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H. Xu, L.-l. Fan / European Journal of Medicinal Chemistry 46 (2011) 1919e1925
56.7, 100.8, 112.0, 116.5, 117.3, 121.0, 121.4, 121.5, 123.3, 124.3, 124.6, 127.5,
129.4, 129.7, 134.4, 136.9, 137.5, 147.6, 148.3; HRMS-ESI: Calcd. for
C21H15N3O2 [M þ H]þ: 342.1237. Found: 342.1239.
m), 7.15 (1H, t, J ¼ 8.0 Hz), 7.37 (2H, d, J ¼ 8.4 Hz), 7.83 (1H, d,
J ¼ 8.4 Hz), 7.90e7.93 (1H, m); 13C NMR (125 MHz, CDCl3)
d: 18.7,
56.7, 98.4, 109.3, 115.5, 115.9, 116.9, 120.1, 121.1, 122.5, 123.9, 127.4,
129.3, 129.8, 130.4, 132.4, 133.8, 137.7, 139.0, 155.7; HRMS-ESI:
Calcd. for C22H18N2O [M þ H]þ: 327.1492. Found: 327.1488.
5.1.2.2. 6-(p-Hydroxyphenyl)-5,6-dihydro-indolo[1,2-a]quinoxaline
(3b). Pale yellow solid, m.p. 146e148 ꢀC; IR cmꢁ1: 738, 747, 1229,
1452, 1508, 1598, 3307; 1H NMR (300 MHz, CDCl3)
d: 4.11 (1H, s,
5.1.2.8. 6-Phenyl-5,6-dihydro-8-methylindolo[1,2-a]quinoxaline
(3h). Pale yellow solid, m.p. 158e160 ꢀC; IR cmꢁ1: 628, 699, 739,
769, 1281, 1433, 1505, 1556, 1598, 3336; 1H NMR (400 MHz, CDCl3)
NH), 4.92 (1H, s, OH), 5.42 (1H, s), 5.87 (1H, s), 6.80e6.88 (3H, m),
6.99e7.04 (2H, m), 7.11 (1H, t, J ¼ 7.5 Hz), 7.22e7.28 (1H, m), 7.35
(2H, d, J ¼ 8.7 Hz), 7.51 (1H, d, J ¼ 7.5 Hz), 7.90e7.93 (1H, m), 7.98
d: 2.43 (3H, s, CH3), 4.16 (1H, s, NH), 5.51 (1H, s), 5.88 (1H, s),
(1H, d, J ¼ 8.1 Hz); 13C NMR (125 MHz, CDCl3)
d
: 56.6, 100.1, 111.6,
6.84e6.86 (1H, m), 6.94 (1H, d, J ¼ 7.2 Hz), 7.00e7.02 (2H, m), 7.15
115.5,116.0,116.9,120.1,120.8,121.0,122.5,124.0,127.3,129.6,129.8,
132.3, 134.2, 137.7, 139.6, 155.77; HRMS-ESI: Calcd. for C21H16N2O
[M þ H]þ: 313.1335. Found: 313.1339.
(1H, t, J ¼ 8.0 Hz), 7.41e7.45 (3H, m), 7.52e7.53 (2H, m), 7.84 (1H, d,
J ¼ 8.4 Hz), 7.92e7.94 (1H, m); 13C NMR (125 MHz, CDCl3)
d: 18.7,
57.3, 98.5, 109.3, 116.0, 116.9, 120.1, 121.2, 122.6, 123.9, 127.4, 128.4,
128.6, 128.8, 129.3, 130.4, 133.8, 137.6, 138.6, 140.1; HRMS-ESI:
Calcd. for C22H18N2 [M þ H]þ: 311.1543. Found: 311.1549.
5.1.2.3. 6-(3-Methoxy-4-hydroxyphenyl)-5,6-dihydro-indolo[1,2-a]
quinoxaline (3c). Pale yellow solid, m.p. 212e214 ꢀC; IR cmꢁ1: 745,
779, 1031, 1150, 1227, 1266, 1454, 1505, 1595, 3317, 3485; 1H NMR
5.1.2.9. 6-(4-N,N-Dimethylaminophenyl)-5,6-dihydro-8-methyl-
indolo[1,2-a]quinoxaline (3i). Pale yellow solid, m.p. 186e188 ꢀC; IR
cmꢁ1: 613, 668, 731, 807, 1276, 1348, 1506, 1560, 1609, 3366; 1H
(400 MHz, CDCl3) d: 3.84 (3H, s, OCH3), 4.14 (1H, s, NH), 5.43 (1H, s),
5.70 (1H, s), 5.90 (1H, s), 6.87e6.89 (1H, m), 6.94e6.96 (1H, m),
7.00e7.08 (4H, m), 7.13 (1H, t, J ¼ 7.6 Hz), 7.25e7.29 (1H, m), 7.53
(1H, d, J ¼ 7.6 Hz), 7.93e7.95 (1H, m), 8.00 (1H, d, J ¼ 8.4 Hz); 13C
NMR (500 MHz, CDCl3) d: 2.44 (3H, s, CH3), 3.00 (6H, s, N(CH3)2),
4.09 (1H, s, NH), 5.41 (1H, s), 5.93 (1H, s), 6.76 (2H, d, J ¼ 9.0 Hz),
6.83e6.85 (1H, m), 6.94 (1H, d, J ¼ 7.0 Hz), 6.99e7.01 (2H, m), 7.14
(1H, t, J ¼ 7.5 Hz), 7.38 (2H, d, J ¼ 8.5 Hz), 7.83 (1H, d, J ¼ 8.5 Hz),
NMR (125 MHz, CDCl3) d: 56.0, 57.1, 100.1, 110.4, 111.6, 114.0, 116.0,
116.9, 120.1, 120.8, 121.0, 121.6, 122.4, 124.0, 127.3, 129.6, 131.8, 134.1,
137.7, 139.7, 145.9, 146.9; HRMS-ESI: Calcd. for C22H18N2O2
[M þ H]þ: 343.1441. Found: 343.1448.
7.91e7.93 (1H, m); 13C NMR (125 MHz, CDCl3)
d: 18.7, 40.5, 56.8,
98.3, 109.3, 112.4, 115.9, 116.9, 119.8, 121.0, 122.3, 123.8, 127.4, 127.5,
129.3, 129.4, 130.3, 133.9, 138.1, 139.5, 150.7; HRMS-ESI: Calcd. for
C24H23N3 [M þ H]þ: 354.1965. Found: 354.1963.
5.1.2.4. 6-(p-Nitrophenyl)-5,6-dihydro-7-methylindolo[1,2-a]qui-
noxaline (3d). Yellow solid, m.p. 160e162 ꢀC; IR cmꢁ1: 704, 737,
1342, 1454, 1507, 1596, 3367; 1H NMR (400 MHz, CDCl3)
d
: 2.12 (3H,
5.1.2.10. 6-(p-Methoxyphenyl)-5,6-dihydro-8-methylindolo[1,2-a]qui-
noxaline (3j). Orange solid, m.p. 194e196 ꢀC; IR cmꢁ1: 742, 763, 825,
1027, 1234, 1262, 1561, 1597, 3318, 3343; 1H NMR (400 MHz, CDCl3)
s, CH3), 4.39 (1H, s, NH), 5.78 (1H, s), 6.76 (1H, d, J ¼ 6.8 Hz),
6.94e7.01 (2H, m), 7.21e7.25 (1H, m), 7.30e7.36 (3H, m), 7.59 (1H,
d, J ¼ 8.0 Hz), 7.89 (1H, d, J ¼ 6.8 Hz), 8.01 (1H, d, J ¼ 8.0 Hz),
d: 2.44 (3H, s, CH3), 3.85 (3H, s, OCH3), 4.12 (1H, s, NH), 5.45 (1H, s),
8.07e8.09 (2H, m); 13C NMR (125 MHz, CDCl3)
d: 8.4, 53.9, 107.9,
5.87 (1H, s), 6.84e6.86 (1H, m), 6.94 (3H, d, J ¼ 8.8 Hz), 7.00e7.02
111.9, 116.50, 116.58, 119.2, 120.5, 120.7, 123.0, 124.0, 124.1, 127.3,
127.8, 130.4, 131.0, 133.5, 134.4, 147.4, 148.8; HRMS-ESI: Calcd. for
C22H17N3O2 [M þ H]þ: 356.1394. Found: 356.1399.
(2H, m), 7.15 (1H, t, J ¼ 8.0 Hz), 7.44 (2H, d, J ¼ 8.4 Hz), 7.83 (1H, d,
J ¼ 8.0 Hz), 7.91e7.94 (1H, m); 13C NMR (125 MHz, CDCl3)
d: 18.7,
55.3, 56.7, 98.4, 109.3, 114.0, 115.9, 116.9, 120.0, 121.1, 122.5, 123.9,
127.4, 129.3, 129.6, 130.4, 132.2, 133.9, 137.8, 139.0, 159.8; HRMS-ESI:
Calcd. for C23H20N2O [M þ H]þ: 341.1648. Found: 341.1651.
5.1.2.5. 6-(p-Hydroxyphenyl)-5,6-dihydro-7-methylindolo[1,2-a]qui-
noxaline (3e). Pale yellow solid, m.p. 204e206 ꢀC; IR cmꢁ1: 740,
754, 1174, 1222, 1454, 1509, 1597, 3300; 1H NMR (400 MHz, CDCl3)
5.1.2.11. 6-(3-Methoxy-4-hydroxyphenyl)-5,6-dihydro-8-methyl-
indolo[1,2-a]quinoxaline (3k). White solid, m.p. 192e194 ꢀC; IR
cmꢁ1: 621, 750, 1029, 1230, 1263, 1321, 1430, 1508, 1560, 1598, 1610,
d
: 1.99 (3H, s, CH3), 5.59 (1H, s), 6.65 (2H, d, J ¼ 8.0 Hz), 6.73e6.75
(1H, m), 6.93e6.95 (2H, m), 7.06 (2H, J ¼ 8.4 Hz), 7.16e7.29 (2H, m),
7.54 (1H, d, J ¼ 7.6 Hz), 7.86e7.89 (1H, m), 7.98 (1H, d, J ¼ 8.8 Hz);
3350, 3506; 1H NMR (400 MHz, CDCl3)
d: 2.44 (3H, s, CH3), 3.84 (3H,
13C NMR (125 MHz, CDCl3)
d: 8.3, 54.6, 107.2, 111.7, 115.5, 116.2,
s, OCH3), 4.12 (1H, s, NH), 5.42 (1H, s), 5.72 (1H, s), 5.89 (1H, s),
6.85e6. 88 (1H, m), 6.95e6.97 (2H, m), 7.01e7.03 (3H, m), 7.08 (1H,
s), 7.16 (1H, t, J ¼ 8.0 Hz), 7.84 (1H, d, J ¼ 8.4 Hz), 7.91e7.94 (1H, m);
116.4, 118.9, 119.8, 120.3, 122.5, 123.6, 127.4, 128.7, 130.7, 132.9,
133.3,134.1,135.7, 155.2; HRMS-ESI: Calcd. for C22H18N2O [M þ H]þ:
327.1492. Found: 327.1499.
13C NMR (125 MHz, CDCl3)
d: 18.7, 56.0, 57.2, 98.5, 109.3, 110.4,
114.0, 115.9, 116.9, 120.1, 121.1, 121.7, 122.5, 123.9, 127.4, 129.3, 130.4,
132.0, 133.8, 137.7, 139.1, 145.9, 146.9; HRMS: Calcd. for C23H20N2O2
[M þ H]þ: 357.1598. Found: 357.1603.
5.1.2.6. 6-(p-Nitrophenyl)-5,6-dihydro-8-methylindolo[1,2-a]quinoxa-
line (3f). Yellow solid, m.p. 218e220 ꢀC; IR cmꢁ1: 730, 758, 1277,
1342, 1504, 1515, 1561, 1595, 3362; 1H NMR (400 MHz, CDCl3)
d: 2.44
(3H, s, CH3), 4.23 (1H, s, NH), 5.67 (1H, s), 5.86 (1H, s), 6.90e6.92 (1H,
m), 6.97 (1H, d, J ¼ 7.6 Hz), 7.04e7.08 (2H, m), 7.19 (1H, t, J ¼ 7.6 Hz),
7.70 (2H, d, J ¼ 8.4 Hz), 7.85 (1H, d, J ¼ 8.8 Hz), 7.94e7.96 (1H, m),
5.1.2.12. 6-(o-Hydroxyphenyl)-5,6-dihydro-8-methylindolo[1,2-a]
quinoxaline (3l). White solid, m.p. 192e194 ꢀC; IR cmꢁ1: 730, 758,
824, 1243, 1278, 1491, 1509, 1560, 1590, 3299; 1H NMR (400 MHz,
8.27 (2H, d, J ¼ 8.4 Hz); 13C NMR (125 MHz, CDCl3)
d: 18.7, 56.5, 98.9,
CDCl3) d: 2.42 (3H, s, CH3), 5.58 (1H, s), 5.93 (1H, s), 6.95e6.99 (4H,
109.4, 116.2, 117.0, 120.7, 121.5, 123.1, 124.0, 124.2, 127.3, 129.1, 129.2,
130.6, 133.8, 136.6, 136.7, 147.4, 148.1; HRMS-ESI: Calcd. for
C22H17N3O2 [M þ H]þ: 356.1394. Found: 356.1387.
m), 7.05 (1H, t, J ¼ 7.6 Hz), 7.13e7.21 (2H, m), 7.23e7.25 (1H, m),
7.34e7.38 (1H, m), 7.81 (1H, d, J ¼ 8.4 Hz), 7.94 (1H, d, J ¼ 8.0 Hz);
13C NMR (125 MHz, CDCl3)
d: 18.7, 57.5, 99.3, 109.2, 117.1, 117.4, 117.8,
119.8, 121.5, 122.1, 122.4, 123.0, 123.9, 128.4, 129.3, 129.9, 130.4,
130.8, 134.2, 135.7, 136.0, 156.7; HRMS-ESI: Calcd. for C22H18N2O
[M þ H]þ: 327.1492. Found: 327.1490.
5.1.2.7. 6-(p-Hydroxyphenyl)-5,6-dihydro-8-methylindolo[1,2-a]qui-
noxaline (3g). Pale yellow solid, m.p. 178e180 ꢀC; IR cmꢁ1: 735,
766, 1220, 1275, 1427, 1508, 1567, 1596, 1611, 3309; 1H NMR
(400 MHz, CDCl3)
OH), 5.43 (1H, s), 5.88 (1H, s), 6.84 (3H, d, J ¼ 8.8 Hz), 6.94e7.02 (3H,
d
: 2.44 (3H, s, CH3), 4.10 (1H, s, NH), 4.98 (1H, s,
5.1.2.13. 6-(p-Methoxyphenyl)-5,6-dihydro-10-methylindolo[1,2-a]
quinoxaline (3m). Yellow solid, m.p. 216e218 ꢀC; IR cmꢁ1: 712, 742,