Synthesis of novel Schiff base benzamides via ring…
1
C=N), 1552–1465 (C=C, aromatic skeletal vibration). H NMR (DMSO, 400 MHz,
(
d ppm): 7.15 (s, 1H, CH), 7.39–8.14 (m, 17H, Ar–H), 8.48 (s, 1H, CH=N, imine),
1
3
9
1
2
1
1
1
.95 (s, 1H, NH), 11.64 (s, 1H, NH). C NMR (DMSO-d6, 100 MHz, d ppm):
66.60 (C=O, C-11), 161.91 (C=O, C-9), 147.61 (C-21), 141.95 (C-25), 139.84 (C-
8), 137.16 (C-5), 134.15 (C-7), 134.03 (C-13), 133.06 (C-22), 132.25 (C-16),
30.99 (C-2), 129.50 (C-23, C-27), 128.83 (C-30, C-32, C-4), 128.54 (C-15, C-7),
28.34 (C-3), 128.08 (C-24, C-26), 127.53 (C-29, C-33), 127.15 (C-31), 126.68 (C-
?
4, C-18), 126.33 (C-6). MS–ESI: m/z = 352 (M ? 1). Anal. Calcd. for
C H N O S (%): C, 71.82; H, 4.69; N, 9.31; found (%): C, 71.80; H, 4.71; N,
2
7 21 3 2
9
.29.
3
-[(2E)-2-(4-Hydroxybenzylidene)hydrazinyl]-3-oxo-1-(thiophen-2-yl)prop-1-en-2-
1
-
yl]benzamide (5l) Pale yellow solid; yield 79%; M.P.: 261–262 °C: IR, t cm
3
:
306 (OH), 3230–3204 (NH), 1630 (C=O), 1596 (C=O) 1562 (C=N), 1552–1506
1
(
C=C, aromatic skeletal vibration). H NMR (DMSO, 400 MHz, d ppm): 7.13 (s,
H, CH), 6.82–8.31 (m, 12H, Ar–H), 8.31 (s, 1H, CH=N, imine), 9.90 (s, 1H, -OH),
1
9
1
5
1
2
6
1
3
.92 (s, 1H, NH), 11.38 (s, 1H, NH). C NMR (DMSO-d6, 100 MHz, d ppm):
66.57 (C=O, C-11), 161.58 (C=O, C-9) 159.83 (C-25), 148.42 (C-21), 137.21 (C-
), 134.21 (C-7), 132.88 (C-13), 132.20 (C-16), 130.81 (C-23, C-27), 129.23 (C-2),
28.80 (C-4), 128.53 (C-3), 127.47 (C-15, C-17) 126.83 (C-14, C-18), 126.02 (C-
2), 125.90 (C-24, C-26), 116.17 (C-6). Anal. Calcd. for C H N O S (%): C,
2
1 17 3 3
4.43; H, 4.38; N, 10.73; found (%): C, 64.41; H, 4.40; N, 10.71.
3
2
3
-[(2E)-2-(2,4-Methylbenzylidene)hydrazinyl]-3-oxo-1-(thiophen-2-yl)prop-1-en-
-
1
-ylbenzamide (5m) Pale yellow solid; yield 80%; M.P.: 182–184 °C: IR, t cm
351–3343 (NH), 1675 (C=O), 1643 (C=O) 1600 (C=N), 1573–1505 (C=C,
:
1
aromatic skeletal vibration). H NMR (DMSO, 400 MHz, d ppm): 2.03 (s, 3H,
CH ), 2.33 (s, 3H, CH ), 7.13 (s, 1H, CH), 7.13–8.11 (m, 11H, Ar–H), 8.48 (s, 1H,
1
CH=N, imine), 9.95 (s, 1H, NH), 11.54 (s, 1H, NH). C NMR (DMSO-d6,
3
3
3
100 MHz, d ppm): 166.58 (C=O, C-11), 161.81 (C=O, C-9), 148.10 (CH=N, C-21),
140.26 (C-25), 138.75 (C-23), 137.17 (C-5), 134.16 (C-7), 132.98 (C-13), 132.23
(
C-16), 130.91 (C-27), 129.91 (C-2), 128.81 (C-24, C-26, C-4), 128.53 (C-15,
C-17), 127.50 (C-3), 127.47 (C-14, C-18), 126.75 (C-22), 126.19 (CH=C, C-6)
1.50 (CH , C-29). 20.2 (CH , C-28). Anal. Calcd. for C H N O S (%): C, 72.32;
2
3
3
29 27 3 2
H, 5.65; N, 8.72; found (%): C, 72.30; H, 5.67; N, 8.70 [24].
3
2
3
-[(2E)-2-(2,4-Dichlorobenzylidene)hydrazinyl]-3-oxo-1-(thiophen-2-yl)prop-1-en-
-
1
-yl]benzamide (5n) Pale yellow solid: yield 74%; M.P.: 244–246 °C: IR, t cm
176 (NH), 1665 (C=O), 1631(C=O) 1581 (C=N), 1551–1512 (C=C, aromatic
:
1
skeletal vibration), 1051 (C–Cl). H NMR (DMSO, 400 MHz, d ppm): 7.13 (s, 1H,
CH), 7.13–8.11 (m, 11H, Ar–H), 8.99 (s, 1H, CH=N imine), 9.95 (s, 1H, NH), 11.54
1
3
(s, 1H, NH). C NMR (DMSO-d6, 100 MHz, d ppm): 168.58 (C=O, C-11). 163.81
(C=O, C-9), 146.8 (CH=N, C-21), 137.17 (C-5), 134.16 (C-7), 132.48 (C-13),
1
4
1
3
32.23 (C-16), 131.9 (C-22), 130.91 (C-2), 129.91 (C-23), 129.7 (C-27), 128.81 (C-
, C-24), 128.53 (C-26), 128.4 (C-15, C-17), 128.1 (C-25), 127.56 (C-3), 127.47 (C-
4, C-18), 126.19 (CH=C, C-6). Anal. Calcd. for C H Cl N O S (%): C, 56.76; H,
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15
2 3 2
.40; N, 9.46; found (%): C, 56.74; H, 3.42; N, 9.44.
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