2
068
Synthesis and Characterization of Newly Fused 1,2-Dihydropyrido[3,4-b]
J. Braz. Chem. Soc.
1
3
Anal. calcd. for C H Cl N O : C, 56.32; H, 3.48; N, 6.91.
Jtrans 16.1 Hz, 1H, H ), 8.54 (d, 2H, H , H ); C NMR
a A C
1
9
14
2
2
4
Found: C, 56.42; H, 3.29; N, 6.91.
(500 MHz, CDCl ) d 14.07, 21.47, 63.87, 113.71, 118.31,
3
1
99.79, 121.88, 127.78, 129.73, 132.85, 133.46, 136.02,
(
E)-6-Chloro-2-(4-(dimethylamino)styryl)-3-(ethoxy-
136.80, 137.28, 138.34, 140.81, 141.54, 159.67; MS (m/z)
+
+
carbonyl)quinoxaline 1,4-dioxide (11c)
384 (12) [M] , 386 (14) [M + 2] , 119 (100). Anal. calcd.
for C H ClN O : C, 62.42; H, 4.45; N, 7.28. Found: C,
Dark red solid; yield 0.12 g (29%); mp 218-220 °C; IR
20
17
2
4
-1
(
(
KBr) ν / cm 3074 (Ar–H), 2965 (C–H saturated), 1743
62.50; H, 4.22; N, 7.38.
C=O ester), 1625 (C=C aliphatic), 1587 (C=C aromatic),
1
357 (N–O), 1269 (C–O), 798 (C–Cl); UV (DMSO)
(E)-2-(4-Bromostyryl)-6-chloro-3-(ethoxycarbonyl)
quinoxaline 1,4-dioxide (11f)
1
λmax / nm 403; H NMR (400 MHz, CDCl ) d 1.50 (t,
3
J 7.0 Hz, 3H, OCH CH ), 3.08 (s, 6H, N(CH ) ), 4.64 (q,
Orange solid; yield 0.10 g (23%); mp 183-185 °C; IR
(KBr) ν / cm 3097 (Ar–H), 2925 (C–H saturated), 1734
2
3
3 2
-1
J 7.0 Hz, 2H, OCH CH ), 6.72 (d, J 8.5 Hz, 2H,Ar), 6.87
2
3
ortho
(
d, Jtrans 16.0 Hz, 1H, H ), 7.49 (d, J 8.5 Hz, 2H,Ar), 7.81
(C=O ester), 1610 (C=C aliphatic), 1540 (C=C aromatic),
b
ortho
(
dd, Jortho 9.2, J 2.2 Hz, 1H, H ), 8.53 (d, J 16.0 Hz, 1H,
1354 (N–O), 1236 (C–O), 804 (C–Cl); UV (DMSO)
W
B
trans
13
1
H ), 8.58 (m, 2H, H , H ); C NMR (400 MHz, CDCl )
λmax / nm 333; H NMR (500 MHz, CDCl ) d 1.43 (t,
a
A
C
3
3
d 14.07, 29.68, 40.13, 63.73, 108.69, 111.97, 119.71,
J 7.2 Hz, 3H, OCH CH ), 4.58 (q, J 7.2 Hz, 2H, OCH CH ),
2
3
2
3
1
1
3
19.75, 121.69, 126.41, 129.75, 133.34, 142.40, 151.83,
51.87, 160.00; MS (m/z) 413 (16) [M] , 415 (6) [M + 2] ,
7.03 (d, Jtrans 16.1 Hz, 1H, H ), 7.37 (d, J
8.6 Hz, 2H,
b
ortho
+
+
Ar), 7.53 (d, Jortho 8.6 Hz, 2H, Ar), 7.80 (dd, Jortho 9.3,
J 2.4 Hz, 1H, H ), 8.30 (d, J 16.1 Hz, 1H, H ), 8.55 (m,
97 (100).Anal. calcd. for C H ClN O : C, 60.95; H, 4.87;
21
20
3
4
W
B
trans
a
13
N, 10.15. Found: C, 60.93; H, 4.84; N, 10.13.
2H, H , H ); C NMR (500 MHz, CDCl ) d 14.05, 63.99,
A C 3
1
14.83, 119.88, 121.95, 129.12, 129.21, 131.11, 132.16,
(
E)-6-Chloro-3-(ethoxycarbonyl)-2-(4-methoxystyryl)
132.28, 133.65, 134.54, 136.83, 137.93, 138.73, 140.14,
159.61; MS (m/z) 448 (22) [M] , 185 (100). Anal. calcd.
+
quinoxaline 1,4-dioxide (11d)
Orange solid; yield 0.10 g (25%); mp 214-215 °C;
IR (KBr) ν / cm 3072 (Ar–H), 2954 (C–H saturated),
738 (C=O ester), 1602 (C=C aliphatic), 1506 (C=C
for C H BrClN O : C, 50.75; H, 3.14; N, 6.23. Found: C,
50.55; H, 3.10; N, 6.11.
19
14
2
4
-
1
1
aromatic), 1338 (N–O), 1250 (C–O), 814 (C–Cl); UV
(E)-6-Chloro-2-(3-nitrostyryl)quinoxaline 1,4-dioxide (12a)
It was washed with boiling ethanol and obtained as a
fluffy yellow solid; yield 0.10 g (29%); mp 242-244 °C; IR
1
(
DMSO) λmax / nm 339; H NMR (500 MHz, CDCl )
3
d 1.49 (t, J 7.2 Hz, 3H, OCH CH ), 3.88 (s, 3H, OCH ),
2
3
3
-1
4
.63 (q, J 7.2 Hz, 2H, OCH CH ), 6.96 (d, J 8.8 Hz, 2H,
(KBr) ν / cm 3070 (Ar–H), 1599 (C=C aliphatic), 1531
2
3
ortho
Ar), 7.11 (d, Jtrans 16.0 Hz, 1H, H ), 7.54 (d, J
8.8 Hz,
(C=C aromatic), 1367 (N–O), 767 (C–Cl); UV (DMSO)
b
ortho
1
2
H, Ar), 7.83 (dd, Jortho 9.2, J 2.1 Hz, 1H, H ), 8.43 (d,
λmax / nm 326; H NMR (500 MHz, DMSO-d ) d 7.71 (d,
W
B
6
13
Jtrans 16.0 Hz, 1H, H ), 8.59 (m, 2H, H , H ); C NMR
Jtrans 16.5 Hz, 1H, H ), 7.80 (d, J 9.2 Hz, 1H, H6), 8.01 (dd,
a
A
C
a
(
500 MHz, CDCl ) d 14.07, 55.44, 63.84, 111.88, 114.55,
Jortho 9.2, J 2.3 Hz, 1H, H ), 8.18 (d, J 8.0 Hz, 1H, H4),
3
W
B
ortho
1
1
4
19.85, 121.89, 128.46, 129.54, 133.45, 135.69, 135.99,
8.24 (dd, Jortho 8.0, J 2.3 Hz, 1H, H2), 8.37 (d, J 16.5 Hz,
W trans
36.90, 137.39, 138.19, 141.43, 159.80, 161.52; MS (m/z)
1H, H ), 8.44 (d, J 2.3 Hz, 1H, H ), 8.50 (m, 2H, H3,
b W A
+
+
13
00 (56) [M] , 402 (18) [M + 2] , 135 (100). Anal. calcd.
H ), 9.20 (s, 1H, H ); C NMR (500 MHz, DMSO-d ) d
C D 6
for C H ClN O : C, 59.93; H, 4.28; N, 6.99. Found: C,
118.39, 119.11, 121.97, 122.35, 130.61, 130.67, 132.60,
133.59, 135.89, 136.39, 137.08, 137.22, 137.56, 139.37,
2
0
17
2
5
5
9.78; H, 4.08; N, 6.91.
+
+
1
48.34; MS (m/z) 343 (99) [M] , 345 (29) [M + 2] , 327
(
E)-6-Chloro-3-(ethoxycarbonyl)-2-(4-methylstyryl)
(100). Anal. calcd. for C H ClN O : C, 55.91; H, 2.93;
16
10
3
4
quinoxaline 1,4-dioxide (11e)
N, 12.23. Found: C, 56.11; H, 2.70; N, 12.56.
Orange solid; yield 0.12 g (32%); mp 202-204 °C; IR
-
1
(
(
KBr) ν / cm 3072 (Ar–H), 2978 (C–H saturated), 1739
(E)-6-Chloro-2-(2-hydroxystyryl)quinoxaline 1,4-dioxide
(12b)
C=O ester), 1599 (C=C aliphatic), 1502 (C=C aromatic),
1
356 (N–O), 1236 (C–O), 802 (C–Cl); UV (DMSO)
It was washed with boiling methylene chloride
and obtained as a yellow solid; yield 0.10 g (32%);
mp 252-254 °C; IR (KBr) ν / cm 3410 (O–H), 3075
1
λmax / nm 333; H NMR (500 MHz, CDCl ) d 1.44 (t,
J 7.2 Hz, 3H, OCH CH ), 2.36 (s, 3H, Ar-CH ), 4.58
3
-
1
2
3
3
(
q, J 7.2 Hz, 2H, OCH CH ), 7.00 (d, J 16.1 Hz, 1H,
trans
(Ar–H), 1599 (C=C aliphatic), 1525 (C=C aromatic), 1369
(N–O), 764 (C–Cl); UV (DMSO) λmax / nm 320; H NMR
2
3
1
H ), 7.18 (d, J
7.5 Hz, 2H, Ar), 7.42 (d, Jortho 7.5 Hz,
b
ortho
2
H, Ar), 7.78 (dd, Jortho 9.2, J 2.2 Hz, 1H, H ), 8.32 (d,
(500 MHz, DMSO-d ) d 6.87 (t, J 8.0 Hz, 1H, Ar), 6.94
W
B
6