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monitored using thin-layer chromatography (TLC). When the
indole component had been completely consumed, the solu-
tions were held at 273 K overnight, and the resulting solid
products (B) were collected by filtration and washed with cold
methanol (2 ꢁ 1.0 ml).
Analysis found: C 62.1, H 3.6, N 8.0%; C19H13BrN2O requires:
C 62.5, H 3.6, N 7.7%.
(E)-2-(1-Benzyl-1H-indole-3-carbonyl)-3-(2-bromophenyl)-
acrylonitrile, (Ic): yield 92%, m.p. 453 K; IR (ATR): 3068
1
(C—H), 2225 (CN), 1616 (C O), 1517 (C C); H NMR
3-(1H-Indol-3-yl)-3-oxopropanenitrile: yield 79%, m.p. 516 K;
IR (KBr): 3225 (N—H), 2253 (CN), 1643 (C O), 1581
(C C) cmꢂ1; 1H NMR (DMSO-d6): ꢀ 4.47 (s, CH2), 7.19–7.27
(m, 2H), 7.47–7.52 (m, 1H), 8.10–8.16 (m, 1H), 8.36 (s, 1H),
12.14 (s, 1H, NH); MS (70 eV) m/z (%): 184 (23, M+)
144 (100), 116 (27), 89 (26).
(CDCl3): ꢀ 5.44 (s, 2H), 7.19–7.29 (m, 2H), 7.33–7.45 (m, 7H),
7.50 (td, J = 7.7, 1.2 Hz, 1H), 7.73 (dd, J = 8.0, 1.1 Hz, 1H), 8.19
(dd, J = 7.8, 1.6 Hz, 1H), 8.36 (s, 1H), 8.46–8.63 (m, 2H); 13C
NMR (CDCl3): ꢀ 51.2 (CH2Ph), 110.5, 114.2 (Cq), 114.5 (Cq),
117,4 (CN), 123.1, 123.6, 124.4, 126.1 (Cq), 127.3, 127.6 (Cq),
128.0, 128.5, 129.2, 130.0, 132.7 (Cq), 132.9, 133.4, 135.1 (Cq),
136.6, 137.0 (Cq), 151.9, 178.3 (C O); MS (70 eV) m/z (%):
442/440 (8/8, M+), 361 (12), 234 (5), 91 (100). Analysis found:
C 67.9, H 4.0, N 6.5%; C26H17BrN2O requires: C 68.0, H 3.9, N
6.4%.
For the reduction of chalcones (I) to dihydrochalcones (II),
the appropriate chalcone (I) (1.0 mmol) was dissolved in a
mixture of 1,4-dioxane and methanol (1:4 v/v, 5 ml) and the
solution were stirred vigorously at 343 K as sodium borohy-
dride (1.0 equivalent) was added portionwise. When the
starting chalcone had been consumed, as indicated by TLC,
the solutions were cooled to ambient temperature and the
resulting precipitates were collected by filtration and washed
with cold methanol (2 ꢁ 1.0 ml). No further purification was
necessary.
3-(1-Methyl-1H-indol-3-yl)-3-oxopropanenitrile: yield 73%,
m.p. 426 K; IR (KBr): 3110 (C—H), 2250 (CN), 1643 (C O),
1581 (C C) cmꢂ1; 1H NMR (CDCl3): ꢀ 3.88 (s, 2H, CH2), 3.90
(s, 3H, CH3), 7.31–7.48 (m, 3H), 7.81 (s, 1H), 8.27–8.37 (m,
1H); 13C NMR (CDCl3): ꢀ 29.6 (CH2), 33.9 (CH3), 110.1, 114.2
(Cq), 114.9 (CN), 122.3, 123.5, 124.2, 126.1 (Cq), 136.2, 137.5
(Cq), 180.5 (C O).
3-(1-Benzyl-1H-indol-3-yl)-3-oxopropanenitrtile: yield 72%,
m.p. 397 K; IR (KBr): 3105 (C—H), 2252 (CN), 1662 (C O),
1602 (C C) cmꢂ1; 1H NMR (CDCl3): ꢀ 3.90 (s, 2H, CH2CN),
5.41 (s, 2H, CH2Ph), 7.21 (dd, J = 7.5, 2.1 Hz, 2H), 7.30–7.40
(m, 6H), 7.85 (s, 1H), 8.37 (dd, J = 8.4, 1.7 Hz, 1H), 13C NMR
(CDCl3): ꢀ 29.8 (CH2), 51.1 (CH2Ph), 110.6, 114.7 (Cq), 114.8
(CN), 122.5, 123.6, 124.4, 126.3 (Cq), 127.2, 128.5, 129.2, 135.1
(Cq), 135.2, 137.1 (Cq), 180.6 (C O). Analysis found: C 78.9,
H 5.4, N 9.9%; C18H14N2O requires: C 78.8, H 5.1, N 10.2%.
For the synthesis of chalcones (I), a mixture of the corre-
sponding oxopropanenitrile (B) (1.0 mmol), 2-bromobenz-
aldehyde (1.2 mmol) and triethylamine (1.2 ml) in ethanol
(4 ml) was heated under reflux for 2 h. Once precursor (B) had
been consumed, as shown by TLC, the mixtures were cooled
to ambient temperature and the resulting solid products (I)
were collected by filtration and washed with cold methanol
(2 ꢁ 1.0 ml); no further purification was required.
2-(2-Bromobenzyl)-3-(1H-indol-3-yl)-3-oxopropanenitrile,
(IIa): yield 82%, m.p. 519 K; IR (ATR): 3259 (N—H), 2247
1
(CN), 1616 (C O), 1579 (C C) cmꢂ1; H NMR (DMSO-
d6): ꢀ 3.34–3.37 (m, 2H), 5.06 (t, J = 9.6 Hz, 1H), 7.21–7.29 (m,
3H), 7.38 (t, J = 8.3 Hz, 1H), 7.52 (bt, 2H), 7.64 (d, J = 8.3 Hz,
1H), 8.18 (d, J = 8.4 Hz, 1H), 8.61 (s, 1H), 12.27 (s, 1H, NH).
13C (DMSO-d6): ꢀ 35.4, 39.9, 112.5, 113.7 (Cq), 118.4 (CN),
121.5, 122.5, 123.6, 124.2 (Cq), 125.4 (Cq), 127.8, 128.4, 129.3
(Cq), 131.6, 132.7, 136.0 (Cq), 136.8, 184.3 (C O); MS
(70 eV) m/z (%): 354/352 (2.9/2.5, M+) 144 (100), 273 (43),
116 (23), 89 (13). Analysis found: C 61.1, H 3.9, N 7.8%;
C18H13BrN2O requires: C 61.2, H 3.7, N 7.9%.
(E)-3-(2-Bromophenyl)-2-(1H-indole-3-carbonyl)acrylonitrile,
(Ia): yield 95%, m.p. 522 K; IR (ATR): 3174 (N—H), 2218
(CN), 1631 (C O), 1579 (C C) cmꢂ1; 1H NMR (DMSO-d6):
ꢀ 7.26–7.35 (m, 2H), 7.53 (t, J = 8.1 Hz, 1H), 7.58 (d, J = 8.0 Hz,
1H), 7.64 (t, J = 8.0 Hz, 1H), 7.86 (d, J = 7.9 Hz, 1H), 8.13 (d, J=
7.9 Hz, 1H), 8.22 (d, J = 8.0 Hz, 1H), 8.28 (s, 1H), 8.52 (s, 1H),
12.39 (s, 1H, NH); 13C NMR (DMSO-d6): ꢀ 113.1 (Cq), 113.9,
115.9 (CN), 117.0, 121.8, 122.8 (Cq), 123.1 (Cq), 125.0, 126.5,
128.7 (Cq), 130.6, 131.4, 133.2 (Cq), 133.7, 136.8 (Cq), 137.2,
151.0, 180.9 (C O); MS (70 eV) m/z (%): 352/350 (22/22, M+)
144 (100), 271 (41), 116 (37), 89 (62). Analysis found: C 61.4,
H 3.0, N 8.1%; C18H11BrN2O requires: C 61.6, H 3.2, N 8.0%.
(E)-3-(2-Bromophenyl)-2-(1-methyl-1H-indole-3-carbonyl)-
acrylonitrile, (Ib): yield 92%, m.p. 436 K; IR (ATR): 3018 (C—
2-(2-Bromobenzyl)-3-(1-methyl-1H-indol-3-yl)-3-oxopropane-
nitrile, (IIb): yield 93%, m.p. 419 K; IR (ATR): 3059 (C—H),
;
2249 (CN), 1641 (C O), 1577 (C C) cmꢂ1 1H NMR
(CDCl3): ꢀ 3.38 (dd, J = 13.8, 9.5 Hz, 1H), 3.61 (dd, J = 13.8,
6.1 Hz, 1H), 3.89 (s, 3H, CH3), 4.53 (dd, J = 9.5, 6.1 Hz, 1H),
7.19 (td, J = 7.7, 1.7 Hz, 1H), 7.28–7.50 (m, 5H), 7.61 (dd, J =
8.0, 1.3 Hz, 1H), 7.89 (s, 1H), 8.43 (ddd, J = 6.8, 3.0, 1.5 Hz,
1H); 13C NMR (CDCl3): ꢀ 33.9 (NCH3), 36.5 (CH2), 40.4 (CH),
110, 114.1 (Cq), 117.9 (CN), 122.7, 123.5, 124.2 (Cq), 124.3,
126.5 (Cq), 128.1, 129.4, 132.4, 132.9, 135.8 (Cq), 136.2, 137.6
(Cq), 183.1 (C O); MS (70 eV) m/z (%): 368/366 (2/2, M+),
287 (9), 158 (100), 130 (17), 83 (61). Analysis found: C 62.3, H
4.1, N 8.0%; C19H15BrN2O requires: C 62.1, H 4.1, N 7.6%.
3-(1-Benzyl-1H-indol-3-yl)-2-(2-bromobenzyl)-3-oxopropane-
nitrile, (IIc): yield 91%, m.p. 419 K; IR (ATR): 3059 (C—H),
1
H), 2212 (CN), 1635 (C O), 1581 (C C) cmꢂ1; H NMR
(CDCl3): ꢀ 3.95 (s, 3H, CH3), 7.35–7.57 (m, 5H), 7.75 (dd, J =
8.0, 1.3 Hz, 1H), 8.20 (dd, J = 7.8, 1.7 Hz, 1H), 8.35 (s, 1H),
8.44–8.54 (m, 1H), 8.58 (s, 1H); 13C NMR (CDCl3): 34.0 (CH3),
110.0, 113.9 (Cq), 114.1 (Cq), 117.8 (CN), 123.1, 123.5, 124.3,
126.1 (Cq), 127.4 (Cq), 128.0, 130.0, 132.8 (Cq), 132.9, 133.5,
137.2, 137.4 (Cq), 152.2, 178.6 (C O); MS (70 eV) m/z (%):
366/364 (38/40, M+), 285 (100), 236 (19), 158 (66), 152 (35).
2250 (CN), 1641 (C O), 1568 (C C) cmꢂ1 1H NMR
;
(CDCl3): ꢀ 3.34 (dd, J = 13.7, 9.8 Hz, 1H), 3.55 (dd, J = 13.6,
6.0 Hz, 1H), 4.50 (dd, J = 9.8, 6.0 Hz, 1H), 5.29–5.45 (m, 2H),
7.12–7.32 (m, 4H), 7.33–7.47 (m, 7H), 7.56 (dd, J = 8.0, 1.2 Hz,
1H), 7.89 (s, 1H), 8.42–8.50 (m, 1H); 13C (CDCl3): ꢀ 37.1
ꢀ
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1042 Garcıa et al. Novel indole-based cyano derivatives
Acta Cryst. (2017). C73, 1040–1049