Propylphosphonium hydrogen carbonate ionic liquid supported on nano-silica as a reusable catalyst for the efficient multicomponent synthesis of fully substituted pyridines and bis-pyridines

Article abstract of DOI:10.1039/c5ra03569d

A new supported phosphonium based ionic liquid, propylphosphonium hydrogen carbonate ionic liquid supported on nano-silica (PPHC-nSiO₂), was prepared and characterized by FT-IR, TGA, SEM and ICP techniques. The resulting catalyst was used for t

Full text of DOI:10.1039/c5ra03569d

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Propylphosphonium hydrogen carbonate ionic
liquid supported on nano-silica as a reusable
catalyst for the efficient multicomponent synthesis
of fully substituted pyridines and bis-pyridines†
Cite this: RSC Adv., 2015, 5, 39978
*
*
Fahime Rahmani, Iraj Mohammadpoor-Baltork, Ahmad R. Khosropour,
Majid Moghadam, Shahram Tangestaninejad and Valiollah Mirkhani
A new supported phosphonium based ionic liquid, propylphosphonium hydrogen carbonate ionic liquid
supported on nano-silica (PPHC–nSiO2), was prepared and characterized by FT-IR, TGA, SEM and ICP
techniques. The resulting catalyst was used for the efficient synthesis of fully substituted pyridines via a
one-pot multicomponent reaction of aldehydes, malononitrile, and thiols under solvent-free conditions.
Expedient synthesis of bis-pyridines from dialdehydes and/or dithiols by using this catalytic system can
be considered as a noteworthy advantage of this method. Furthermore, there was no obvious loss of
catalytic activity even after 5th cycle.
Received 27th February 2015
Accepted 24th April 2015
DOI: 10.1039/c5ra03569d
www.rsc.org/advances
recoverable catalyst for the synthesis of these important
heterocyclic compounds.
Introduction
During the recent years, ionic liquids (ILs) have received
signicant attention due to their unique properties such as
negligible volatility, high thermal stability, good conductivity
and low ammability.30–32 On the other hand, a great deal of
attention has been paid to the phosphonium based ILs as
potential substitutes for the corresponding ammonium based
ILs.33–40 It was found that the phosphonium ILs displayed
higher thermal stability and ionic conductivity than those of the
corresponding ammonium counterparts. These characteristic
aspects seem to be noteworthy advantages of phosphonium ILs,
so these ILs have been efficiently used as solvents/catalysts in a
wide variety of chemical transformations such as ether-
ication,41 synthesis of isoindolin-1-one,42 reductive carbonyla-
tion of nitrobenzenes,43 thiocarbonylation,44 palladium
catalyzed Heck reactions,45 Buchwald–Hartwig amination,46
hydroformylation,47 palladium mediated Suzuki cross-coupling
reactions,48 esterication,49 Diels–Alder reaction,50 asymmetric
phase-transfer alkylation,51 Rh-catalyzed asymmetric hydroge-
nation of enamides,52 synthesis of cyclic carbonate,53 degrada-
tion of phenols,54 Michael addition of mercaptans to a,b-
unsaturated ketones,55 Baylis–Hillman reaction,56 asymmetric
uorination of 3-substituted benzofuran-2(3H)-ones,57 Halex
reactions58 and synthesis of highly substituted imidazoles.59
In continuation of our study on the application of supported
catalysts for the development of valuable synthetic methodol-
ogies,60–63 herein we report an efficient synthesis of fully
substituted pyridines and bis-pyridines catalyzed by propyl-
phosphonium hydrogen carbonate ionic liquid supported on
Heterocyclic systems containing pyridine rings have received
great attention, because this framework is present in a great
number of pharmaceuticals, biologically active molecules,
naturally occurring and synthetic compounds.1–4 Among the
pyridine derivatives, 2-amino-4-aryl-6-sulfanylpyridine-3,5-
dicarbonitriles are of particular importance due to their thera-
peutic applications in the treatment of urinary incontinence,5
Parkinson's disease, hypoxia, asthma, kidney and Creutzfeldt–
Jakob diseases.4,6–8 Also, some of these compounds display anti-
prion,9 anti-hepatitis B virus,10,11 anti-bacterial12,13 and anti-
cancer14–16 activities. The synthesis of these pyridine derivatives,
therefore, has attracted enormous attention of synthetic organic
chemists and a substantial number of methods for the prepa-
ration of 2-amino-4-aryl-6-sulfanylpyridine-3,5-dicarbonitriles
have been developed of which the three-component reaction
of aldehyde, malononitrile, and thiol is the most important.17–29
However, many of these methods suffer from one or more of the
disadvantages such as long reaction times, low yields, forma-
tion of side products, high temperature, tedious workup, and
the use of non-reusable catalysts and toxic organic solvents,
which led to serious environmental and safety problems.
Consequently, it is still vitally needed to introduce a more
environmental friendly and efficient method using
a
Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan
81746-73441, Iran. E-mail: imbaltork@sci.ui.ac.ir; khosropour@chem.ui.ac.ir; Fax:
+98-031-36689732; Tel: +98-031-37932705
† Electronic supplementary information (ESI) available: See DOI:
10.1039/c5ra03569d
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Scheme 1 Synthesis of fully substituted pyridines and bis-pyridines
catalyzed by PPHC–nSiO2.
nano-silica (PPHC–nSiO2) under solvent-free conditions
(Scheme 1).
Results and discussion
Synthesis and characterization of propylphosphonium
hydrogen carbonate ionic liquid supported on nano-silica
(PPHC–nSiO2)
The procedure for synthesis of PPHC–nSiO2 is depicted in
Scheme 2. First, nano-silica was reacted with 3-chloropropyl-
trimethoxysilane (CPTS) in dry toluene to produce the CP–nSiO2.
Then, the reaction of CP–nSiO2 with triphenylphosphine was
carried out in dry toluene under reux conditions to afford pro-
pylphosphonium chloride supported on nano-silica (PPC–nSiO2).
Finally, the desired basic ionic liquid, propylphosphonium
hydrogen carbonate supported on nano-silica (PPHC–nSiO2) was
prepared by treatment of PPC–nSiO2 with solid potassium
hydrogen carbonate in distilled water at room temperature. The
catalyst was characterized by FT-IR, TGA, SEM and ICP techniques.
The FT-IR spectra of nano-silica (Fig. 1a) and PPHC–nSiO2
(Fig. 1b) exhibit characteristic peaks at around 1100, 810, and 465
cmꢀ1 which are assigned Si–O–Si stretching, and the band at
about 3425 cmꢀ1 belongs to the Si–OH groups and adsorbed
water. Moreover, in the FT-IR spectrum of PPHC–nSiO2 (Fig. 1b),
the distinctive bands at around 3053 cmꢀ1 (sp2 C–H), 2938 (C–H
Fig. 1 FT-IR spectra of: (a) nano-SiO2; (b) PPHC–nSiO2 and (c) the 5-
times reused catalyst.
stretching of the alkyl chain), 1742 cmꢀ1 (C]O), 1658, 1617 and
1553 cmꢀ1 (C]C), 1438 cmꢀ1 (P–Ar), 749 cmꢀ1 (P–C), 723 and
687 cmꢀ1 (aromatic C–H bending vibrations) were observed
which are absent in the nano-silica. The above results indicate
that the ionic liquid was successfully graed onto the nano-silica.
The thermal stability of PPHC–nSiO2 catalyst was examined
by thermogravimetric analysis (TGA). The TG curve indicates
that the weight loss starts from about 205 ꢁC, and the complete
loss of the IL and decomposition of the organic moities mainly
occur in the temperature range from 205–640 ꢁC (Fig. 2).
Consequently, the PPHC–nSiO2 catalyst exhibited good thermal
stability below 205 ꢁC. The shape and surface morphology of the
nano-silica and PPHC–nSiO2 were investigated by scanning
electron microscopy (SEM). As shown in Fig. 3, the surface
morphology of these two samples is different, which is a good
indication of supporting the IL on nano-silica. The P content of
PPHC–nSiO2 catalyst, measured by ICP, was 5.643 mg Lꢀ1. This
ꢀ
result reveals that the amount of HCO3 on the nano-silica is
0.455 mmol gꢀ1 of the catalyst.
Synthesis of fully substituted pyridines and bis-pyridines
catalyzed by propylphosphonium hydrogen carbonate ionic
liquid supported on nano-silica (PPHC–nSiO2)
At the commencement, the three-component reaction of 3,4-
dimethoxybenzaldehyde (1 mmol), malononitrile (2 mmol) and
Scheme
2 Synthesis of propylphosphonium hydrogen carbonate
ionic liquid supported on nano-silica (PPHC–nSiO2).
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Table 1 Optimization of the reaction conditions for the synthesis of
fully substituted pyridinesa
Entry
Catalyst (mol%)
Time (min)
Yieldb (%)
1
2
3
4
5
6
7
8
—
210
150
100
50
150
20
35
20
40
20
0
30
35
71
35
95
70
95
42
95
Nano-SiO2 (15 mg)
KHCO3 (3)
Fig. 2 TGA curve of PPHC–nSiO2 catalyst.
PMIMHC–nSiO2 (0.7)
PPC–nSiO2 (0.7)
PPHC–nSiO2 (0.7)
PPHC–nSiO2 (0.5)
PPHC–nSiO2 (1)
PPHC–nSiO2 (0.7)
PPHC–nSiO2 (0.7)
9c
10d
a
3,4-Dimethoxybenzaldehyde (1 mmol), malononitrile (2 mmol), 4-
methylthiophenol (1 mmol), at 50 ꢁC under solvent-free conditions.
b
d
c
Isolated yield. Reaction was performed at room temperature.
Reaction was performed at 75 ꢁC.
nSiO2, and PPHC–nSiO2 at 50 ꢁC under solvent-free conditions.
Among the screened catalysts, PPHC–nSiO2 exhibited excellent
catalytic activity (Table 1, entry 6). We then proceeded further to
optimize the catalyst loading and temperature for this reaction.
To determine the optimum amount of PPHC–nSiO2 catalyst, the
model reaction was carried out using 0.5, 0.7 and 1 mol% of the
catalyst, which afforded the desired product in 70%, 95% and
95% yields, respectively. Increasing the amount of the catalyst
beyond 0.7 mol% did not show any improvement. Finally, the
effect of temperature was evaluated; increasing the temperature
from 50 to 75 ꢁC did not improve the yield, whereas decreasing
the temperature resulted in lower yield of the desired product.
Based on the obtained results, the optimal conditions were
identied as 3,4-dimethoxybenzaldehyde (1 mmol), malononi-
trile (2 mmol) and 4-methylthiophenol (1 mmol) in the presence
of 0.7 mol% PPHC–nSiO2 at 50 ꢁC under solvent-free conditions.
With the above mentioned optimized conditions, the
generality and scope of this method for the synthesis of a series
of fully substituted pyridines were explored. As shown in
Table 2, a variety of aromatic aldehydes with electron-donating
and electron-withdrawing substituents at the ortho, meta, and
para positions of aromatic ring were reacted smoothly with
malononitrile and various thiols in the presence of catalytic
amounts of PPHC–nSiO2 to afford the corresponding fully
substituted pyridines in high yields (Table 2, entries 1–14).
Under the same conditions, polycyclic aldehydes such as
naphthalene-2-carbaldehyde and anthracene-9-carbaldehyde
took part in this three-component reaction to give the desired
products in high yields (Table 2, entries 15–20). The reaction of
heterocyclic aldehydes such as pyridine-3-carbaldehyde and 5-
methylfuran-2-carbaldehyde with thiols and malononitrile was
also proceeded smoothly to furnish the corresponding fully
Fig. 3 SEM images of: (a) nano-silica and (b) PPHC–nSiO2 catalyst.
4-methylthiophenol (1 mmol) was selected as a model for the
optimization of the reaction conditions. As depicted in Table 1,
no yield of the product was obtained when the reaction was
performed in the absence of the catalyst, even aer prolonged
reaction time, indicating the necessity of the catalyst for the
reaction to proceed (Table 1, entry 1). To improve the reaction
efficiency and yield of the desired product, the model reaction
was examined in the presence of various catalysts such as nano-
SiO2,
KHCO3,
1-methyl-3-propylimidazolium
hydrogen
carbonate supported on nano-silica (PMIMHC–nSiO2), PPC–
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Table 2 Synthesis of fully substituted pyridines in the presence of PPHC–nSiO2 catalyst
Entry
Aldehyde
Thiol
Product
Time (min)
Yielda (%)
1
20
94
2
22
95
3
4
30
23
90
88
5
40
83
6
25
87
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Table 2 (Contd.)
Entry
Aldehyde
Thiol
Product
Time (min)
Yielda (%)
7
23
90
8
20
95
9
22
92
10
11
12
20
25
25
86
80
88
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Table 2 (Contd.)
Entry
Aldehyde
Thiol
Product
Time (min)
Yielda (%)
13
25
80
14
25
88
15
30
83
16
25
90
17
33
80
18
25
85
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Table 2 (Contd.)
Entry
19
Aldehyde
Thiol
Product
Time (min)
Yielda (%)
30
80
20
21
27
30
85
80
22
20
83
23
30
94
24
30
92
a
Isolated yield.
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substituted pyridines in high yields (Table 2, entries 21 and 22).
In addition, sterically hindered aldehyde such as 3-(bis(3,4-
dimethoxyphenyl)methyl)benzaldehyde performed this reaction
rapidly and smoothly to give the desired products in excellent
yields (Table 2, entries 23 and 24). The results showed that the
presence of electron-withdrawing or electron-donating substit-
uents on the aromatic rings of the starting materials had no
signicant effect on the yields of the products and reaction
times.
The experimental procedure is very simple and the reactions
were generally clean and no side products were produced; in all
cases, fully substituted pyridines were obtained as the sole
products.
Another outstanding advantage of this catalytic system lies
in the synthesis of bis-pyridines from dialdehydes and dithiols.
The results are summarized in Schemes 3 and 4. The reaction of
dialdehydes such as terephthaldialdehyde and iso-
phthaldialdehyde with thiols and malononitrile was performed
efficiently in the presence of PPHC–nSiO2 catalyst and the cor-
responding fully substituted bis-pyridines were obtained in 78–
92% yields (Scheme 3). In an alternative route, dithiols such as
benzene-1,4-dithiol and anthracene-9,10-dithiol were reacted
with aldehydes and malononitrile in the presence of catalytic
amounts of PPHC–nSiO2 to generate the desired fully
substituted bis-pyridines in 80–92% yields (Scheme 4). The
synthesis of bis-pyridines through such a one-pot multi-
component reaction using this catalytic system can be regar-
ded as a useful practical attainment in the preparation of these
widely used heterocyclic compounds.
Scheme
PPHC–nSiO2.
4
Synthesis of bis-pyridines from dithiols catalyzed by
malononitrile in the presence of the catalyst to give the inter-
mediate A. Then, the base-catalyzed Michael addition of the
second molecule of malononitrile to A followed by concurrent
addition of thiolate to the nitrile group and cyclization leads to
the formation of dihydropyridine B and regenerates the catalyst
for the next catalytic cycle. Finally, Oxidative aromatization (air)
A plausible mechanism for the synthesis of fully substituted
pyridines by using PPHC–nSiO2 is depicted in Scheme 5.
Initially, aldehyde undergoes Knoevenagel condensation with
Scheme 3 Synthesis of bis-pyridines from dialdehydes catalyzed by Scheme 5 Plausible mechanism for the synthesis of fully substituted
PPHC–nSiO2.
pyridines catalyzed by PPHC–nSiO2.
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DMSO-d6 solution on a Bruker-Avance 400 spectrometer.
Elemental analysis was done on LECO, CHNS-932 analyzer.
Thermogravimetric analysis (TGA) was carried out on a Mettler
TG50 instrument under air ow at a uniform heating rate of
5
ꢁC minꢀ1 in the range of 30–700 ꢁC. The P content of the
catalyst was measured by an inductively coupled plasma optical
emission spectrometry (ICP-OES), using a Perkin-Elmer 7300DV
ICP analyzer. Scanning electron microscopy measurements
were performed on a Carl Zeiss EVO MA 10 scanning electron
microscope (SEM).
Preparation of propylphosphonium hydrogen carbonate
ionic liquid supported on nano-silica (PPHC–nSiO2). To a
suspension of nano-silica (2 g) in dry toluene (25 mL) was added
3-chloropropyltrimethoxysilane (3 mL) and the resulting
mixture was stirred under reux conditions for 24. The reaction
mixture was cooled to room temperature, ltered and the solid
material was washed with toluene and a mixture of water–
ethanol. The resulting chloropropyl functionalized nano-silica
(CP–nSiO2) was dried under vacuum at 60 ꢁC. Then, to a
mixture of CP–nSiO2 (2 g) in dry toluene (25 mL) was added
triphenylphosphine (8 g) and the resulting mixture was stirred
under reux conditions for 24 h. Aer cooling to room
temperature, the mixture was ltered, and the solid material
was washed with toluene and ethanol. The resulting propyl-
phosphonium chloride supported on nano-silica (PPC–nSiO2)
Fig. 4 Reusability of the PPHC–nSiO2 catalyst.
of dihydropyridine B affords the desired fully substituted pyri-
dine 3.
Recyclability of the catalyst
Finally, the recyclability and reusability, as an attractive prop-
erty of the catalyst, was examined in the three-component
reaction of 3,4-dimethoxybenzaldehyde, malononitrile and
4-methylthiophenol. Aer the reaction was completed, EtOH
(10 mL) was added. The catalyst was easily separated by simple
ltration, washed with EtOH (10 mL), dried in vacuo and then
reused for the next cycle. The data shown in Fig. 4 illustrate that
the PPHC–nSiO2 catalyst can be reused at least ve times
without any signicant loss of its efficiency and activity.
Comparison of the FT-IR spectra of the fresh and reused catalyst
shows no obvious change in the structure of the catalyst and
characteristic bands, suggesting the stability of the catalyst
during the reaction (Fig. 1c).
ꢁ
was dried under vacuum at 50 C. Finally, A mixture of PPC–
nSiO2 (2 g) and solid potassium hydrogen carbonate (5 g) in
distilled water (40 mL) was stirred vigorously at room temper-
ature for 24 h. The mixture was ltrated and the solid material
was washed with disꢁtilled water until neutral and then dried
under vacuum at 70 C to afford the desired ionic liquid, pro-
pylphosphonium hydrogen carbonate supported on nano-silica
(PPHC–nSiO2).
General procedure for synthesis of fully substituted pyri-
dines in the presence of PPHC–nSiO2 catalyst. A mixture of
aldehyde (1 mmol), malononitrile (2 mmol), thiol (1 mmol) and
PPHC–nSiO2 catalyst (15 mg, containing 0.7 mol% HCO3ꢀ) was
stirred at 50 ꢁC under solvent-free conditions for the desired
time according to Table 2. The progress of the reaction was
monitored by TLC (eluent: petroleum ether/EtOAc, 5 : 3). Aer
completion of the reaction, the mixture was cooled to room
temperature and then EtOH (10 mL) was added. The catalyst
was separated by ltration and washed with EtOH (10 mL). The
ltrate was evaporated and the crude product was puried by
recrystallization from EtOAc or EtOH to afford the pure product.
2-Amino-4-(4-nitrophenyl)-6-(phenylsulꢁfanyl)pyridine-3,5-
dicarbonitrile (Tables 2, 3a). Mp 291–292 C (ref. 17 287–289
ꢁC). IR (KBr): nmax ¼ 3348, 3320, 2217, 1640, 1553, 1534, 1354,
Conclusions
In conclusion, we have disclosed a convenient, efficient and
straightforward protocol for the synthesis of fully substituted
pyridines via a one-pot multicomponent reaction of a wide
range of aldehydes, malononitrile, and thiols using heteroge-
neous and reusable PPHC–nSiO2 catalyst under solvent-free
conditions. The present methodology is also applicable to the
synthesis of bis-pyridines from dialdehydes and/or dithiols. In
addition, mild conditions, avoidance of toxic solvent, short
reaction times, high yields, recyclability without losing catalytic
activity, easy work-up and ease of catalyst separation are the
important features of this procedure. These advantages render
this protocol facile and suitable to generate a diversied library
of fully substituted pyridine and bis-pyridine derivatives.
1
1248, 1164, 823 cmꢀ1. H NMR (400 MHz, DMSO-d6) d ¼ 8.44
(d, J ¼ 8.8 Hz, 2H), 7.69 (br s, 2H), 7.89 (d, J ¼ 8.8 Hz, 2H), 7.61–
7.63 (m, 2H), 7.51–7.53 (m, 3H).
Experimental
General information
2-Amino-4-(4-nitrophenyl)-6-(4-methylphenylsulfanyl)pyridine-
3,5-dicarbonitrile (Table 2, 3b). Mp 300–302 ꢁC. IR (KBr): nmax
¼
Melting points were determined using a Stuart Scientic SMP2 3438, 3328, 2215, 1623, 1545, 1525, 1448, 1383, 1266, 1116, 809,
apparatus. FT-IR spectra were recorded on a Nicolet-Impact 760 cmꢀ1. 1H NMR (400 MHz, DMSO-d6) d ¼ 8.43 (d, J ¼ 8.8 Hz,
400D instrument in the range of 400–4000 cmꢀ1. H and 13C 2H), 7.88 (d, J ¼ 8.8 Hz, 2H), 7.48 (d, J ¼ 8.0 Hz, 2H), 7.32 (d, J ¼
1
NMR (400 and 100 MHz) spectra were recorded in CDCl3 or 8.0 Hz, 2H), 7.07 (br s, 2H), 2.38 (s, 3H). 13C NMR (100 MHz,
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DMSO-d6) d ¼ 166.0, 159.7, 158.3, 150.3, 148.2, 128.1, 126.6, 1264, 1160, 885, 742 cmꢀ1. 1H NMR (400 MHz, DMSO-d6) d ¼ 7.66
121.5, 119.6, 115.8, 112.3, 111.5, 93.4, 87.0, 24.9. Anal. calcd for (br s, 2H), 7.38 (d, J ¼ 8.0 Hz, 2H), 7.22 (d, J ¼ 8.0 Hz, 2H), 7.12 (s,
C
20H13N5O2S; C, 62.00; H, 3.38; N, 18.08; S, 8.28. Found: C, 1H), 7.04 (s, 2H), 3.76 (s, 3H), 3.71 (s, 3H), 2.29 (s, 3H). 13C NMR
62.09; H, 3.40; N, 18.02; S, 8.36%.
2-Amino-4-(3-nitrophenyl)-6-(4-methylphenylsulfanyl)pyridine- 126.7, 125.7, 121.5, 119.6, 116.0, 115.3, 112.2, 110.9, 93.4, 88.6,
3,5-dicarbonitrile (Table 2, 3c). Mp 225–227 ꢁC. IR (KBr): nmax
55.6, 55.3, 25.1. Anal. calcd for C22H18N4O2S; C, 65.65; H, 4.51; N,
(100 MHz, DMSO-d6) d ¼ 165.9, 159.8, 159.6, 150.3, 148.2, 130.5,
¼
3484, 3348, 2213, 1619, 1544, 1525, 1446, 1356, 1265, 1160, 13.92; S, 7.97. Found: C, 65.73; H, 4.54; N, 13.82; S, 8.09%.
1069, 889, 735 cmꢀ1
.
1H NMR (400 MHz, DMSO-d6) d ¼ 8.34
2-Amino-4-(3,4-dimethoxyphenyl)-6-(3-methoxyphenylsulfanyl)
(s, 1H), 8.23 (d, J ¼ 8.0 Hz, 2H), 7.86 (d, J ¼ 7.6 Hz, 2H), 7.72 pyridine-3,5-dicarbonitrile (Table 2, 3i). Mp 213–215 ꢁC. IR (KBr):
(t, J ¼ 8.0 Hz, 3H), 5.22 (br s, 2H), 1.23 (s, 3H). 13C NMR (100 nmax ¼ 3353, 3338, 3159, 2210, 1626, 1545, 1522, 1465, 1399,
MHz, DMSO-d6) d ¼ 172.0, 166.5, 160.1, 149.0, 147.9, 147.0, 1244, 1098, 1013, 816 cmꢀ1. 1H-NMR (400 MHz, DMSO-d6): d ¼
136.0, 131.6, 129.0, 128.4, 120.9, 115.3, 114.9, 112.8, 111.7, 93.1, 7.80 (br s, 2H), 7.40 (t, J ¼ 8.1 HZ, 1H), 7.21 (d, J ¼ 1.4 Hz, 1H),
21.0. Anal. calcd for C20H13N5O2S; C, 62.00; H, 3.38; N, 18.08; S, 7.14–7.18 (m, 4H), 7.08 (dd, 1J ¼ 2.5 Hz, 2J ¼ 0.8 Hz, 1H), 3.86 (s,
8.28. Found: C, 62.09; H, 3.35; N, 18.01; S, 8.38%.
3H), 3.81 (s, 3H), 3.80 (s, 3H). 13C NMR (100 MHz, DMSO-d6) d ¼
2-Amino-4-(3-bromophenyl)-6-(4-methylphenylsulfanyl)pyridine- 165.9, 159.7, 159.5, 158.3, 150.3, 148.2, 130.2, 128.1, 126.6,
3,5-dicarbonitrile (Table 2, 3d). Mp 230–232 C. IR (KBr): nmax
ꢁ
¼
125.8, 121.5, 119.6, 115.8, 115.6, 115.3, 112.2, 111.4, 93.4, 86.9,
3433, 3325, 2214, 1640, 1527, 1426, 1339, 1233, 1143, 1017, 810, 55.6, 55.5, 55.3. Anal. calcd for C22H18N4O3S; C, 63.14; H, 4.34;
1
763 cmꢀ1. H NMR (400 MHz, DMSO-d6) d ¼ 7.85 (br s, 2H), N, 13.39; S, 7.66. Found: C, 63.19; H, 4.36; N, 13.32; S, 7.77%.
7.78–7.82 (m, 2H), 7.54–757 (m, 2H), 7.48 (d, J ¼ 8.1 Hz, 2H),
2-Amino-4-(2-chlorophenyl)-6-(b-naphthylsulfanyl)pyridine-
7.32 (d, J ¼ 7.9 Hz, 2H), 2.38 (s, 3H). 13C NMR (100 MHz, DMSO- 3,5-dicarbonitrile (Table 2, 3j). Mp 253–255 ꢁC. IR (KBr): nmax
¼
d6) d ¼ 167.1, 159.6, 157.9, 148.4, 146.7, 140.5, 135.0, 131.7, 3393, 3130, 2217, 1650, 1611, 1447, 1337, 1260, 1206, 1117,
130.2, 129.0, 128.4, 120.9, 115.3, 112.8, 110.8, 93.2, 23.0. Anal. 1019, 873, 759 cmꢀ1. H NMR (400 MHz, DMSO-d6) d ¼ 8.29
1
calcd for C20H13BrN4S; C, 57.02; H, 3.11; N, 13.30; S, 7.61. (s, 1H), 8.03 (t, J ¼ 8.7 Hz, 3H), 7.95 (br s, 2H), 7.58–7.74 (m,
Found: C, 56.93; H, 3.09; N, 13.25; S, 7.72%.
7H). 13C NMR (100 MHz, DMSO-d6) d ¼ 167.0, 159.6, 159.5,
2-Amino-4-(4-isopropylphenyl)-6-(4-methylphenylsulfanyl)- 158.6, 132.2, 131.4, 130.2, 128.4, 128.0, 127.7, 127.6, 127.1,
pyridine-3,5-dicarbonitrile (Table 2, 3e). Mp 193–196 ꢁC. IR 126.7, 125.3, 120.1, 115.9, 115.3, 114.9, 94.1, 87.3. Anal. calcd
(KBr): nmax ¼ 3355, 3212, 2214, 1621, 1542, 1510, 1454, 1305, for C23H13ClN4S; C, 66.90; H, 3.17; N, 13.57; S, 7.77. Found: C,
1261, 1015, 807, 732 cmꢀ1. H NMR (400 MHz, DMSO-d6) d ¼ 66.98; H, 3.15; N, 13.51; S, 7.89%.
1
7.78 (br s, 2H), 7.44–750 (m, 4H), 7.26–7.37 (m, 4H), 2.97–3.04
2-Amino-4-(3-bromophenyl)-6-(b-naphthylsulfanyl)pyridine-
(m, 1H), 2.38 (s, 3H), 1.27 (d, J ¼ 6.8 Hz, 6H). 13C NMR 3,5-dicarbonitrile (Table 2, 3k). Mp 207–208 ꢁC. IR (KBr): nmax
¼
(100 MHz, DMSO-d6) d ¼ 167.7, 160.6, 156.0, 143.7, 139.5, 3438, 3327, 2216, 1623, 1547, 1337, 1257, 1152, 1051, 1027, 820,
135.0, 130.1, 123.6, 118.2, 117.7, 116.0, 115.5, 109.9, 109.3, 763 cmꢀ1. 1H NMR (400 MHz, DMSO-d6) d ¼ 8.26 (d, J ¼ 1.4 Hz,
30.5, 22.0, 20.9. Anal. calcd for C23H20N4S; C, 71.85; H, 5.24; N, 1H), 8.00–8.04 (m, 3H), 7.80–7.85 (m, 2H), 7.79–7.80 (m, 1H),
14.57; S, 8.34. Found: C, 71.93; H, 5.27; N, 14.51; S, 8.44%.
7.56–7.64 (m, 6H). 13C NMR (100 MHz, CDCl3) d ¼ 171.1, 166.5,
2-Amino-4-(3-methoxyphenyl)-6-(4-methylphenylsulfanyl)- 161.1, 159.4, 148.4, 147.1, 146.7, 140.1, 136.0, 134.9, 130.1,
pyridine-3,5-dicarbonitrile (Table 2, 3f). Mp 250–253 ꢁC. IR 129.0, 127.9, 123.3, 120.9, 115.3, 114.9, 112.8, 111.6, 93.0. Anal.
(KBr): nmax ¼ 3363, 2218, 1634, 1551, 1498, 1314, 1256, 1181, calcd for C23H13BrN4S; C, 60.40; H, 2.87; N, 12.25; S, 7.01.
1019, 839, 803 cmꢀ1. H NMR (400 MHz, DMSO-d6) d ¼ 7.80 Found: C, 60.49; H, 2.89; N, 12.19; S, 7.12%.
1
(br s, 2H), 7.48–7.52 (m, 3H), 7.31 (d, J ¼ 8.0 Hz, 2H), 7.16 (d,
2-Amino-4-(3-methoxyphenyl)-6-(b-naphthylsulfanyl)pyridine-
J ¼ 4.0 Hz, 2H), 7.09 (d, J ¼ 7.7 Hz, 1H), 3.82 (s, 3H), 2.38 (s, 3,5-dicarbonitrile (Table 2, 3l). Mp 204–206 ꢁC. IR (KBr): nmax
¼
3H). 13C NMR (100 MHz, DMSO-d6) d ¼ 170.1, 160.1, 159.6, 3405, 3326, 3227, 2213, 1645, 1546, 1521, 1426, 1339, 1245,
158.3, 150.3, 149.3, 131.1, 128.1, 126.6, 121.5, 119.6, 115.8, 1143, 1017, 810, 761 cmꢀ1. H NMR (400 MHz, DMSO-d6) d ¼
1
112.3, 111.4, 95.0, 86.9, 55.3, 24.5. Anal. calcd for 8.26 (d, J ¼ 1.2 Hz, 1H), 8.00–8.04 (m, 3H), 7.79 (br s, 2H), 7.60–
C
21H16N4OS; C, 67.72; H, 4.33; N, 15.04; S, 8.61. Found: C, 7.65 (m, 3H), 7.49–7.53 (m, 1H), 7.14–7.17 (m, 3H), 3.84 (s, 3H).
67.82; H, 4.37; N, 14.96; S, 8.75%.
2-Amino-4-(3,4-dimethoxyphenyl)-6-(phenylsulfanyl)pyridine- 134.9, 134.3, 133.9, 133.7, 133.0, 131.4, 130.4, 130.3, 128.9,
3,5-dicarbonitrile (Table 2, 3g). Mp 223–225 ꢁC (ref. 25 227 C). 127.9, 127.6, 127.4, 126.7, 124.5, 114.9, 114.6, 54.6. Anal. calcd
13C NMR (100 MHz, DMSO-d6) d ¼ 166.7, 160.1, 159.5, 157.1,
ꢁ
IR (KBr): nmax ¼ 3414, 3326, 3227, 2211, 1644, 1545, 1520, 1317, for C24H16N4OS; C, 70.57; H, 3.95; N, 13.72; S, 7.85. Found: C,
1245, 1235, 1012, 814, 708 cmꢀ1. 1H NMR (400 MHz, DMSO-d6) 70.51; H, 3.97; N, 13.65; S, 7.94%.
d ¼ 7.77 (br s, 2H), 7.60–7.62 (m, 2H), 7.50–7.52 (m, 3H), 7.22
2-Amino-4-(2,4-dichlorophenyl)-6-(b-naphthylsulfanyl)pyridine-
(s, 1H), 7.15 (s, 2H), 3.86 (s, 3H), 3.81 (s, 3H). 13C NMR (100 3,5-dicarbonitrile (Table 2, 3m). Mp 146–147 ꢁC. IR (KBr): nmax
¼
MHz, DMSO-d6) d ¼ 165.9, 160.5, 160.2, 158.3, 151.3, 148.2, 3332, 3226, 3086, 2210, 1634, 1603, 1482, 1417, 1315, 1243,
130.2, 126.6, 122.0, 119.9, 116.0, 115.3, 112.2, 111.6, 94.0, 88.1, 1181, 1017, 839, 810 cmꢀ1. H NMR (400 MHz, DMSO-d6) d ¼
1
55.5, 55.3.
8.30 (s, 1H), 8.08 (d, J ¼ 8.5 Hz, 1H), 7.99–8.04 (m, 3H), 7.63–7.66
2-Amino-4-(3,4-dimethoxyphenyl)-6-(4-methylphenylsulfanyl)- (m, 2H), 7.59 (dd, 1J ¼ 8.4 Hz, 2J ¼ 1.4 Hz, 2H), 7.39 (d, J ¼ 1.6,
pyridine-3,5-dicarbonitrile (Table 2, 3h). Mp 229–232 ꢁC. IR 1H), 7.30 (dd, 1J ¼ 8.4 Hz, 2J ¼ 1.6 Hz, 2H). 13C NMR (100 MHz,
(KBr): nmax ¼ 3435, 3310, 2210, 1617, 1546, 1525, 1417, 1317, DMSO-d6) d ¼ 173.9, 171.9, 171.2, 166.2, 159.8, 159.6, 157.0,
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130.6, 130.4, 129.3, 128.8, 128.3, 128.1, 127.6, 126.5, 125.7,
124.4, 119.5, 116.1, 114.6, 114.3. Anal. calcd for C23H12Cl2N4S;
C, 61.75; H, 2.70; N, 12.52; S, 7.17. Found: C, 61.69; H, 2.71; N,
12.57; S, 7.29%.
2-Amino-4-(anthracene-9-yl)-6-(3-methoxyphenylsulfanyl)-
pyridine-3,5-dicarbonitrile (Table 2, 3s). Mp 250–252 ꢁC. IR
(KBr): nmax ¼ 3324, 3270, 2217, 1640, 1510, 1446, 1337, 1254,
1152, 1051, 1026, 820, 763 cmꢀ1. 1H-NMR (400 MHz, DMSO-d6):
1
2
2-Amino-4-(3,4-dimethoxyphenyl)-6-(b-naphthylsulfanyl)-
d ¼ 8.87 (s, 1H), 8.24 (dd, J ¼ 7.12 Hz, J ¼ 2.3 Hz, 2H), 8.03
(br s, 2H), 7.60–7.70 (m, 7H), 7.44 (t, J ¼ 7.9 Hz, 1H), 7.28–7.33
ꢁ
pyridine-3,5-dicarbonitrile (Table 2, 3n). Mp 192–193 C. IR
(m, 1H), 7.12 (dd, 1J ¼ 7.1 Hz, 2J ¼ 1.8 Hz, 1H), 3.85 (s, 3H). 13
C
(KBr): nmax ¼ 3409, 3309, 2210, 1619, 1547, 1509, 1446, 1356,
1264, 1161, 1063, 881, 742 cmꢀ1. 1H NMR (400 MHz, DMSO-d6)
d ¼ 8.26 (d, J ¼ 1.2 Hz, 1H), 8.02 (t, J ¼ 8.4 Hz, 3H). 7.74 (br s,
2H), 7.59–7.66 (m, 3H), 7.23 (s, 1H), 7.16 (s, 2H), 3.86 (s, 3H),
3.81 (s, 3H). 13C NMR (100 MHz, DMSO-d6) d ¼ 174.3, 172.9,
172.6, 166.2, 159.8, 159.6, 157.0, 130.6, 130.3, 129.4, 128.7,
127.6, 127.5, 126.5, 125.6, 124.3, 119.5, 116.0, 114.7, 113.9, 55.5,
55.4. Anal. calcd for C25H18N4O2S; C, 68.48; H, 4.14; N, 12.78; S,
7.31. Found: 68.40; H, 4.17; N, 12.72; S, 7.44%.
NMR (100 MHz, DMSO-d6) d ¼ 175.0, 171.3, 166.2, 159.8, 159.6,
157.0, 130.6, 130.2, 129.4, 128.8, 128.2, 128.1, 127.6, 126.5,
125.8, 124.3, 119.5, 116.0, 114.7, 114.4, 55.4. Anal. calcd for
C
28H18N4OS; C, 73.34; H, 3.96; N, 12.22; S, 6.99. Found: C, 73.28;
H, 3.92; N, 12.16; S, 7.12%.
2-Amino-4-(anthracene-9-yl)-6-(b-naphthylsulfanyl)pyridine-
3,5-di carbonitrile (Table 2, 3t). Mp 267–270 ꢁC. IR (KBr): nmax
¼
3355, 3212, 2214, 1621, 1415, 1308, 1261, 1114, 789 cmꢀ1. H
NMR (400 MHz, DMSO-d6) d ¼ 8.88 (s, 1H), 8.35 (s, 1H), 8.24–
8.35 (m, 2H), 8.03–8.09 (m, 5H), 7.80 (dd, 1J ¼ 8.5 Hz, 2J ¼
1.8 Hz, 1H), 7.70–7.73 (m, 2H), 7.60–7.66 (m, 6H). 13C NMR
(100 MHz, DMSO-d6) d ¼ 166.0, 159.6, 159.5, 158.6, 133.3, 132.2,
131.4, 130.2, 128.46, 128.41, 128.3, 128.0, 127.7, 127.6, 127.0,
126.7, 125.3, 119.6, 115.9, 115.3, 115.0, 93.5, 87.2. Anal. calcd
for C31H18N4S; C, 77.80; H, 3.79; N, 11.71; S, 6.70. Found: C,
77.71; H, 3.75; N, 11.63; S, 6.82%.
1
2-Amino-4-(b-naphthyl)-6-(4-methylphenylsulfanyl)pyridine-
3,5-dicarbonitrile (Table 2, 3o). Mp 238–241 ꢁC. IR (KBr): nmax
¼
3403, 3318, 2217, 1642, 1528, 1426, 1312, 1243, 1027, 811,
762 cmꢀ1. 1H NMR (400 MHz, DMSO-d6) d ¼ 8.06–8.17 (m, 4H),
7.87 (br s, 2H), 7.64–7.70 (m, 3H), 7.51 (d, J ¼ 7.3 Hz, 2H), 7.33
(d, J ¼ 7.6 Hz, 2H), 2.39 (s, 3H). 13C NMR (100 MHz, DMSO-d6)
d ¼ 167.1, 161.1, 160.0, 134.3, 132.1, 131.4, 130.3, 128.4, 127.7,
127.6, 126.7, 125.3, 119.6, 116.0, 115.3, 114.6, 94.1, 88.9, 23.5.
Anal. calcd for C24H16N4S; C, 73.45; H, 4.11; N, 14.28; S, 8.17.
Found: C, 73.52; H, 4.09; N, 14.22; S, 8.29%.
2-Amino-4-(3-pyridine)-6-(4-methylphenylsulfanyl)pyridine-
ꢁ
3,5-dicarbonitrile (Table 2, 3u). Mp 310–312 C. IR (KBr): nmax
2-Amino-4-(b-naphthyl)-6-(3-methoxyphenylsulfanyl)pyridine-
¼ 3438, 3327, 3216, 2216, 1624, 1549, 1510, 1426, 1337, 1259,
1154, 1019, 813 cmꢀ1. 1H NMR (400 MHz, CDCl3) d ¼ 8.81–8.84
3,5-dicarbonitrile (Table 2, 3p). Mp 175–180 ꢁC. IR (KBr): nmax
¼
1
2
3403, 3325, 3150, 2214, 1648, 1547, 1516, 1427, 1339, 1294, 1145,
1017, 813, 768 cmꢀ1. 1H NMR (400 MHz, DMSO-d6): d ¼ 8.12–8.17
(m, 2H), 8.07 (s, 2H), 7.93 (br s, 2H), 7.67 (s, 3H), 7.41–7.43 (m,
1H), 7.21 (s, 2H), 7.09 (d, J ¼ 7.1 Hz, 1H), 3.82 (s, 3H). 13C NMR
(100 MHz, DMSO-d6) d ¼ 166.0, 159.6, 159.5, 158.6, 133.3, 132.2,
131.4, 130.2, 128.46, 128.41, 128.3, 128.0, 127.7, 127.6, 127.0,
126.7, 125.3, 119.6, 115.9, 115.3, 115.0, 93.5, 87.2, 55.3. Anal.
calcd for C24H16N4OS; C, 70.57; H, 3.95; N, 13.72; S, 7.85. Found:
C, 70.65; H, 3.92; N, 13.67; S, 7.79%.
(m, 1H), 7.88–7.91 (m, 1H), 7.53 (dd, J ¼ 7.9 Hz, J ¼ 4.8 Hz,
2H), 7.45 (d, J ¼ 8.0 Hz, 2H), 7.29 (d, J ¼ 9.2 Hz, 2H), 5.55 (br s,
2H), 2.45 (s, 3H). 13C NMR (100 MHz, CDCl3) d ¼ 162.8, 160.5,
160.2, 132.4, 132.3, 131.9, 131.6, 130.9, 130.6, 129.6, 129.5,
128.8, 125.9, 118.7, 114.4, 26.2. Anal. calcd for C19H13N5S; C,
66.45; H, 3.82; N, 20.39; S, 9.34. Found: C, 66.54; H, 3.78; N,
20.33; S, 9.27%.
2-Amino-4-(5-methylfuryl)-6-(methylphenylsulfanyl)pyridine-
3,5-dicarbonitrile (Table 2, 3v). Mp 189–192 ꢁC. IR (KBr): nmax
¼
2-Amino-4-(b-naphthyl)-6-(b-naphthylsulfanyl)pyridine-3,5-
3402, 3316, 2210, 1628, 1545, 1514, 1409, 1343, 1263, 1016,
825 cmꢀ1. 1H NMR (400 MHz, DMSO-d6): d ¼ 7.69 (br s, 2H), 7.46
(d, J ¼ 8.0 Hz, 2H), 7.36 (d, J ¼ 3.5 Hz, 1H), 7.30 (d, J ¼ 8.0 Hz,
2H), 6.49 (t, J ¼ 2.6 Hz, 1H), 2.41 (s, 3H), 2.37 (s, 3H). 13C NMR
(100 MHz, DMSO-d6) d ¼ 167.6, 160.1, 155.6, 144.0, 143.1, 139.5,
135.2, 130.0, 123.6, 118.2, 117.3, 116.2, 109.8, 108.9, 20.8, 13.4.
Anal. calcd for C19H14N4OS; C, 65.88; H, 4.07; N, 16.17; S, 9.26.
Found: C, 65.80; H, 4.06; N, 16.13; S, 9.39%.
ꢁ
dicarbonitrile (Table 2, 3q). Mp 208–211 C. IR (KBr): nmax
¼
3414, 3325, 2217, 1643, 1522, 1417, 1339, 1238, 1116, 809,
703 cmꢀ1. 1H NMR (400 MHz, DMSO-d6) d ¼ 8.29 (s, 1H), 8.19
(s, 1H), 8.14 (d, J ¼ 8.4 Hz, 1H), 8.02–8.07 (m, 5H), 7.86 (br s,
2H), 7.63–7.68 (m, 6H). 13C NMR (100 MHz, DMSO-d6) d ¼
159.7, 156.9, 134.7, 134.1, 133.3, 132.8, 131.3, 130.7, 129.4,
128.8, 128.2, 127.8, 127.6, 127.3, 127.0, 126.6, 125.9, 125.7,
124.9, 124.3, 114.9, 114.4. Anal. calcd for C27H16N4S; C, 75.68;
H, 3.76; N, 13.07; S, 7.48. Found: C, 75.60; H, 3.73; N, 13.00; S,
7.59%.
2-Amino-4-(3-(bis(3,4-dimethoxyphenyl)methyl)phenyl)-6-(p-
tolythio)pyridine-3,5-dicarbonitrile (Table 2, 3w). Mp 238–
240 ꢁC. IR (KBr): nmax ¼ 3432, 3236, 2983, 2217, 1628, 1545,
1514, 1425, 1342, 1262, 1116, 1015, 810 cmꢀ1 1H NMR (400
.
2-Amino-4-(anthracene-9-yl)-6-(4-methylphenylsulfanyl)pyridine-
ꢁ
3,5-dicarbonitrile (Table 2, 3r). Mp 254–256 C. IR (KBr): nmax
¼
MHz, DMSO-d6): d ¼ 7.79 (br s, 2H), 7.47–7.51 (m, 4H), 7.30 (t,
J ¼ 8.0 Hz, 4H), 6.92 (d, J ¼ 8.4 Hz, 2H), 6.73 (d, J ¼ 1.7 Hz, 2H),
6.63 (dd, 1J ¼ 8.2 Hz, 2J ¼ 1.7 Hz, 2H), 5.60 (s, 1H), 3.73 (s, 6H),
3.65 (s, 6H), 2.37 (s, 3H). 13C NMR (100 MHz, DMSO-d6) d ¼
170.9, 166.6, 159.5, 158.4, 148.5, 147.3, 146.7, 139.6, 135.9,
134.9, 131.6, 130.1, 129.1, 129.0, 128.4, 123.4, 120.9, 115.3,
115.0, 112.8, 111.7, 93.0, 55.4, 55.2, 54.5, 20.9. Anal. calcd for
3438, 3327, 2216, 1623, 1416, 1394, 1257, 1098, 1015, 817 cmꢀ1
.
1H NMR (400 MHz, CDCl3) d ¼ 8.57 (s, 1H), 8.03 (dd, 1J ¼ 6.1 Hz,
2J ¼ 3.4 Hz, 2H), 7.45–7.48 (m, 8H), 7.25 (d, J ¼ 8.0 Hz, 2H), 5.49
(br s, 2H), 2.39 (s, 3H). 13C NMR (100 MHz, DMSO-d6) d ¼ 162.8,
160.4, 160.2, 149.8, 135.9, 132.4, 132.3, 131.8, 131.6, 130.9,
130.5, 129.6, 129.5, 128.8, 125.6, 119.0, 114.5, 112.5, 23.7. Anal.
calcd for C28H18N4S; C, 75.99; H, 4.10; N, 12.66; S, 7.25. Found:
C, 75.89; H, 4.14; N, 12.72; S, 7.14%.
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C37 H32N4O4S; C, 70.68; H, 5.13; N, 8.91; S, 5.10. Found: C, C, d ¼ 166.5, 160.1, 135.1, 134.3, 133.9, 133.2, 133.0, 131.6, 131.5,
70.79; H, 5.16; N, 8.83; S, 5.22%. 131.4, 130.3, 130.2, 128.9, 127.9, 127.6, 127.4, 126.7, 124.5,
2-Amino-4-(3-(bis(3,4-dimethoxyphenyl)methyl)phenyl)-6- 115.0, 114.6, 93.1, 87.0. Anal. calcd for C40H22N8S2; C, 70.78; H,
(phenylthio)pyridine-3,5-dicarbonitrile (Table 2, 3x). Mp 203– 3.27; N, 16.51; S, 9.45. Found: C, 70.86; H, 3.22; N, 16.44; S,
205 ꢁC. IR (KBr): nmax ¼ 3405, 3325, 2214, 1643, 1538, 1433, 9.37%.
1
1347, 1216, 1124, 1019, 821 cmꢀ1. H NMR (400 MHz, DMSO-
1,4-Bis(2-amino-4-(4-nitrophenyl-3,5-dicyano)-4-pyridyl)dithi
d6): d ¼ 7.50 (br s, 2H), 7.34 (d, J ¼ 7.8 Hz, 4H), 7.20 (d, J ¼ ophenol (Scheme 4, 7a). Mp 173–175 ꢁC. IR (KBr): nmax ¼ 3422,
8.2 Hz, 2H), 6.90 (d, J ¼ 8.4 Hz, 4H), 6.72 (d, J ¼ 8.5 Hz, 3H), 6.63 3335, 3227, 2217, 1632, 1550, 1350, 1264, 1116, 822 cmꢀ1. H
1
(d, J ¼ 8.3 Hz, 2H), 5.56 (s, 1H), 3.72 (s, 6H), 3.63 (s, 6H). 13C NMR (400 MHz, DMSO-d6): d ¼ 8.25 (dd, 1J ¼ 6.8 Hz, 2J ¼ 2.0 Hz,
1
2
NMR (100 MHz, DMSO-d6) d ¼ 173.0, 166.5, 159.5, 158.4, 148.4, 4H), 7.52 (dd, J ¼ 6.8 Hz, J ¼ 6.4 Hz, 4H), 7.10 (s, 4H), 4.53
147.2, 146.7, 139.5, 135.8, 134.9, 131.6, 131.1, 129.0, 128.4, (s, 4H). 13C NMR (100 MHz, DMSO-d6) d ¼ 183.1, 151.8, 151.78,
123.3, 120.9, 116.0, 115.0, 112.8, 111.6, 92.9, 55.7, 55.4, 54.4. 151.73, 150.8, 149.6, 129.9, 127.9, 124.1, 123.5, 118.4, 114.1,
Anal. calcd for C36H30N4O4S; C, 70.34; H, 4.92; N, 9.11; S, 5.22. 113.5. Anal. calcd for C32H16N10O4S2; C, 57.48; H, 2.41; N, 20.95;
Found: C, 70.43; H, 4.90; N, 9.05; S, 5.35%.
S, 9.59. Found: C, 57.39; H, 2.45; N, 20.90; S, 9.69%.
1,4-Bis(2-amino-6-phenylsufanyl-4-pyridyl-3,5-dicarbonitrile)-
1,4-Bis(2-amino-4-(3-nitrophenyl-3,5-dicyano)-4-pyridyl)dithi
benzene (Scheme 3, 5a). Mp 309–310 ꢁC. (ref. 28 310–311 ꢁC) IR ophenol (Scheme 4, 7b). Mp 145–156 ꢁC. IR (KBr): nmax ¼ 3423,
(KBr): nmax ¼ 3405, 3326, 3227, 2213, 1645, 1521, 1546, 1465, 3333, 3229, 2214, 1632, 1550, 1510, 1348, 1265, 1114, 825 cmꢀ1
.
1343, 1245, 1117, 803 cmꢀ1. 1H NMR (400 MHz, DMSO-d6): d ¼ 1H NMR (400 MHz, DMSO-d6): d ¼ 8.34 (s, 2H), 8.23 (d, J ¼ 8.1
7.81 (br s, 4H), 7.60–7.63 (m, 4H), 7.45–7.58 (m, 4H), 7.49–7.51 Hz, 2H), 7.86 (d, J ¼ 7.6 Hz, 2H), 7.72 (t, J ¼ 7.9 Hz, 2H), 7.07
(m, 6H). 13C NMR (100 MHz, DMSO-d6) d ¼ 175.6, 171.1, 170.5, (s, 4H), 4.78 (br s, 4H). 13C NMR (100 MHz, DMSO-d6) d ¼ 182.5,
159.8, 159.6, 134.8, 129.6, 129.4, 128.7, 127.0, 115.2, 114.9. Anal. 166.0, 160.1, 159.5, 134.8, 133.9, 131.5, 130.3, 130.1, 129.7,
calcd for C32H18N8S2; C, 66.42; H, 3.14; N, 19.36; S, 11.08. Found: 129.4, 126.8, 114.9, 114.6. Anal. calcd for C32H16N10O4S2; C,
C, 66.49; H, 3.12; N, 19.30; S, 11.17%.
57.48; H, 2.41; N, 20.95; S, 9.59. Found: C, 57.40; H, 2.43; N,
1,4-Bis(2-amino-6-(4-methylphenylsulfanyl)-4-pyridyl-3,5- 20.88; S, 9.48%.
dicarbonitrile)benzene (Scheme 3, 5b). Mp 310–313 ꢁC. IR
1,4-(2-Amino-4-(3-boromophenyl-3,5-dicyano)-4-pyridyl)dith-
(KBr): nmax ¼ 3403, 3150, 2214, 1648, 1547, 1516, 1463, 1342, iophenol (Scheme 4, 7c). Mp 140–142 ꢁC. IR (KBr): nmax ¼ 3415,
1294, 1115, 849 cmꢀ1. 1H NMR (400 MHz, CDCl3) d ¼ 7.52 (d, J ¼ 3326, 3231, 2217, 1632, 1450, 1387, 1262, 1113, 810 cmꢀ1
.
8.2 Hz, 4H), 7.46 (d, J ¼ 8.2 Hz, 4H), 7.35 (d, J ¼ 8.1 Hz, 2H), 7.20 1H NMR (400 MHz, DMSO-d6): d ¼ 7.47 (d, J ¼ 7.9 Hz, 2H), 7.32–
(d, J ¼ 7.6 Hz, 2H), 5.45 (br s, 4H), 2.36 (s, 6H). 13C NMR (100 7.38 (m, 4H), 7.25 (d, J ¼ 7.8 Hz, 2H), 7.01 (s, 4H), 4.35 (s, 4H).
MHz, CDCl3) d ¼ 172.9, 170.9, 159.2, 140.4, 135.8, 135.7, 133.8, 13C NMR (100 MHz, DMSO-d6) d ¼ 180.7, 166.7, 160.1, 159.5,
130.2, 129.9, 129.5, 115.1, 111.9, 21.4. Anal. calcd for 157.0, 139.6, 135.1, 134.9, 133.9, 131.5, 130.3, 130.1, 123.2,
C
34H22N8S2; C, 67.31; H, 3.65; N, 18.47; S, 10.57. Found: C, 114.9. Anal. calcd for C32H16Br2N8S2; C, 52.19; H, 2.19; N, 15.22;
67.21; H, 3.69; N, 18.40; S, 10.70%.
S, 8.71. Found: C, 52.08; H, 2.23; N, 15.17; S, 8.84%.
1,3-Bis(2-amino-6-phenylsulfanyl-4-pyridyl-3,5-dicarbonitrile)
9,10-Bis(2-amino-4-(3-methoxybenzyl)-3,5-dicyano-4-pyridyl)-
benzene (Scheme 3, 5c). Mp 280–283 ꢁC. IR (KBr): nmax ¼ 3438, anthracene dithiol (Scheme 4, 7d). Mp 280–283 ꢁC. IR (KBr):
3327, 3216, 2216, 1623, 1545, 1554, 1475, 1339, 1257, 1115, nmax ¼ 3401, 3327, 3150, 2212, 1643, 1453, 1296, 1143, 1016, 843,
1
823 cmꢀ1. H NMR (400 MHz, DMSO-d6): d ¼ 7.84 (br s, 4H), 765 cmꢀ1. 1H NMR (400 MHz, DMSO-d6): d ¼ 7.89–7.93 (m, 4H),
7.60–7.65 (m, 3H), 7.57–7.59 (m, 3H), 7.48–7.54 (m, 8H). 13C 7.67–7.73 (m, 8H), 7.49–7.57 (m, 2H), 6.86 (d, J ¼ 4.8 Hz, 2H),
NMR (100 MHz, DMSO-d6) d ¼ 167.7, 160.1, 159.5, 150.2, 134.8, 4.14 (s, 4H), 3.58 (s, 6H). 13C NMR (100 MHz, DMSO-d6) d ¼
133.9, 131.5, 130.5, 130.1, 129.7, 129.4, 126.8, 114.9, 114.6. Anal. 180.1, 160.17, 160.11, 159.0, 158.5, 158.2, 153.5, 150.0, 138.5,
calcd for C32H18N8S2; C, 66.42; H, 3.14; N, 19.36; S, 11.08. Found: 129.0, 128.5, 119.4, 115.2, 113.2, 113.0, 89.6, 55.0. Anal. calcd for
C, 66.52; H, 3.11; N, 19.28; S, 11.19%.
C42H26N8O2S2; C, 68.28; H, 3.55; N, 15.17; S, 8.68. Found: C,
1,3-Bis(2-amino-6-(4-methylphenylsufanyl)-4-pyridyl-3,5-dica 68.39; H, 3.58; N, 15.10; S, 8.79%.
rbonitrile)benzene (Scheme 3, 5d). Mp 289–291 ꢁC. IR (KBr):
9,10-Bis(2-amino-4-(3-boromophenyl-3,5-dicyano)-4-pyridyl)-
anthracene dithiol (Scheme 4, 7e). Mp 152–154 ꢁC. IR (KBr):
nmax ¼ 3348, 3270, 2217, 1582, 1409, 1345, 1216, 1117, 842 cmꢀ1
.
1H NMR (400 MHz, DMSO-d6): d ¼ 7.84 (br s, 4H), 7.61 (d, J ¼ 8.0 nmax ¼ 3335, 3246, 3121, 2217, 1632, 1442, 1387, 1263, 1116, 811,
Hz, 3H), 7.48–7.54 (m, 6H), 7.32 (d, J ¼ 8.0 Hz, 3H), 2.38 (s, 6H). 783 cmꢀ1. 1H NMR (400 MHz, DMSO-d6): d ¼ 7.66–7.72 (m, 6H),
13C NMR (100 MHz, DMSO-d6) d ¼ 166.7, 160.1, 159.5, 157.0, 7.24–756 (m, 10H), 4.13 (s, 4H). 13C NMR (100 MHz, DMSO-d6) d
139.6, 135.1, 134.9, 133.9, 131.6, 131.5, 130.3, 130.1, 123.2, ¼ 165.9, 158.3, 150.3, 130.2, 128.1, 126.6, 125.7, 121.5, 119.6,
114.9, 114.6, 20.9. Anal. calcd for C34H22N8S2; C, 67.31; H, 3.65; 115.8, 115.6, 115.3, 112.2, 111.4, 93.4, 86.9. Anal. calcd for
N, 18.47; S, 10.57. Found: C, 67.20; H, 3.64; N, 18.41; S, 10.68%.
C40H20Br2N8S2; C, 57.43; H, 2.41; N, 13.39; S, 7.67. Found: C,
1,3-Bis(2-amino-6-b-naphthylsulfanyl-4-pyridyl-3,5-dicarbo- 57.51; H, 2.38; N, 13.34; S, 7.77%.
ꢁ
nitrile)benzene (Scheme 3, 5e). Mp 287–290 C. IR (KBr): nmax
9,10-Bis(2-amino-4-(b-naphthyl-3,5-dicyano)-4-pyridyl)anthr-
ꢁ
¼ 3437, 3377, 3216, 2216, 1623, 1525, 1545, 1464, 1338, 1257, acene dithiol (Scheme 4, 7f). Mp 228–231 C. IR (KBr): nmax
¼
1116, 829 cmꢀ1. 1H NMR (400 MHz, DMSO-d6): d ¼ 8.64 (s, 1H), 3405, 3326, 3150, 2214, 1648, 1453, 1343, 1294, 1116, 828 cmꢀ1
.
8.27 (s, 1H), 8.21 (d, J ¼ 6.7 Hz, 2H), 8.00–8.06 (m 7H), 7.87– 1H NMR (400 MHz, DMSO-d6): d ¼ 8.02 (s, 10H), 7.67–7.71
7.91 (m, 6H), 7.63–7.66 (m, 5H). 13C NMR (100 MHz, DMSO-d6) (m, 4H), 6.54 (s, 8H), 4.14 (s, 4H). 13C NMR (100 MHz, DMSO-d6)
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d ¼ 181.3, 165.8, 159.7, 159.4, 158.3, 150.3, 148.0, 130.5, 128.1, 20 N. M. Evdokimov, A. S. Kireev, A. A. Yakovenko,
126.5, 125.7, 121.5, 119.6, 115.8, 115.5, 115.3, 112.2, 111.3, 93.4,
86.8. Anal. calcd for C48H26N8S2; C, 74.02; H, 3.36; N, 14.39; S,
8.23. Found: C, 74.13; H, 3.32; N, 14.45; S, 8.12%.
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Financial support of this work by the Research Council of the
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