S. Kamble et al. / Ultrasonics Sonochemistry 19 (2012) 812–815
813
were prepared following the literature procedure [16]. Sonication
was performed in SPECTRALAB-UCB-30 ultrasonic bath with a fre-
quency of 40 kHz and a nominal power of 100 W. The reaction flask
was located in the maximum energy area in the water bath. The
temperature of the water bath was maintained at 25–30 °C.
2H), 7.25–7.38 (m, 6H); 13C NMR (75 MHz, CDCl3): 7.5, 7.7, 12.3,
15.9, 26.2, 34.1, 36.7, 52.1, 53.7, 58.9, 59.5, 114.3, 115.2, 118.7,
126.2, 127.4, 127.8, 129.2, 129.8, 141.5, 146.2, 146.7, 213.5.
2-(a
-Anilinobenzyl)cyclohexanone (Table 3, Entry 6a): IR (KBr):
t
3382, 3055, 3026, 2944, 1694, 1603, 1511, 1260, 869 cmÀ1
;
1H
NMR (300 MHz, CDCl3): d 1.63–1.94 (m, 6H, 3 Â CH2), 2.29–2.49
(m, 2H, CH2), 2.76 (d, 1H, CH), 4.62 (d, 0.87 H, anti isomer), 4.79
(d, 0.13 H, syn isomer), 6.54 (d, 2H, Ar–H), 6.65 (d, 1H, Ar–H),
7.02 (s, 2H, Ar–H), 7.18 (d, 1H, Ar–H), 7.27 (s, 2H, Ar–H), 7.48 (s,
2H, Ar–H); 13C NMR (75 MHz, CDCl3): 23.7, 27.7, 31.2, 41.6, 57.3,
58.3, 113.8, 117.8, 127.2,127.2, 128.4, 129.0, 141.9, 147.5, 213.1.
2-[(4-Hydroxy-3-methoxyphenyl)(phenylamino)methyl)]cyclo-
3. General procedure
A mixture of aldehyde (1 mmol), amine (1 mmol) and acetophe-
none
(1 mmol)/cyclohexanone
(1 mmol)/aliphatic
ketone
(1 mmol) in 5–10 mL of aq. 50% hydrotropic solution was stirred
until a clear solution was formed. The mixture was irradiated un-
der ultrasonic waves at ambient temperature. After completion
of reaction, the crude product obtained by addition of cold water
was filtered, washed with water and recystallised from ethanol
to afford pure b-amino carbonyl compound.
hexanone (Table 3, Entry 6d): IR (KBr):
t
3474, 3354, 3052, 2937,
1702, 1606, 1533, 1437, 1265, 1166, 1033, 865, 746 cmÀ1
;
1H
NMR (300 MHz, CDCl3): d 1.66–1.73 (m, 2H), 1.85–1.92 (m, 4H),
2.34–2.44 (m, 2H), 2.68–2.70 (m, 1H), 3.85 (s, 3H), 4.51 (d, 0.96
H, anti isomer), 4.54 (d, 0.14H, syn isomer), 5.53 (s, 1H, NH),
6.52–6.54 (m, 2H), 6.51–6.65 (m, 2H), 6.81–6.84 (m, 3H), 6.90 (s,
1H), 7.03–7.08 (m, 2H); 13C NMR (75 MHz, CDCl3): 23.5, 27.7,
31.0, 55.8, 57.5, 58.1, 109.1, 113.8, 114.0, 117.7, 120.4, 129.0,
133.4, 144.8, 146.7, 147.0, 212.7.
4. Spectral data of representative compounds
3-Anilino-1,3-diphenylpropan-1-one (Table 2, Entry 4a): IR
(KBr):
t ;
3385, 3025, 2917, 1669, 1600, 1509, 1291, 861 cmÀ1 1H
NMR (300 MHz, CDCl3): d 3.41–3.58 (m, 2H, CH2), 5.00–5.04 (dd,
1H, CH), 6.57 (d, 2H, Ar–H), 6.60–6.71 (m, 1H, Ar–H), 7.01–7.10
(m, 2H, Ar–H), 7.22–7.64 (m, 1H, Ar–H), 7.43 (t, 2H, Ar–H), 7.53
(t, 4H, Ar–H), 7.55 (d, 1H, Ar–H), 7.90 (d, 2H, Ar–H); 13C NMR
(75 MHz, CDCl3): 46.1, 55.0, 114.0, 118.0, 126.3, 127.3, 128.1,
128.6, 128.7, 129.0, 133.2; DEPT of CH2 at 46.1.
5. Results and discussion
We initially focused our attention on the selection of appropri-
ate hydrotrope for the present work. The different hydrotropes
such as sodium benzene sulphonate (NaBS), sodium p-xylene sul-
phonate (NaXS) and sodium p-toluene sulphonate (NaPTS) were
selected for this purpose. We opted to use 50% (w/v) aqueous solu-
tions of selected hydrotropes as a solvent, since this concentration
was suitable for the maximum solubilization of organic com-
pounds. Our next task was to assess the efficiency of the aqueous
hydrotropic solutions in the synthesis of b-amino carbonyl com-
pounds. Accordingly, a model reaction between acetophenone,
benzaldehyde and aniline in 50% of aq. NaBS, NaXS and NaPTS
was carried at ambient temperature under ultrasound irradiation.
On the completion of reaction as monitored by thin layer chroma-
tography (TLC), the reaction mixture was diluted with cold water
during which the product separated. The filtration of reaction mix-
ture followed by recrystallization afforded the corresponding prod-
uct of a high purity, which gave correct spectral analysis. The
3-(4-Chlorophenylamino)-3-(4-methoxyphenyl)-1-phenylpro-
pane-1-one (Table 2, Entry 4e): IR (KBr):
t 3383, 3062, 2929, 1668,
1603, 1505, 1256, 808 cmÀ1 1H NMR (300 MHz, CDCl3): d 3.33 (s,
;
3H, OCH3), 3.49 (dd, 1H, CH2), 3.78 (dd, 1H, CH2), 4.90 (s, 1H, NH),
6.45 (t, Ar–H, 2H), 6.85 (d, Ar–H, 2H), 7-04 (t, Ar–H, 2H), 7.32 (t, Ar–
H, 2H), 7.47 (t, Ar–H, 2H), 7.59 (s, Ar–H, 1H), 7.91 (d, Ar–H, 2H); 13
C
NMR (75 MHz, CDCl3): 46.0, 54.6, 55.1, 96.1, 114.2, 115.2, 127.3,
128.1, 128.6, 128.9, 133.3, 136.7, 145.2, 158.9, 197.9; DEPT of
CH2 at 46.0.
1-Anilino-1-phenylpentan-3-one (Table 2, Entry 4t): IR (KBr):
3427, 3350, 3042, 2914, 1687, 1652, 1560, 1227, 1144, 1028,
885 cmÀ1 1H NMR (300 MHz, CDCl3): d 0.97–0.99 (m, 2H), 2.31–
t
;
2.35 (m, 2H), 2.90–2.92 (m, 2H), 4.70 (brs, 1H, NH), 4.79–4.83
(m, 1H), 6.52–6.55 (m, 2H), 6.60–6.63 (m, 1H), 7.07–7.10 (m,
Table 2
Ultrasound promoted synthesis of b-amino carbonyl compounds in 50% aq.NaPTS solutiona
Entry
R1
R2
R3
Time (h)
Yieldb (%)
M.P. (°C)
Lit. M.P. [18,19] (°C)
4a
4b
4c
4d
4e
4f
4g
4h
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
H
H
H
H
H
0.75
1.70
1.10
2.00
1.10
1.70
1.75
1.30
1.70
2.25
1.50
2.00
2.50
1.70
2.25
2
91
87
86
90
93
95
90
89
91
92
92
92
88
85
83
81
82
81
70
82
167–168
138–140
162–165
187–188
113–115
117–119
136–138
114–117
149–152
156–158
110–112
138–140
116–119
135–137
126–127
90–92
169–170
140–142
167–168
190–192
116–118
118–119
142–143
118–119
153–155
159–160
114–115
141–143
119–120
141–142
130–132
87–88
3-NO2
4-CH3
4-COOH
4-Cl
4-Cl
H
4-CH3
4-Cl
4-COOH
H
4-Cl
H
4-CH3
4-Cl
H
4-OCH3
4-Cl
4-OCH3
4-Cl
3-NO2
4-Cl
4-Cl
3-NO2
H
H
H
H
H
Ph
Ph
Ph
4-ClC6H4
4-ClC6H4
4-ClC6H4
4-Cl C6H4
n-C3H7
n-C3H7
n-C3H7
n-C3H7
C5H9O
4-CH3
4-Cl
4-NO2
H
2
2
3.5
2
96–98
88–90
104–106
114–116
97–98
85–86
101–103
118–119
H
H
H
4s
4t
a
All products were characterized by IR, 1H NMR and 13C NMR spectroscopy.
Isolated yields after recrystallization.
b