Assessment of the Catalytic Activities of Novel Br o¨ nsted Acidic Ionic Liquid Catalysts
19
2
.3.2 One Pot Three Component Reaction
of Benzaldehyde, Urea and Ethylacetoacetate
2.3.3.2 3-(phenylamino)-1,3-diphenyl-propan-1-one IR (KBr,
-
1
1
t, cm ): 3398, 1675, 1598, 1519, 872. H NMR d: 7.83 (d,
H), 7.54 (m, 2H), 7.41 (t, 1H), 7.3 (d, 2H), 7.2 (m, 2H), 7.01
2
In a typical synthesis benzaldehyde (20 mmol), urea
(t, 1H), 6.93 (d, 2H), 6.67 (m, 2H), 6.5 (t, 1H), 5. 33 (br S,
1H), 4.9 (t, J = 4 Hz, 1H), 3.6 (dd, J = 14.4 Hz, 1H), 3.40
(dd, J = 15.6 Hz, 1 H). Elemental analysis for C H NO:
(
(
30 mmol), ethylacetoacetate (20 mmol) and catalyst
0.1 mmol BILs or 50 mg solid catalysts) were mixed in a
2
1 19
1
00 mL flask. Reaction was conducted at 353 K for 2–4 h.
Theoretical (%): C, 83.72; H, 6.31; N, 4.65. Experimental
(%): C, 83.98; H, 6.20; N, 4.46.
After the completion of the reaction, the catalyst was
removed by simple filtration/decantation. Products were
isolated via flash column chromatography (petroleum
ether/ethyl acetate, 3:1).
2.3.4 Esterification Reaction
The esterification reaction was conducted at 298–403 K for
2
h using benzyl alcohol (10 mmol), hexanoic acid
2.3.2.1 5-Ethoxycarbonyl-4-phenyl-6-methyl-3,4-dihydro-
pyrimidin-2(1H)-one (3,4-dihydropyrimidinones—[A]) IR
(
(
10 mmol), toluene (5 g) as solvent, and the catalyst
0.2 mmol BILs or 100 mg solid acid catalysts) in the
-
1
(
KBr, t, cm ): 1090, 1221, 1645, 1700, 1723, 3115, 3245.
autoclave. The post-reaction procedures were the same as
that of the acylation reaction.
1
H NMR d: 9.17 (s, 1H), 7.75 (s, 1H), 7.20–7.30 (m, 5H),
.10 (d, 1H), 3.95 (q, 2H), 2.20 (s, 3H), 1.07 (t, 3H). Ele-
mental analysis for C H N O : Theoretical (%): C, 64.60;
5
1
4 16 2 3
H, 6.20; N, 10.76. Experimental (%): C, 64.8; H, 6.08; N,
3
Results and Discussion
1
0.60.
3.1 Catalyst Characterizations
2.3.2.2 4-Phenyl-2,6-dimethyl-1,4-dihydro-3,5-ethoxycar-
bonyl pyridine (1,4-dihydropyridinones—[B]) IR (KBr,
BIL-1 and BIL-2 (Scheme 1) were synthesized by a two
step synthetic protocol. First, N-methylimidazole/pyridine
was alkylated with benzyl chloride and the resulting qua-
ternary chloride (a/b) was transformed into BIL-1/BIL-2 by
using concentrated sulfuric acid as anion exchange and
sulphonating reagents, respectively. Samples were charac-
terized using FT-IR, NMR and elemental analysis. For
comparative study, solid acid catalysts such as H-ZSM-5,
H-BEA and Al-SBA-15 were prepared. Recently, it has
been reported that the catalytic activity of zeolite beta can
be significantly improved if it is dealuminated using oxalic
acid at pH 2 [18]. Hence, in this study, H-BEA was dea-
luminated with oxalic acid at pH 2 (sample designated as
H-BEA-pH2) and investigated in catalytic reactions. Solid
-
1
1
t, cm ): 1090, 1210, 1485, 1650, 1685, 3340. H NMR d:
8
.76 (s, 1H), 7.02–7.17 (m, 5H), 4.81 (s, 1H), 3.94 (q, 4H),
2
.22 (s, 6H), 1.09 (t, 6H). Elemental analysis for
C H NO : Theoretical (%): C, 69.28; H, 7.04; N, 4.25.
4
1
9
23
Experimental (%): C, 69.48; H, 6.90; N, 4.16.
2
.3.3 One Pot Three Component Reaction
of Benzaldehyde, Aniline and Ketones
A mixture of benzaldehyde (20 mmol), aniline (20 mmol),
cyclohexanone/acetophenone (20 mmol) and catalyst
(
0.1 mmol BILs or 50 mg solid catalysts) was stirred in
ethanol (10 g) at room temperature for different time
intervals. After completion of the reaction, catalyst was
removed by simple filtration/decantation. The filtrate was
acids were characterized using XRD, N -adsorption and
2
XRF. The details of their textural properties are given in
washed with NaHCO (aq) and brine, and the products
3
were dried over MgSO . The solvent was removed under
4
N
N
N
N
Cl
(a)
reduced pressure. Pure b-amino ketone was recrystallized
from ethanol.
Toluene
or
+
Cl
(b)
N
N
2
.3.3.1 2-((phenyl) (phenylamino) methyl)-cyclohexa-
-
Cl
N
N
1
1
none IR (KBr, t, cm ): 3396, 1697, 1600, 1501, 810. H
NMR d: 7.43 (d, 2H), 7.33 (m, 2H), 7.11 (t, 1H), 7.0 (d,
HSO4
(BIL-1)
SO3H
H SO
2
4
2
H), 6.75 (m, 2H), 6.6 (t, 1H), 5.2 (br S, 1 H), 4.85(d,
J = 4.4 Hz, 1H), 2.91–2.95 (m, 1 H), 2.20–2.31 (m, 2H),
.86–2.04 (m 4H), 1.5–1.76 (m, 2H). Elemental analysis
for C H NO: Theoretical (%): C, 81.72; H, 7.52; N, 5.01.
+
SO H
3
1
(BIL-2)
N
HSO4
1
9 21
Experimental (%): C, 81.95; H, 7.46; N, 4.87.
Scheme 1 Synthetic protocol for BILs
123