196
CHO
A. Ziarati et al. / Chinese Chemical Letters 24 (2013) 195–198
NH2
Table 1
Optimization of model reaction.
R1
O
Entry
Solvent/condition
Catalyst (mol%)
Time (h)
Yield (%)a
+
H
N
R3
R2
R1
1
2
MeCN/rt
CH2Cl2/rt
H2O/rt
CuI (12%)
10
10
10
10
10
10
9
62
87
31
88
89
54
82
81
85
94
98
98
4
1
CuI (12%)
nano CuI
EtOH, rt
O
O
R3-N
3
C
O
3
CuI (12%)
4
MeOH/rt
EtOH/rt
EtOH/reflux
EtOH/rt
EtOH/rt
EtOH/rt
EtOH/rt
EtOH/rt
EtOH/rt
CuI (12%)
NH2
NH HN
O
5
CuI (12%)
R2
R2
6
CuI (12%)
+
O
O
7
None
5a-r
8
MgO (15%)
InCl3 (20%)
Nano CuI (1%)
Nano CuI (2%)
Nano CuI (3%)
10
10
4
R2
9
4
2
10
11
12
4
Scheme 1. Synthesis of tricarboxamides using CuI nanoparticles as catalyst.
4
a
Isolated yields.
sonicated to react for 30 min. When the reaction was completed,
gray precipitate was obtained. The solid was filtered and washed
with distilled water and dried.
To obtain a visual image of this catalyst, powder X-ray
diffraction (XRD) and scanning electron microscopy (SEM) was
carried out (see Figs. S1 and S2 in supporting information). As
shown in the XRD pattern, all reflection peaks can be readily
indexed to pure cubic crystal phase of nanocrystalline copper
iodide. Crystallite size of CuI has been found to be 20 nm, which
FT-IR (KBr, cmꢀ1):
(400 MHz, DMSO-d6):
NCH), 3.82 (d, 1H, J = 9.7 Hz, CH), 4.18 (d, 1H, J = 9.7 Hz, CH), 7.02–
7.64 (m, 12H, Ar), 8.12 (brs, 1H, NH), 9.60 and 9.74 (2s, 2H, 2 NH);
13C NMR (100 MHz, DMSO-d6):
148.7, 145.4, 145.1, 129.9, 126.7, 125.4, 124.1, 122.9, 121.6, 118.5,
63.7, 50.1, 46.9, 33.7, 33.4, 26.4. Anal. Calcd. for C31H34N4O7: C,
64.81; H, 5.92; N, 9.76. Found: C, 64.55; H, 5.72; N, 9.94. MS (EI) (m/
z): 574 (M+).
n
3288, 3268, 1682, 1650, 1617; 1H NMR
1.10–1.58 (m, 10H, 5CH2), 3.59 (s, 1H,
d
d 173.2, 168.6, 167.1, 150.6, 149.8,
was calculated by the Debye-Scherrer equation (D = Kl/bcos u)
and confirmed by SEM. The increased surface area due to small
particle size increased reactivity. This factor is responsible for the
accessibility of the substrate molecules on the catalyst surface.
In addition, the specific surface area was measured by nitrogen
physisorption (the BET method), the specific surface area was
approximately 2.94 m2/g.
1
2
2
0
N -tert-Butyl-N ,N -bis(4-chlorophenyl)-1-phenylethane-1,2,2-
tricarboxamide (5k): White solid; mp 317–319 8C, FT-IR (KBr,
cmꢀ1):
d6):
1H, J = 10.6 Hz, CH), 7.09–7.63 (m, 13H, Ar), 8.32 (s, 1H, NH), 9.58
and 9.79 (2s, 2H, 2 NH); 13C NMR (100 MHz, DMSO-d6):
173.4,
n
3301, 3287, 1678, 1647, 1636; 1H NMR (400 MHz, DMSO-
1.18–1.27 (s, 9H, 3CH3), 3.77 (d, 1H, J = 10.5 Hz, CH), 4.19 (d,
d
d
2.2. General procedure for the preparation of tricarboxamides (5a–r)
168.1, 166.9, 151.2, 151.0, 147.6, 147.1, 129.8, 128.1, 125.9, 125.5,
124.8, 122.8, 121.7, 119.2, 62.1, 49.6, 46.3, 29.9. Anal. Calcd. for
A solution of aldehyde (2 mmol), Meldrum’s acid (2 mmol), CuI
nanoparticles (2 mol%) and ethanol (4 mL) was stirred for 30 min.
Then, cyclohexyl isocyanide (2 mmol) and amine (4 mmol) was
added and vigorously stirred for the appropriate time (Table 1,
monitored by TLC). After completion of reaction, the solid was
filtered off and washed with chloroform. The residue was dissolved
in hot methanol and then filtered until the heterogeneous catalyst
was recovered. The filtrate solution was recrystallized to afford the
pure product in 89%–98% yield.
C
27H28Cl2N3O3: C, 64.62; H, 5.18; N, 7.88. Found: C, 63.65; H, 5.11;
N, 7.98. MS (EI) (m/z): 511 (M+).
1
2
2
0
N -tert-Butyl-N ,N -bis(4-bromophenyl)-1-(4-chloropheny-
l)ethane-1,2,2-tricarboxamide (5p): Yellowish solid; mp 320–
322 8C, FT- IR (KBr, cmꢀ1):
NMR (400 MHz, DMSO-d6):
n
d
3296, 3258, 1688, 1651, 1617; 1H
1.21–1.29 (s, 9H, 3CH3), 3.81 (d, 1H,
J = 11.0 Hz, CH), 4.16 (d, 1H, J = 10.9 Hz, CH), 7.09–7.73 (m, 12H,
Ar), 8.16 (s, 1H, NH), 9.68 and 9.81 (2s, 2H, 2 NH); 13C NMR
(100 MHz, DMSO-d6):
147.5, 146.2, 128.8, 127.5, 126.3, 124.8, 123.1, 122.0, 118.9, 62.7,
50.1, 46.3, 29.2. Anal. Calcd. for C27H27Br2ClN3O3: C, 51.03; H, 4.18;
N, 6.61. Found: C, 52.37; H, 4.12; N, 6.48. MS (EI) (m/z): 633 (M+).
d 173.7, 167.8, 167.1, 151.9, 151.0, 148.3,
2
2
0
1
N ,N -Bis(4-chlorophenyl)-N -cyclohexyl-1-phenylethane-1,2,2-
tricarboxamide (5b): White solid; mp 309–311 8C, FT- IR (KBr,
cmꢀ1):
d6):
n
3280, 3262, 1681, 1643, 1607; 1H NMR (400 MHz, DMSO-
0
d
1.11–1.62 (m, 10 H, 5CH2), 3.52 (s, 1H, NCH), 3.81 (d, 1H,
N1-tert-Butyl-N2,N2 -bis(4-methoxyphenyl)-1-(4-nitropheny-
J = 11.2 Hz, CH), 4.14 (d, 1H, J = 11.2 Hz, CH), 6.99–7.51 (m, 13H,
l)ethane-1,2,2-tricarboxamide (5r): Yellowish solid; mp 329–
Ar), 8.21 (brs, 1H, NH), 9.62 and 9.75 (2s, 2H, 2 NH); 13C NMR
331 8C, FT-IR (KBr, cmꢀ1): 3296, 3271, 1690, 1664, 1621; 1H
NMR (400 MHz, DMSO-d6): d 1.20–1.32 (s, 9H, 3CH3), 3.86 (d, 1H,
n
(100 MHz, DMSO-d6):
d
173.2, 168.6, 167.1, 151.6, 150.9, 147.3,
147.1, 129.7, 128.3, 126.1, 125.6, 124.5, 122.3, 121.9, 118.7, 62.5,
49.4, 46.2, 33.4, 33.1, 26.8. Anal. Calcd. for C29H29Cl2N3O3: C, 64.68;
H, 5.39; N, 7.81. Found: C, 63.77; H, 5.16; N, 7.93. MS (EI) (m/z): 537
(M+).
J = 8.1 Hz, CH), 4.22 (d, 1H, J = 8.1 Hz, CH), 7.05–7.61 (m, 12H, Ar),
8.11 (s, 1H, NH), 9.57 and 9.76 (2s, 2H, 2 NH); 13C NMR (100 MHz,
DMSO-d6):
d 172.6, 168.9, 167.3, 151.1, 149.6, 148.8, 145.2, 145.1,
129.4, 126.3, 125.1, 124.5, 123.3, 121.2, 118.7, 63.9, 50.4, 46.7, 29.5.
Anal. Calcd. for C29H33N4O7: C, 63.49; H, 5.88; N, 10.21. Found: C,
64.11; H, 5.78; N, 9.95. MS (EI) (m/z): 548 (M+).
2
2
0
1
N ,N -Bis(4-bromophenyl)-1-(4-chlorophenyl)-N -cyclohexy-
lethane-1,2,2-tricarboxamide (5g): White solid; mp 314–318 8C, FT-
IR (KBr, cmꢀ1): 3287, 3265, 1680, 1646, 1611; 1H NMR (400 MHz,
n
DMSO-d6):
d
1.13–1.57 (m, 10H, 5CH2), 3.55 (s, 1H, NCH), 3.79 (d,
3. Results and discussion
1H, J = 11.4 Hz, CH), 4.17 (d, 1H, J = 11.3 Hz, CH), 7.06–7.68 (m,
12H, Ar), 8.19 (brs, 1H, NH), 9.63 and 9.77 (2s, 2H, 2 NH); 13C NMR
In our initial experiments, the model reaction conditions were
established based on the reactions between benzaldehyde
(2 mmol), 4-chloroaniline (4 mmol), cyclohexyl isocyanide
(2 mmol) and Meldrum’s acid (2 mmol) in different solvents and
catalysts. This reaction was carried out using the aprotic (Table 1,
entries 1 and 2) and protic solvents (Table 1, entries 3–5). The best
result was obtained in ethanol (Table 1, entry 5). Next, we studied
the model reaction in ethanol at different temperatures (Table 1,
(100 MHz, DMSO-d6):
d 173.4, 168.1, 167.5, 151.8, 151.2, 148.0,
147.8, 146.5, 129.2, 127.4, 125.9, 124.3, 122.7, 122.1, 118.6, 62.6,
49.8, 46.7, 33.5, 33.0, 27.0. Anal. Calcd. for C29H28Br2ClN3O3: C,
52.60; H, 4.23; N, 6.35. Found: C, 52.43; H, 4.16; N, 6.51. MS (EI) (m/
z): 659 (M+).
2
2
0
1
N ,N -Bis(4-methoxyphenyl)-1-(4-nitrophenyl)-N -cyclohexy-
lethane-1,2,2-tricarboxamide (5i): Yellowish solid; mp 323–325 8C,