966
E. Labarrios, A. Jerezano, F. Jiménez, M. del Carmen Cruz,
F. Delgado, L. G. Zepeda, and J. Tamariz
Vol 51
(Z)-2-(3-Methoxyphenylthio)-3-(dimethylamino)-1-p-tolylprop-
(s, 1H, H-3); 13C NMR (75.4 MHz, CDCl3): d 44.0 ((CH3)2N),
55.1 (CH3O-C-30), 55.2 (CH3O-C-300), 94.2 (C-2), 110.1 (C-400),
110.4 (C-200), 112.4 (C-20), 116.0 (C-40), 117.2 (C-600), 120.1
(C-60), 128.7 (C-50), 129.7 (C-500), 142.5 (C-100), 142.6 (C-10),
158.7 (C-3), 158.9 (C-30), 160.0 (C-300), 195.7 (CO); MS (70eV):
m/z 343 (M+, 5), 342 (26), 310 (19), 288 (9), 281 (12), 235 (22),
215 (23), 193 (21), 149 (33), 135 (100), 111 (36), 107 (62), 97
(44), 77 (94), 71 (32); HRMS (EI, [M+]): m/z calcd for
2-en-1-one (4i). Following the procedure as for 4a, with 6i (1.00 g,
3.7mmol) and DMFDMA (0.650g, 5.46 mmol), afforded 4i
(0.81g, 67%) as a brown gum. Rf 0.30 (hexane/EtOAc, 1:1); IR
(film):
n ;
1630, 1588, 1421, 1281, 1042 cmꢂ1 1H NMR
(300 MHz, CDCl3): d 2.34 (s, 3H, CH3Ar), 3.22 (s, 6H, (CH3)2N),
3.75 (s, 3H, OCH3), 6.60 (ddd, J = 8.1, 2.4, 0.9Hz, 1H, H-400),
6.70 (dd, J = 2.4, 1.8 Hz, 1H, H-200), 6.74 (ddd, J = 7.8, 1.8,
0.9 Hz, 1H, H-600), 7.09–7.14 (m, 2H, H-30), 7.14 (dd, J = 8.1,
7.8 Hz, 1H, H-500), 7.38–7.44 (m, 2H, H-20), 7.90 (s, 1H, H-3);
13C NMR (75.4MHz, CDCl3): d 21.3 (CH3Ar), 44.0 ((CH3)2N),
55.1 (CH3O), 94.4 (C-2), 110.1 (C-400), 110.3 (C-200), 117.2
(C-600), 128.1 (2ꢃ C-20), 128.3 (2 ꢃ C-30), 129.6 (C-500), 138.2
(C-10), 139.8 (C-40), 142.4 (C-100), 158.4 (C-3), 159.9 (C-300), 195.6
(CO); MS (70 eV): m/z 327 (M+, 100), 310 (22), 254 (10), 208 (84),
175 (25), 172 (27), 162 (18), 119 (26), 91 (25), 72 (20); HRMS
(EI, [M+]): m/z calcd for C19H21NO2S: 327.1293; found: 327.1279.
(Z)-2-(3-Methoxyphenylthio)-3-(dimethylamino)-1-m-tolylprop-
2-en-1-one (4j). Following the procedure as for 4a, with 6j (1.00 g,
3.7 mmol) and DMFDMA (0.650 g, 5.46mmol), afforded 4j
(0.96 g, 80%) as a brown gum. Rf 0.32 (hexane/EtOAc, 1:1); IR
C19H21NO3S: 343.1242; found: 343.1242.
(Z)-1-(3-Bromo-4-methoxyphenyl)-2-(3-methoxyphenylthio)-
3-(dimethylamino)prop-2-en-1-one (4m). Following the procedure as
for 4a, with 6m (0.100g, 0.27 mmol) and DMFDMA (0.048g,
0.40 mmol), afforded 4m (0.099g, 86%) as a brown gum. Rf 0.36
(hexane/EtOAc, 1:1); IR (film): n 1631, 1587, 1420, 1281 cmꢂ1
;
1H NMR (300MHz, CDCl3): d 3.26 (br s, 6H, (CH3)2N), 3.76
(s, 3H, CH3O-C-300), 3.89 (s, 3H, CH3O-C-40), 6.62 (dd, J = 8.1,
2.3, Hz, 1H, H-400), 6.67 (t, J = 2.3 Hz, 1H, H-200), 6.71 (br d,
J = 8.1 Hz, 1H, H-600), 6.80 (d, J = 8.4 Hz, 1H, H-50), 7.16
(t, J = 8.1 Hz, 1H, H-500), 7.49 (dd, J =8.4, 2.1 Hz, 1H, H-60), 7.75
(d, J = 2.1 Hz, 1H, H-20), 7.97 (s, 1H, H-3); 13C NMR (75.4 MHz,
CDCl3): d 44.0 ((CH3)2N), 55.1 (CH3O-C-300), 56.2 (CH3O-C-40),
93.5 (C-2), 110.2 (C-400), 110.3 (C-200), 110.5 (C-50), 110.6
(C-30), 117.1 (C-600), 128.9 (C-60), 129.8 (C-500), 133.5 (C-20),
134.5 (C-10), 142.3 (C-100), 157.0 (C-40), 158.1 (C-3), 160.0
(C-300), 193.6 (CO); MS (70 eV): m/z 424 (M+ + 3, 6), 423
(M+ + 2, 16), 422 (M+ + 1, 7), 421 (M+, 13), 267 (5), 265 (10),
209 (14), 208 (100), 175 (14), 174 (27), 161 (11), 72 (16);
HRMS (EI, [M+]): m/z calcd for C19H20BrNO3S: 421.0347;
found: 421.0346.
(film): n 1631, 1587, 1280, 1041 cmꢂ1 1H NMR (300 MHz,
;
CDCl3): d 2.31 (s, 3H, CH3Ar), 3.19 (br s, 6H, (CH3)2N), 3.74
(s, 3H, CH3O), 6.60 (ddd, J = 8.1, 2.4, 0.9 Hz, 1H, H-400), 6.71
(dd, J = 2.4, 1.8 Hz, 1H, H-200), 6.74 (ddd, J = 7.8, 1.8, 0.9 Hz, 1H,
H-60), 7.14–7.29 (m, 5H, H-500, H-20, H-40, H-50, H-60), 7.86 (s,
1H, H-3); 13C NMR (75.4 MHz, CDCl3): d 21.1 (CH3Ar), 43.8
((CH3)2N), 54.9 (CH3O), 94.5 (C-2), 109.9 (C-400), 110.2 (C-200),
117.1 (C-600), 124.7 (C-60), 127.3 (C-50), 128.2 (C-20), 129.5
(C-500), 130.1 (C-40), 137.3 (C-30), 141.1 (C-10), 142.2 (C-100),
158.6 (C-3), 159.8 (C-300), 195.7 (CO); MS (70eV): m/z 327
(M+, 59), 278 (18), 272 (24), 245 (19), 230 (19), 208 (41), 174
(33), 172 (31), 119 (100), 91 (94), 65 (39); HRMS (EI, [M+]): m/z
calcd for C19H21NO2S: 327.1293; found: 327.1293.
(Z)-1-(2-Bromophenyl)-2-(3-methoxyphenylthio)-3-(dimethylamino)
prop-2-en-1-one (4n). Following the procedure as for 4a, with 6n
(0.100 g, 0.29 mmol) and DMFDMA (0.050 g, 0.44 mmol) afforded
4n (0.091 g, 78%) as a brown gum. Rf 0.32 (hexane/EtOAc, 1:1); IR
(film): n 1637, 1587, 1420, 1310 cmꢂ1 1H NMR (500 MHz,
;
CDCl3): d 3.17 (br s, 3H, NCH3), 3.34 (br s, 3H, NCH3), 3.75 (s,
3H, CH3O), 6.61 (dd, J= 8.4, 2.4 Hz, 1H, H-400), 6.66–6.78 (m, 2H,
H-200, H-600), 7.04–7.25 (m, 4H, H-500, H-20, H-40, H-50), 7.50 (br d,
J= 7.2 Hz, 1H, H-60), 7.99 (br s, 1H, H-3); 13C NMR (125 MHz,
CDCl3): d 38.6 (CH3N), 48.6 (CH3N), 55.2 (CH3O), 110.3 (C-400),
110.7 (C-200), 117.5 (C-600), 119.1 (Ar), 126.7 (Ar), 127.4 (ArH),
129.3 (ArH), 129.6 (2ArH), 132.3 (ArH), 142.0 (Ar), 143.3 (Ar),
158.4 (C-3), 159.9 (C-300), 194.2 (CO); MS (70 eV): m/z 393
(M+ + 2, 10), 392 (M+ + 1, 7), 391 (M+, 12), 313 (20), 312 (100),
269 (14), 267 (11), 205 (10), 174 (11), 162 (11), 121 (6); HRMS
(EI, [M+]): m/z calcd for C18H18BrNO2S: 391.0242; found: 391.0244.
Methyl (Z)-2-(4-methoxyphenoxy)-3-(dimethylamino)acrylate
(3f). Following the procedure as for 4a, with 5f (0.10 g,
0.5 mmol) and DMFDMA (0.091g, 0.76 mmol), afforded 3f
(0.11 g, 88%) as a yellow solid. Rf 0.26 (hexane/EtOAc, 1:1); mp
(Z)-1-(4-Methoxyphenyl)-2-(3-methoxyphenylthio)-3-(dimethylamino)
prop-2-en-1-one (4k). Following the procedure as for 4a, with 6k
(0.100g, 0.35 mmol) and DMFDMA (0.062 g, 0.52 mmol),
afforded 4k (0.101 g, 85%) as a brown gum. Rf 0.32 (hexane/
EtOAc, 1:1); IR (film): n 1627, 1587, 1420, 1280cmꢂ1; 1H NMR
(500 MHz, CDCl3): d 3.23 (br s, 6H, (CH3)2N), 3.75 (s, 3H,
CH3OC-300), 3.80 (s, 3H, CH3OC-40), 6.60 (ddd, J = 8.0, 2.5,
0.5 Hz, 1H, H-400), 6.70 (br t, J = 2.0 Hz, 1H, H-200), 6.74 (ddd,
J= 8.0, 2.0, 0.5 Hz, 1H, H-600), 6.80–6.84 (m, 2H, H-30), 7.14 (t,
J= 8.0 Hz, 1H, H-500), 7.52–7.56 (m, 2H, H-20), 7.91 (s, 1H, H-3);
13C NMR (125 MHz, CDCl3): d 44.0 ((CH3)2N), 55.1 (OCH3),
55.2 (CH3O), 94.2 (C-2), 110.1 (C-400), 110.4 (C-200), 112.9 (2 ꢃ C-
30), 117.2 (C-600), 129.7 (C-500), 130.3 (2 ꢃ C-20), 133.3 (C-10),
142.5 (C-100), 158.1 (C-3), 160.0 (C-300), 161.0 (C-40), 194.9 (CO);
MS (70 eV): m/z 343 (M+, 91), 326 (21), 255 (12), 208 (58), 187
(86), 174 (47), 161 (31), 135 (100), 121 (21), 77 (43); HRMS (EI,
[M+]): m/z calcd for C19H21NO3S: 343.1242; found: 343.1243.
(Z)-1-(3-Methoxyphenyl)-2-(3-methoxyphenylthio)-3-(dimethylamino)
prop-2-en-1-one (4l). Following the procedure as for 4a, with 6l
(0.10 g, 0.35 mmol) and DMFDMA (0.062g, 0.52 mmol),
afforded 4l (0.099g, 83%) as a brown gum. Rf 0.35 (hexane/
EtOAc, 1:1); IR (film): n 1631, 1587, 1473, 1283cmꢂ1; 1H NMR
(300 MHz, CDCl3): d 3.26 (s, 6H, (CH3)2N), 3.68 (s, 3H, CH3O),
3.77 (s, 3H, CH3O), 6.62 (ddd, J = 8.1, 2.4, 0.9 Hz, 1H, H-400),
6.71 (t, J = 2.4Hz, 1H, H-200), 6.75 (ddd, J = 8.1, 1.8, 0.9Hz, 1H,
H-600), 6.91 (ddd, J = 8.1, 2.4, 0.9 Hz, 1H, H-40), 6.99 (dd, J = 2.4,
1.5 Hz, 1H, H-20), 7.05 (ddd, J = 7.5, 1.5, 0.9 Hz, 1H, H-60), 7.16
(t, J = 8.1 Hz, 1H, H-500), 7.23 (dd, J = 8.1, 7.5 Hz, 1H, H-50), 7.97
1
116–118ꢀC; IR (film): n 1694, 1640, 1504, 1304, 1087cmꢂ1; H
NMR (300 MHz, CDCl3): d 2.97 (s, 6H, (CH3)2N), 3.63 (s, 3H,
CO2CH3), 3.76 (s, 3H, OCH3), 6.79–6.91 (m, 4H, H20, H-30),
7.14 (s, 1H, H-3); 13C NMR (75.4MHz, CDCl3): d 42.1 ((CH3)
2N), 51.1 (CO2CH3), 55.6 (CH3O), 114.6 (2 ꢃ C-30), 115.4
(2ꢃ C-20), 116.0 (C-2), 139.7 (C-3), 153.3 (C-10), 154.1 (C-40),
167.0 (CO2CH3); MS (70eV): m/z 252 (M+ + 1, 49), 251 (M+,
100), 250 (30), 220 (26), 192 (66), 164 (20), 95 (5); HRMS (EI,
[M+]): m/z calcd for C13H17NO4: 251.1158; found: 251.1166.
General procedure for the synthesis of benzo[b]thiophenes
2a–n and benzo[b]furans 1a–j.
Methyl 6-methoxybenzo[b]thiophene-2-carboxylate (2a). Under a
N2 atmosphere, a mixture of 4a (0.100g, 0.37 mmol) and I2
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet