Solvent-free synthesis of new 2,4,6-triarylpyridines catalyzed by a Bronsted acidic ionic liquid as a green and reusable catalyst

Article abstract of DOI:10.1002/jhet.697

Some new 4-(aryl)-2,6-di-2-naphthylpyridines and 4-(aryl)-2,6-di-2- thienylpyridines have been prepared through three-component condensation of 2-acetylnaphthalene or 2-acetylthiophene, aromatic aldehydes, and ammonium acetate in presence of 1-(4-sulfonyl

Full text of DOI:10.1002/jhet.697

September 2011
Solvent-Free Synthesis of New 2,4,6-Triarylpyridines
Catalyzed by a Brønsted Acidic Ionic Liquid as a
Green and Reusable Catalyst
1117
Hossein Behmadi,a* Shima Naderipour,a Seyed Mahdi Saadati,b
Mohammad Barghamadi,c Mohammad Shaker,a
and Niloofar Tavakoli-Hoseinia
aDepartment of Chemistry, Faculty of Sciences, Islamic Azad University,
Mashhad Branch, Mashhad, Iran
bYoung Researchers Club, Islamic Azad University, Mashhad Branch, Mashhad, Iran
cDepartment of Sciences, Islamic Azad University, Sabzevar Branch, Sabzevar, Iran
*E-mail: hos_behmadi@yahoo.com
Received June 6, 2010
DOI 10.1002/jhet.697
Published online 27 May 2011 in Wiley Online Library (wileyonlinelibrary.com).
Some new 4-(aryl)-2,6-di-2-naphthylpyridines and 4-(aryl)-2,6-di-2-thienylpyridines have been pre-
pared through three-component condensation of 2-acetylnaphthalene or 2-acetylthiophene, aromatic
aldehydes, and ammonium acetate in presence of 1-(4-sulfonylbutyl) pyridinium hydrogensulfate
[(CH2)4SO3HPy][HSO4], a Brønsted acidic ionic liquid as a green and reusable catalyst in solvent-free
conditions. Also some new 4,4’-(1,4-phenylene)-bis-(2,6-di-aryl pyridine) was prepared.
J. Heterocyclic Chem., 48, 1117 (2011).
INTRODUCTION
products are low because of the formation of mixtures
of pyridines and various by-products [12]. These com-
pounds have also been synthesized through the reaction
of N-phenacylpyridinium salts with a,b-unsaturated
ketones in the presence of ammonium acetate [7,13].
However, the pyridinium salts and the unsaturated
ketones have to be synthesized first, so this method is
relatively expensive. More recently, many improved
methods for preparation of 2,4,6-triarylpyridines have
been reported such as reaction of a-ketoketene dithioace-
tals with methyl ketones in the presence of ammonium
acetate [14], reaction of N-phosphinylethanimines with
aldehydes [15], addition of lithiated b-enaminophospho-
nates to chalcones [16], condensation of acetophenones,
benzaldehydes, and NH4OAc in the presence of NaOH
under solvent-free condition [17] and one-pot reaction
of acetophenones, benzaldehydes and NH4OAc both
with and without catalyst [18].
The pyridine ring systems are of interest because of
the occurrence of their saturated and partially saturated
derivatives in biologically active compounds and natural
products such as NAD nucleotides, pyridoxol (vitamin
B6), and pyridine alkaloids [1]. Because of their p-
stacking ability, some pyridines are used in supramolec-
ular chemistry [2]. Some examples are used as pharma-
ceuticals (as antimalarial, vasodilator, anesthetic, anti-
convulsant, and antiepileptic), dyes, additives (as antiox-
idant), agrochemicals (as fungicidal, pesticidal, and her-
bicidal), veterinary (as anthelmintic, antibacterial, and
antiparasitic), and also in qualitative and quantitative
analysis [1,3–6].
Owing to their wide range of pharmacological activity
and industrial and synthesis applications, a number of
methods have been reported for the synthesis of
¨
Krohnke-type pyridines [7]. Previously, 2,4,6-triarylpyri-
dines have been prepared by the condensation of 1,5-
diketones with formamide-formic acid [8] and by other
synthetic procedures including the Chichibabin method
[9–12]. Following this procedure, the yields of single
Ionic liquids (ILs) have received great attention in
diverse areas ranging from synthetic and catalytic chem-
istry to biotechnology, electrochemistry, and material
science [19–22]. The fixation of known homogeneous
C
V
2011 HeteroCorporation

1118
H. Behmadi, S. Naderipour, S. M. Saadati, M. Barghamadi, M. Shaker, and N. Tavakoli-Hoseini
Vol 48
Scheme 1. Structure of the catalyst.
RESULTS AND DISCUSSION
Knowing the chemical and pharmacological impor-
¨
tance of the Krohnke pyridines, we have recently
focused on introducing a facile and efficient synthesis of
these pyridines. Thus, a range of 4-(aryl)-2,6-di-2-naph-
thylpyridines were synthesized by heating a mixture
of 2-acetylnaphthalene or 2-acetylthiophene, aromatic
aldehydes and NH4OAc in the presence of 1-(4-sulfo-
nylbutyl) pyridinium hydrogensulfate [(CH2)4SO3
HPy][HSO4], in solvent-free conditions. Also, we syn-
thesized a series of bis pyridines by heating a mixture
of terephthalaldehyde, an acetophenone and NH4OAc in
the presence of this IL. The products recrystallized and
showed a single spot on TLC and were pure enough for
all practical purposes. The results are summarized in
Tables 1–3.
catalysts on room temperature ionic liquids (RTILs) is
an ideal combination to achieve the advantages of both
homogeneous and heterogeneous catalysis [23–25].
The introduction of Brønsted-acidic functional groups
into cations or anions of the ILs, especially the ASO3H
functional groups, obviously enhanced their acidities and
water solubilities [26–28]. Therefore Brønsted acidic ILs
can be used as highly efficient acidic catalysts. 1-(4-sulfo-
nylbutyl) pyridinium hydrogensulfate [(CH2)4SO3H-
Py][HSO4] is one of Brønsted acidic ILs that can be easily
prepared from the inexpensive available reagents [29].
Promoted by these findings and because of our inter-
est in the synthesis of new heterocyclic compounds
with potential biological activities, in this article, we
wish to report an efficient approach to the synthesis of
new 2,4,6-triarylpyridines (3a-j), (4a-g), and (7a-e)
using 1-(4-sulfonylbutyl) pyridinium hydrogensulfate
[(CH2)4SO3HPy][HSO4] (Scheme 1), a Brønsted acidic
IL, as a green and reusable catalyst (Schemes 2 and 3).
Mechanistically, it is reasonable that the first step
involves an Aldol condensation of an 2-acetylnaphtha-
lene or 2-acetylthiophene with aromatic aldehyde and
after losing of water and Michael addition to the second
mole of 2-acetylnaphthalene or 2-acetylthiophene, lead-
ing to 1,3,5-diaryl-1,5-diketone 9. Then through the
interaction of ammonium acetate and 9, and oxidation
of 2,4,6-triaryl-1,4-dihydropyridine 10, by air, the prod-
uct 3, 4 can be obtained (Scheme 3).
With IL [(CH2)4SO3HPy][HSO4], the effect of the cata-
lyst to substrate molar ratio on the reaction was investi-
gated in model reaction 3e (4-chloro benzaldehyde and 2-
acetylnaphthalene) to optimize the reaction conditions.
The reaction was carried out at around the melting point
Scheme 2. Synthesis of triarylpyridine.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

September 2011
Solvent-Free Synthesis of New 2,4,6-Triarylpyridines Catalyzed
by a Brønsted Acidic Ionic Liquid as a Green and Reusable Catalyst
1119
Scheme 3. Mechanism of the reaction.
of ammonium acetate (120ꢀC). It was found that the use
of 5% mol ratio of catalyst gave low yield even after lon-
ger reaction duration. In comparison, 10% mol ratio of
the catalyst, led to a 70% yield of product. Increasing in
the amount of catalyst could not bring much better results
(Table 4). Therefore, all compounds were synthesized
with 10% mol ratio of the catalyst at 120ꢀC.
trothermal type 9100 melting point apparatus. The FTIR spec-
trometer used was Bruker Tensor 27. The FTIR spectra were
1
taken using KBr pellets. The HNMR (500 MHz) spectra were
recorded on a Bruker DRX 500 spectrometer. The mass spec-
tra were determined on a Shimadzu GCMS 17A instrument.
Elemental analysis was performed on a Thermo Finnigan Flash
EA microanalyzer. The purity of the substances and the pro-
gress of the reactions were monitored by TLC on silica gel.
Typical procedure for the synthesis of 4-(Aryl)-2,6-di-2-
naphthylpyridines. A mixture of an aromatic aldehyde (1.0
mmol), 2-acetylnaphthalene or 2-acetylthiophene (2.0 mmol),
NH4OAc (1.3 mol %) and [(CH2)4SO3HPy][HSO4] (10 mol
%) was heated on the oil bath at 120ꢀC. The progress of reac-
tion was monitored by TLC. After completion of the reaction,
the reaction mixture was cooled to room temperature. The pre-
cipitate was filtered off and recrystallized from THF to give
the pure product (Scheme 2).
Typical procedure for the synthesis of 4,40-(1,4-phenyl-
ene)-bis-(2,6-di-aryl pyridine). A mixture of an terephthalal-
dehyde (1.0 mmol), an acetophenone (4.0 mmol), NH4OAc
(1.3 mol %) and [(CH2)4SO3HPy][HSO4] (10 mol %) was
heated on the oil bath at 120ꢀC. The progress of reaction was
monitored by TLC. After completion of the reaction, the reac-
tion mixture was cooled to room temperature. The precipitate
was filtered off and recrystallized from DMSO to give the
pure product (Scheme 2).
In conclusion, we have reported a highly efficient and
easy access method for the synthesis of biological sig-
nificance 2,4,6-triarylpyridines. Our method has several
advantages including mild conditions, good yields, uti-
lize cheap available ammonium source, simple opera-
tion, and work-up. The reaction times are shorter and
the yields are high. It’s also noteworthy to mention that
the catalyst can be recovered and reused without loss of
its structure and activity.
EXPERIMENTAL
All chemicals were commercially available and used without
further purification. Melting points were recorded on an elec-
Table 1
Synthesis of new 4-(aryl)-2,6-di-2-naphthylpyridines (3a-j).
Table 2
Time Yield
(%)a
M.p.
(ꢀC)
Entry
Ar1
Ar2
(min)
Synthesis of new 4-(aryl)-2,6-di-2-thienylpyridines (4a-g).
3a
3b
3c
3d
3e
3f
3g
3h
3i
2-naphthyl 4-OMeC6H4
60
80
70
70
55
75
80
60
60
50
88
78
75
80
85
73
70
83
70
85
185-187
99-101
Time
(min)
Yield
(%)a
M.p.
(ꢀC)
Entry
Ar1
Ar2
2-naphthyl
2-naphthyl
2-naphthyl
2-naphthyl
2-naphthyl
2-naphthyl
2-naphthyl
2-naphthyl
2-naphthyl
3-MeC6H4
4-MeC6H4
3-ClC6H4
163-165
123-125
180-182
139-141
196-198
147-149
198-200
231-233
4a
4b
4c
4d
4e
4f
2-thienyl
2-thienyl
2-thienyl
2-thienyl
2-thienyl
2-thienyl
2-thienyl
4-MeC6H4
3-ClC6H4
4-ClC6H4
35
25
35
25
25
25
15
71
76
85
81
70
79
75
117-119
82-85
133-131
84-86
143-145
150-152
224-226
4-ClC6H4
3-BrC6H4
2-OHC6H4
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
3-BrC6H4
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
3j
4g
a Yields refer to isolated products.
a Yields refer to isolated products.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

1120
H. Behmadi, S. Naderipour, S. M. Saadati, M. Barghamadi, M. Shaker, and N. Tavakoli-Hoseini
Vol 48
Table 3
Synthesis of new 4,40-(1,4-phenylene)-bis-
7.64-7.70 (m, 5H), 7.78 (d, 1H, J ¼ 15.5 Hz), 7.90 (d, 2H, J
¼ 8 Hz), 8.02-8.07 (m, 2H), 8.14-8.22 (m, 5H), 8.24 (d, 2H, J
¼ 15.5 Hz), 8.97 (s, 2H) ; MS, m/z: 485. Anal. Calcd. for
C31H20BrN: C, 76.55; H, 4.14; N, 2.88. Found: C, 76.70; H,
4.25; N, 2.75.
(2,6-di-aryl pyridine) (7a-e).
Time
(min.)
Yield
(%)a
M.p.
(ꢀC)
Entry
Ar3
4-(2-Hydroxyphenyl)-2,6-di-2-naphthylpyridine 3g. FTIR (KBr
disc): m ¼3423 (OH), 1636, 1529, 1122, 1005, 827, 758 cmꢁ1
;
1HNMR (500 MHz, DMSO-d6) d: 7.50-7.52 (t, 1H, J ¼ 8.5
Hz), 7.62-7.67 (m, 4H), 7.68-7.75 (m, 1H), 8.01-8.04 (m, 2H),
8.05 (d, 2H, J ¼ 8.5 Hz), 8.14-8.28 (m, 5H), 8.55 (d, 1H, J ¼
8.5 Hz), 8.63 (s, 2H), 8.91 (s, 2H), 9.08 (broad, 1H, OH); MS,
m/z: 423. Anal. Calcd. for C31H21NO: C, 87.92; H, 5.00; N,
3.31. Found: C, 88.05; H, 5.10; N, 3.22.
7a
7b
7c
7d
7e
2-naphthyl
2-thienyl
C6H5
4-BrC6H4
4-NO2C6H4
85
80
80
75
70
92
91
90
95
95
243-245
190-192
187-189
288-290
266-268
a Yields refer to isolated products.
4-(2-Nitrophenyl)-2,6-di-2-naphthylpyridine 3h. FTIR (KBr
;
1HNMR
disc): m ¼ 1655, 1593, 1529, 1354, 850, 742 cmꢁ1
Recycling of the catalyst. In our studies, the recycle of cat-
alyst [(CH2)4SO3HPy][HSO4] was also investigated by using
the preparation of 3e as a model. The product was isolated
from aqueous solution by extraction and the aqueous phase
was washed with Et2O, and then reused in the same reactions.
In second run, the yield of product 3e was obtained 81% (with
a minor decrease in yield).
(500 MHz, DMSO-d6) d: 7.57-7.62 (m, 5H), 7.79-7.87 (m,
2H), 7.94 (t, 1H, J ¼ 7.6 Hz), 8-8.03 (m, 2H), 8.09-8.12 (m,
5H), 8.18 (s, 2H), 8.52-8.55 (d, 1H, J ¼ 7.6 Hz), 8.89 (s, 2H);
MS, m/z: 452. Anal. Calcd. for C31H20N2O2: C, 82.28; H,
4.45; N, 6.19. Found: C, 82.30; H, 4.52; N, 6.15.
4-(3-Nitrophenyl)-2,6-di-2-naphthylpyridine 3i. FTIR (KBr
disc): m ¼ 1602, 1529, 1344, 830, 758cmꢁ1
;
1HNMR (500
Spectral data.
4-(4-Methoxyphenyl)-2,6-di-2-naphthyl-
MHz, DMSO-d6) d: 7.58-7.63 (m, 4H), 7.90 (t, 1H, J ¼ 8 Hz),
8-8.02 (m, 2H), 8.10-8.15 (m, 4H), 8.39 (d, 1H, J ¼ 8 Hz),
8.51 (s, 2H), 8.57-8.61 (m, 3H), 8.90 (s, 1H), 8.97 (s, 2H);
MS, m/z: 452. Anal. Calcd. for C31H20N2O2: C, 82.28; H,
4.45; N, 6.19. Found: C, 82.30; H, 4.55; N, 6.17.
pyridine 3a. FTIR (KBr disc): m ¼ 1600, 1542, 1514, 1246,
1
1179, 1026, 826, 753 cmꢁ1; HNMR (500 MHz, DMSO-d6) d:
3.86 (s, 3H, CH3O), 7.10-7.25 (d, 2H), 7.52-7.68 (m, 4H), 8-
8.16 (m, 8H), 8.39 (s, 2H), 8.52-8.68 (d, 2H), 8.95 (s, 2H); m/
z: 437. Anal. Calcd. for C32H23NO: C, 87.84; H, 5.30; N, 3.20.
Found: C, 87.65; H, 5.37; N, 3.30.
4-(4-Nitrophenyl)-2,6-di-2-naphthylpyridine 3j. FTIR (KBr
disc): m ¼ 1660, 1592, 1548, 1343, 953, 825, 758 cmꢁ1
;
4-(3-Methylphenyl)-2,6-di-2-naphthylpyridine 3b. FTIR (KBr
1HNMR (500 MHz, DMSO-d6) d: 7.58-7.63 (m, 4H), 8-8.02
(m, 2H), 8.13 (d, 4H, J ¼ 8.8 Hz), 8.43 (s, 4H), 8.50 (s, 2H),
8.59 (d, 2H, J ¼ 8.8 Hz), 8.98 (s, 2H); MS, m/z: 452 Anal.
Calcd. for C31H20N2O2: C, 82.28; H, 4.45; N, 6.19. Found: C,
82.32; H, 4.50; N, 6.16.
disc): m ¼ 1664, 1604, 1315, 1182, 1052, 985, 821, 785 cmꢁ1
;
1HNMR (500 MHz, DMSO-d6) d: 2.38 (s, 3H, CH3), 7.30 (d,
1H, J ¼ 7.5 Hz), 7.38 (t, 1H, J ¼ 7.5 Hz), 7.66 (t, 3H, J ¼ 7
Hz), 7.71 (t, 3H, J ¼ 7 Hz), 8.02-8.04 (d, 1H), 8.06-8.18 (m,
9H), 8.93 (s, 2H); MS, m/z: 421. Anal. Calcd. for C32H23N: C,
91.18; H, 5.50; N, 3.32. Found: C, 91.40; H, 5.60; N, 3.20.
4-(4-Methylphenyl)-2,6-di-2-naphthylpyridine 3c. FTIR (KBr
4-(4-Methylphenyl)-2,6-di-2-thienylpyridine 4a. FTIR (KBr
disc): m ¼ 1647, 1592, 1589, 1414, 987, 815, 723 cmꢁ1
;
1HNMR (500 MHz, DMSO-d6) d: 2.49 (s, 3H), 7.27-7.32 (m,
4H), 7.68-7.72 (d, 1H), 7.77-7.85 (m, 3H), 8.05 (d, 2H, J ¼
4.8 Hz), 8.32 (d, 2H, J ¼ 4.8 Hz); MS, m/z: 333. Anal. Calcd.
for C20H15NS2: C, 72.03; H, 4.53; N, 4.20. Found: C, 72.20;
H, 4.60; N, 4.14.
disc): m ¼ 1594, 1542, 1393, 1194, 856, 814, 756 cmꢁ1
;
1HNMR (500 MHz, DMSO-d6) d: 2.43 (s, 3H, CH3), 7.43 (d,
2H, J ¼ 8 Hz), 7.57-7.62 (m, 4H), 8.00 (m, 2H, J ¼ 9 Hz),
8.05 (d, 2H, J ¼ 8 Hz), 8.11 (d, 2H, J ¼ 8.5 Hz), 8.14 (d, 2H,
J ¼ 9 Hz), 8.40 (s, 2H), 8.58 (d, 2H, J ¼ 8.5 Hz), 8.95 (s,
2H); MS, m/z: 421. Anal. Calcd. for C32H23N: C, 91.18; H,
5.50; N, 3.32. Found: C, 91.42; H, 5.59; N, 3.20.
4-(3-Chlorophenyl)-2,6-di-2-thienylpyridine 4b. FTIR (KBr
disc): m ¼1647, 1601, 1411, 977, 784, 711 cmꢁ1
;
1HNMR
(500 MHz, DMSO-d6) d: 7.35 (t, 2H, J ¼ 4 Hz), 7.74-7.78 (t,
1H), 7.85 (d, 1H), 8.09-8.13 (m, 3H), 8.27-8.29 (d, 1H, J ¼
7.2 Hz), 8.34 (d, 1H, J ¼ 7.2 Hz), 8.45 (d, 2H, J ¼ 4 Hz),
8.79 (s, 1H); MS, m/z: 353. Anal. Calcd. for C19H12ClNS2: C,
64.48; H, 3.42; N, 3.96. Found: C, 64.61; H, 3.50; N, 3.85.
4-(4-Chlorophenyl)-2,6-di-2-thienylpyridine 4c. FTIR (KBr
4-(3-Chlorophenyl)-2,6-di-2-naphthylpyridine 3d. FTIR (KBr
1
disc): m ¼ 1663, 1605, 1179, 1050, 984, 820, 789 cmꢁ1; HNMR
(500 MHz, DMSO-d6) d: 7.49-7.54 (m, 2H), 7.67 (t, 2H, J ¼ 6.5
Hz), 7.71 (t, 2H, J ¼ 6.5 Hz), 7.80 (d, 1H, J ¼ 15.5 Hz ), 7.88
(d, 2H, J ¼ 6.5 Hz), 8.03 (d, 1H, J ¼ 8 Hz), 8.07 (d, 1H, J ¼ 8
Hz), 8.12-8.16 (m, 5H), 8.22 (d, 2H, J ¼ 15.5 Hz), 8.98 (s, 2H) ;
MS, m/z: 441. Anal. Calcd. for C31H20ClN: C, 84.25; H, 4.56; N,
3.17. Found: C, 84.20; H, 4.60; N, 3.25.
disc): m ¼ 1646, 1596, 1415, 982, 816, 727 cmꢁ1
;
1HNMR
1HNMR (500 MHz, DMSO-d6) d: 7.33 (t, 2H, J ¼ 3.6 Hz),
Table 4
4-(4-Chlorophenyl)-2,6-di-2-naphthylpyridine 3e. FTIR (KBr
disc): m ¼ 1676, 1597, 1541, 1508, 1091, 819, 759 cmꢁ1
;
The effects of catalyst amount on the synthesis of 3e.
1HNMR (500 MHz, DMSO-d6) d: 7.49-7.64 (m, 4H), 7.66 (d,
2H, J ¼ 8 Hz), 8.02 (d, 2H, J ¼ 8.5 Hz), 8.10-8.14 (m, 4H),
8.19 (d, 2H, J ¼ 8 Hz), 8.43 (s, 2H), 8.58 (d, 2H, J ¼ 8.5
Hz), 8.96 (s, 2H) ;MS, m/z: 441. Anal. Calcd. for C31H20ClN:
C, 84.25; H, 4.56; N, 3.17. Found: C, 84.18; H, 4.60; N, 3.27.
Catalyst amount
(% mole)
Time
(min.)
Yield
(%)
Entry
1
2
3
4
5
10
15
20
110
60
45
70
78
86
4-(3-Bromophenyl)-2,6-di-2-naphthylpyridine
(KBr disc): m ¼ 1662, 1606, 1179, 975, 820, 794 cmꢁ1
3f. FTIR
;
50
45
1HNMR (500 MHz, DMSO-d6) d: 7.44 (t, 1H, J ¼ 8 Hz),
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

September 2011
Solvent-Free Synthesis of New 2,4,6-Triarylpyridines Catalyzed
by a Brønsted Acidic Ionic Liquid as a Green and Reusable Catalyst
1121
7.53-7.55 (d, 2H), 7.70-7.74 (d, 1H), 7.89-7.95 (m, 3H), 8.07-
8.09 (d, 2H), 8.35-8.37 (d, 2H, J ¼ 3.6 Hz); MS, m/z: 353.
Anal. Calcd. for C19H12ClNS2: C, 64.48; H, 3.42; N, 3.96.
Found: C, 64.61; H, 3.55; N, 3.88.
4,4’-(1,4-Phenylene)-bis-(2,6-di-4-nitro phenyl pyridine)
7e. FTIR (KBr disc): m ¼ 1666, 1585, 1523, 1335, 1213, 811
cmꢁ1
;
1HNMR (500 MHz, DMSO-d6) d: 7.84 (d, 4H, J ¼
15.5 Hz), 8.03 (s, 5H), 8.07 (d, 3H, J ¼ 15.5 Hz), 8.39-8.41
(s, 12H); MS, m/z: 716. Anal. Calcd. for C40H24N6O8: C,
67.04; H, 3.38; N, 11.73. Found: C, 67.20; H, 3.29; N, 11.85.
4-(3-Bromophenyl)-2,6-di-2-thienylpyridine 4d. FTIR (KBr
;
1HNMR
disc): m ¼ 1646, 1600, 1411, 977, 784, 711 cmꢁ1
(500 MHz, DMSO-d6) d: 7.35 (t, 2H, J ¼ 4 Hz), 7.74-7.78 (t,
1H), 7.85 (d, 1H), 8.09-8.13 (m, 3H), 8.27-8.29 (d, 1H, J ¼
7.2 Hz), 8.34 (d, 1H, J ¼ 7.2 Hz), 8.45 (d, 2H, J ¼ 4 Hz),
8.79 (s, 1H); MS, m/z: 396. Anal. Calcd. for C19H12BrNS2: C,
57.29; H, 3.04; N, 3.52. Found: C, 57.15; H, 3.15; N, 3.58.
4-(2-Nitrophenyl)-2,6-di-2-thienylpyridine 4e. FTIR (KBr
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Phillips, D.; Raithby, P. R.; Schofield, E.; Sparr, E.; Tocher, D. A.;
Zehnder, M.; Zimmermann, Y. J Chem Soc Dalton Trans 2000, 2219;
(b) Cave, G. W. V.; Hardie, M. J.; Roberts, B. A.; Raston, C. L. Eur J
Org Chem 2001, 17, 3227; (c) Jetti, R. K. R.; Nagia, A.; Xue, F.;
Mak, T. C. W. Chem Commun 2001, 919; (d) Watson, Z. C.; Bampos,
N.; Sanders, J. K. M. New J Chem 1998, 1135.
1
disc): m ¼ 1654, 1605, 1510, 1414, 1342, cmꢁ1; HNMR (500
MHz, DMSO-d6) d: 7.34 (t, 2H, J ¼ 4 Hz), 7.71 (t, 1H, J ¼
8.4 Hz), 7.85 (t, 1H, J ¼ 8.4 Hz), 7.89 (s, 1H), 7.96-8 (m,
1H), 8.11 (t, 3H, J ¼ 8.8 Hz), 8.18 (d, 1H, J ¼ 8.8 Hz), 8.36
(d, 2H,
J
¼
4 Hz); MS, m/z: 364. Anal. Calcd. for
C19H12N2O2S2: C, 62.62; H, 3.32; N, 7.69. Found: C, 62.75;
H, 3.25; N, 7.73.
4-(3-Nitrophenyl)-2,6-di-2-thienylpyridine
4f. FTIR
(KBr
[3] Kim, B. Y.; Ahn, J. B.; Lee, H. W.; Kang, S. K.; Lee, J.
H.; Shin, J. S.; Ahn, S. K.; Hong, C. I.; Yoon, S. S. Eur J Med Chem
2004, 39, 433.
disc): m ¼ 1649, 1599, 1531, 1409, 1350, cmꢁ1; HNMR (500
MHz, DMSO-d6) d: 7.35 (t, 2H, J ¼ 4 Hz), 7.74-7.78 (t, 1H),
7.85 (d, 1H), 8.09-8.13 (m, 3H), 8.27-8.29 (d, 1H, J ¼ 7.2
Hz), 8.34 (d, 1H, J ¼ 7.2 Hz), 8.45 (d, 2H, J ¼ 4 Hz), 8.79
(s, 1H); MS, m/z: 364. Anal. Calcd. for C19H12N2O2S2: C,
62.62; H, 3.32; N, 7.69. Found: C, 62.75; H, 3.23; N, 7.75.
1
[4] Enyedy, I. J.; Sakamuri, S.; Zaman, W. A.; Johnson, K. M.;
Wang, S. Bioorg Med Chem Lett 2003, 13, 513.
[5] Pillai, A. D.; Rathod, P. D.; Franklin, P. X.; Patel, M.; Niv-
sarkar, M.; Vasu, K. K.; Padh, H.; Sudarsanam, V. Biochem Biophys
Res Commun 2003, 301, 183.
4-(4-Nitrophenyl)-2,6-di-2-thienylpyridine
4g. FTIR
(KBr
disc): m ¼ 1650, 1602, 1509, 1417, 1339, 759 cmꢁ1; HNMR
(500 MHz, DMSO-d6) d: 7.35 (t, 2H, J ¼ 4 Hz), 7.79-7.83 (d,
1H), 8.06 (s, 1H), 8.10-8.13 (m, 2H), 8.17 (d, 2H, J ¼ 8.8
Hz), 8.29 (d, 2H, J ¼ 8.8 Hz), 8.41(d, 2H, J ¼ 4 Hz); MS, m/
z: 364. Anal. Calcd. for C19H12N2O2S2: C, 62.62; H, 3.32; N,
7.69. Found: C, 62.78; H, 3.25; N, 7.80.
1
ˇ ´
[6] Klimesova, V.; Svoboda, M.; Waisser, K.; Pour, M.; Kaus-
´
tova, J. IL Farmaco 1999, 54, 666.
¨
[7] Krohnke F. Synthesis 1976, 1, 1.
[8] Chubb, F.; Hay, A. S.; Sandin, R. B. J Am Chem Soc
1953, 75, 6042.
[9] Dilthey, W.; Bauriedel, G.; Burger, B.; Geisselbrecht, G.;
von Ibach, F.; Kiefer, F.; Seeger, A.; Simon, O.; Taucher, R.; Winkler,
J. J Prakt Chem 1921, 102, 209.
4,4’-(1,4-Phenylene)-bis-(2,6-di-2-naphtyl pyridine) 7a. FTIR
;
1HNMR
(KBr disc): m ¼ 1656, 1626, 1183, 977, 819 cmꢁ1
[10] Lombard, R.; Stephen, J. P. Bull Soc Chim Fr 1958, 6, 1458.
[11] Zecher, W.; Krohnke, F. Chem Ber 1961, 94, 690.
[12] Frank, R. L.; Seven, R. P. J Am Chem Soc 1949, 71, 2629.
(500 MHz, DMSO-d6) d: 7.66-7.73 (m, 7H), 7.87 (d, 3H, J ¼
15.6 Hz), 8.04 (d, 4H, J ¼ 7.6 Hz), 8.08-8.10 (d, 9H), 8.18 (t,
7H, J ¼ 7.6 Hz), 8.25 (d, 3H, J ¼ 15.6 Hz), 8.99 (s, 3H); MS,
m/z: 736. Anal. Calcd. for C56H36N2: C, 91.27; H, 4.92; N,
3.80. Found: C, 91.45; H, 4.85; N, 3.93.
¨
[13] Krohnke, F.; Zecher, W. Angew Chem Int Ed 1962, 1, 626.
[14] (a) Potts, K.T.; Cipullo, M. J.; Ralli, P.; Theodoridis, G. J
Am Chem Soc 1981, 103, 3584; (b) Potts, K.T.; Cipullo, M. J.; Ralli,
P.; Theodoridis, G. J Am Chem Soc 1981, 103, 3585.
[15] Kobayashi, T.; Kakiuchi, H.; Kato, H. Bull Chem Soc Jpn
1991, 64, 392.
4,4’-(1,4-Phenylene)-bis-(2,6-di-2-thienyl
pyridine)
7b. FTIR (KBr disc): m ¼ 1648, 1588, 1419, 973, 819, 720
cmꢁ1
;
1HNMR (500 MHz, DMSO-d6) d: 7.34 (t, 2H, J ¼ 4
[16] Palacios, F.; de Retana, A. M. O.; Oyarzabal, J. Tetrahe-
dron Lett 1996, 37, 4577.
Hz), 7.48 (d, 1H, J ¼ 16.4 Hz), 7.75-7.79 (m, 3H), 7.83-7.87
(d, 1H, J ¼ 16.4 Hz), 7.90-7.93 (m, 1H), 7.97-8.00 (m, 8H),
8.08-8.10 (d, 2H), 8.39 (d, 2H, J ¼ 4 Hz); MS, m/z: 560.
Anal. Calcd. for C32H20N2S4: C, 68.54; H, 3.59; N, 5.00.
Found: C, 68.67; H, 3.70; N, 4.94.
[17] Cave, G. W. V.; Raston, C. L. Chem Commun 2000, 5, 2199.
[18] Tu, S.; Li, T.; Shi, F.; Fang, F.; Zhu, S.; Wei, X.; Zong, Z.
Chem Lett 2005, 34, 732.
[19] Wasserscheid, P.; Keim, W. Angew Chem Int Ed 2000, 39,
3772.
4,4’-(1,4-Phenylene)-bis-(2,6-di-phenyl pyridine) 7c. FTIR
(KBr disc): m ¼ 1655, 1605, 1509, 1417, 1336, 1224, 979,
[20] Olivier-Bourbigou, H.; Magan, L.J. J Mol Catal A: Chem
2002, 419, 182.
¨
[21] Ranke, J.; Stolte, S.; Stormann, R.; Arning, J.; Jastorff, B.
1
832, 770 cm-1; HNMR (500 MHz, DMSO-d6) d: 7.59 (t, 7H,
J ¼ 7.5 Hz), 7.69 (t, 3H, J ¼ 7.5 Hz), 7.79 (d, 3H, J ¼ 15.5
Hz), 7.99 (s, 6H), 8.04 (d, 3H, J ¼ 15.5 Hz), 8.18 (d, 6H, J ¼
7.5 Hz); MS, m/z: 536. Anal. Calcd. for C40H28N2: C, 89.52;
H, 5.26; N, 5.22. Found: C, 89.65; H, 5.15; N, 5.33.
Chem Rev 2007, 107, 2183.
[22] Greaves, T. L.; Drummond, C. J. Chem Rev 2008, 108,
206.
4,4’-(1,4-Phenylene)-bis-(2,6-di-4-bromo phenyl pyridine)
7d. FTIR (KBr disc): m ¼ 1655, 1607, 1418, 1336, 1221, 978,
[26] Arfan, A.; Bazureau, J. P. Org Process Res Dev 2005, 9, 743.
[27] Qiao, K.; Yokoyama, C. Catal Commun 2006, 7, 450.
[28] Wasserscheid, P.; Sesing, M.; Korth, W. Green Chem 2002,
4, 134.
1
817 cmꢁ1; HNMR (500 MHz, DMSO-d6) d: 7.80 (t, 9H, J ¼
9 Hz), 8.00 (s, 6H), 8.01-8.04 (d, 3H), 8.13 (d, 6H, J ¼ 9 Hz);
MS, m/z: 848. Anal. Calcd. for C40H24Br4N2: C, 56.37; H,
2.84; N, 3.29. Found: C, 56.50; H, 2.91; N, 3.24.
[29] Wang, W.; Shau, L.; Cheng, W.; Yang, J.; He, M. Catal
Commun 2008, 9, 337.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet