1
25
50
80
80
80
60
60
60
40
20
42
51
82
97
92
84
102
164
146
184
1.5
[a] Reaction conditions: 2-bromopyridine (0.25 mmol), [4-(diphenylamino)phenyl]boronic acid (0.375 mmol), Pd(OAc)2, K3PO4·7H2O
(0.5 mmol), iPrOH/H2O (1.35 mL/0.65 mL), air. The reaction was monitored by TLC. [b] Isolated yields.
Eur. J. Org. Chem. 2011, 3009–3015
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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C. Liu, Q. Ni, J. Qiu
FULL PAPER
Table 6. Suzuki reactions of heteroaryl halides with [4-(di- heteroarenes also exhibited high reactivity and yields. For
phenylamino)phenyl]boronic acid.[a]
example, 2-bromoquinoline produced the expected biaryl 23
in 94% yield within 5 min (Table 6, Entry 11). In addition,
deactivated 2-chloropyrazine coupled with [4-(di-
phenylamino)phenyl]boronic acid under the reaction condi-
tions used provided a yield of 86% in 35 min (Table 6, En-
try 12). Note that this catalytic system is also suitable for
sulfur-containing heteroaryl bromides. A quantitative yield
of product 25 was obtained by using 2-bromothiophene as
a coupling partner in 1 h (Table 6, Entry 13). To the best of
our knowledge, product 25 is a very important intermediate
in OLEDs or DSSCs. Our protocol for the formation of 25
is simpler and more efficient than other previously reported
procedures.[13,26,27] Moreover, 5-halogenated heteroarenes,
such as 5-bromopyrimidine and 5-bromoindole, provided
good yields (Table 6, Entries 14 and 15). However, the 3-
halogenated heteroarenes were less active and gave lower
yields even over a prolonged period (Table 6, Entries 17 and
18). Thus, this work provides an efficient and very practical
method for the synthesis of 4-substituted triphenylamine
derivatives, which have been widely used in advanced func-
tional materials such as OLEDs and DSSCs.
Comparison of the Two Alternative Cross-Coupling Paths
To determine the diversity of the two synthetic paths,
control experiments were carried out under the same reac-
tion conditions. We found that the two synthetic paths lead-
ing to product 1 gave different results. The cross-coupling
of 4-bromobenzonitrile with [4-(diphenylamino)phenyl]-
boronic acid gave nearly a quantitative yield, whereas (4-
bromophenyl)diphenylamine coupled with (4-cyanophen-
yl)boronic acid resulted in only traces of the product. To
verify this finding, in another control experiment product
25 was synthesized, giving the same results as in the synthe-
sis of product 1. This phenomenon can be explained clearly
by the electronic effect of the coupling partners. The di-
phenylamino group, a strong electron-rich group in aryl
bromides, lowers the reaction rate, whereas it enhances the
nucleophilicity of [4-(diphenylamino)phenyl]boronic acid
and increases the rate of the transmetallation step in the
Suzuki reaction.
Conclusions
We have developed a highly efficient methodology for the
synthesis of 4-substituted triphenylamine derivatives using
a Pd(OAc)2-catalysed Suzuki reaction in 66% aqueous
iPrOH. A wide range of substrates, including aryl bromides
and heteroaryl halides, readily underwent the Suzuki reac-
[a] Reaction conditions: heteroaryl halide (0.25 mmol), [4-(di-
phenylamino)phenyl]boronic acid (0.375 mmol), Pd(OAc)2
(1.5 mol-%), K3PO4·7H2O (0.5 mmol), iPrOH/H2O (1.35 mL/
0.65 mL), 80 °C, air. The reaction was monitored by TLC. [b] Iso-
lated yields. [c] Reaction conditions: 2,6-dibromopyridine
(0.25 mmol), [4-(diphenylamino)phenyl]boronic acid (0.75 mmol),
Pd(OAc)2 (3.0 mol-%), K3PO4·7H2O (1.0 mmol), iPrOH/H2O
(1.35 mL/0.65 mL), 80 °C, air.
tion with [4-(diphenylamino)phenyl]boronic acid to give
good to excellent yields.
Experimental Section
General: Unless otherwise noted, all the reactions were carried out
in air. All aryl halides were purchased from Alfa Aesar, Avocado;
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Eur. J. Org. Chem. 2011, 3009–3015

Synthesis of 4-Aryl-Substituted Triphenylamine Derivatives
[4-(diphenylamino)phenyl]boronic acid was purchased from Energy
Chemical, China. All the substrates were used without purification.
1H NMR spectra were recorded with a Bruker Avance II 400 spec-
trometer. Chemical shifts are reported in ppm relative to TMS. MS
data for the products were collected with an EIMS instrument
Micromass GCT or a Bruker Apex IV FTMS spectrometer. All
products were isolated by short-column chromatography on silica
gel (200–300 mesh) by using petroleum ether (60–90 °C) unless
otherwise noted. Compounds described in the literature were char-
acterized by comparison of the 1H NMR spectra with reported
data.
25 °C): δ = 9.43 (d, J = 2.4 Hz, 1 H, Py), 8.47–8.44 (m, 1 H, Py),
7.9 (d, J = 8.8 Hz, 2 H, C6H4), 7.80 (d, J = 8.8 Hz, 1 H, Py), 7.31
(t, J = 8.0 Hz, 4 H, Ph), 7.17–7.10 (m, 8 H, Ph and C6H4) ppm.
13C NMR (100 MHz, CDCl3, 25 °C): δ = 161.9 (CPy), 150.6 (CPy),
146.8 (CPh), 145.4 (CPy), 142.1 (C6H4), 131.7 (CPy), 129.5 (CPh),
128.7 (C6H4), 125.6 (CPh), 124.2 (C6H4), 121.6 (CPh), 118.7 (C6H4)
ppm. MS (EI): m/z = 367.1 [M]+.
4-(5-Fluoropyridin-2-yl)-N,N-diphenylaniline (15): Yield: 83.4 mg,
98%; white solid, m.p. 126–127 °C. 1H NMR (400 MHz, CDCl3,
25 °C): δ = 8.50 (d, J = 2.8 Hz, 1 H, Py), 7.81 (d, J = 8.8 Hz, 2 H,
C6H4), 7.67–7.64 (m, 1 H, Py), 7.46–7.42 (m, 1 H, Py), 7.29–7.26
(t, J = 8.0 Hz, 4 H, Ph), 7.14–7.12 (t, J = 8.4 Hz, 6 H, Ph), 7.05 (t,
J = 7.2 Hz, 2 H, C6H4) ppm. 13C NMR (100 MHz, CDCl3, 25 °C):
δ = 159.7 [d, 1J(13C,19F) = 253.7 Hz, CPy], 153.36 (CPy), 148.8
(CPh), 147.4 (C6H4), 137.47 [d, 2J(13C,19F) = 30.0 Hz, CPy], 131.7
(C6H4), 129.4 (CPh), 127.6 (C6H4), 124.8 (CPh), 123.9 [d, 2J(13C,19F)
= 18.8 Hz, CPy], 123.37 (CPh), 123.09 (CPy), 120.9 (C6H4) ppm. MS
(EI): m/z = 340.1 [M]+.
General Procedure for the Suzuki Reaction of Aryl Bromides with
[4-(Diphenylamino)phenyl]boronic Acid: A mixture of aryl bromide
(0.25 mmol), [4-(diphenylamino)phenyl]boronic acid (0.375 mmol),
Pd(OAc)2 (0.5 mol-%), K3PO4·7H2O (0.5 mmol), distilled water
(0.65 mL) and iPrOH (1.35 mL) was stirred at room temperature
in air for the indicated time. The mixture was added to brine
(15 mL) and extracted four times with ethyl acetate (4ϫ15 mL).
The solvent was evaporated under vacuum, and the product was
isolated by short-column chromatography on silica gel (200–
300 mesh).
4-(5-Methylpyridin-2-yl)-N,N-diphenylaniline (16): Yield: 78.0 mg,
93%; light-green solid, m.p. 108–110 °C. 1H NMR (400 MHz,
CDCl3, 25 °C): δ = 8.47 (s, 1 H, Py), 7.84 (d, J = 8.4 Hz, 2 H,
C6H4), 7.58–7.51 (m, 2 H, Py), 7.28–7.24 (m, 4 H, Ph), 7.15–7.12
(m, 6 H, Ph), 7.04 (t, J = 7.2 Hz, 2 H, C6H4), 2.36 (s, 3 H, CH3)
ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ = 154.3 (CPy), 149.7
(CPy), 148.4 (C6H4), 147.5 (CPh), 137.5 (CPy), 132.9 (C6H4), 131.0
(CPy), 129.3 (CPh), 127.5 (C6H4), 124.6 (CPh), 123.3 (CPh), 123.1
(C6H4), 119.5 (CPy), 18.2 (CH3) ppm. MS (EI): m/z = 336.1 [M]+.
General Procedure for the Suzuki Reaction of Heteroaryl Halides
with [4-(Diphenylamino)phenyl]boronic Acid: A mixture of het-
eroaryl halides (0.25 mmol), [4-(diphenylamino)phenyl]boronic
acid (0.375 mmol), Pd(OAc)2 (1.5 mol-%), K3PO4·7H2O
(0.5 mmol), distilled water (0.65 mL) and iPrOH (1.35 mL) was
stirred at 80 °C in air for the indicated time. The mixture was added
to brine (15 mL) and extracted four times with ethyl acetate
(4ϫ15 mL). The solvent was evaporated under vacuum, and the
product was isolated by short-column chromatography on silica gel
(200–300 mesh).
4-(6-Methoxypyridin-2-yl)-N,N-diphenylaniline (18): Yield: 87.1 mg,
99%; white solid, m.p. 109–110 °C. 1H NMR (400 MHz, CDCl3,
25 °C): δ = 7.94 (d, J = 8.8 Hz, 2 H, C6H4), 7.59 (t, J = 8.0 Hz, 1
H, Py), 7.29–7.25 (m, 5 H, Py and Ph), 7.15–7.11 (m, 6 H, Ph),
7.04 (t, J = 7.2 Hz, 2 H, C6H4), 6.64 (d, J = 8.0 Hz, 1 H, Py), 4.01
(s, 3 H, OCH3) ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ =
163.7 (CPy), 154.3 (CPy), 148.6 (CPh), 147.5 (C6H4), 139.2 (CPy),
132.7 (C6H4), 129.3 (CPh), 127.5 (C6H4), 124.7 (CPh), 123.2 (CPh),
123.1 (C6H4), 112.1 (CPy), 108.4 (CPy), 53.2 (OCH3) ppm. MS
(ESI): m/z (%) = 353 [M + H]+, 375 [M + Na]+.
4Ј-(Diphenylamino)biphenyl-2-carbonitrile (2): Yield: 83.1 mg, 96%;
white solid, m.p. 131–132 °C. 1H NMR (400 MHz, CDCl3, 25 °C):
δ = 7.74–7.71 (m, 1 H, C6H4), 7.61–7.57 (m, 1 H, C6H4), 7.50 (d,
J = 8.0 Hz, 1 H, C6H4), 7.43–7.41 (m, 2 H, C6H4), 7.39–7.35 (m,
1 H, C6H4), 7.30–7.26 (m, 4 H, Ph), 7.16–7.12 (m, 6 H, Ph),7.06
(t, J = 7.2 Hz, 2 H, C6H4) ppm. 13C NMR (100 MHz, CDCl3,
25 °C): δ = 148.5 (C6H4), 147.4 (CPh), 145.3 (C6H4), 134.0 (C6H4),
132.9 (C6H4), 131.3 (C6H4), 129.9 (C6H4), 129.7 (C6H4), 129.6
(CPh), 127.1 (C6H4), 125.2 (CPh), 123.7 (CPh), 122.5 (C6H4), 119.2
(CN), 110.9 (C6H4) ppm. MS (EI): m/z = 346.1 [M]+.
6-[4-(Diphenylamino)phenyl]picolinonitrile (19): Yield: 79.3 mg,
91%; light-green solid, m.p. 129–130 °C. 1H NMR (400 MHz,
CDCl3, 25 °C): δ = 7.89–7.79 (m, 4 H, C6H4 and Py), 7.55 (d, J =
7.2 Hz, 1 H, Py), 7.29 (t, J = 8.0 Hz, 4 H, Ph), 7.15–7.07 (m, 8 H,
Ph and C6H4) ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ = 158.6
(CPy), 149.8 (CPh), 147.1 (C6H4), 137.5 (CPy), 133.7 (CPy), 130.2
(C6H4), 129.5 (CPh), 127.9 (C6H4), 125.8 (CPy), 125.2 (CPh), 123.8
(CPh), 122.6 (CPy), 122.3 (C6H4), 117.5 (CN) ppm. MS (ESI): m/z
= 348 [M + H]+, 370 [M + Na]+, 386 [M + K]+.
4Ј-(Diphenylamino)biphenyl-2-carbaldehyde (4): Yield: 81.8 mg,
94%; light-yellow solid, m.p. 135–136 °C. 1H NMR (400 MHz,
CDCl3, 25 °C): δ = 10.0 (s, 1 H, CHO), 8.02–7.99 (m, 1 H, C6H4),
7.62–7.60 (m, 1 H, C6H4), 7.47 (d, J = 7.6 Hz, 2 H, C6H4), 7.31–
7.28 (m, 4 H, Ph), 7.24–7.21 (m, 2 H, C6H4), 7.17–7.12 (m, 6 H,
Ph), 7.07 (t, J = 7.2 Hz, 2 H, C6H4) ppm. 13C NMR (100 MHz,
CDCl3, 25 °C): δ = 192.7 (CHO), 148.0 (C6H4), 147.4 (CPh), 145.7
(C6H4), 133.7 (C6H4), 133.5 (C6H4), 130.9 (C6H4), 130.6 (C6H4),
129.4 (CPh), 127.6 (C6H4), 127.4 (C6H4), 124.9 (CPh), 123.5 (CPh),
122.5 (C6H4) ppm. MS (EI): m/z = 349.1 [M]+.
1-{6-[4-(Diphenylamino)phenyl]pyridin-2-yl}ethanone (20): Yield:
90.7 mg, 98%; light-green solid, m.p. 154–155 °C. 1H NMR
(400 MHz, CDCl3, 25 °C): δ = 7.98 (d, J = 8.8 Hz, 2 H, C6H4),
7.91–7.83 (m, 3 H, Py), 7.29 (t, J = 8.0 Hz, 4 H, Ph), 7.16–7.14 (t,
J = 8.6 Hz, 6 H, Ph), 7.07 (t, J = 7.2 Hz, 2 H, C6H4), 2.79 (s, 3 H,
COCH3) ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ = 200.6
(CO), 156.1 (CPy), 153.3 (CPy), 149.2 (CPh), 147.3 (C6H4), 137.5
(CPy), 131.8 (C6H4), 129.4 (CPh), 127.7 (C6H4), 125.0 (CPh), 123.5
(CPh), 122.8 (C6H4), 122.7 (CPy), 119.1 (CPy), 25.7 (CH3) ppm. MS
(ESI): m/z = 365 [M + H]+, 387 [M + Na]+, 403 [M + K]+.
4Ј-(Diphenylamino)biphenyl-2-ol (11): Yield: 73.3 mg, 87%; white
solid, m.p. 121–122 °C. 1H NMR (400 MHz, CDCl3, 25 °C): δ =
7.33–7.21 (m, 8 H, C6H4 and Ph), 7.17–7.14 (m, 6 H, Ph), 7.05 (t,
J = 7.2 Hz, 2 H, C6H4), 6.99–6.96 (t, 2 H, C6H4), 5.23 (s, 1 H, OH)
ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ = 152.6 (C6H4), 147.6
(CPh), 147.5 (C6H4), 130.5 (C6H4), 130.3 (C6H4), 129.9 (C6H4),
129.5 (CPh), 128.9 (C6H4), 127.9 (C6H4), 124.8 (CPh), 123.7 (C6H4),
123.3 (CPh), 120.9 (C6H4), 115.8 (C6H4) ppm. MS (EI): m/z = 337.1
[M]+.
4-(6-Fluoropyridin-2-yl)-N,N-diphenylaniline (21): Yield: 82.3 mg,
97%; white solid, m.p. 78–79 °C. 1H NMR (400 MHz, CDCl3,
25 °C): δ = 7.88 (d, J = 8.4 Hz, 2 H, C6H4), 7.81–7.75 (m, 1 H,
4-(5-Nitropyridin-2-yl)-N,N-diphenylaniline (14): Yield: 86.3 mg, Py), 7.55–7.52 (dd, J = 2.4, 7.6 Hz, 1 H, Py), 7.30–7.25 (m, 4 H,
94%; red solid, m.p. 156–157 °C. 1H NMR (400 MHz, CDCl3,
Ph), 7.14–7.04 (m, 8 H, Ph and C6H4), 6.79 (m, 1 H, Py) ppm.
Eur. J. Org. Chem. 2011, 3009–3015
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3013

C. Liu, Q. Ni, J. Qiu
FULL PAPER
13C NMR (100 MHz, CDCl3, 25 °C): δ = 164.6 [d, 1J(13C,19F) = and C6H4), 7.32–7.21 (m, 4 H, Ph), 7.19–7.15 (m, 6 H, Ph), 7.07
5
236.2 Hz, CPy], 156.09 [d, J(13C,19F) = 13.4 Hz, CPy], 149.3 (CPh),
(t, J = 7.2 Hz, 2 H, C6H4) ppm. 13C NMR (100 MHz, CDCl3,
147.3 (C6H4), 141.49 [d, J(13C,19F) = 7.7 Hz, CPy], 130.9 (C6H4), 25 °C): δ = 149.8 (CQuino), 148.1 (CQuino), 147.5 (CPh), 147.1
3
129.4 (CPh), 127.8 (C6H4), 125.0 (CPh), 123.5 (CPh), 122.7 (CPy), (C6H4), 133.4 (CQuino), 132.3 (CQuino), 131.3 (CQuino), 129.4 (CPh),
116.46 [d, 4J(13C,19F) = 4.1 Hz, CPy], 106.88 [d, 2J(13C,19F) =
37.7 Hz, CPy] ppm. MS (ESI): m/z = 341 [M + H]+, 363 [M +
Na]+, 379 [M + K]+.
129.2 (CQuino), 129.1 (C6H4), 128.2 (CQuino), 128.1 (CQuino), 127.9
(CQuino), 126.9 (C6H4), 124.8 (CPh), 123.7 (CPh), 123.4 (C6H4) ppm.
MS (EI): m/z = 372.1 [M]+.
4,4Ј-(Pyridine-2,6-diyl)bis(N,N-diphenylaniline)
(22):
Yield:
3-[4-(Diphenylamino)phenyl]thiophene (29): Yield: 58.0 mg, 72%;
pink solid, m.p. 112–114 °C. H NMR (400 MHz, CDCl3, 25 °C):
1
1
94.9 mg, 67%; white solid, m.p. 191–193 °C. H NMR (400 MHz,
CDCl3, 25 °C): δ = 8.01 (d, J = 8.4 Hz, 4 H, C6H4), 7.73 (t, J =
8.0 Hz, 1 H, Py), 7.57 (d, J = 7.6 Hz, 2 H, Py), 7.26 (t, J = 8.0 Hz,
8 H, Ph), 7.16–7.13 (m, 12 H, Ph), 7.04 (t, J = 7.2 Hz, 4 H, C6H4)
ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ = 156.3 (CPy), 148.7
(CPh), 147.5 (C6H4), 137.4 (CPy), 133.3 (C6H4), 129.3 (CPh), 127.8
(C6H4), 124.7 (CPh), 123.24 (CPh), 123.19 (C6H4), 117.4 (CPy) ppm.
MS (ESI): m/z = 566 [M + H]+.
δ = 7.48 (d, J = 8.4 Hz, 2 H, C6H4), 7.37–7.35 (t, J = 3.6 Hz, 3 H,
Thio), 7.27–7.24 (t, J = 7.8 Hz, 4 H, Ph), 7.10 (t, J = 8.0 Hz, 6 H,
Ph), 7.02 (t, J = 7.2 Hz, 2 H, C6H4) ppm. 13C NMR (100 MHz,
CDCl3, 25 °C): δ = 147.7 (CPh), 146.9 (C6H4), 141.9 (CThio), 130.2
(C6H4), 129.3 (CPh), 127.2 (C6H4), 126.2 (CThio), 126.1 (CThio),
124.3 (CPh), 124.1 (CThio), 122.9 (CPh), 119.3 (C6H4) ppm. MS (EI):
m/z = 327.1 [M]+.
N,N-Diphenyl-4-(quinolin-2-yl)aniline (23): Yield: 87.7 mg, 94%;
yellow solid, m.p. 172–174 °C. 1H NMR (400 MHz, CDCl3, 25 °C):
δ = 8.19 (d, J = 8.4 Hz, 1 H, Quino), 8.14 (d, J = 8.8 Hz, 1 H,
Quino), 8.05 (d, J = 8.8 Hz, 2 H, C6H4), 7.81 (t, J = 8.8 Hz, 2 H,
Quino), 7.70 (t, J = 7.2 Hz, 1 H, Quino), 7.49 (t, J = 7.6 Hz, 1 H,
Quino), 7.28 (t, J = 8.0 Hz, 4 H, Ph), 7.20–7.15 (m, 6 H, Ph), 7.06
(t, J = 7.2 Hz, 2 H, C6H4) ppm. 13C NMR (100 MHz, CDCl3,
25 °C): δ = 156.9 (CQuino), 149.1 (CQuino), 148.3 (CPh), 147.4
(C6H4), 136.6 (CQuino), 133.3 (C6H4), 129.6 (CQuino), 129.3 (CPh),
128.4 (C6H4), 127.4 (CQuino), 126.9 (CQuino), 125.9 (CQuino), 124.8
(CPh), 123.4 (CPh), 123.2 (C6H4), 118.6 (CQuino) ppm. MS (ESI):
m/z = 373 [M + H]+.
Supporting Information (see footnote on the first page of this arti-
cle): Experimental procedures, characterization data and 1H and
13C NMR spectra of all cross-coupling products.
Acknowledgments
We thank the National Natural Science Foundation of China
(21076034, 20923006, 20836002, 20725619), the Fundamental Re-
search Funds for the Central Universities (DUT11LK15), the
Graduate Student Education Reform Fund of Dalian University
(JG0916) and the Program for New Century Excellent Talents in
University for financial support.
N,N-Diphenyl-4-(pyrazin-2-yl)aniline (24): Yield: 69.4 mg, 86%;
1
tawny solid, m.p. 81–82 °C. H NMR (400 MHz, CDCl3, 25 °C): δ
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= 8.96 (s, 1 H, Pyra), 8.56 (s, 1 H, Pyra), 8.42 (d, J = 2.4 Hz, 1 H,
Pyra), 7.89 (d, J = 8.8 Hz, 2 H, C6H4), 7.29 (t, J = 8.0 Hz, 4 H,
Ph), 7.16 (d, J = 8.8 Hz, 6 H, Ph), 7.08 (t, J = 7.2 Hz, 2 H, C6H4)
ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ = 152.5 (CPyra), 149.6
(CPh), 147.2 (C6H4), 144.0 (CPyra), 142.0 (CPyra), 141.7 (CPyra),
129.5 (CPh), 129.4 (C6H4), 127.8 (C6H4), 125.2 (CPh), 123.7 (CPh),
122.6 (C6H4) ppm. MS (EI): m/z = 323.1 [M]+.
N,N-Diphenyl-4-(pyrimidin-5-yl)aniline (26): Yield: 71.1 mg, 88%;
light-yellow solid, m.p. 165–167 °C. 1H NMR (400 MHz, CDCl3,
25 °C): δ = 9.15 (s, 1 H, Pyr), 8.92 (s, 2 H, Pyr), 7.45 (d, J = 8.8 Hz,
2 H, C6H4), 7.30 (t, J = 8.0 Hz, 4 H, Ph), 7.16 (t, J = 8.8 Hz, 6 H,
Ph), 7.08 (t, J = 7.2 Hz, 2 H, C6H4) ppm. 13C NMR (100 MHz,
CDCl3): δ = 156.8 (CPyr), 154.3 (CPyr), 148.9 (CPh), 147.2 (C6H4),
133.9 (CPyr), 129.5 (CPh), 127.6 (C6H4), 127.1 (C6H4), 125.0 (CPh),
123.7 (CPh), 123.2 (C6H4) ppm. MS (EI): m/z = 323.1 [M]+.
4-(1H-Indol-5-yl)-N,N-diphenylaniline (27): Yield: 85.5 mg, 94%;
1
brown solid, m.p. 69–70 °C. H NMR (400 MHz, CDCl3, 25 °C):
δ = 8.16 (s, 1 H, NH), 7.83 (s, 1 H, Indo), 7.54 (d, J = 8.4 Hz, 2
H, C6H4), 7.43 (s, 2 H, Indo), 7.28–7.23 (m, 5 H, Ph and Indo),
7.16–7.13 (m, 6 H, Ph), 7.01 (t, J = 7.2 Hz, 2 H, C6H4), 6.59 (t, J
= 2.4 Hz, 1 H, Indo) ppm. 13C NMR (100 MHz, CDCl3, 25 °C): δ
= 147.9 (CPh), 146.3 (C6H4), 137.0 (CIndo), 135.2 (C6H4), 132.9
(CIndo), 129.3 (CPh), 128.5 (CIndo), 128.1 (C6H4), 124.9 (CIndo),
124.5 (C6H4), 124.2 (CPh), 122.7 (CPh), 121.7 (CIndo), 118.8 (CIndo),
111.3 (CIndo), 103.0 (CIndo) ppm. MS (ESI): m/z = 361 [M + H]+,
383 [M + Na]+, 399 [M + K]+.
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N,N-Diphenyl-4-(quinolin-3-yl)aniline (28): Yield: 68.9 mg, 74%;
white solid, m.p. 145–146 °C. 1H NMR (400 MHz, CDCl3, 25 °C):
δ = 9.18 (d, J = 2.0 Hz, 1 H, Quino), 8.26 (d, J = 1.6 Hz, 1 H,
Quino), 8.13 (d, J = 8.4 Hz, 1 H, Quino), 7.87 (d, J = 8.0 Hz, 1 H,
Quino), 7.72 (t, J = 7.2 Hz, 1 H, Quino), 7.60–7.55 (m, 3 H, Quino
3014
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 3009–3015

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Received: January 18, 2011
Published Online: April 14, 2011
Eur. J. Org. Chem. 2011, 3009–3015
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3015