Month 2016
Synthesis and Characterization of Hydroxy Substituted Pyridinium Type of Ionic
Liquids via Conventional/ Silica Supported Approaches and Their Applications
5
CONCLUSION
compounds (2a–f) along with metal bromide. After
completing the anion reaction with the assistance of Sox
let extraction by using dry THF for extraction, we have
separated metallic bromide free ionic liquids in quantitative
We have prepared hydroxy substituted pyridinium salts
using easily available starting material under conventional
and silica-supported approaches. We have examined the
catalytic activities of our synthesized ionic liquid for
aralkyl substrate under free radical bromination using
NBS. We have conducted different concentration of ionic
liquids for these reactions, and the optimized catalyst con-
yield.
-
[BHPy]PF
6
2a. Yield: 0.51 g, 82%; Mp.: 132–134°C;
1
13
H NMR (D
O) δ: 4.56 (s, 2H); 6.80–8.09 (m, 9H);
C
2
NMR δ: 54.4, 112.5, 115.6, 118.0, 127.7, 127.9, 128.6,
129.2, 134.7, 139.7; MS: m/e: 331; Anal. Calcd. for
À4
centration is 1.69×10 mmol. We found that pyridinium-
C
H
12
12
F NOP: C, 43.50; H, 3.62; N, 4.22; Found: C,
6
type ionic liquids acted as a potential candidate to reduce
the reaction time with higher yield. We have examined the
catalytic activity for one-pot preparation of quinolone by
using our synthesized pyridinium type of ionic liquids during
one-pot preparation; we have screened the catalyst concen-
43.40; H, 3.52; N, 4.04.
-
1
4
[BHPy]BF 2b. Yield: 0.43g, 84%; Liquid; H NMR
13
(D O) δ: 4.62 (s, 2H); 6.82–8.12 (m, 9H); C NMR δ:
2
54.5, 112.6, 115.8, 118.2, 127.4, 127.9, 128.6, 130.2,
134.8, 140.7; MS: m/e: 273; Anal. Calcd. for
À5
À5
tration from 4.82×10 mmol; 9.64×10 mmol among
C
H
12
12BF
NO: C, 52.74; H, 4.39; N, 5.12; Found: C,
4
À4
5
2.68; H, 4.28; N, 5.02.
the concentration we have found that 1.44×10 mmol is
-
1
[
BHPy]CF SO 2c.
Yield: 0.52g, 82%; Liquid; H
optimized concentration. One-pot quinoline derivative prep-
aration bromide counter ion containing ionic liquids showed
3
3
13
NMR (D O) δ: 4.60 (s, 2H); 6.94–8.09 (m, 9H);
C
2
-
4
-
6
-
NMR δ: 54.2, 112.5, 115.4, 117.9, 127.8, 127.7, 128.7,
29.0, 134.6, 139.4; MS: m/e: 335; Anal. Calcd. for
C H F NO S: C, 46.56; H, 3.58; N, 4.17; Found: C,
better catalytic activity than the other BF , PF , and CF SO
3
3
1
counter ions. Among the two bromide counter ions,
pyridinium bromide showed better activity than the 4-nitro
pyridinium salts.
13 12
3
4
4
6.42; H, 3.42; N, 4.14.
-
[
NBHPy]PF 2d. Yield: 0.56g, 93 %; Mp.: 149–151°C;
6
1
13
H NMR (D O) δ: 5.28 (s, 2H); 7.20–7.70 (m, 9H);
C
2
NMR δ: 72.4, 119.6, 127.8, 128.7, 129.5, 135.4, 138.6,
41.8, 142.9, 162.6; MS: m/e: 376; Anal. Calcd. for
P: C, 38.29; H, 2.92; N, 7.44; Found: C,
8.08; H, 2.80; N, 7.32.
EXPERIMENTAL
1
General Procedure For n-Alkylation. 2-hydroxy pyridine
1.051×10 mmol; 1.0 equi.) is treated with benzyl
bromide/4-nitrobenzyl bromide (1.156×10 mmol; 1.05
equi.) in the presence of 20mL of dry MeCN under
refluxing condition between 5 to 8h will give n-alkylated
products of compound 1a and 1b in quantitative yield.
C H F N O
12 11 6 2 3
3
À2
(
-
1
2
[
4
NBHPy]BF 2e. Yield: 0.50 g, 98 %; Liquid; H NMR
13
(
D O) δ: 5.34 (s, 2H); 7.19–7.76 (m, 9H); C NMR δ:
2
7
1
2.1, 119.6, 127.6, 128.9, 129.5, 135.4, 138.2, 141.7,
42.7, 162.4; MS: m/e: 318.03 Anal. Calcd. for
-
1
C H BF N O : C, 45.28; H, 3.45; N, 8.80; Found: C,
12 11 4 2 3
45.16; H, 3.36; N, 8.72.
[
BHPy]Br 1a. Yield: 2.53g, 90 %; Liquid; H NMR
D O) δ: 4.69 (s, 2H); 6.75–8.06 (m, 9H); C NMR δ:
1
3
(
2
5
1
4.2, 112.3, 115.3, 117.9, 127.3, 127.7, 128.4, 129.0,
34.5, 139.4; MS: m/e: 266; Anal. Calcd. for
Acknowledgments. Author thanks Dr. R. Sundaram, Assistant
Professor, Department of Chemistry, Presidency College,
Chennai-5 for cooperation and moral support.
C H BrNO: C, 54.13; H, 4.50; N, 5.26; Found: C,
5
12 12
4.02; H, 4.42; N , 5.18.
-
[
NBHPy]Br 1b. Yield: 3.17 g, 96 %; Mp.: 148–150°C;
1
13
H NMR (D O) δ: 5.30 (s, 2H); 7.16–7.69 (m, 9H);
C
2
NMR δ: 72.1, 119.4, 127.6, 128.4, 129.1, 135.0, 138.2,
41.7, 142.7, 162.0; MS: m/e: 311 Anal. Calcd. for
C H BrN O : C, 46.30; H, 3.53; N, 9.00; Found: C,
REFERENCES AND NOTES
1
[
1] Lozano, P.; De Diego, T.; Carrie, D.; Vaultier, M.; Iborra, J. L.
J Mol Catal B 2003, 21, 9.
2] Wang, P.; Zakeeruddin, S. M.; Comte, P.; Exnar, I.; Gratzel,
12
11
2 3
46.18; H, 3.38; N, 8.92.
[
General Procedure for Anion Exchange Reaction. Compound
a/b with bromide salt with different inorganic salts like
M. J Am Chem Soc 2003, 125, 1166.
1
[3] Zefer, C.; Ocakoglu, K.; Ozsoy, C.; Icli, S. Electrochim Acta
2
009, 54, 5709.
NaBF , K PF , and LiCF SO for anion exchange reaction.
4
4
6
3
3
[
4] Hsieh, Y. N.; Horng, R. S.; Ho, W. Y.; Huang, P. C.; Hsu,
À3
Substituted pyridinium bromide 1a/b (1.878 × 10 mmol;
C. Y.; Whang, T. J.; Kuei, C. H. Chromatographia 2008, 67, 413.
[5] Jin, J. M.; Ye, C.; Phillips, B. S.; Zabinski, J. S.; Liu, X.; Liu,
W.; Shreeve, J. M. J Mater Chem 2006, 16, 1529.
1
.0equi) mixed with required anion containing inorganic
À3
salt (1.916 × 10 mmol; 1.02equi) in the presence of
[
6] Zeng, Z.; Philips, B. S.; Xiao, J.; Shreeve, J. M. Chem Mater
1
0 mL of deionized water at room temperature for
2
008, 20, 2719.
stirring for 2 h afforded the anion exchanged products of
[7] Armstrong, D. W.; Anderson, J. L. Anal Chem 2003, 75, 4851.
DOI 10.1002/jhet
Journal of Heterocyclic Chemistry