Silica-supported Solvent Approaches More Facile than the Conventional for Erlenmeyer Synthesis with Our Pyridinium Salts

Article abstract of DOI:10.1002/jhet.3120

The synthesis of pyridinium salts by both conventional/silica-supported muffle furnace and microwave approaches is described. We have optimized the Erlenmeyer synthesis of azalactone with various concentrations of our synthesized pyridinium salts. Among t

Full text of DOI:10.1002/jhet.3120

April 2018
Silica-supported Solvent Approaches More Facile than the Conventional
for Erlenmeyer Synthesis with Our Pyridinium Salts
929
*
Chitrarasu Manikandan and Kilivelu Ganesan
PG & Research Department of Chemistry, Presidency College (Autonomous), Chennai 600 005, India
*
E-mail: kiliveluganesan@yahoo.co.in
Received October 3, 2017
DOI 10.1002/jhet.3120
Published online 13 February 2018 in Wiley Online Library (wileyonlinelibrary.com).
The synthesis of pyridinium salts by both conventional/silica-supported muffle furnace and microwave
approaches is described. We have optimized the Erlenmeyer synthesis of azalactone with various
concentrations of our synthesized pyridinium salts. Among these, bromide-containing pyridinium salts
showed excellent catalytic activity than the others.
J. Heterocyclic Chem., 55, 929 (2018).
Applications of oxazolone derivatives are extended
owing to the presence of an exocyclic double bond at
4-position, which gives some useful and interesting
pharmaceutical drugs like immunomodulatory [24], anti-
inflammatory [25], antifungal [26], and antibacterial [27]
purpose. Greener approach is the construction of chemical
compounds and processes that eliminate or minimize the
generation and usage of environmental-polluting
substances [28]. In literature, different routes were used
including the use of several bases such as K3PO4 [29],
DIPEA [30], basic ILs [31], some of transition metal
catalysis [32–34], and microwave-assisted reactions [35],
even though the conventional Erlenmeyer reaction that is
still used to prepare oxazolone derivatives is very
interesting. Herein, we wish to report the preparation of
substituted pyridinium salts under conventional/silica-
supported solvent-free muffle/microwave medium. We
have tried Erlenmeyer reaction in the presence of
optimized concentration of our substituted pyridinium
salts and compared the same reaction with available
literature [36].
INTRODUCTION
Ionic liquids (ILs) have special behavior like tunability,
which allows their physical and chemical properties to be
altered as desired by changing the structure of counterions
[1,2]. ILs have attracted more and more attention in recent
days because of their distinct behaviors like acted as
solvents [3–6], electrolyte [7,8], catalysis [3,9–11],
stationary phase for chromatography [12], and lubricants
[13], as well their unique behaviors of low corrosiveness,
low volatility, thermal stabilities, low combustibility, and
recyclability [14,15]. Nguyen Chau et al. reported the
microwave-assisted synthesis of some imidazolium salts
and its catalytic activities for condensation reactions [16].
Most of the available literatures for ILs are composed
of an unsymmetrically substituted nitrogen organic
cation such as imidazolium/pyridinium with an inorganic
counteranion like PFꢀ6 , Brꢀ, BF4ꢀ, and Clꢀ [17–19].
Monopyridinium salts acted as both solvent and ligand to
assist for copper-catalyzed cross-coupling reactions [20].
Oxazolone and its derivatives play a very crucial role in
the medicinal aspects such as anticancer, anti-microbial,
antidiabetic, anti-obesity, and antidepressant [21]. Owing to
the presence of several active sites are permits to produce a
larger variety of biologically target molecules [22,23].
RESULTS AND DISCUSSION
Benzylbromide/nitrobenzylbromide/1,3,5-tris(bromomethyl)
tri-2,4,6-methylbenzene was treated with 4-(4-nitrobenzyl)
pyridine (NBP) under conventional/silica-supported
solvent-free muffle furnace/microwave approach, and
benzyl/4-nitrobenzyl bromide/1,3,5-tris(bromomethyl)tri-
2,4,6-methylbenzene was treated with substituted
derivative of pyridine moieties in the presence of 30 mL
of dry MeCN under refluxing condition for 7–21 h to
© 2018 Wiley Periodicals, Inc.

930
C. Manikandan and K. Ganesan
Vol 55
afford the N-alkylated pyridinium bromides 1a/1b/3a in
95–97% yield (Scheme 1).
Quartinization reaction between substituted pyridine with
benzyl/4-nitrobenzylbromide (NBB). NBB is much faster
than the benzyl bromide, so we extend the quartinization
mentioned reacting substrate under solvent-free, nontoxic
routes is more suitable than the conventional Erlenmeyer
synthesis of azalactone from aryl aldehyde and hippuric
acid in the presence of anhydrous K2CO3 with 25 mL
AcOH at ambient reaction condition for 5 h. There are no
appreciable changes.
with
1,3,5-tris-(bromomethyl)-2,4,6-tri-methylbenzene.
These reactions are required long time for completion, so
we planned to reduce the reaction period as well as
nontoxic solvent-free methodology. We have examined the
n-alkylation reaction under muffle/microwave conditions.
Muffle furnace approach is nearly 15 times faster than the
conventional route. Microwave route is much faster than
muffle route. So quartinization reaction with previously
After completion of the quartinization reaction, anion
exchange reaction is carried out in the presence of
various counterion containing inorganic salts like K4PF6,
NaBF4, and LiCF3SO3 in the presence of water and at
ambient condition with stirring for 2 h to give anion-
exchanged products of compounds (2a–f) and (3b–d) in
quantitative yield (Scheme 1).
Scheme 1. Synthesis of pyridinium salts under conventional, solid-supported, and microwave approaches. [Color figure can be viewed at
wileyonlinelibrary.com]
Scheme 2. Overview of reported [37–39] versus this work synthetic routes (A, B, and C vs. D) for the synthesis of (4E)-4-benzylidene-2-(4-nitrophenyl)
oxazol-5(4H)-one. [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

April 2018
Silica-supported Solvent Approaches More Facile than the Conventional for
Erlenmeyer Synthesis with Our Pyridinium Salts
931
We have to separate the pyridinium salt from metal
bromide, which is not easy because the usual organic
solvent extraction is not feasible owing to the water-
soluble nature of both metallic bromide and pyridinium
salt. Under this circumstance, we carried out the Soxhlet
extraction in the presence of dry tetrahydrofuron for 2 h
under refluxing condition to give metallic bromide-free
pyridinium salt with excellent yield. After completion of
Soxhlet extraction, we have checked with aqueous
AgNO3 solution; fortunately, we did not obtain any pale
yellow precipitate, so we can further conformed that our
pyridinium salt is metal bromide free. The synthesized
compounds (2a–f) and (3b–d) are confirmed with
spectral and analytical data.
CATALYTIC ACTIVITY
Flavio et al. reported the modified Erlenmeyer reaction
between electron donating and withdrawing aryl aldehyde
Table 1
1.92 × 10ꢀ5 mmol concentration of substituted pyridinium salts for Erlenmeyer reaction.
Substituted aryl aldehyde
p-NO2
m-NO2
Time
O-NO
H
p-Cl
p-OH
Time
2
Time
Yield
(%)
Yield
(%)
Time
(min)
Yield
(%)
Time
(min)
Yield
(%)
Time
(min)
Yield
(%)
Yield
(%)
Catalyst
(min)
(min)
(min)
1a
1b
2a
2b
2c
2d
2e
2f
3a
3b
3c
3d
16
19
19
24
24
33
30
38
14
19
23
26
84
78
83
80
80
73
73
66
82
85
80
73
17
19
21
24
26
32
35
33
15
18
25
27
78
75
77
74
74
68
62
68
76
71
68
65
21
21
22
27
28
36
35
33
18
20
27
29
74
76
72
72
70
64
62
62
84
74
69
69
21
33
28
28
34
28
39
38
22
24
26
31
71
68
63
54
64
50
47
48
72
66
64
52
24
25
38
46
47
41
43
48
23
35
42
48
66
60
56
62
61
58
60
56
66
69
54
65
20
45
52
40
52
55
58
58
39
51
55
57
83
58
72
74
71
61
59
60
74
70
66
66
Reaction condition: p-nitrobenzaldehyde (6.173 × 10–3 mmol; 1.0 equiv), hippuric acid (6.749 × 10–3 mmol; 1.02 equiv), AcOH (25 mL), and our catalyst
(1.92 × 10–5 mmol). Absence of pyridinium salt: no appreciable change even after 5 h; yield of isolated product.
Table 2
3.84 × 10ꢀ5 mmol concentration of substituted pyridinium salts for Erlenmeyer reactions.
Substituted aryl aldehyde
p-NO
m-NO2
Time
O-NO
H
p-Cl
p-OH
Time
2
2
Time
(min)
Yield
(%)
Yield
(%)
Time
(min)
Yield
(%)
Time
(min)
Yield
(%)
Time
(min)
Yield
(%)
Yield
(%)
Catalyst
(min)
(min)
1a
1b
2a
2b
2c
2d
2e
2f
3a
3b
3c
3d
11
15
11
15
17
28
26
30
09
11
16
16
86
90
87
80
86
78
78
80
90
89
82
89
11
17
12
17
17
25
30
30
09
11
17
16
81
80
82
73
81
72
60
60
85
84
77
84
11
19
14
18
19
25
32
32
11
13
19
18
76
78
80
76
74
69
70
70
82
85
76
80
11
17
18
20
21
23
29
32
08
14
14
16
83
80
77
75
71
70
68
68
85
83
83
75
10
10
23
30
37
28
30
40
09
20
28
34
84
82
75
70
64
66
55
59
84
74
78
66
14
33
31
19
19
40
39
40
25
39
57
62
84
60
70
74
76
58
62
58
76
65
58
68
Reaction condition: p-nitrobenzaldehyde (6.173 × 10ꢀ3 mmol; 1.0 equiv), hippuric acid (6.749 × 10ꢀ3 mmol; 1.02 equiv), AcOH (25 mL), and our
catalyst (3.84 × 10ꢀ5 mmol). Absence of pyridinium salt: no appreciable change even after 5 h; yield of isolated product.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

932
C. Manikandan and K. Ganesan
Vol 55
Table 3
5.76 × 10ꢀ5 mmol concentration of substituted pyridinium salts for Erlenmeyer reactions.
Substituted aryl aldehyde
p-NO
m-NO2
Time
O-NO
H
p-Cl
p-OH
Time
2
2
Time
(min)
Yield
(%)
Yield
(%)
Time
(min)
Yield
(%)
Time
(min)
Yield
(%)
Time
(min)
Yield
(%)
Yield
(%)
Catalyst
(min)
(min)
1a
1b
2a
2b
2c
2d
2e
2f
3a
3b
3c
3d
04
10
07
11
12
14
14
15
04
07
09
12
95
96
90
85
89
98
90
90
98
90
92
95
05
12
08
12
12
16
14
14
04
06
11
13
90
84
85
80
84
90
81
78
93
85
87
90
06
16
09
14
13
14
16
15
05
10
13
14
88
86
85
76
78
80
82
74
92
85
85
84
05
14
08
14
15
16
16
18
04
09
10
10
83
78
83
77
78
74
74
68
87
85
79
75
07
06
09
10
13
14
12
12
06
07
08
11
89
86
83
83
84
78
70
82
90
84
79
80
08
25
12
10
11
38
31
28
14
19
28
35
89
76
82
86
80
68
74
74
84
85
82
78
Reaction condition: p-nitrobenzaldehyde (6.173 × 10ꢀ3 mmol; 1.0 equiv), hippuric acid (6.749 × 10ꢀ3 mmol; 1.02 equiv), AcOH (25 mL), and our
catalyst (5.76 × 10ꢀ5 mmol). Absence of pyridinium salt: no appreciable change even after 5 h; yield of isolated product.
with various substituted hippuric acids in the presence of
Hunig’s base to afford the quantitative yield but need for
long period nearly 24 h for completion [37]. Parveen
et al. reported the preparation of azalactone and its
derivatives from various aryl aldehydes and hippuric acid
in the presence of higher concentration (20% mol) of ILs
at 100°C to give quantitative yield [38]. Azalactone and
its derivatives were derived from required reactants in the
presence of [Et3NH][HSO4] for 15–140 min to afford
from moderate to quantitative yield. Parveen et al.
employed to prepare their target molecules and used
special reaction setup; unfortunately, they received only
moderate yield [38].
We wanted to conduct the Erlenmeyer synthesis of
azalactone from aryl aldehyde and hippuric acid under
the absence of catalyst and anhydrous K2CO3 with
25 mL of CH3COOH at ambient reaction condition for
5 h. There are no appreciable changes. Same reacting
substrates along with optimized very low concentration of
CONCLUSIONS
our pyridinium salts at ambient reaction condition stirring
from 4 to 62 min to afford the target molecules 4 (a–f ) in
excellent yields (Scheme 2). We have examined the
catalytic activities of our pyridinium cation with different
anions. We found that trimeric pyridinium bromide
showed excellent catalytic response than the others. We
have examined the Erlenmeyer reaction with various
We have synthesized trimeric pyridinium cation with
different counterions under conventional refluxing
condition as well as solid supported neat reaction
condition. We have observed that the solid-supported
solvent-free approach reached the target molecule
method. We have studied the Erlenmeyer synthesis of
azalactone reaction in the presence of trimeric pyridinium
salts. We examined the catalytic concentration of our
concentrations of TPB like (1.92
×
10ꢀ5 mmol/
3.84 × 10ꢀ5 mmol/5.76 × 10ꢀ5 mmol) among these
concentrations; 5.76 × 10ꢀ5 mmol showed effective
response. While increasing the catalyst concentration,
there are no appreciable changes made, and results are
summarized (shown in Tables 1–3).
trimeric pyridinium salt from 1.92
×
10ꢀ5 to
3.84 × 10ꢀ5 mmol and higher concentrations and
found that 5.76 × 10ꢀ5 mmol concentrations give higher
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

April 2018
Silica-supported Solvent Approaches More Facile than the Conventional for
Erlenmeyer Synthesis with Our Pyridinium Salts
933
yield with shorter reaction time. So 5.76 × 10ꢀ5 mmol is
the optimum concentration for Erlenmeyer synthesis of
azalactone reaction.
After completing the anion exchange reaction with the
assistance of Soxhlet extraction by using dry
tetrahydrofuron for extraction, we have separated metallic
bromide-free pyridinium salts in quantitative yield.
1-Benzyl-4-(4-nitrobenzyl)
pyridine-1-ium
hexafluorophosphate 2a.
Yield: 0.40 g, 92%; mp 143–
EXPERIMENTAL
1
145°C. H-NMR (400 MHz, CDCl3) δ: 2.25 (s, 2H), 4.54
(s, 2H), 7.70–8.06 (m, 5H), 8.07–8.30 (m, 4H), 8.46–
8.98 (m, 4H). 13C-NMR (100 MHz, CDCl3) δ: 39.8,
60.0, 121.2, 124.6, 128.8, 129.3, 131.3, 135.7, 140.9,
144.5, 145.9, 147.2, 160.8. MS: m/z: 450.31; anal. calcd
for C19H17F6N2O2P: C, 50.63; H, 3.77; N, 6.21; found:
C, 50.55; H, 3.69; N, 6.13.
Preparation of substituted pyridinium bromide under
conventional route.
Required equivalent of NBP is
treated with BB/NBB/TBMTMB in the presence of
20 mL of dry MeCN under refluxing condition for 7–
21 h to afford the substituted pyridinium bromides 1a/1b/
3a in 88–90% yield.
1-Benzyl-4-(4-nitrobenzyl) pyridine-1-ium tetrafluoroborate
Yield: 0.40 g, 93%; mp 155–160°C. 1H-NMR
Preparation of substituted pyridinium bromide under
2b.
silica-supported
solvent-free
routes.
Required
(400 MHz, CDCl3) δ: 2.23 (s, 2H), 4.52 (s, 2H), 7.68–8.05
(m, 5H), 8.05–8.28 (m, 4H), 8.44–8.96 (m, 4H). 13C-NMR
(100 MHz, CDCl3) δ: 39.9, 63.8, 121.3, 124.7, 128.9,
129.4, 131.4, 135.9, 140.5, 144.6, 145.1, 147.3, 160.9.
MS: m/z: 392.16; anal. calcd for C19H17BF4N2O2: C,
58.13; H, 4.33; N, 7.13; found: C, 58.05; H, 4.25; N, 7.05.
equivalence, which is used in conventional route but
without solvent, is transferred into mortar and pestle
followed by fine grinding with silica gel (60–120) mesh.
The silica-supported reactant is divided into two portions
and kept in muffle/microwave reactor and monitors the
reaction using thin-layer chromatography.
1-Benzyl-4-(4-nitrobenzyl)
pyridine-1-ium
1-Benzyl-4-(4-nitrobenzyl) pyridine-1-ium bromide 1a.
trifluoromethanesulfonate 2c.
Yield: 0.40 g, 93%; mp
1
1
Yield: 1.0 g, 98%; mp 135–140°C. H-NMR (400 MHz,
160–165°C. H-NMR (400 MHz, CDCl3) δ: 2.26 (s, 2H),
4.55 (s, 2H), 7.71–8.08 (m, 5H), 8.08–8.31 (m, 4H),
8.47–8.99 (m, 4H). 13C-NMR (100 MHz, CDCl3) δ:
39.1, 62.0, 121.4, 124.8, 128.1, 129.5, 131.6, 135.3,
140.1, 144.7, 145.9, 147.4, 160.1. MS: m/z: 454.42; anal.
calcd for C20H17F3N2O5S: C, 52.81; H, 3.74; N, 6.16;
found: C, 52.73; H, 3.66; N, 6.08.
CDCl3) δ: 2.20 (s, 2H), 4.49 (s, 2H), 7.65–8.02 (m, 5H),
8.04–8.25 (m, 4H), 8.41–8.93 (m, 4H). 13C-NMR
(100 MHz, CDCl3) δ: 39.6, 59.0, 122.0, 124.4, 128.6,
129.1, 131.1, 135.1, 140.0, 144.3, 145.8, 147.0, 160.6.
MS: m/z: 385.25; anal. calcd for C19H17BrN2O2: C,
59.18; H, 4.41; N, 7.26; found: C, 59.10; H, 4.33; N, 7.18.
1,4-Bis(4-nitrobenzyl)pyridine-1-ium bromide 1b.
Yield:
1,4-Bis(4-nitrobenzyl)pyridine-1-ium hexafluorophosphate
1
Yield: 0.50 g, 91%; mp 135–140°C. 1H-NMR
1.0 g, 98%; mp 115–120°C. H-NMR (400 MHz, CDCl3)
δ: 2.26 (s, 2H), 4.49 (s, 2H), 7.65–8.04 (m, 4H), 8.41–
8.92 (m, 8H). 13C-NMR (100 MHz, CDCl3) δ: 39.6,
65.0, 121.0, 124.4, 128.6, 129.1, 131.1, 135.3, 144.3,
145.8, 147.0, 150.0, 160.6. MS: m/z: 430.25; anal. calcd
for C19H16BrN3O4: C, 52.99; H, 3.71; N, 9.76; found: C,
52.91; H, 3.63; N, 9.68.
2d.
(400 MHz, CDCl3) δ: 2.33 (s, 2H), 4.57 (s, 2H), 7.72–
8.04 (m, 4H), 8.47–8.98 (m, 8H). 13C-NMR (100 MHz,
CDCl3) δ: 39.9, 63.6, 121.9, 124.8, 128.5, 129.3, 131.4,
135.7, 144.0, 145.3, 147.7, 150.9, 160.8. MS: m/z:
495.31; anal. calcd for C19H16F6N3O4P: C, 46.03; H,
3.23; N, 8.48; found: C, 45.95; H, 3.15; N, 8.40.
1,10,1″-(2,4,6-Trimethylbenzene-1,3,5-triyl)tris(methylene)
1,4-Bis(4-nitrobenzyl)pyridine-1-ium tetrafluoroborate 2e.
tris(4-(4-nitrobenzyl)pyridine-1-ium)bromide 3a.
Yield:
1
Yield: 0.50 g, 90%; mp 130–135°C. H-NMR (400 MHz,
1.63 g, 98%; mp 105–110°C. 1H-NMR (400 MHz,
CDCl3) δ: 2.35 (s, 9H), 3.15 (s, 6H), 5.99 (s, 6H), 7.65–
7.79 (d, 12H), 8.10–8.22 (d, 12H). 13C-NMR (100 MHz,
CDCl3) δ: 11.9, 28.9, 62.0, 124.4, 128.3, 130.6, 131.1,
132.1, 141.6, 145.4, 148.4, 160.7. MS: m/z: 1041.62;
anal. calcd for C48H45Br3N6O6: C, 55.29; H, 4.32; N,
8.06; found: C, 55.21; H, 4.24; N, 7.98.
CDCl3) δ: 2.29 (s, 2H), 4.53 (s, 2H), 7.67–8.08 (m, 4H),
8.49–8.95 (m, 8H). 13C-NMR (100 MHz, CDCl3) δ:
39.8, 62.9, 121.1, 124.8, 128.8, 129.0, 131.7, 135.5,
144.7, 145.9, 147.1, 150.3, 160.8. MS: m/z: 437.15; anal.
calcd for C19H16BF4N3O2: C, 52.05; H, 3.66; N, 9.60;
found: C, 51.97; H, 3.58; N, 9.52.
1,4-Bis(4-nitrobenzyl)pyridine-1-ium
General procedure for anion exchange reaction.
Substituted pyridinium bromide 1a/1b/3a (1.038
trifluoromethanesulfonate 2f.
Yield: 0.50 g, 88%; mp
1
×
150–155°C. H-NMR (400 MHz, CDCl3) δ: 2.33 (s, 2H),
4.58 (s, 2H), 7.71–8.05 (m, 4H), 8.51–8.96 (m, 8H). 13C-
NMR (100 MHz, CDCl3) δ: 39.8, 63.2, 121.1, 124.7,
128.9, 129.5, 131.3, 135.9, 144.5, 145.9, 147.1, 150.9,
160.2. MS: m/z: 499.42; anal. calcd for C20H16F3N3O2S:
C, 48.05; H, 3.20; N, 8.40; found: C, 47.97; H, 3.12;
N, 8.32.
10ꢀ3 mmol; 1.0 equiv) mixed with required equivalent of
inorganic salts such as NaBF4, K4PF6, LiCF3SO3
(1.038 × 10ꢀ3 mmol; 1.0 equiv) in the presence of 10 mL
of deionized water at ambient reaction condition for
stirring 2 h to afford the anion-exchanged products of
compounds (2a–f) and (3b–d) along with metal bromide.
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C. Manikandan and K. Ganesan
Vol 55
1,10,1″-(2,4,6-Trimethylbenzene-1,3,5-triyl)tris(methylene)
tris(4-(4-nitrobenzyl)pyridine-1-ium) hexafluorophosphate
3b.
(400 MHz, CDCl3) δ: 2.37 (s, 9H), 3.05 (s, 6H), 6.14 (s,
6H), 7.67–7.81 (d, 12H), 8.12–8.24 (d, 12H). 13C-NMR
(100 MHz, CDCl3) δ: 11.7, 28.8, 62.1, 124.6, 128.1,
130.8, 131.3, 133.3, 141.9, 145.6, 148.6, 160.9. MS: m/z:
1236.08; anal. calcd for C48H45F18N6O6P3: C, 46.61; H,
[14] Tokuda, H.; Tsuzuki, S.; Susan, A. B. H.; Haya-mizu, K.;
Watanabe, M. M. J. Phys. Chem. B. 2006, 110, 19593.
[15] Andrade, C. K. Z.; Alves, L. M. Curr. Org. Chem. 2005, 9, 195.
[16] Nguyen Chau, D.; Ngoc Le, H.; Thi Nguyen, P.; Ngoc Le, T.
Green Chem. 2014, 7, 167.
Yield: 0.50 g, 87%; mp 198–200°C. 1H-NMR
[17] Welton, T. Chem. Rev. 1999, 99, 2071.
[18] Wasserscheid, P.; Welton, T. J. Phys. Chem. 2008, 119, 20299.
[19] Armstrong, D. W.; Anderson, J. L. Anal. Chem. 2003, 75, 4851.
[20] Xue, H.; Shreeve, J. M. Eur. J. Inorg. Chem. 2005, 13, 2573.
[21] Wasserscheid, P.; Welton, T. Green Chem 2008, 77, 160.
[22] (a) Taile, V.; Hatzade, K.; Gaidhane, P.; Ingle, V. Turkish J.
Chem. 2009, 33, 295; (b) Harrison, A. G.; Young, A. B. J. Am. Soc. Mass
Spectrum. 2004, 15, 446.
[23] (a) Fisk, J. S.; Mosey, R. A.; Tepe, J. J. Chem. Soc. Rev 2007,
36, 1432; (b) Mosey, R. A.; Fisk, J. S.; Tepe, J. J. Tetrahedron: Asymme-
try 2008, 19, 2755.
[24] (a) Fray, M. J. J. Chem. Educ 2014, 91, 136; (b) Nicholson, J.
W.; Wilson, A. D. J. Chem. Educ. 2004, 81, 1362.
[25] Mesaik, M. A.; Rahat, S.; Khan, K. M.; Zia, U.; Choudhary,
M. I.; Murad, S.; Ismail, Z.; Attaur, R.; Ahmad, A. Bioorg. Med. Chem
2004, 12, 2049.
[26] Hassanein, H. H.; Khalifa, M. M.; El-Samaloty, O. N.;
El-Rahim, M. A.; Taha, R. A.; Magda, M. F. I. Arch. Pharmacal Res.
2008, 31, 562.
3.67;0N, 6.79; found: C, 46.53; H, 3.59; N, 6.71.
1,1 ,1″-(2,4,6-Trimethylbenzene-1,3,5-triyl)tris(methylene)
tris(4-(4-nitrobenzyl)pyridine-1-ium)tetrafluoroborate 3c.
1
Yield: 0.50 g, 75%; mp 205–208°C. H-NMR (400 MHz,
CDCl3) δ: 2.39 (s, 9H), 3.07 (s, 6H), 6.11 (s, 6H), 7.70–
7.84 (d, 12H), 8.15–8.27 (d, 12H). 13C-NMR (100 MHz,
CDCl3) δ: 11.5, 28.5, 62.5, 124.9, 128.1, 130.3, 131.4,
133.1, 141.8, 145.9, 148.7, 160.8. MS: m/z: 1062.32;
anal. calcd for C48H45B3F12N6O6: C, 54.22; H, 4.23; N,
7.90; found: C, 54.14; H, 4.15; N, 7.82.
1,10,1″-(2,4,6-Trimethylbenzene-1,3,5-triyl)tris(methylene)
tris(4-(4-nitrobenzyl)pyridine-1-ium) trifluoromethanesulfonate
[27] Tandon, M.; Coffen, D. L.; Gallant, P.; Keith, D.; Ashwell, M.
A. Bioorg. Med. Chem. Lett. 2004, 14, 1909.
3d.
Yield: 0.50 g, 76%; mp 170–175°C.1H-NMR
[28] Anastas, P. T.; Kirchhoff, M. M. Acc. Chem. Res 2002, 35,
686.
[29] Cleary, T.; Brice, J.; Kennedy, N.; Chavez, F. Tetrahedron Lett.
2010, 51, 625.
[30] Cleary, T.; Rawalpally, T.; Kennedy, N.; Chavez, F. Tetrahe-
dron Lett. 2010, 51, 1533.
[31] Patil, S. G.; Bagul, R. R.; Kamble, V. M.; Navale, V. A. A.
J. Chem. Pharm. Res. 2011, 3, 285.
(400 MHz, CDCl3) δ: 2.40 (s, 9H), 3.25 (s, 6H), 6.16 (s,
6H), 7.74–7.87 (d, 12H), 8.19–8.31 (d, 12H). 13C-NMR
(100 MHz, CDCl3) δ: 11.3, 28.4, 62.7, 124.3, 128.7,
130.9, 131.7, 133.4, 141.6, 145.2, 148.5, 160.8. MS: m/z:
1249.11; anal. calcd for C51H45F9N6O15S3: C, 48.99; H,
3.63; N, 6.73; found: C, 48.91; H, 3.55; N, 6.65.
[32] Tikdari, A.; Fozooni, S.; Hamidian, H. Molecules 2008, 13,
3246.
[33] (a) Chandrasekhar, S.; Karri, P. Tetrahedron Lett. 2007, 48,
785; (b) Conway, P. A.; Devine, K.; Paradisi, F. A. Tetrahedron 2009,
65, 2935.
[34] Ahmadi, S. J.; Sadjadi, S.; Hosseinpour, M. A. Ultrason.
Sonochem 2013, 20, 408.
Acknowledgments. C. M. thanks R. Tamilarasan and P.
Ganapathi, Senior Research Scholar, Presidency College,
Chennai-5, for cooperation and moral support.
[35] Xiao, J.; Ye, C.; Shreeve, M. Org. Lett. 2005, 7, 1963.
[36] (a) Manikandan, C.; Ganesan, K. Syn Lett. 2016, 27, 1527; (b)
Manikandan, C.; Ganesan, K. Syn Commun. 2014, 44, 3362; (c)
Manikandan, C.; Ganesan, K. J Heterocyclic Chem 2017, 54, 503; (d)
Ganapathi, P.; Ganesan, K. Am. J. Chem. & Appl. 2014, 1, 40; (e)
Ganapathi, P.; Ganesan, K. Syn Commun. 2014, 45, 2135. f)
Naveenkumar, R.; Ganapathi, P.; Ganesan, K. J Heterocyclic Chem
2017, 54, 51; (g) Ganapathi, P.; Ganesan, K.; Vijaykanth, V.;
Arunagirinathan, N. Journal of Molecular Liquids. 2016, 219, 180.
[37] Flavio, C.; Nicole, K.; Thimma, R.; Thamos Williamson, R.;
Thomas, C. Organic Process Research & Development 2010, 14, 579.
[38] Parveen, M.; Ahmad, V.; Malla, A.; Azaz, S.; Silva, M.;
Pereira Silva, P. S. New J. Chem. 2015, 39, 469.
REFERENCES AND NOTES
[1] Hakala, U. Green Chem. 2009, 20, 275.
[2] Earle, M. J.; Seddon, K. R. Pure Appl. Chem. 2000, 72, 1391.
[3] Sun, P.; Armstrong, D. W. Anal. Chim. Acta 2010, 661, 1.
[4] Han, D.; Row, K. H. Molecules 2010, 15, 2405.
[5] Visser, A. E.; Swatloski, R. P.; Reichert, W. M.; May-ton, R.;
Sheff, S.; Wierzbicki, A.; Davis, J. H. J.; Rogers, D. Environ. Sci.
Technol. 2002, 36, 2523.
[6] Shin, J.-H.; Henderson, W. A.; Passerini, S. Electro-chem
Commun. 2003, 5, 1016.
[7] Pont, A.-L.; Marcilla, R.; Meatza, I. D.; Grande, H.;
Mecerreyes, D. J Power Sources 2009, 188, 558.
[8] Shi, F.; Gu, Y.; Zhang, Q.; Deng, Y. Canal Surveys from Asia
2004, 8, 179.
[39] Salami-Ranjbaran, E.; Khosropour, A. R.; Mohammadpoor-
Baltork, I.; Moghadam, V.; Tangestaninejad, S.; Mirkhani, V. ACS Comb.
Sci. 2015, 17, 452.
[9] Yue, C.; Mao, A.; Wei, Y.; Lu, M. Catal. Commun. 2008, 9,
1571.
[10] Yi, F. P.; Sun, H. Y.; Pan, X. H.; Xu, Y.; Li, J. Z. Chin. Chem.
Lett. 2009, 20, 275.
SUPPORTING INFORMATION
[11] Zhang, Q.; Zhang, S.; Deng, Y. Green Chem. 2011, 13, 2619.
[12] Somers, A. E.; Howlett, P. C.; MacFarlane, D. R.; Forsyth, M.
Lubricants. 2013, 1, 3.
[13] Bermudez, M.-D.; Jimenez, A.-E.; Sanes, J.; Carrion, F.-J.
Molecules 2009, 14, 2888.
Additional Supporting Information may be found online
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet